Abstract: The horizontal and vertical offset for the M×N DCT block boundaries are determined for a decompressed image originally produced by a DCT-based compression system, regardless of the amount of compression and/or cropping that had been applied to the image.

Abstract: A method for authenticating animation, the method comprises the steps of capturing an image; converting the captured image into a wire mesh data for permitting animation of the image; providing movement data, which directs movement of the wire mesh data, and texture data indicating the covering for the wire mesh; electronically transmitting the wire mesh data, texture data and movement data; encrypting the movement data; and electronically transmitting the encryption the movement data for verifying that the animation is unaltered during transmission from its source.

Abstract: A method for embedding message data in a digital image sequence having two or more frames, includes the steps of: providing a dispersed message image representative of the message data; and adding spatially shifted versions of the dispersed message image to successive frames of the digital image sequence.

Abstract: An efficient method for determining the compressed rate of a digital image with a given set of compression parameters, the method comprises the steps of forming a plurality of non-overlapping image regions, each of which includes a plurality of contiguous pixels, from the digital image where the total number of pixels contained in all of the contiguous regions is less than the total pixels in the digital image; compressing each region with the given set of compression parameters; and, combining the resulting rate from each region to form an estimate of the compressed rate of the digital image.

Abstract: A method of generating a plurality of quantization parameter sets for compressing a digital image to different rates, the method comprises the steps of providing characteristics of an intended display medium; specifying a plurality of threshold viewing distances from the display medium; generating a plurality of quantization parameter sets, one for each threshold viewing distance, using a human visual system model; and, indexing each quantization parameter set by the corresponding threshold viewing distance.

Abstract: A method for compressing a digital image having both saturated text and/or line art and pictorial imagery, the method comprises the steps of: receiving the digital image as blocks of pixels; analyzing the block content to determine if all or any combination of the saturated text and/or line art, pictorial imagery or other types of image data are present; assigning the saturated text and/or line art, the pictorial imagery, the other types of image data to one of a plurality of categories; compressing the block of saturated text and/or line art, if any, according to a first predetermined compression method; compressing the pictorial imagery, if any, according to a second predetermined compression method; compressing the other types of imagery, if any, according to other predetermined compression methods; and providing means of conveying the image categories to a decoder.

Abstract: The method and system embeds digital meta-data into an original image in such a way that the meta-data can be completely removed at a later time to allow loss less recovery of the original image. The loss less recovery of the original image allows for a digital signature of the image to be embedded in the image itself and later recovered and used to verify the authenticity of a received image.

Abstract: A method selecting a quality parameter for use in compressing a digital image, the method comprises the steps of creating a plurality of quantizer parameter sets, each having a corresponding quality parameter; compressing the digital image with the plurality of quantizer parameter sets for providing a corresponding plurality of compressed file sizes; creating a rate-distortion curve from the plurality of quantizer parameter sets and the corresponding compressed file sizes; providing a maximum and minimum quality parameters; providing a target compressed file size; and selecting a quality parameter based on the rate distortion curve, the maximum and minimum quality parameters and the target compressed file size.

Abstract: A message is embedded into a digital image by forming a digitized version of the message and convolving the digitized message with a random phase carrier to form a scrambled message. The scrambled message is then combined with the digital image to form an embedded message image that is near impossible to extract without knowledge of the formation of the random phase carrier.

Abstract: A frame in an uncompressed digital video signal is selected for encoding as a high-fidelity still image. The digital video signal is MPEG encoded to produce an MPEG encoded bitstream and additional bits are employed to encode the selected frame, to produce the MPEG encoded bitstream. The additional bits are determined by fixing the values of MQUANT and "intra DC mult" for all macroblocks in the selected frame. In an alternative method, the extra bits are determined by repeating the selected frame a plurality of times in the digital video signal prior to encoding the selected frame.

Abstract: A method for encoding color image data of the type having multiple color planes for a printer that prints the color planes in a given sequence includes the steps of: compressing the image data in the last color plane in the printing sequence and storing the resulting compressed data; using information relating to the image data in the previous color plane(s) to predict the image data in the next color plane to be printed; forming difference image data between the image data in the next color plane to be printed and the predicted image data for that color plane; and compressing the difference image data and storing the resulting compressed data. These steps are repeated until the image data for all of the color planes have been compressed and stored.

