Digital Camera Patent Abstract
A host computer includes a device driver which is adaptive to a
digital camera and has a storage driver function for writing/reading
image data representative of a still picture in/out of the camera
by bulk transfer, an image driver function for receiving image data
representative of a moving picture from the camera by isochronous
transfer, an audio driver function for receiving speech data from
the camera by isochronous transfer, and an operation driver function
having operation commands on the shooting operation of the camera.
During an electronic conference the host can receive image data
representative of a moving picture and speech data as well as, if
necessary, image data representative of a still picture prepared
beforehand from the camera. The host also can receive image data
representative of a new still picture taken during the conference
from the camera. Digital Camera Patent Claims
What is claimed is:
1. A computer system comprising: a host computer for electronic
conferencing with another computer; a digital camera for picking
up a scene with an image sensor and recording image data representative
of said scene in a recording medium; and a high-speed serial interface
connecting said digital camera to said host computer; said host
computer comprising a device driver including: a first device function
for recognizing said digital camera as a storage driver, which records
data representative of a still picture, and at least one of writing
and reading said image data at least one of in and out of the recording
medium; a second device function for recognizing said digital camera
as an image device, which generates image data representative of
a moving picture, and reading said image data out of the image sensor
at a preselected period; and a third device function for recognizing
said digital camera as an operating device and feeding an operation
command to said digital camera; said digital camera comprising a
controller for driving, in response to an access made from one of
said first device function, said second device function, and said
third device function of said host computer via said high-speed
serial interface, portions of said digital camera corresponding
to said access to thereby control data transfer and a shooting operation,
wherein said high-speed serial interface comprises at least one
of a USB (Universal Serial Bus) serial interface and an IEEE 1394
serial interface, wherein, when said high-speed serial interface
comprises said USB serial interface, during an electronic conference
between said host computer and said another computer, the image
data representative of a still picture is transferred by said first
device function using bulk transfer, which transfers image data
at an idle position of a transfer frame, and wherein, when said
high-speed serial interface comprises said IEEE 1394 serial interface,
during said electronic conference between said host computer and
said another computer, the image data representative of said still
picture is transferred by said first device function using asynchronous
transfer, which transfers data when a bus is idle in a preselected
transfer cycle.
2. A system in accordance with claim 1, wherein the image data
representative of a moving picture is transferred by said second
device function using isochronous transfer, which transfers a preselected
amount of data every preselected frame, and wherein the operation
command is transferred by said third device function using at least
one of interrupt transfer and control transfer, which transfers
data when polling at a preselected period.
3. A system in accordance with claim 1, wherein the image data
representative of a moving picture is transferred by said second
device using isochronous transfer, which transfers data by seizing
a channel every preselected transfer cycle, and wherein the operation
command is transferred by said third device function using said
asynchronous transfer.
4. A system in accordance with claim 1, wherein said digital camera
further comprises a speech input section for generating digital
speech data representative of an input speech signal, and wherein
said device driver of said host computer further comprises a fourth
device function for receiving said digital speech data from said
speech input section together with the image data representative
of a moving picture via said high-speed serial interface.
5. A system in accordance with claim 2, wherein said digital camera
further comprises a speech input section for generating digital
speech data representative of an input speech signal, and wherein
said device driver of said host computer further comprises a fourth
device function for receiving said digital speech data from said
speech input section together with the data representative of a
moving picture via said high-speed serial interface.
6. A system in accordance with claim 3, wherein said digital camera
further comprises a speech input section for generating digital
speech data representative of an input speech signal, and wherein
said device driver of said host computer further comprises a fourth
device function for receiving said digital speech data from said
speech input section together with the image data representative
of a moving picture via said high-speed serial interface.
7. A system in accordance with claim 4, wherein said host computer
further comprises a communicating section for interchanging data
with another computer via a communication channel, and wherein said
computer system comprises an electronic conference system capable
of sending at least one of the image data representative of at least
one of a moving picture and a still picture, and said digital speech
data received via said high-seed serial interface to said another
computer via said communicating section.
8. A system in accordance with claim 5, wherein said host computer
further comprises a communicating section for interchanging data
with another computer via a communication channel, and wherein said
computer system comprises an electronic conference system capable
of sending at least one of the image data representative of at least
one of a moving picture and a still picture, and said digital speech
data received via said high-speed serial interface to said another
computer via said communicating section.
9. A system in accordance with claim 6, wherein said host computer
further comprises a communicating section for interchanging data
with another computer via a communication channel, and wherein said
computer system comprises an electronic conference system capable
of sending at least one of the image data representative of at least
one of a moving picture and a still picture, and said digital speech
data received via said high-speed serial interface to said another
computer via said communicating section.
10. A system in accordance with claim 1, wherein said digital camera
further comprises a storage for rewritably storing system software
assigned to said digital camera, and wherein said device driver
of said host computer further comprises a fifth device function
for rewriting said system software via said high-speed serial interface.
11. A system in accordance with claim 7, wherein said digital camera
further comprises a storage for rewritably storing system software
assigned to said digital camera, and wherein said device driver
of said host computer further comprises a fifth device function
for rewriting said system software via said high-speed serial interface.
12. A system in accordance with claim 8, wherein said digital camera
further comprises a storage for rewritably storing system software
assigned to said digital camera, and wherein said device driver
of said host computer further comprises a fifth device function
for rewriting said system software via said high-speed serial interface.
13. A system in accordance with claim 9, wherein said digital camera
further comprises a storage for rewritably storing system software
assigned to said digital camera, and wherein said device driver
of said host computer further comprises a fifth device function
for rewriting said system software via said high-speed serial interface.
