GB2338619A - Apparatus and method for transmitting a compressed image - Google Patents
Apparatus and method for transmitting a compressed image Download PDFInfo
- Publication number
- GB2338619A GB2338619A GB9813097A GB9813097A GB2338619A GB 2338619 A GB2338619 A GB 2338619A GB 9813097 A GB9813097 A GB 9813097A GB 9813097 A GB9813097 A GB 9813097A GB 2338619 A GB2338619 A GB 2338619A
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- image
- memory
- compressed
- operably coupled
- compressor
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
- H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
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- Compression Or Coding Systems Of Tv Signals (AREA)
Abstract
A communication system 1 for transferring an image includes at least one remote station 2 operably coupled to a plurality of image capture devices 3, 4 for capturing images and a base station 5 operably coupled to at least one image displaying device 6. The remote station 2 includes an apparatus for compressing an image which includes a compressor 10 and a selecting means 7 for selecting a memory 8 containing a reference image. The compressor 10 loads the reference image from memory 8 and compares it to the image from image capture device 3 or 4. The resulting difference image is compressed and transmitted to the base station while the captured image is stored in memory 8 as the new reference image.
Description
2338619 APPARATUS ANI) METHOD FOR IMAGE COMPRESSING
Field of the Inuntion
This invention relates to an apparatus, a communication system and a method for compressing and transferring an image.
Back-around of thg Invention Communication systems for transferring images include a plurality of remote stations for capturing images and a base station for displaying the captured image. In order to transfer the captured image one of the following video compression standards are used.
is The video compression standards known as MPEG-1, MPEG-2, H.261 and H.263 use the resemblance of consecutive frames in order to reduce the redundant data thus, resulting in compressed information.
With the use of the above mentioned standards for exploiting the redundancy between two consecutive frames, a decompressed version of the most recently compressed frame is stored in a single frame memory With the aid of the information stored in the frame memory, motion estimation and compensation is applied between the present and last frame to obtain a prediction for the present frame. This can be used to compress the data further.
In order to use compression method, a refernce image file has to be transmitted. This is a full image on which the commpressed diffrence image data is based. It is of necessity a large file and systems using a large numbers of image capture devices has to cater for transmition of a large number of such files. This transmition will take a prohibitive period of time.
This invention seeks to provide an apparatus for compressing and decompressing images, a communication system for transferring images and and a method for transferring images which mitigates at least some of the above mentioned disadvantages.
2 Summary of the Invention
According to a first aspect of the invention there is provided an apparatus for image compressing and or decompressing. The apparatus includes an image compressor and decompressor, an input operably coupled, in use, to a plurality of image capture devices for providing a captured image, a compressor operably coupled to the input for providing a compressed image, plurality of memories operably coupled to the compressor for storing the compressed image, and a selecting means. The selecting means are characterised by: selecting at least one image capture device from the plurality of image capture devices, selecting a first compressed image from the plurality of memories which is related to the selected image capture device, and providing a second compressed image to replace the said first compressed image. The second compressed image is a manipulation of the captured image with the first compressed image.
When the apparatus is included at a communication system which includes a remote station and a base station, each image capture device relates to a memory in the remote station and in the base station. The memory, in use, contains a reference image.
By image capture device it is meant a device for capturing images for example a video camera.
Advantageously, when alternating from one image capture device to another there is no need for transferring a new reference image to the base station, thus a short period of time is needed to transfer a new image.
In that manner, the number of the plurality memories is equal to the number the plurality of the image capture devices and each memory is related to a different image capture device.
Furthermore, each memory contains one compressed image.
In the preferred embodiment of the invention, the memory is a frame memory and the image capture device is a video camera or a digital camera.
3 In the preferred embodiment of the invention, the apparatus includes an image decompressor which is characterised by: providing an input operably coupled to a first communication device for receiving an image from the compressor which provides a received image and providing a reference image which is stored at one of the memories. The decompressor provides a reference image which is a manipulation of the received image with the reference image.
In that manner, the decompressor further includes a second communication device operably coupled to the compressor for transferring the compressed image.
In that manner, the decompressor is further characterised by: providing an address to each one of the compressed images transferred by the second communication device and to each one of the memories of the plurality of memories and directing said compressed image to the addressed memory.