Abstract: A public key encryption system for authenticating an image includes a digital camera having embedded therein a private key unique to the digital camera. A known public key uniquely based upon the private key is used to decrypt digital data encrypted with the private key to establish authenticity of the image. The encryption system further comprises means for generating one or more patterns each composed of at least one individual area that is visible together with the image of the object, means for designating at least one individual area as an active area of the image suitable for authentication and for generating location data identifying the active area, and means for calculating image hash from image data of the active area of the image using a predetermined hash algorithm.

Abstract: A secure photographic system includes: a photographic film bearing an image and indicia representing a desired digital image security feature relating to the image; a scanner for scanning the image on the film to generate a digital image; means for detecting the indicia on the film to generate a security feature control signal; and digital image processing means responsive to the security feature control signal and the digital image for applying the desired digital image security feature to the digital image.

Abstract: An improved method for removing blocking artifacts in regions of slowly varying intensity in an electronic image decoded from a transform coded representation of an image, includes the steps of: receiving signals indicative of DC and AC coefficient values of transformed blocks of image data; modifying the DC value in each of the blocks based on the level of activity within the block and the DC values in neighboring blocks; performing AC prediction in each block using the modified DC values; replacing the AC values in each block with the AC predicted values based on the level of activity within the block and the modified DC values in neighboring blocks; and reconstructing the image using the modified DC and AC coefficient values.

Abstract: The system and method reduces the quantization artifacts in the addition and removal of a digital watermark to and from a selected resolution image of a hierarchical image storage system where the watermark removal record is placed in a higher resolution image component. For those applications where preserving the image quality of a higher resolution image component is more critical than preserving the image quality of a lower resolution image component, the low-resolution image is modified according to the teachings of the present invention to minimize and in many cases eliminate the quantization artifacts at the higher resolution component.

Abstract: An encoding method is described for image bitplanes whereby an arithmetic coder using conditioning contexts based on pixels from both the current bitplane and previously decoded bitplanes is employed. For the same number of contexts (which is important for minimizing memory usage), the method provides for higher compression than those methods based on a single bitplane context. An additional improvement over the prior art is that the method eliminates the need to form a Gray code bit plane representation, as is commonly done to reduce the correlation among bit planes. However, if used on conjunction with the gray code, a small improvement in compression performance will still be realized.

Abstract: An electronic camera is disclosed that employs a color transformation stage 14 for transforming primary color signals into luminance and chrominance signals. The luminance signal is subjected to a lossy compression in the compression stage 16a, and then decoded in the decompression stage 32 to generate a feedback signal having lossy artifacts. The feedback signal is used in the generation of the chrominance signals prior to their compression, which causes the later-reconstructed chrominance signals to have fewer artifacts due to the compression algorithm.

Abstract: In accordance with the present invention, the R,G,B color image signals from a single sensor having a color filter array are all transformed to .GAMMA.-space by changing them to R.sup.1/.GAMMA., G.sup.1/.GAMMA., B.sup.1/.GAMMA., respectively, where .GAMMA. is approximately 2.4. In this space, all operations such as color differencing, interpolation of those missing pixels required for color differencing, compression, decompression, edge enhancement and final interpolation of all missing pixels are performed without further transformation of the image signals. For the same final bit rate, noise in the reproduced image is reduced by refraining from interpolating the missing color pixels prior to compression of the image data.

Abstract: The method of the present invention operates upon the imaging signals from a color filter array image sensor to compress the image signals prior to color interpolation by separating the signals into three color planes. Missing green pixels are recovered through interpolation methods, either by bilinear or other techniques, in order to form color ratio signals long B/G.sub.missing and log R/G.sub.missing which allows for proper interpolation after decompression without color artifacts. Upon playback or reception, an inverse compression is applied and missing green, red and blue pixels are interpolated to provide three full planes of color image data.

Abstract: The method of the present invention operates upon the imaging signals from a color filter array image sensor to compress the image signals prior to color interpolation by separating the signals into three color planes. Missing green pixels are recovered through interpolation methods, either by bilinear or other techniques, in order to form color ratio signals log B/G.sub.missing and log R/G.sub.missing which allows for proper interpolation after decompression without color artifacts. Upon playback or reception, an inverse compression is applied and missing green, red and blue pixels are interpolated to provide three full planes of color image data.