14. In a digital camera for picking up a scene with an image sensor
and recording image data representative of said scene in a recording
medium and operable under a control of an outside apparatus via
a high-speed serial interface, said outside apparatus comprises:
a device driver comprising: a first device function for recognizing
said digital camera as a storage driver, which records data representative
of a still picture, and at least one of writing and reading said
image data at least one of in and out of the recording medium; a
second device function for recognizing said digital camera as an
image device, which generates image data representative of a moving
picture, and reading said image data out of the image sensor at
a preselected period; and a third device function for recognizing
said digital camera as an operating device and feeding an operation
command to said digital camera; said digital camera comprising a
controller for driving, in response to an access made from one of
said first device function, said second device function, and said
third device function of said host computer via said high-speed
serial interface, portions of said digital camera corresponding
to said access to thereby control data transfer and a shooting operation,
wherein said high-speed serial interface comprises at least one
of a USB (Universal Serial Bus) serial interface and an IEEE 1394
serial interface, wherein, when said high-speed serial interface
comprises said USB serial interface, during an electronic conference
between said outside apparatus and another outside apparatus, the
image data representative of a still picture is transferred by said
first device function using bulk transfer which transfers image
data at an idle position of a transfer frame, and wherein, when
said high-speed serial interface comprises said IEEE 1394 serial
interface, during said electronic conference between said outside
apparatus and another outside apparatus, the image data representative
of said still picture is transferred by said first device function
using asynchronous transfer, which transfers data when a bus is
idle in a preselected transfer cycle.
15. A system in accordance with claim 14, wherein, when said high-speed
serial interface comprises said USB serial interface, during said
electronic conference between said host computer and said another
computer: the image data representative of a moving picture is transferred
by said second device function using isochronous transfer, which
transfers a preselected amount of data every preselected frame,
and the operation command is transferred by said third device function
using at least one of interrupt transfer and control transfer, which
transfers data when polling at a preselected period.
16. A system in accordance with claim 14, wherein, when said high-speed
serial interface comprises said IEEE 1394 serial interface, during
said electronic conference between said host computer and said another
computer: the image data representative of said moving picture is
transferred by said second device using isochronous transfer, which
transfers data by seizing a channel every preselected transfer cycle,
and the operation command is transferred by said third device function
using said asynchronous transfer.
17. A computer system comprising: a host computer for electronic
conferencing with another computer; a digital camera for picking
up a scene with an image sensor and recording image data representative
of said scene in a recording medium; and a high-speed serial interface
connecting said digital camera to said host computer, wherein said
host computer comprises: first means for recognizing said digital
camera as a storage driver, which records data representative of
a still picture and at least one of writes and reads said image
data at least one of in and out of the recording medium; second
means for recognizing said digital camera as an image device, which
generates image data representative of a moving picture, and reads
said image data out of the image sensor at a preselected period;
and third means for recognizing said digital camera as an operating
device and for feeding an operation command to said digital camera,
wherein said digital camera comprises means for driving portions
of said digital camera corresponding to said access, in response
to an access made from one of said first means, said second means,
and said third means of said host computer via said high-speed serial
interface, wherein said high-speed serial interface comprises at
least one of a USB (Universal Serial Bus) serial interface and an
IEEE 1394 serial interface, wherein, when said high-speed serial
interface comprises said USB serial interface, during an electronic
conference between said host computer and said another computer,
the image data representative of a still picture is transferred
using bulk transfer, which transfers image data at an idle position
of a transfer frame, and wherein, when said high-speed serial interface
comprises said IEEE 1394 serial interface, during said electronic
conference between said host computer and said another computer,
the image data representative of said still picture is transferred
using asynchronous transfer, which transfers data when a bus is
idle in a preselected transfer cycle.
18. A system in accordance with claim 17, wherein said digital
camera comprises means for generating digital speech data representative
of an input speech signal, and wherein said host computer further
comprises fourth means for receiving said digital speech data from
said means for generating, together with the image data representative
of a moving picture via said high-speed serial interface.
19. A system in accordance with claim 17, wherein said digital
camera comprises means for rewritably storing system software assigned
to said digital camera, and wherein said host computer further comprises
fifth means for rewriting said system software via said high-speed
serial interface.
20. A system in accordance with claim 1, wherein said electronic
conference between said host computer and said another computer
comprises a video conference.
21. A system in accordance with claim 14, wherein said electronic
conference between said host computer and said another computer
comprises a video conference.
22. A system in accordance with claim 17, wherein said electronic
conference between said host computer and said another computer
comprises a video conference.
23. A method of communicating between a host computer for electronic
conferencing with another computer and a digital camera for picking
up a scene with an image sensor and recording image data representative
of said scene in a recording medium, said method comprising: connecting
said digital camera to said host computer with a high-speed serial
interface; recognizing said digital camera as a storage driver,
which records data representative of a still picture and at least
one of writes said image data in and reads said image data out of
the recording medium; recognizing said digital camera as an image
device, which generates image data representative of a moving picture
and reads said image data out of the image sensor at a preselected
period; recognizing said digital camera as an operating device;
electronic conferencing said host computer with said another computer;
controlling portions of said digital camera in response to a command
made from said host computer via said high-speed serial interface,
to thereby control data transfer between said digital camera and
said host computer and a shooting operation of said digital camera;
and performing, during said electronic conference between said host
computer and said another computer, bulk transfer of image data
between said digital camera and said host computer at an idle position
of a transfer frame.
