Image analysis – Image compression or coding
Reexamination Certificate
2000-10-06
2004-09-14
Johns, Andrew W. (Department: 2621)
Image analysis
Image compression or coding
C345S211000
Reexamination Certificate
active
06792148
ABSTRACT:
BACKGROUND
The present invention relates to wireless communications. In particular, the present invention relates to a camera accessory for use with a mobile station in a wireless radiocommunication system.
The ability to conduct a telephone conversation while providing the participants with the ability to view each other is now and has been unquestionably desirable in a wide variety of situations. Advances in wireless telecommunications has made video phone communications more plausible as bandwidth increases and users demand an increasing array of features.
Prior art video phone technology exists, but has generally required expensive equipment and has required channels with wider than normal bandwidth. Providing video phone capabilities over standard telephone channels remains challenging due to the large amount of data generated by a typical image data channel. In order to provide realistic full motion live digital video, for example, it is generally accepted that at least 30 frames per second or the equivalent thereof be transmitted. A single uncompressed digital image having a typical frame size of 640×480 pixels and 3 colors components per pixel, e.g. RGB, requires a capability to process approximately 1 Megabyte of data per frame or roughly 30 Megabytes of data per second. Some systems use intraframe and interframe compression schemes to reduce the amount of data generated while preserving an effective 30 frames per second however, such systems often rely on motion based compression and are compromised when motion becomes excessive. In addition, such systems are often completely integrated and cannot interface with, for example, an external camera device.
Meanwhile, advances in modern digital cameras yields cameras equipped with extensive processing capabilities, capable of providing high quality high resolution digital images. Such cameras are typically equipped with high resolution color LCD displays, image processing circuitry and the like. However problems arise when expensive features associated with high end digital cameras are not needed, as when operating as an accessory in a telephonic system.
On the other end of the spectrum, a wide variety of simple CCD cameras exist which generate a raw video signal and may contain basic image processing such as, for example, frame grabbing or the like but fail to contain any further processing. One of the primary disadvantages associated with this type of system is that the processing required for practical image transfer on a limited channel resource, e.g. compression, encoding, decoding must be performed by the mobile terminal. Especially troublesome from a cost standpoint is the prospect of making the processing power available in the mobile terminal but having it remain unused if the user does not elect to use a camera.
In anticipation of an ever increasing demand for image transfer capabilities in the telephone network, some important standards have emerged. For example, the International Telecommunications Union (ITU) has developed a Common Intermediate Format (CIF) for image transfer as an optional part of the ITU-T's H.261 and H.263 standards. CIF specifies 288 non-interlaced luminance lines, containing 352 pixels. CIF specifies frame rates of 7.5, 10, 15, or 30 per second. When providing CIF compliant video, the number of resulting bits cannot exceed 256 K bits (where K equals 1024). The following table provides a summary:
Videoconferencing
Image resolution
Picture Format
In Pixels
H.261
H.263
SQCIF (Sub-QCIF)
128 × 96
N/A
Required
QCIF
176 × 44
Required
Required
CIF
352 × 288
Optional
Optional
4CIF
702 × 576
N/A
Optional
It should be noted that the ITU has been in existence since the 1800s and originated to standardize telegraphic communications and had traditionally be concerned with wired communications. Accordingly, the above standards were developed to facilitate the transfer of images over wired networks.
Modern wireless mobile terminals on the other hand are presently equipped with an increasing array of features and are incorporating better display technology to facilitate, for example, Internet accessibility. Simultaneously, as the ability to conduct, for example, video conferencing is enhanced by the emergence of the wireless Internet, no satisfactory prior art system is availably to allow widespread video conferencing or still image transfer from, for example, a mobile terminal.
Problems arise in that systems which provide video conferencing are generally expensive or fail to provide easy integration with existing mobile terminal hardware. In addition, such systems are bulky and diminish the portability related advantages provided by ever decreasing form factors associated with modern mobile terminals. Such a system is described in U.S. Pat. No. 5,550,754 to McNelley, et al. Therein a teleconferencing camcorder or telecamcorder is described wherein a video camera can produce images which can be recorded on a video tape or provided in a videoconferencing mode. The device can connect with a network and can display images on a built in display. McNelly's device however suffers drawbacks including bulkiness and an abundance of features which are unnecessary. McNelly's system further fails to fully develop compression concepts which are essential to modern digital image and video processing.
In U.S. Pat. No. 5,491,507 to Umezawa et al, video telephone equipment is described wherein a user may transmit and receive pictures and speech from a unit which can be held in one hand. A camera is permanently mounted to the casing which camera can alter its angle. However, Umezawa is directed primarily to packaging and fails to disclose detailed features, such as compression, involving the operation of the video telephone in a wireless radiocommunication system.
In still other systems, such as that described in Yuyama et al, where a portable compact imaging and displaying apparatus is provided, many features are integrated into a single unit or apparatus raising the costs associated with the unit. In addition, drawbacks exist in that it is not possible to use the camera section as an accessory and further limitations exist in providing, for example, compression features sufficient to allow ultimate transfer in a wireless radiocommunication system. Instead, Yuyama et al described how images may be transferred over a telephone line after establishing a connection using a conventional POTS style off-hook and connection sequence.
Thus, it can be seen that while digital cameras and even videophones exist and may be exploitable for teleconferencing and the like, the difficulty posed by, for example, providing a camera accessory to a mobile terminal in a wireless radiocommunication system remains unaddressed.
It would be appreciated in the art therefore for a method and apparatus for providing a camera accessory for a mobile terminal in a wireless radiocommunication system. Such a system could provide still and live motion video images over an air interface without the need for expensive digital cameras or videoconferencing systems.
It would further be appreciated in the art for a method and apparatus which would provide, for example, the ability to provide a camera accessory which would not require expensive display or battery technology.
SUMMARY
To fulfill the needs of the art, a method and apparatus for providing a camera accessory including compression is described.
Thus in accordance with various exemplary embodiments of the present invention, a camera accessory is provided which camera accessory may be detachably coupled to a wireless mobile terminal associated with a wireless radiocommunication system. Such a detachable coupling may be by various means, such as, for example, mechanical attachments as will be described in greater detail hereinafter. The wireless mobile terminal may further include an image data interface and, as described, a physical or mechanical interface for detachably coupling the camera accessory thereto. Accordingly, one or more frames of im
Bengtsson Henrik
Carlsson Torsten
Gustafsson Kjell
Hollström Magnus
Lennartsson Ola
Burns Doane Swecker & Mathis L.L.P.
Johns Andrew W.
Nakhjavan Shervin
Telefonaktiebolaget LM Ericsson (publ)
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