In the preferred embodiment of the invention, the first and the second communication devices are radio devices for transmitting images over the air.
In alternative embodiments of the invention, the first and second communication devices are line communication devices for transferring image over a physical communication line such as a telephone line.
In a second aspect of the present invention, a method of compressing an image is provided. The method includes the steps of. providing a plurality of image capture devices operably coupled to a compressor for capturing images, providing a plurality of memories operably coupled to the compressor for storing the captured images, selecting a memory and an image capture device for compressing an image provided by the selected image capture device and providing a compressed image to be stored at the said selected memory. The compressed image is a manipulation of a captured image with a prestored reference image at the selected memory.
In this manner, the method further includes the steps of.. providing a decompressor operably coupled to the plurality of memories, providing an address for each one of the memories, and providing a selecting means for selecting a reference image stored at one of the 4 memories according to a given address to be decompressed by the decompressor.
Preferably, the selecting means further includes means for selecting an input capture device from the plurality of input capture devices.
In the preferred embodiment of the invention, the method further includes the steps of. providing a first communication device operably coupled to the decompressor, providing a second communication device operably coupled to the compressor, transferring said compressed image from the second communication device to the first communication device and decompressing said compressed image according to the reference image having an addressed matched to the address provided by said compressed image.
Preferably, the reference image, which is stored at any one of the memories, is a decompressed image.
In this manner, the reference image which is stored at one of the plurality of memories coupled to the decompressor is a result of manipulation of a compressed image received from the compressor and the earlier stored reference image.
Preferably, the first and the second communication devices are radio transceivers.
According to a third aspect of the invention there is provided a communication system for transferring an image. The communication system includes at least one remote station operably coupled to a plurality of image capture devices for capturing images and a base station operably coupled to at least one image displaying device for displaying an image captured by one of the image capture devices of the at least one remote station. The remote station is characterised by: a selecting means operably coupled to a plurality of image capture devices and to a plurality of memories for selecting an image capture device and a reference image which is stored at a memory which is related to the image capture device, a compressor operably coupled to the selecting means and to a second communication device for providing a compressed image which is a manipulation of the reference image with the captured image and transferring the compressed image to the base station for displaying on the at least one displaying device.
In that manner, the base station is characterised by: a selecting means operably coupled to at least one displaying device and to a plurality of memories for selecting a reference image which is related to the image capture device and a decompressor operably coupled to the selecting means and to a first communication device for decompressing the compressed image transferred by the remote station with reference to the reference image which is stored at a selected memory.
Preferably, the compressed image comprises a difference of the captured image and an earlier stored reference image.
In that manner, the reference image is an addition of the earlier stored reference image with the compressed image.
A preferred embodiment of the invention will now be described, by way of example only, with reference to the drawings.
Brief Description of the Drawim
FIG. 1 is a block diagram of a communication system for transferring images according to the preferred embodiment of the invention which includes apparatus in accordance with further aspects of the invention; FIG. 2 is an explanatory diagram of an image compressing process; FIG. 3 is an explanatory diagram of an image decompressing process; and FIG. 4 is a flow chart of a method for transferring images according to the preferred embodiment of the invention.
Detailed Description of the Drawings
Referring firstly to FIG. 1, a communication system 1 for capturing and transferring images is shown. The communication system 1 at least one remote station 2 operably coupled to image capture 6 devices 3 and 4, and a base station 5 operably coupled to at least one image displaying device 6.
The remote station 2 includes a selecting means 7, for example a multiplexer, memories 8 and 9, a compressor 10 and a second communication device 11.
The base station 5 includes a selecting means 12, memories 13 and 14, a decompressor 15 and a first communication device 16.
In operation, a request for capture of an image by image capture device 3 is initiated by the base station 5. The request is transmitted by the communication device 16, for example a radio device, and received by the communication device 11 at the remote station 2. The selecting means 7 of the remote station 2 selects, according to an address which was sent by the base station 5, the image capture device 3 and the appropriate associated memory 8. The image capture device 3 captures an image and transfers the captured image to the compressor 10 via the selecting means 7. The compressor 10 compresses the captured image according to one of the video compression standards such as MPEG-1, MPEG-2, H.261 and H.263 and stores a new reference image in the memory 8 via the selecting means 7. In addition, the compressor 10 transfers the compressed image via the second communication device 11 to the base station 5. At the base station 5, the first communication device 16 receives the compressed image and transferrs it to the decompressor 15. The selecting means 12 selects according to the address, the memory 13 in which a reference image is stored and the displaying device 6. The decompressor 15 decompresses the compressed image and merges it with the reference image. The result of the merging is the captured image which is then displayed on the displaying device 6.