24. A method according to claim 23, further comprising: performing
isochronous transfer of a preselected amount of moving picture data
between said digital camera and said host computer every preselected
frame; and performing at least one of interrupt transfer and control
transfer of said operation command between said digital camera and
said host computer when polling at a preselected period.
25. A computer system comprising: a host computer for electronic
conferencing with another computer; a digital camera for picking
up a scene with an image sensor and recording image data representative
of said scene in a recording medium; and a high-speed serial interface
connecting said digital camera to said host computer; said host
computer comprising a device driver including: a first device function
for recognizing said digital camera as a storage driver, which records
data representative of a still picture, and at least one of writing
and reading said image data at least one of in and out of the recording
medium; a second device function for recognizing said digital camera
as an image device, which generates image data representative of
a moving picture, and reading said image data out of the image sensor
at a preselected period; and a third device function for recognizing
said digital camera as an operating device and feeding an operation
command to said digital camera; said digital camera comprising a
controller for driving, in response to an access made from one of
said first device function, said second device function, and said
third device function of said host computer via said high-speed
serial interface, portions of said digital camera corresponding
to said access to thereby control data transfer and a shooting operation,
wherein said high-speed serial interface includes a capability of
selectively connecting said digital camera to said host computer
with a USB (Universal Serial Bus) serial interface and an IEEE 1394
serial interface, wherein, when said high-speed serial interface
comprises said USB serial interface, during an electronic conference
between said host computer and said another computer, the image
data representative of a still picture is transferred by said first
device function using bulk transfer, which transfers image data
at an idle position of a transfer frame, and wherein, when said
high-speed serial interface comprises said IEEE 1394 serial interface,
during said electronic conference between said host computer and
said another computer, the image data representative of said still
picture is transferred by said first device function using asynchronous
transfer, which transfers data when a bus is idle in a preselected
transfer cycle.
Digital Camera Patent Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a computer system using a digital
camera and more particularly to a computer system using a digital
camera and advantageously applicable to an electronic conference
system or similar real-time transmission system.
2. Description of the Background Art
Today, thanks to the increasing processing speed and performance
of a CPU (Central Processing Unit), personal computers, for example,
are extensively used as communication tools capable of dealing with
multimedia data including video data and audio data. For example,
a plurality of personal computers may be connected together by a
communication channel in order to construct an electronic conference
system. In this kind of system, the personal computers each can
send the real-time image of the individual situation and real-time
speech to the other computer or computers.
Japanese patent laid-open publication No. 126756/1998, for example,
discloses a computer system applicable to the electronic conference
system. Basically, in the computer system disclosed in this document,
a video capture board is mounted on a host computer, e.g., a personal
computer. The video capture board transforms an analog moving picture
signal input from a video camera to digital moving picture data.
The digital moving picture data are sent from the host computer
to another computer joining in a conference via, e.g., a MODEM.
However, not many of personal computers available on the today's
market are loaded with a video capture board as standard equipment.
A video capture board must therefore be installed in a personal
computer by troublesome manual operation. While a video capture
board may be connected to a personal computer, the connection is
not practicable without resorting to, e.g., a printer port, resulting
in a short data transfer rate.
A USB (Universal Serial Bus) interface, which is a high-speed serial
interface increasingly equipped with as standard equipment, may
be substituted for a video capture board having the above-described
problems. A moving picture inputting system or an image pickup apparatus
constructed to input moving picture data to a host computer via
a USB interface is disclosed in, e.g., Japanese Patent Laid-Open
Publication Nos. 136245/1998, 155133/1998 and 232924/1998. In this
type of system or apparatus, a CCD (Charge Coupled Device) or similar
image pickup apparatus transforms an image signal output from an
image sensor to digital image data and stores the digital image
data in a field memory or a FIFO (First-In First-Out) memory. The
digital image data are read out of the memory at a timing and in
an amount matching with the transfer rate of the USB interface.
This allows moving picture data to be transferred from the image
pickup apparatus to a host computer via the USB interface.
In an electronic conference system, a person participating in a
conference sometimes desires to present a material while discussing
with the other person. In such a case, the material must be input
to a host computer and then sent to the other participant. In the
above-described conventional system, for example, the material may
be shot by a video camera or a CCD camera and then sent in the form
of moving picture data. However, resolution available with a video
camera or a CCD camera is too poor for the material to be read.
It is therefore necessary to connect a scanner or similar peripheral
unit to the host computer so as to input data representative of
the material to the host computer beforehand or to read the material
and send the resulting data each time. The peripheral unit connected
to the host computer makes the entire system and manipulation thereof
sophisticated.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
computer system using a digital camera and capable of inputting
image data representative of a moving picture or a still picture
taken beforehand or taken on the spot in a host computer with a
simple configuration.
In accordance with the present invention, a computer system is
generally made up of a host computer, a digital camera for picking
up a scene with an image sensor and recording image data representative
of the scene in a recording medium, and a high-speed serial interface
connecting the digital camera to the host computer. The host computer
includes a device driver having at least a first device function
for recognizing the camera as a storage driver, which records data
representative of a still picture, and writing or reading the image
data in or out of the recording medium, a second device function
for recognizing the camera as an image device, which generates image
data representative of a moving picture, and reading the image data
out of the image sensor at a preselected period, and a third device
function for recognizing the camera as an operating device and feeding
an operation command to the digital camera. The camera includes
a controller for driving, in response to an access made from any
one of the first to third device functions of the host computer
via the high-speed serial interface, the portions of the camera
corresponding to the access to thereby control data transfer and
a shooting operation.
