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Digital Camera Patent Abstract
A digital camera system is formed from a host device and a camera
module. The host device has a user interface for receiving user
input that controls the operation of a connected camera module and
a first processor operable in response to user input via the user
interface specifying a camera action, to create a request message.
The camera module has image capturing means and a second processor
operable to decode a request message to control the image capturing
means. When the camera module is attached to the host device the
first and second processors are connected for communication.
Digital Camera Patent Claims
1. A digital camera system comprising: a user interface for receiving
user input that controls the operation of a connected camera module;
image capturing means; a first processor operable in response to
user input via the user interface specifying a camera action, to
create a request message; a second processor, connected to the first
processor and operable to decode a request message to control the
image capturing means, wherein the user interface, and the first
processor are housed within a host digital device and the image
capturing means and the second processor are housed within a camera
module connected to the host digital device.
2. A digital camera system as claimed in claim 1, wherein the first
processor in the host digital device and the second processor in
the camera module are arranged to communicate directly using a message
based protocol, whereby the second processor directly controls the
image capturing means and the host device only indirectly controls
the image capturing means via the second processor.
3. A digital camera system as claimed in claim 1, further comprising
image processing means housed within the camera module for processing
data provided by the image capturing means to create image data,
wherein the second processor is operable to decode a request message
to control the image processing means and the image capturing means.
4. A digital camera system as claimed in claim 1, wherein the first
processor in the host digital device and the second processor in
the camera module are arranged to communicate directly using a message
based protocol, whereby the second processor directly controls the
image capturing means and image processing means and the host device
only indirectly controls the image capturing means and image processing
means via the second processor.
5. A digital camera system as claimed in claim 1, further comprising
a removable memory for storing image data that has been created
under the control of the second processor, wherein the removable
memory is housed in the host digital device.
6. A digital camera system as claimed in claim 1, further comprising
a memory for storing image data that has been created under the
control of the second processor, wherein the memory is housed in
the host digital device.
7. A digital camera system as claimed in claim 1, further comprising
a display for displaying images captured by the image capturing
means, wherein the display is housed in the host digital device.
8. A digital camera system as claimed in claim 7, wherein the camera
module is arranged to compress image data to create compressed image
data and the digital host device is arranged to decompress compressed
image data to recover image data for display on the display.
9. A digital camera system as claimed in claim 7, wherein the camera
module is arranged to compress image data to create compressed image
data and the digital host device is arranged to provide compressed
image data to the camera module and to receive in reply decompressed
image data for display on the display.
10. A digital camera system as claimed in claim 1, wherein the
camera module is attachable to and detachable from the host digital
device.
11. A digital camera system as claimed in claim 1, wherein a request
message specifies a camera action.
12. A method of controlling a digital camera that comprises a host
device and a camera module, comprising the steps of: providing user
input at a host device; converting the user input, in the host device,
to a request message; transferring the request message from the
host device to the camera module; and converting the request message,
in the camera module, to control signals for controlling image capture.
13. A camera module, for connection to a host digital device, comprising:
an input interface; image capturing means; and a processor, connected
to the input interface, operable to decode a request message and
to produce control signals for directly controlling the image capturing
means.
14. A camera module as claimed in claim 13, further comprising
image processing means wherein the processor is operable to decode
a request message and produce control signals for directly controlling
the image capturing means and the image processing means.
15. A camera module as claimed in claim 14, wherein the image processing
means provides an input or inputs to the processor.
16. A camera module as claimed in claim 15, wherein the input(s)
are indicative of the brightness and the contrast of an image.
17. A camera module as claimed in claim 14, wherein the image processing
means comprises a configurable hardwired imaging accelerator.
18. A camera module as claimed in claim 13, wherein the processor
is operable to produce a control signal for setting the configuration
of the image capturing means.
19. A camera module as claimed in claim 18, wherein the processor
is operable to produce a control signal for setting the configuration
of camera opto-mechanics.
20. A camera module as claimed in claim 19, wherein the camera
opto-mechanics comprise lens position, aperture size and shutter
speed.
21. A camera module as claimed in claim 18, wherein the processor
is operable to produce a control signal for setting the configuration
of a strobe.
22. A camera module as claimed in claim 18, wherein the processor
is operable to produce a control signal for setting the configuration
of an image sensor.
23. A camera module as claimed in claim 13, wherein the processor
provides auto-focusing.
24. A camera module as claimed in claim 13, wherein the processor
provides auto-exposure.
25. A camera module as claimed in claim 13, wherein the processor
provides an optical zoom function.
26. A camera module as claimed in claim 13, wherein the processor
provides an auto white balance function.
27. A camera module as claimed in claim 13, wherein the processor
operates in accordance with a computer program that may be varied
or replaced.
28. A camera module as claimed in claim 13, wherein the image capturing
means comprises a CCD image sensor.
29. A camera module as claimed in claim 13, further comprising
conversion means for converting interlaced type data from the image
capturing means to progressive type data.
30. A camera module as claimed in claim 13, wherein the processor
is arranged to display image data only by transferring it to an
attached host device.
31. A camera module as claimed in claim 13, wherein the processor
is arranged to store image data only by transferring it to an attached
host device.
32. A camera module as claimed in claim 13, arranged to compress
image data to create compressed image data.
33. A camera module as claimed in claim 13, wherein the camera
module is arranged to compress image data to create compressed image
data for transfer to a connected host device and to decompress compressed
image data received from an attached host device to produce decompressed
image data.
34. A camera module as claimed in claim 13, wherein a request message
specifies a camera action.
35. A method of controlling the operation of a camera module comprising
the steps of: receiving at the camera module a request message;
converting the request message, in a processor of the camera module,
to control signals for controlling image capture.
36. A host digital device, for connection to a camera module, comprising:
a user interface for receiving user input that controls the operation
of a connected camera module; an output interface for providing
data to a connected camera module; an input interface for receiving
image data from a connected camera module; and a processor operable
in response to user input via the user interface specifying a camera
action, to create a request message and to provide the request message
to a connected camera module via the output interface.
37. A host device as claimed in claim 36, wherein a request message
specifies a camera action.
38. A host device as claimed in claim 36, wherein the processor
is arranged to communicate directly with a processor of an attached
camera module using a message based protocol.
39. A host digital device as claimed in claim 36, further comprising:
a removable memory for storing image data that has been captured
and processed under the control of the camera module.
40. A host digital device as claimed in claim 36, further comprising:
a memory for storing image data that has been captured and processed
under the control of the camera module.
41. A host device as claimed in claim 36, further comprising a
display for displaying an image captured by an attached camera module.
42. A host device as claimed in claim 41, further arranged to decompress
compressed image data to recover image data for displaying an image
on the display.
43. A host device as claimed in claim 41, wherein the processor
is arranged to provide compressed image data to a connected camera
module and to receive in reply decompressed image data for displaying
an image on the display.
44. A method of controlling the operation of a camera module from
a host device to which it is connected, comprising the steps of:
providing user input at the host device; converting the user input,
in the host device to a request message; transferring the request
message to the camera module.
45. A computer program comprising program instructions which when
executed cause a computer to operate as a host device as claimed
in claim 36.
46. A computer program comprising program instructions for causing
a computer to perform the method of claim 44.
47. A computer program which when loaded into a host digital device
enables a processor in the host digital device to communicate directly
with a processor of an attached camera module using a message based
protocol.
48. A computer program as claimed in claim 47, embodied a record
medium or stored in a computer memory.
Digital Camera Patent Description
[0001] Embodiments of the present invention relate to a digital
camera module and a digital host device.
[0002] Until recently, if a user of a digital device (e.g. computer,
mobile phone, PDA etc.) also wanted to take digital photographs,
the user would have had to use a separate dedicated digital still
camera (DSC).
[0003] However, it is undesirable for the user to have to purchase
and carry two separate dedicated digital devices. To address this
problem, digital devices with integrated cameras have been developed
and camera modules for attachment to digital devices have been developed.
[0004] However, the image quality and camera functionality provided
by integrated cameras and camera modules is significantly less than
that provided by a dedicated DSC. For example, for current camera
modules for a mobile telephone the resolution is at most 350,000
pixels, whereas a DSC can now have a resolution of greater than
4 million pixels.
[0005] It is not possible to simply add more of the functionality
from a DSC into a camera module as this will compromise the primary
functionality of the digital device to which it is attached. The
primary functionality of a digital device varies from device to
device, but for a mobile phone it may be telecommunication functions.
[0006] It would therefore be desirable to enable a digital device
to be used to take, higher quality images without compromising the
primary function of the digital device.
[0007] According to one aspect of the present invention there is
provided a digital camera system comprising: a user interface for
receiving user input that controls the operation of a connected
camera module; image capturing means; a first processor operable
in response to user input via the user interface specifying a camera
action, to create a request message; a second processor, connected
to the first processor and operable to decode a request message
to control the image capturing means, wherein the user interface,
and the first processor are housed within a host digital device
and the image capturing means and the second processor are housed
within a camera module connected to the host digital device.
[0008] According to another aspect of the present invention there
is provided a method of controlling a digital camera that comprises
a host device and a camera module, comprising the steps of: providing
user input at a host device; converting the user input, in the host
device, to a request message; transferring the request message from
the host device to the camera module; and converting the request
message, in the camera module, to control signals for controlling
image capture.
[0009] According to a further aspect of the present invention there
is provided a camera module, for connection to a host digital device,
comprising: an input interface; image capturing means; and a processor,
collected to the input interface, operable to decode a request message
and to produce control signals for directly controlling the image
capturing means.
[0010] According to another aspect of the present invention there
is provided a method of controlling the operation of a camera module
comprising the steps of: receiving at the camera module a request
message; converting the request message, in a processor of the camera
module, to control signals for controlling image capture.
[0011] According to a further aspect of the present invention there
is provided a host digital device, for connection to a camera module,
comprising: a user interface for receiving user input that controls
the operation of a connected camera module; an output interface
for providing data to a connected camera module; an input interface
for receiving image data from a connected camera module; and a processor
operable in response to user input via the user interface specifying
a camera action, to create a request message and to provide the
request message to a collected camera module via the output interface.
[0012] According to another aspect of the present invention there
is provided a method of controlling the operation of a camera module
from a host device to which it is connected, comprising the steps
of: providing user input at the host device; converting the user
input, in the host device, to a request message; transferring the
request message to the camera module.
[0013] According to a still further aspect of the present invention
there is provided a computer program which when loaded into a host
digital device enables a processor in the host digital device to
communicate directly with a processor of an attached camera module
using a message based protocol.
[0014] Thus in embodiments of the invention, the host device processor
is decoupled from controlling the camera modules functions. The
host device processor need not know how to control the workings
of the camera module. It need only communicate using a message based
protocol.
[0015] Thus in embodiments of the invention, the host device may
be an existing host device with a software update. That is, no hardware
modifications are required in the host.
[0016] The use of a separate dedicated processor in the camera
module enables the operation of the camera module to be easily updated
by changing or updating the software controlling the processor in
the camera module. This will have no effect on the host device.
[0017] The use of a separate dedicated processor in the camera
module enables process intensive tasks such as auto white balance,
auto focusing and auto exposure without adding to the workload of
the processor of the host.
[0018] According to one aspect of the present invention there is
provided a clip-set for a camera module, comprising: a first input
interface for receiving data from an image sensor; image processing
means for processing data received via the first input interface;
and a processor for controlling the image processing means.
[0019] According to another aspect of the present invention there
is provided a method of controlling the operation of a camera module
comprising the steps of: receiving at a camera module chip-set a
request message; converting the request message, in processing means
of the camera module chi-set, to control signals for controlling
image capture.
[0020] For a better understanding of the present invention reference
will now be made by way of example only to the accompanying drawings
in which
[0021] FIG. 1 illustrates a prior art host device and camera module
combination;
[0022] FIG. 2 illustrates a host device and camera module combination
according to one embodiment of the present invention.
[0023] FIG. 1 illustrates a prior art digital device 2 hosting
a prior art digital camera module 1. The digital camera module 1
comprises an input interface 20 and an output data interface 18
connected to the host 2. The input interface 20 is connected to
provide an input signal to a CMOS image sensor 3. The CMOS image
sensor receives light which has traveled through an optical lens
system 60, and an optical filter 64, before reaching the image sensor
3. The image sensor 3 provides an output signal to an imaging hardware
accelerator 19, which provides image data to the host 2 via the
output data interface 18.
[0024] The imaging hardware accelerator is a pipeline structured
hardwired signal processing apparatus. Data is processed stage by
stage sequentially. It is fast, has a low power consumption and
a small size. The image hardware accelerator comprises a pre-processing
unit 15 and image pipeline 16. The pre-processing unit 15 processes
data received from the image sensor 3 before it is reconstructed
as an image by the image pipeline 16. This processing may, for example,
include: defect correction, gain control or black level offset matching.
[0025] The host device 2 comprises an input data interface 43 that
is connected to the camera module's output data interface 18 and
an output interface 45 that is connected to the camera module's
input interface 20. The connection between the interfaces is releasable.
[0026] A CPU 41 is connected to the output interface 45. The CPU
41 directly controls the CMOS image sensor 3 via the interfaces
45, 20. The CPU 41 writes directly to registers in a timing generator
73 in the image sensor 3.
[0027] A bus system 56 connects together the input data interface
43, the CPU 41, a memory 46, a removable storage system comprising
a removable memory 47 and device interface 48, a user input interface
51, a display system comprising an LCD 53 and display device interface
52. In this embodiment the digital host device 2 is a mobile phone
and also comprises a digital signal processing (DSP) unit 42.
[0028] The user interface 51 is used to provide inputs to the host
CPU 41, which directly controls the camera module 1. The image data
provided by the camera module 1 can be stored in the memory 46 or
removable memory 47 or displayed on LCD 53 depending upon input
from the user interface 51.
[0029] FIG. 2 illustrates a digital device 2 hosting a digital
camera module 1, according to one embodiment of the present invention.
The host device in this example is a mobile cellular telephone.
However, in other implementations the host digital device 2 may
be a computer, a personal digital assistant etc.
[0030] The Camera Module
[0031] The digital camera module 1 comprises a camera module chip-set
4, and camera hardware. The camera hardware includes a strobe system
including a strobe interface controller and a strobe light 68, an
image sensor 3 that receives light via an optical system and an
opto-mechanical system. The optical system has, in order, an adjustable
lens system 60, a variable optical aperture, a mechanical shutter
and an optical filter 64. The opto-mechanical system comprises a
lens driver 66 for controlling the positions of the lens in the
lens system 60 and a shutter driver 65 that sets the speed of operation
of the shutter and the size of the optical aperture. The camera
chip-set has a strobe interface 24 that is connected to the strobe
interface 67, a opto-mechanical interface 23 that is connected separately
to the shutter driver 65 and the lens driver 66, a sensor control
interface 21 that is connected to the timing gate of the image sensor
3, and a sensor data interface 12 for receiving data from the image
sensor 3.
[0032] Each of the sensor control interface 21, opto-mechanical
interface 23 and strobe interface 24 are connected to a bus system
25.
[0033] The sensor data interface 12 is connected to a data type
converter that also includes a memory controller 13 and a field
memory 14. The data type converter is connected to an imaging hardware
accelerator 19, which provides image data to the host 2 via an output
data interface 18.
[0034] Imaging hardware accelerator 19 comprises, in order, a pre-processing
unit 15, an image pipeline 16 and a data compressor 17.
[0035] The camera chipset 4 also has an input interface 20 for
receiving data from the host 2. The input interface 20 is connected
to camera module CPU 11. The camera module CPU 11 is connected to
a bus system 9 that connects separately to the pre-processing unit
15 and the image pipeline 16 of the imaging hardware accelerator
19. The camera module CPU 11 also connects to the bus system 25.
[0036] How the Camera Module Works
[0037] The camera module CPU 11 is able to directly control the
image processing stages via the bus 9. The CPU 11 is able to directly
control the image capture stages via the bus system 25 using:
[0038] a) The strobe interface 24;
[0039] b) The opto-mechanical interface 23;
[0040] c) The sensor control interface 21.
[0041] The CPU 11 may for example specify if a strobe should be
used via the strobe interface 24.
[0042] The CPU 11 may for example specify by how much a lens should
be moved by how much an IRIS aperture should be increased or decreased
or control the shutter speed via the opto-mechanical interface 23.
The CPU 11 will generally write directly to registers in the optical
system.
[0043] The CPU 11 may for example control the operation of the
image sensor 3 via the sensor control interface 21. For example,
if the image sensor apparatus 3 is a CCD sensor unit comprising
CCD sensor array 71 and Timing Generator 73, the CPU 11 may send
commands to clear CCD charge or to change parameters of the timing
generator 73.
[0044] The image sensor 3 receives light which has traveled through
the configurable optical lens system 60, a configurable optical
aperture and an optical filter 64, before reaching the image sensor
3. The image sensor provides an output data signal to a configurable
imaging hardware accelerator 19, via the data type converter. The
imaging accelerator 19 provides compressed image data to the host
2 via the output data interface 18. The CPU 11 sends command signals
directly to the camera hardware (lens system 60, aperture, mechanical
shutter, strobe 68 and image sensor 3) and the imaging accelerator
19 optics to configure them.
[0045] In this example the image sensor 3 is a charge couple device
(CCD) image sensor.
[0046] It comprises a charge coupled device array 71 that provides
an output via an analogue to digital converter (ADC) 72 to the sensor
data interface 12 of the camera module chip-set 4. The CCD array
71 and the ADC 72 are synchronized by a timing generator 73. The
timing gate also controls the CCD array through driver 74. The timing
gate 73 is connected to the sensor control interface 21 of the camera
module chip-set 4. The CPU 11 is able to directly control the operation
of the image sensor 3.
[0047] In this example, the CCD array 71 operates in an interlaced
and not a progressive fashion and the imaging accelerator is optimized
for working on data from a progressive image sensor. The image sensor
data provided to the sensor data interface 12 is converted from
an interlaced format to a progressive format by the data type converter.
The data in interlaced format is read to field memory 14 by the
memory controller 13, and then read from the field memory 14 in
a progressive format by the memory controller and provided to the
imaging accelerator 19. If the image sensor 3 was a CMOS image sensor
or a progressive CCD image sensor, the data type converter need
not be present, or if present, need not be used. The CPU 11 may
interrogate the image sensor 3 during initialization to determine
what type of image sensor it is and configure its operation accordingly,
including but not limited to whether or not the data type converter
is used.
[0048] The imaging accelerator 19 receives data in a progressive
format. The pre-processing unit 15 processes this data before it
is reconstructed as an image. These processes may include: (a) defect
correction, (b) gain control (c) black level offset matching.
[0049] The image pipeline 15, then reconstructs the processed data
as image data. It performs three types of processes:
[0050] 1) Image reconstruction normally by CFA interpolation.
[0051] 2) Color space conversion, which means, converting color
space from RGB to YUV.
[0052] 3) Post-processing, which typically includes (a) white balancing,
(b) Gamma controlling, (c) Edge enhancement.
[0053] The data compressor 17 compresses the image data using JPEG
or JPEG2000 compression and provided the compressed image data to
the output data interface 18.
[0054] The pre-processing unit 15 and the image pipeline 16 provide
inputs to the CPU 11 via the bus system 9. The inputs provided by
the imaging accelerator 19 may include:
[0055] (i) Contrast information,
[0056] (ii) Brightness information,
[0057] (iii) The hardware status (the values of internal register).
In other embodiment, this information is provided from the sensor
data interface 12.
[0058] The CPU 11 processes these inputs in accordance to a stored
algorithm to create command signals. These are sent to the camera
hardware to control the image capture stage and to the image accelerator
19 to control the image processing stage. A feed-back loop may therefore
be created, whereby the CPU 11 varies the camera hardware settings
which varies the data provided to the imaging accelerator 19 which
varies the inputs to the CPU 11. The CPU 11 is therefore able to
determine if the opto-mechanics are set correctly and, if not, it
sends command signals to the opto-mechanics to adjust settings via
the opto-mechanics interface 23. A command signal may control the
movement of the lens by 0.2 mm, for example.
[0059] The CPU 11 may perform auto aperture adjustment. The CPU
calculates appropriate aperture size and shutter speed from the
inputs, and sends command signals via the opto-mechanical interface
23 to set the aperture size and shutter speed and also, if necessary,
it sends command signals via the strobe interface 24 to set the
strobe 68 to be prepared to flash.
[0060] The CPU 11 may also control optical-zoom function.
[0061] The CPU 11 may perform auto focusing. The CPU 11 analyzes
the inputs from the imaging accelerator 19, calculates the appropriate
lens position, and sends command signals via the opto-mechanical
interface 23 to set lenses in the calculated positions.
[0062] The camera-CPU may set the imaging accelerator. The camera-CPU
analyzes the inputs (brightness and contrast of the environment),
and sends a command signal to set a filter of the imaging accelerator
19 to an appropriate setting. This adjusts the manner in which images
are reconstructed e.g. to obtain appropriate white balance. The
CPU 11 may therefore provide auto white-balance in the image data.
[0063] The CPU 11 may adjust the compression algorithm used by
the compressor.
[0064] It should therefore be appreciated that the CPU 11 can control
the camera hardware through various interfaces and can control the
hardwired imaging accelerator 19. The CPU 11 does not, however,
play any part in processing image data. The imaging accelerator
processes the image data.
[0065] The Host Device
[0066] The host device 2 comprises an input data interface 43 that
is connected to the camera module's output data interface 18 and
an output control interface 45 that is connected to the camera module's
input interface 20. The connection between the interfaces is releasable.
[0067] A host CPU 41 is connected to the output control interface
45. A bus system 56 connects together the input data interface 43,
the host CPU 41, a memory 46, a removable storage system comprising
a removable storage 47 and device interface 48, a user input interface
51, a display system comprising an LCD 53 and display device interface
52. In this embodiment the digital host device 2 is a mobile phone
and also comprises a digital signal processing (DSP) unit 42 which
connects the bus system 56 to a cellular radio transceiver 40. In
other embodiments, the digital host device may be a computer or
a portable digital host such as a personal digital assistant (PDA)
or a mobile computer.
[0068] The user interface 51 is used to provide inputs to the host
CPU 41. These are generally used to control the primary functions
of the host 2, such as making mobile telephone calls, however, when
the camera module 1 is attached they can also be used to control
the camera module operation. The image data provided by the camera
module 1 can be stored in the memory 46 or removable storage 47
or displayed on LCD 53 depending upon input from the user interface
51.
[0069] The memory 46, removable storage 47, user interface 51 and
LCD 53 of the host 2 are used to provide camera functionality when
the camera module 1 is attached. The camera module chip-set 4 does
not need a large dedicated memory as the memory of the host is used
for data storage.
[0070] No hardware component changes in the host are mandated by
embodiments of the present invention compared with the prior art
host 2 of FIG. 2. The operation of the host 2 is, however, different.
This change in functionality may be achieved by changing the host
device's software. It may be possible to up-grade existing hosts
to be used in embodiments of the present invention by updating their
software. Such an update may be provided by loading a computer program
from a storage medium into the host device or downloading a program
into the host device 2.
[0071] Message Based Architecture
[0072] The software change to the host causes it to indirectly,
as opposed to directly, control the camera module 1 using a message
based protocol between the host CPU 41 and the camera CPU 11 that
specifies actions that are to be taken but not how they are to be
implemented. The CPU 11 of the camera module 1 is used to produce
the command signals for controlling the camera hardware and implementing
the camera functions, the host CPU 41 of the host is no longer used
to create command signals. The actions specified by a request message
may include, for example, prepare to take a picture, take a picture,
zoom-in, zoom-out, store an image, display an image etc.
[0073] The CPU 11 has its own operating system and software. The
CPU 11 implements the settings in the camera hardware and the imaging
accelerator 19. These settings are calculated by the software algorithm
based upon inputs from the imaging accelerator 19 and the action
that is to be carried out e.g. zoom, prepare to take picture, take
picture etc. The CPU 11 does not itself specify the action. The
action is specified by the host CPU 41 of the host device. The specified
function is communicated to the CPU 11 in a request message that
is sent via the output interface of the host 2 to the input interface
20 of the camera module 1. The camera module CPU 11 decodes the
request message specifying an action, determines what functions
are required to achieve this action and produces command signals
for implementing the necessary camera functions.
[0074] The host CPU 41 is therefore unconcerned about how to implement
a particular function, it merely interprets inputs received via
the user interface 51 to create a message that specifies a particular
action or action. The messages have a standardized format that is
understood by the camera CPU 11 and the host CPU 41. The host CPU
41 therefore has no direct control over the camera hardware. It
controls it indirectly via the camera-CPU 11.
[0075] The camera CPU 11 implements the functions required to carry
out an action specified by received message, intelligently according
to its software algorithm by sending command signals to the camera
hardware and/or imaging accelerator 19. These functions may involve
auto focusing, auto exposure, lens movement for optical zoom, strobe
control, image sensor control and image accelerator control.
[0076] The host device need not know what functions the camera
can perform, how to combine certain functions to achieve an action,
or how to control the camera components to implement a function.
[0077] The camera module can be simply upgraded by upgrading the
software algorithm used by the CPU 11. There is no need to update
the software of the host device 2.
[0078] Description of Process
[0079] When a user uses the user interface 51 to indicate that
(s)he may want to take a picture, the host CPU 41 sends a message
specifying "prepare for taking a picture" to the camera
module CPU 11. The CPU 11 controls the settings for capturing and
processing an image. At first the CPU 11 acquires brightness and
contrast information of the environment from pre-processing unit
through bus-system 9. CPU 11 analyzes these information in accordance
with the algorithm, and calculates the amount of lens movement for
clear focusing, shutter speed and aperture size for appropriate
exposure, setting of image accelerator 19 for appropriate white
balance. Then the CPU 11 produces the appropriate control signals
to the opto-mechanical interface 23, the strobe interface 24, the
sensor control interface 21 and the image accelerator 19. Thus the
CPU 11 controls auto-focusing, shutter speed, auto-exposure, whether
to flash the strobe or not, and appropriate lens position for required
zoom. After the Camera-CPU 11 has achieved the appropriate settings
it sends a reply message to the host CPU 41 to notify it. It may
also send image data so that an image can be displayed on LCD 53.
[0080] When a user uses the user interface 51 to indicate that
(s)he wants to take a picture, the host CPU 41 sends a message specifying
"take a picture" to the camera module CPU 11. It may also
specify the picture quality and where the image should be saved
(i.e. internal memory 46 or removable memory 47). The camera-CPU
11 decodes the received message and takes necessary actions. The
camera-CPU 11 may set parameters (e.g., gain or data acquiring mode)
of timing gate (TG) 73 and driver 74 of image sensor unit 3 through
sensor control interface 21. Or the camera-CPU 11 may change the
compression rate by changing parameters of data compressor 17. The
camera-CPU 11 then controls the camera hardware to take a picture.
The captured data is processed through the data-type converter (if
necessary) and the imaging accelerator 19 of the camera chip-set
before being sent to the host for storage in the memory 46.
[0081] In one embodiment, when a user wishes to display a stored
image, the image data is transferred from removable memory 47 to
memory 46 (if necessary), and processed by host CPU 41 and DSP unit
42 and displayed on LCD 53. In this embodiment the replay is controlled
by the host-CPU 41 and camera module 1 does not do anything. Thus
the display of an image may be achieved without attaching a camera
module 1.
[0082] In another embodiment when a user wishes to display a stored
image, the camera module chip-set 4 controls the display of the
stored image. The camera module additionally comprises a data de-compressor
29 associated with the data compressor 17 and a serial interface
28. The data decompressor 29 and serial interface 28 are interconnected
via the bus system 25, which is also connected to memory controller
13. The host device 2 additionally has a serial interface 44 that
connects with the serial interface 28 of the camera module 1.
[0083] The host CPU 41 transfers image data from removable memory
47 to memory 46 (if necessary) and then transmits to through serial
interface 44 to the serial interface 28 of the camera module 1.
The received image data is stored temporarily in the field memory
14 via the bus system 25 by the CPU 11. The CPU 11 then transfers
it to decompressor 29 via the bus system 25 for decompression and
then transmits it through the serial interface 28 to the serial
interface 44 of the host 2 where it is displayed on LCD 53.
[0084] Although embodiments of the present invention have been
described in the preceding paragraphs with reference to various
examples, it should be appreciated that modifications to the examples
given can be made without departing from the scope of the invention
as claimed. For example, the CCD image sensor 3 may be replaced
by a CMOS image sensor.
[0085] Whilst endeavoring in the foregoing specification to draw
attention to those features of the invention believed to be of particular
importance it should be understood that the Applicant claims protection
in respect of any patentable feature or combination of features
hereinbefore referred to and/or shown in the drawings whether or
not particular emphasis has been placed thereon. |