In the preferred embodiment of the invention the image capture devices are video cameras, the memories 8, 9, 13 and 14 are frame memories wherein each memory contains one compressed image and the first communication device 11 and the second communication device 16 are radio device for transmitting images over the air.
An alternative to the use of a radio link embodiment is a physical communication line such as an optical fibre link.
7 Other embodiments which involve a combinations of types of image capture device with different types of communication devices are also possible.
The compression process will be described now with reference to FIG. 2. The compressor 10 loads a reference image 20 from the memory 8, compares the reference image 20 to a captured image 21 which was captured by the image capture device 3. The result of the comparison is a difference image 22. The difference image 22 is compressed and transferred by the second communication device 11, for example a radio device, to the base station 5. In addition, the compressor 10 stores the captured image 21 in the memory 8 and provides a new reference image.
The decompression process will be described now with reference to FIG. 3. The decompressor 15 loads a earlier stored reference image 23 from memory 14, decompresses the difference image 22, adds the difference image 22 to the earlier stored reference image 23 to form a new reference image 24 which is then stored at memory 14.
Thus, the communication system 1 operates according to a method that will now be explicitly described with reference to FIG. 4.
The method starts, of course, with step 100, providing the image cornmunication system 1 as earlier described.
The next step, step 102 which is performed at the remote station 2, is capturing an image by the image capture device 3. The captured image is manipulated by the compressor 10, as is shown in step 104. The manipulation method has also been described above with reference to FIG. 2. The result of the manipulation is a manipulated image which is the difference of a reference image which was stored at memory 8 and the captured image. The next step, step 105, is the transferring of the manipulated image.
The base station receives the manipulated image, step 106 and manipulates the received image to provide the captured image in step 108. A detailed description of the manipulation method by the decompressor 15 of the base station 5 was described above with reference to FIG. 3. The last step, step 110, is displaying the capture image on the displaying device 6.
8 Glaims 1. An apparatus for image compressing and or decompressing, comprising: an input operably coupled to plurality of image capture devices for capturing an image and for providing a captured image; a compressor operably coupled to the input for compressing the captured image and for providing a compressed image; a plurality of memories operably coupled to the compressor for storing the compressed image wherein each memory is related to a particular image capture device; which apparatus being characterised by a selecting means which, in use, selects at least one image capture device from the plurality of image capture devices; selects a first compressed image from a memory of the plurality of memories which is related to the selected image capture device; and providing a second compressed image to replace said first compressed image, wherein the second compressed image is a manipulation of the captured image with the first compressed image.
is 2. An apparatus as claimed in claim 1, wherein the number of the plurality memories is equal to the number the plurality of the image capture devices and each memory is related to a different image capture device.
3. An apparatus as claimed in any one of claim 1 or 2, wherein each memory contains one compressed image.
4. An apparatus as claimed in any one of claims 1,2 and 3, wherein the memory is a frame memory.
9 5. An apparatus as claimed in any one of claims 1,2,3 and 4, wherein the image capture device is a video camera.
6. An apparatus as claimed in any one of claims 1 to 5, wherein the 5 image capture device is a digital camera.
7. An apparatus as claimed in any one of claims 1 to 6 is an image compressor.
8. An apparatus as claimed in any one of claims 1 to 6 includes an image decompressor having an input operably coupled to a first communication device for receiving a received image from the compressor; and providing a reference image which stored at one of the plurality of memories which is a manipulation of the received image with the reference image.
9. An apparatus as claimed in any one of preceding claims, further comprises: a second communication device operably coupled to the compressor for transferring the compressed image.
10. An apparatus as claimed in claim 9, further characterised by: providing an address to each one of the compressed image transferred by the second communication device and to each one of the memories of the plurality of memories which are coupled to the decompressor; and directing the said compressed image to the addressed memory.
11. An apparatus as claimed in claims 9 or 10, wherein the first and the second communication devices are radio device for transmitting images over the air.