Also, in accordance with the present invention, in a digital camera
for picking up a scene with an image sensor and recording image
data representative of the scene in a recording medium and operable
under the control of an outside apparatus via a high-speed serial
interface, the outside apparatus includes a device driver having
at least a first device function for recognizing the camera as a
storage driver, which records data representative of a still picture,
and writing or reading the image data in or out of the recording
medium, a second device function for recognizing the camera as an
image device, which generates image data representative of a moving
picture, and reading the image data out of the image sensor at a
preselected period, and a third device function for recognizing
the camera as an operating device and feeding an operation command
to the digital camera. The camera includes a controller for driving,
in response to an access made from any one of the first to third
device functions of the host computer via the high-speed serial
interface, the portions of the digital camera corresponding to the
access to thereby control data transfer and a shooting operation.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will become more apparent from the following detailed
description taken with the accompanying drawings in which:
FIG. 1 is a block diagram showing a computer system using a digital
camera embodying the present invention and corresponding to a protocol;
FIG. 2 shows how FIGS. 2A and 2B are combined;
FIGS. 2A and 2B are schematic block diagrams each showing particular
part of hardware included in the illustrative embodiment;
FIG. 3 is an external view showing a specific setup of the illustrative
embodiment; and
FIG. 4 is an external view showing a specific comparative setup
of a computer system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 through 3 of the drawings, a computer system
using a digital camera embodying the present invention is shown.
As shown in FIG. 3 specifically, the computer system is generally
made up of a personal computer or similar host computer 10, a USB
interface or high-speed serial interface 20, and a digital camera
30 removably connected to the host computer 10 via the USB interface
or cable 20. While the computer system plays the role of an image
transfer system, it is implemented as a terminal included in, e.g.,
an electronic conference system in the illustrative embodiment.
In the illustrative embodiment, the host computer 10 recognizes
the digital camera 30 as three different devices via the USB interface
20 at the same time. The three devices are a storage device for
storing still pictures taken beforehand, an image device for recording
image data representative of a real-time moving picture, and an
operating device for allowing the operator of the host computer
10 to operate the storage device and image device. In the event
of an electronic conference, the host computer 10 uses the digital
camera 30 as a single peripheral unit having the above three different
functions.
More specifically, as shown in FIG. 1, the host computer 10 includes
a USB controller 102 for controlling the USB interface 20 and a
USB port 104. A device driver 106, which is unique to the illustrative
embodiment and adaptive to the digital camera 30, is also mounted
on the host computer 10. As for a protocol, an application 108 for,
e.g., an electronic conference system processes image data input
via the device driver 106 by communication.
The USB controller 102 is a user interface including software belonging
to a data link layer for controlling functions common to peripheral
units. The USB controller 102 detects and sets a peripheral unit
connected to the USB interface 20. Particularly, the USB controller
102 serves as a host for the USB interface 20 in that it generates
a timing of consecutive frames to be transferred at the intervals
of 1 millisecond and controls the scheduling of the individual frame
at the time of data transfer between the peripheral unit and the
device driver or upper layer 106. The USB port 104 belongs to a
physical layer to which the USB cable 20a is connected. The USB
port 104 plays the role of a transceiver driver that detects the
supply of power and the connection and disconnection of a peripheral
unit, and also detects the input or output of data.
The device driver 106 is implemented as driver software for driving
and controlling the individual function of the digital camera 30
via the USB interface 20. More specifically, in the illustrative
embodiment, the device driver 106 is system control software to
be installed from a CD-ROM (Compact Disk Read Only Memory) so as
to cooperate with an OS (Operating System) or similar basic software.
Particularly, in the illustrative embodiment, the device driver
106 includes a storage driver or storage-class driver function 110,
an image driver or image-class driver function 112, and an operation
driver or driver function 116, which implements an operating device.
The device driver 106 additionally includes an audio driver or audio-class
driver function 114 and a system rewrite driver 118.
The storage driver 110 recognizes the digital camera 30 as a storage
for storing image data or image files representative of still pictures.
The storage driver 110 then controls a procedure for writing the
image data or image files in a memory card, not shown, or reading
them out of the memory card. The memory card is removably loaded
on the digital camera 30, as will be described specifically later.
In the illustrative embodiment, when a write request or a read request
is generated, the storage driver 110 accesses the memory card by
outputting a write command or a read command under the control of
the application 108. At this instant, data transfer should preferably
be implemented by bulk transfer that transfers data during the idle
time of a frame. Bulk transfer allows the maximum sixty-four bytes
of data to be transferred every period.
The image driver 112 recognizes the digital camera 30 as an image
pickup apparatus for generating data representative of a moving
picture. The image driver 112 controls a procedure for reading the
above image data out of an image pickup system included in the camera
30. In the illustrative embodiment, isochronous transfer, which
transfers a preselected amount of image data every frame, is advantageously
applicable to the image driver 112.
When a microphone is mounted on the digital camera 30, the audio
driver 114 receives data representative of a speech input via the
microphone. Isochronous transfer is advantageously applicable to
the audio driver 114 also, so that a preselected amount of audio
data can be transferred every frame in accordance with the control
of the image driver 112. So long as any other peripheral unit having
an isochronous transfer capability is not connected to the USB port
104, the audio driver 114 using isochronous transfer can transfer
the maximum 1,023 bytes of image data representative of a moving
picture and the maximum sixty-four bytes of speech data frame by
frame.
The operation driver 116 outputs various commands for operating
the digital camera 30 in accordance with the operator's manipulation
of, e.g., a mouse connected to the host computer 10. The commands
include a command representative of a shutter speed, a lens opening,
zoom magnification or similar setting for a shot, a command for
taking a still picture in response to a shutter release button depressed,
and a command for causing a strobe to flash. For the transfer of
data representative of such commands, interrupt transfer or control
transfer that periodically polls a device every frame should preferably
be used.
The system rewrite driver 118 is used to rewrite system software
installed in the camera 30. When new functions should be added to
the camera 30 or when the functions of the camera 30 should be altered,
the system rewrite driver 118 feeds new system software of higher
version to the camera 10. Again, bulk transfer is desirable for
data transfer because it guarantees the contents of data.
On the other hand, the protocol configuration of the digital camera
(simply camera hereinafter) 30 includes a USB port 302 and a USB
controller 304 adaptive to the USB interface 20, and a system controller
306 adaptive to the device driver 106 of the host computer 10. The
USB port 302 belongs to a physical layer to which the USB cable
20a is connected. The USB port 302 is a transceiver driver that
receives power via the USB port 104 of the host computer 10 and
detects the input and output of data.
The USB controller 304 includes software belonging to a data link
layer adaptive to the USB interface 20. The USB controller 304 is
an interface for detecting the commands, which are included in the
interrupt transfer and control transfer fed from the host computer
10, and controlling data conversion in accordance with the isochronous
transfer or the bulk transfer. The USB controller 304 delivers the
detected commands to the system controller 306.
The system controller or main controller 306 of the camera 30 drives
the various sections of the camera 30, including the image pickup
system and a recording system, in accordance with the commands received
from the host computer 10. In the illustrative embodiment, the system
controller 306 has a function of analyzing the above commands. Particularly,
operating the various sections on the basis of the result of analysis,
the system controller 306 controls the periodic reading of image
data representative of a moving picture out of the image pickup
system for the isochronous transfer. Further, the system controller
306 controls the writing of image data or files representative of
still pictures in the memory card or the reading of the same out
of the memory card in accordance with bulk transfer. In addition,
in the illustrative embodiment, the system controller 306 executes
control when the system software fed from the host computer 10 by
bulk transfer should be rewritten.
FIG. 2A shows the configuration of the camera 30 more specifically.
As shown, the camera 30 includes an image sensor 308 to which the
image of a scene to be picked up is incident via optics, not shown,
including a lens. The image sensor 308 transforms the incident image
to, e.g., R, G and B (Red, Green and Blue) image signals and may
advantageously be implemented by a CCD or similar solid-state image
sensor. The output of the image sensor 308 is connected to an analog-to-digital
converter (ADC) 310. The ADC 310 converts the analog image signals
output from the image sensor 308 to corresponding digital data.
The output of the ADC 310 is connected to a memory controller 312
and a YC (luminance and chrominance) signal processing 316.
A memory controller 312 selectively writes the image data output
from the ADC 310 or the image data output from the YC signal processing
316 in a frame memory 314. Also, the memory controller 312 selectively
feeds, under the control of the system controller 306, image data
representative of a moving picture to either an LCD (Liquid Crystal
Display) interface (I/F) 320 or the USB controller 304 every preselected
period. Further, the memory controller 312 delivers image data representative
of a still picture taken to a memory card I/F 322. In this sense,
the memory controller 312 plays the role of a data controller as
well. In the illustrative embodiment, the memory controller 312
should preferably reduce, or thin, the image data representative
of a moving image by a preselected number of pixels when such data
are transferred by isochronous transfer. In such a case, the memory
controller 312 will read out the data by an amount and at a rate
matching with the transfer rate of the USB interface 20.
In the illustrative embodiment, the YC signal processing 316 executes
white balance adjustment, tone correction and other conventional
preprocessing and calculations for transforming the R, G and B image
data to YC data, i.e., a luminance signal (Y) and chrominance signals
(C). The output of the YC signal processing 316 is connected to
the memory controller 312 and a compression/expansion 318. The compression/expansion
318 compresses the image data output from the YC signal processing
316 with a preselected coding scheme. In the illustrative embodiment,
the compression/expansion 318 includes an expanding circuit that
expands compressed image data at the time of reproduction of a stored
image.
The LCD I/F 320 transfers the image data fed from the memory controller
312 to an LCD or monitor 326. The LCD 326 displays, e.g., a moving
picture representative of a scene being picked up or a still picture,
or preview picture, picked up. Such an image is represented by the
image data input to the LCD 326 via the LCD I/F 320. In the illustrative
embodiment, when the USB interface 20 is connected to the digital
camera 30, the LCD 326 is not used. That is, the LCD 326 is used
mainly as a finder at the time of an ordinary shot.
The memory card I/F 322 writes the data or the file representative
of a still picture in a memory card 324 or reads it out of the card
324 under the control of the system controller 306, although connection
between the I/F 322 and the card 324 is not shown specifically.
Particularly, in the illustrative embodiment, when the host computer
10 accesses the digital camera 30, the memory card I/F 322 transfers
the data or the file read out of the memory card 324 to the USB
controller 304 or writes data or a file received via the USB controller
304 in the memory card 324.
The memory card 324 is a recording medium removably mounted to
the camera 30 and is loaded with a plurality of EEPROMs (Electrically
Erasable and Programmable ROMs) or similar memory devices.
In the illustrative embodiment, the camera 30 additionally includes
a microphone or speech input section 328, an amplifier 330, an ADC
332, and a speech data processing 334. The microphone 328, implemented
by a miniature condenser microphone by way of example, feeds a speech
signal input thereto to the amplifier 330. The amplifier 330 amplifies
the speech signal to a preselected amplitude and delivers the amplified
speech signal to the ADC 332.
The ADC 332 converts the input speech signal to digital speech
data and feeds the digital speech signal to the speech data processing
334. The speech data processing 334 executes band compression and
other preselected processing with the digital speech signal. When
the host computer 10 accesses the camera 30, the data output from
the speech data processing 334 is fed to the USB controller 304
under the control of the system controller 306.
The system controller 306 is a microcontroller for controlling
the image pickup system including the image sensor 308, the signal
processing system, and the display, and recording sections. For
this aim, the system controller 306 is interconnected to the components
of the camera 30. For simplicity, such interconnections are symbolically
depicted with the arrows 307 in FIG. 2A. An EEPROM 336 storing control
programs is connected to the system controller 306. In the illustrative
embodiment, the program stored in the EEPROM 336 can be freely rewritten
by an access input from the host computer 10 via the USB interface
20.
On the other hand, the host computer 10 may advantageously be implemented
by a personal computer having a USB as standard equipment, e.g.,
a personal computer with PC97 having the 1,997 or later specifications.
For example, as shown in FIG. 2B, the host computer 10 includes
a CPU (Central Processing Unit) 120 that drives a MODEM 124, a CRT
(Cathode Ray Tube) or display 126 and a speaker 128 for thereby
executing, e.g., an electronic conference application. It is to
be noted that FIG. 2B shows only part of the host computer 10 essential
for the understanding of the illustrative embodiment.
The CPU 120 operates on the basis of an OS, a device driver and
an application stored in a main memory 122. In the illustrative
embodiment, to execute an electronic conference application, the
CPU 120 controls the camera 30 via the USB interface 20 in order
to receive data representative of a moving picture and speech data
or data representative of a still picture. The received data are
input to the MODEM 124.
The MODEM or data transmitting unit 124 is connected to a subscriber
line or similar preselected communication channel for sending data
with a preselected procedure. In the illustrative embodiment, the
MODEM 124 sends image data and speech data received from the camera
30 to another computer joining in an electronic conference. Also,
the MODEM 124 receives image data and speech data sent from another
computer. The image data received from another computer is displayed
on the CRT 126 via a display controller 130.
In the illustrative embodiment, the CRT 126 is a color display
and should preferably have a multiwindow display capability. More
specifically, the CRT 126 may advantageously display a picture received
from another computer and a remote moving picture received from
the digital camera 30 together as well as characters. The display
controller 130 writes the image or images to be displayed on the
CRT 126 in a VRAM (Video Random Access Memory) 132 and controls
the display thereof.
On the other hand, the speech data input via the MODEM 124 is fed
to a sound controller 134. The sound controller 134 reconstructs
the speech data into the original speech signal and drives the speaker
128 with the speech signal.
The operation of the illustrative embodiment will be described
hereinafter on the assumption that it executes an electronic conference
application by way of example. First, a person participating in
the conference shoots materials necessary for the conference with
the camera 30 and so as to store the resulting image data in the
memory card 324. At this stage of operation, the camera 30 is, of
course, not connected to the USB 20 interface, but is used as an
ordinary digital camera.
After shooting the materials, the participant connects one end
of the USB cable 20a to the host computer 10 and the other end of
the same to the camera 30. The participant then sets the digital
camera 30 at a preselected position on the display 126, as shown
in FIG. 3 specifically. The host computer 10 may be held in either
one of an ON state and an OFF state at the time when the USB cable
20a is connected therefore, because the USB cable 20a has a hot-plug
function.
Assume that the participant connects the USB cable 20a to the host
computer 10 and then turns on the host computer 10. Then, the host
computer 10 starts up the OS thereof, checks the device drivers
and controllers, and then loads them on an operation menu, thereby
constructing a system particular to the host computer 10. At this
instant, the host computer 10 feeds power to a peripheral unit connected
thereto via the USB port 104 and USB cable 20a. Subsequently, the
USB controller 102, which has a host function, detects the peripheral
unit connected to the USB cable 20a by control transfer so as to
determine the kind of the peripheral unit and the kinds of transfer
that the peripheral unit can deal with. Such a procedure is generally
referred to as configuration. The camera 30, which is the peripheral
unit in the illustrative embodiment, requests the host computer
10 to send all transfer services, including isochronous transfer
and bulk transfer, to the camera 30. In response, the host computer
10 displays an icon representative of the camera 30 on, e.g., the
operation menu. This allows the participant to operate the camera
30 and allows data to be transferred.
After the above-described connection, the participant starts up
an electronic conference application on the host computer 10 and
then operates it in a preselected way for calling the other computer
via the MODEM 124. As a result, a communication channel is set up
between the host computer 10 and the other computer. At this instant,
the application 108 delivers a moving picture and speech transfer
request to the device driver 106 and thereby starts up the image
driver 112 and audio driver 114 included in the device driver 106.
Subsequently, the USB controller 102 sends a moving picture transfer
command and a speech transfer command to the camera 30 in the form
of token packets, each at a particular timing of transfer frames.
The camera 30 starts driving the image sensor 308 and microphone
328 immediately after the receipt of power from the host computer
10. The camera 30 is therefore continuously picking up and processing
the participant's image and speech. In this condition, the USB controller
304 included in the camera 30 detects the moving picture transfer
command and speech transfer command sent from the host computer
10. These commands are fed from the USB controller 304 to the system
controller 306. In response, the system controller 306 first reads
a preselected amount of image data, which have been reduced to a
preselected number of pixels, out of the frame memory 314 and delivers
them to the USB controller 304. The preselected amount of image
data may be 1,023 bytes of image data by way of example. The USB
controller 304 constructs the input image data into a data packet
and transfers it to the host computer 10 by isochronous transfer.
Subsequently, the system controller 306 controls the speech data
processing 334 in order to process speech data input via the microphone
328, amplifier 330, and ADC 332. The system controller 306 first
feeds sixty-four bytes of processed speech data to the USB controller
304. Again, the USB controller 304 constructs the input speed data
into a data packet and sends it to the host computer 10 by isochronous
transfer.
The procedure described above is repeated thereafter. Specifically,
the host computer 10 sends the moving picture transfer command and
speech transfer command every 1 millisecond. Every time the digital
camera 30 receives the above commands, it transfers, e.g., 1,023
bytes of image data and sixty-four bytes of speech data to the host
computer 10 by isochronous transfer. Consequently, a transfer rate
of about 10 Mbps (megabits per second) is achievable as to image
data, so that about 10 frames can be transferred with, e.g., a CIF
(Common Intermediate Format) resolution. More specifically, in the
camera 30, after one frame of image data has been read out of the
frame memory 314, the next frame is read out of the image sensor
308, written to the frame memory 314, and then read out. In this
manner, consecutive frames are sequentially read out and transferred.
Real-time speech data can be transferred at a rate of 64 kbps (kilobits
per second).
The host computer 10 executes preselected processing (compression,
if necessary) with the image data representative of a moving picture
and speech data received from the digital camera 30. The processed
image data and speech data are sent to another computer via the
MODEM 124 and communication channel. On receiving image data and
speech data from the other computer, the host computer 10 drives
the display controller 130 and sound controller 134 so as to display
the other participant, who is operating the other computer, on the
CRT 126 while outputting a speech via the speaker 128. In this manner,
the participants can converse with each other while watching each
other's real-time expressions.
When the participant operating the host computer 10 desires to
present a material during the conference, the participant clicks
the icon representative of the camera 30 with, e.g., a mouse and
then selects an item for accessing the memory card 324. This starts
up the storage driver 110 included in the device driver 106 and
causes the USB controller 102 to send a card access command to the
camera 30 by interrupt transfer.
In the camera 30, the USB controller 304 detects the card access
command sent from the host computer 10 and delivers it to the system
controller 306. In response, the system controller 306 accesses
the memory card 324 via the memory card I/F 322. The system controller
306 then reads image data representative of, e.g., index images
of the still pictures out of the memory card 324, sixty-four bytes
at a time, at a bulk transfer timing. Such image data are fed to
the USB controller 304. The USB controller 304 constructs the input
image data into packet data and sends them to the host computer
10 by bulk transfer.
The host computer 10 executes error checking with the image data
received from the camera 30 by using a CRC (Cyclic Redundancy Check)
code. If the image data are free from errors, the host computer
10 returns an ACK (ACKnowledge) handshake packet representative
of successful receipt to the camera 30; if otherwise, the former
returns a NACK (Not ACKnowledge) handshake packet representative
of an error to the latter. On receiving the NACK handshake packet,
the camera 30 again sends the same image data to the host computer
10 at the next bulk transfer timing.
The host computer 10, received the entire index image data from
the camera 30, forms a window separate from the moving picture on
the CRT 126 and displays the index images in the window. The participant,
watching the index images on the CRT 126, selects the desired still
picture or material. The host computer 10 sends the resulting command
indicative of the still picture selected to the camera 30 at an
interrupt transfer timing. In response, the camera 30 again accesses
the memory card 324, reads the image data representative of the
still picture selected out of the memory card 324, and sends the
image data to the host computer 10 by bulk transfer.
If the receipt of the image data representative of the still picture
selected is successful, the host computer 10 displays the still
picture on the CRT 126. If the participant accepts the still picture
appearing on the CRT 126, the host computer 10 sends the image data
to another computer via the MODEM 124. The two participants are
now capable of discussing with each other while watching the still
picture or material prepared beforehand.
As stated above, every time a material or still picture prepared
beforehand is required, image data representative of the material
is read out of the memory card 324 and transferred from the camera
30 to the host computer 10 by bulk transfer. The host computer 10
displays the material on the CRT 126 and sends it to the other computer.
Likewise, when the host computer 10 receives data representative
of a material in the form of a still picture from the other computer,
it displays it on the CRT 126 and allows the participant to discuss
with the participant operating the other computer. To allow the
material discussed to be again used later, the host computer 10
may transfer the received image data representative of the material
to the camera 30 by bulk transfer, so the image data can be written
to the memory card 324.
Assume that the participant operating the host computer 10 needs
a new material for discussion that has not picked up by the camera
30 beforehand. Then, the participant clicks the icon representative
of the digital camera 30 and then selects an item relating to a
shoot mode. In response, the host computer 10 starts up the operation
driver 116 and allows the participant to operate the camera 30 via
the host computer 10. For example, when the participant positions
a desired material in front of the camera 30, a remote image representative
of the material appears on the display 126 because of the previously
stated transfer of a moving picture. As the participant, watching
the remote picture, focuses the digital camera 30 to the material,
the host computer 10 sends the resulting operation command to the
camera 30 by interrupt transfer. In response, the system controller
306 controls the optics of the camera 30 for focusing the camera
30. Likewise, when the participant performs a zooming operation
in order to enlarge the picture, the host computer 10 again sends
the resulting command to the camera 30 by interrupt transfer. In
response, the camera 30 controls the optics or the memory controller
312 thereof in such a manner as to enlarge the picture by optical
or electronic zooming.
After the desired picture has been so framed, the participant can
select the release of the shutter of the camera 30 on the host computer
10 so as to shoot the material in the form of a still picture. The
participant may select a strobe function available with the camera
30 on the host computer 10 in order to illuminate the material at
the time of the release of the shutter, if desired. Image data representative
of the new material is also sent from the camera 30 to the host
computer 10 by bulk transfer. Such image data may also be written
to the memory card 324, as needed.
As stated above, to receive image data representative of a moving
picture from the camera 30 together with speech data, the host computer
10 starts up the image driver 112 and audio driver 114. The camera
30 then transfers a preselected amount of data to the host computer
10 by isochronous transfer every transfer frame. The host computer
10 starts up, if necessary, the storage driver 110, causing the
camera 30 to transfer data representative of still pictures taken
beforehand by bulk transfer. In the same time instant, the host
computer 10 also confirms the data representative of still pictures.
Further, the host computer 10 starts up, if necessary, the operation
driver 116, so that the participant can pick up a still picture
any time during discussion. Image data representative of this still
picture is also transferred from the camera 30 to the host computer
10. In this manner, not only image data representative of a moving
picture and speech data but also image data representative of still
pictures can be sent from the camera 30 to the host computer 10
for facilitating discussions.
On the other hand, assume that the program or data stored in the
EEPROM 336 of the camera 30 must be rewritten due to the extension
or the alteration of the functions of the camera 30. Then, the participant
or operator again connects the camera 30 and host computer 10 by
use of the USB cable 20a. Subsequently, the operator selects the
icon indicative of the digital camera 30 in, e.g., the operation
menu and then selects an item relating to system rewriting. In response,
the host computer 10 starts up the system rewrite driver 118. When
the operator inserts a floppy disk storing, e.g., a new program
of higher version into the host computer 10, the host computer 10
reads the program.
After the reading of the new program, the USB controller 102 of
the host computer 10 sends a system rewrite command to the camera
30. In response, in the camera 30, the USB controller 304 delivers
the system write command to the system controller 306, preparing
for the rewriting of the EEPROM 336. Subsequently, the host computer
10 sequentially sends the data of the new program or software to
the camera 30 by bulk transfer. In the camera 30, the USB controller
304 executes code error checking with the data each time of bulk
transfer and sends an ACK packet or a NACK packet to the host computer
10. The data successfully received are input to the system controller
306 and then written to the EEPROM 336 by a preselected procedure.
As a result, the entire new program or data are written to the EEPROM
336.
As described above, the illustrative embodiment provides the host
computer 10 with the device driver 106 adaptive to the camera 30
and including the storage driver 110, image driver 112, audio driver
114, and operation driver 116. Therefore, in the event of an electronic
conference, a single camera 30 can be connected to the host computer
10 by the USB cable 20a and effectively used as an apparatus for
providing the host computer 10 with image data representative of
a moving picture and speech data as well as data representative
of still pictures. In addition, with the system rewrite driver 118
also included in the device driver 106, it is possible to readily
add new functions to the digital camera 30 or to readily alter the
functions of the camera 30 via the USB interface 20.
FIG. 4 shows a specific setup of a comparative computer system.
As shown, the comparative computer system includes a host computer
600 and a digital camera 500 connected to the host computer 600
as an apparatus for generating image data, which is representative
of a moving picture. A microphone 510 is also connected to the host
computer 600 and plays the role of an apparatus for generating speech
data. Further, a card reader/writer 530 is connected to the host
computer 600 when image data representative of still pictures are
desired. The card reader/writer 530 writes or reads image data in
or out of a memory card removably loaded on the digital camera 520.
By contrast, in the illustrative embodiment, only the camera 30
is connected to the host computer 10 by the USB cable 20a, as described
with reference to FIG. 3. The illustrative embodiment is therefore
far simpler in configuration than the computer system of FIG. 4
and can effectively start operating only if use is made of, e.g.,
an icon representative of the camera 30.
While the illustrative embodiment has concentrated on an electronic
conference application, the present invention is practicable with
any other application in which image data representative of a moving
picture, speech data, data representative of still pictures and
shooting operations are dealt with either individually or in combination.
In the illustrative embodiment, the camera 30 is connected to the
host computer 10 by the USB interface 20. If desired, the USB interface
20 may be replaced with IEEE 1394 that is a high-speed serial interface,
in which case the USB ports 104 and 302 and USB controllers 102
and 304, FIGS. 1 and 2, will be interpreted as IEEE 1394 ports and
IEEE 1394 controllers, respectively. Further, when use is made of
the IEEE 1394 interface, it is desirable to transfer image data
representative of a moving picture and speech data by IEEE 1394
isochronous transfer, which is repeated every 125 microseconds.
Also, it is desirable to transfer image data representative of still
pictures and operation commands by IEEE 1394 asynchronous transfer,
which transfers data when a bus is idle after isochronous transfer.
Furthermore, the camera 30 may be replaced with a digital movie
camera of the type taking and recording a moving picture or of the
type taking and recording a still picture in addition to a moving
picture.
In summary, it will be seen that the present invention provides
a computer system capable of executing, e.g., an electronic conference
application with a simple system configuration including a digital
camera, and realizing effective transfer of data representative
of a moving picture or a still picture or the effective operation
of the camera.
The entire disclosure of Japanese patent application No. 360815/1999
filed Dec. 20, 1999 including the specification, claims, accompanying
drawings and abstract of the disclosure is incorporated herein by
reference in its entirety.
While the present invention has been described with reference to
the illustrative embodiment, it is not to be restricted by the embodiment.
It is to be appreciated that those skilled in the art can change
or modify the embodiment without departing from the scope and spirit
of the present invention.
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