12. An apparatus as claimed in any one of the claims 9,10 or 11, 35 wherein the first and second communication devices are line communication device for transferring image over a physical communication line.
13. A method of compressing image, comprising the steps of. providing a plurality of image capture devices operably coupled to a compressor for capturing images; providing a plurality of memories operably coupled to the compressor for storing the captured images; selecting a memory and an image capture device for compressing 10 an image provided by the selected image capture device; and providing a compressed image to be stored at said selected memory, wherein said compressed image is a manipulation of a captured image with an earlier compressed image stored at the selected memory.
is 14. A method as claimed in claim 13, further comprises the steps of. providing a decompressor operably coupled to the plurality of memory; providing an address for each one of the memories; and 20 providing a selecting means for selecting a reference image stored at one of the memories according to a given address to be decompressed by the decompressor.
15. A method as claimed in any one of the claims 13 or 14, wherein 25 the selecting means further comprises: means for selecting an input capture device from the plurality of input capture device.
16. A method as claimed in any one of the claims 13,14 or 15, further 30 comprises the steps of. providing a first communication device operably coupled to the decompressor; providing a second communication device operably coupled to the compressor; 11 transferring the said compressed image from the second communication device to the first communication device; and decompressing the said compressed image according to the reference image having an addressed matched to the address provided by the said compressed image.
17. A method as claimed in any one of the claims 13 to 16, wherein the compressed image which is stored at any one of the memories is a difference between the captured image and a pre-stored compressed image.
18. A method as claimed in any one of the claims 13 to 16, wherein the reference image which is stored at the plurality of memories coupled to the decompressor is a manipulation of a compressed image received from the compressor and the reference compressed image.
19. A method as claimed in any one of the claims 13 to 18, wherein the first and the second communication device are radio transceivers.
20. A communication system for transferring image includes at least one remote station operably coupled to a plurality of image capture devices for capturing images and a base station operably coupled to at least one image displaying device for displaying an image captured by one of the image capture devices of the at least one remote station, wherein the at least one remote station characterised by: a selecting means operably coupled to a plurality of image capture devices and to a plurality of memories; a compressor operably coupled to the selecting means and to a second communication device for compressing a captured image which was captured by one of the image capture devices of the remote station ant to provide a compress image which is stored at a selected memory; and transferring the compressed image to the base station to be display on the at least one displaying device.
12 - v 21. A communication system as claimed in claim 20, wherein the base station is characterised by: a selecting means operably coupled to at least one displaying device and to a plurality of memories; a decompressor operably coupled to the selecting means and to a first communication device for decompressing the compressed image transferred by the remote station with reference to a reference image which is stored at a selected memory.
22. A communication system as claimed in claims 20 and 21, wherein the compressed image comprises a differences of the captured image and a prestored compressed image.
23. A communication system as claimed in any one of the claims 20, 21 and 22, wherein the reference image is an addition of a pre-stored reference image to the compressed image.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9813097A GB2338619A (en) | 1998-06-18 | 1998-06-18 | Apparatus and method for transmitting a compressed image |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9813097A GB2338619A (en) | 1998-06-18 | 1998-06-18 | Apparatus and method for transmitting a compressed image |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9813097D0 GB9813097D0 (en) | 1998-08-19 |
| GB2338619A true GB2338619A (en) | 1999-12-22 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9813097A Withdrawn GB2338619A (en) | 1998-06-18 | 1998-06-18 | Apparatus and method for transmitting a compressed image |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2338619A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1439162A (en) * | 1972-07-19 | 1976-06-09 | Fujitsu Ltd | Video signal transmission and reception systems |
| EP0637892A2 (en) * | 1993-08-05 | 1995-02-08 | Matsushita Electric Industrial Co., Ltd. | System and method for transmitting images at high efficiency |
-
1998
- 1998-06-18 GB GB9813097A patent/GB2338619A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1439162A (en) * | 1972-07-19 | 1976-06-09 | Fujitsu Ltd | Video signal transmission and reception systems |
| EP0637892A2 (en) * | 1993-08-05 | 1995-02-08 | Matsushita Electric Industrial Co., Ltd. | System and method for transmitting images at high efficiency |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9813097D0 (en) | 1998-08-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |