Image transmission system with preview mode

Claim 2

A still image communication system of the type having means at the transmitter for performing a block cosine transformation on an image for bandwidth compression, means at the receiver for displaying a low resolution preview image during transmission of a full resolution image, and means at the receiver for terminating transmission of the image, characterized by: means at the transmitter for subsampling a full resolution image to produce the low resolution preview image, and for compressing and transmitting the low resolution preview image, followed by the full resolution image; and means at the receiver for displaying the low resolution image, and replacing the low resolution image block-by-block with the full resolution image as the full resolution image is received.

Claim 3

The still image communication system claimed in claim 1, further characterized by: control means at the transmitter for selectively operating the transmitter in a preview mode where only the preview image is transmitted.

Claim 4

The still image communication system claimed in claim 2, wherein the image is a color image having a full resolution luminance component and a chrominance component, and further characterized by: a. the means at the transmitter for subsampling, compressing, and transmitting the image, subsamples the luminance component to produce a low resolution preview luminance component, and compresses and transmits, in order, the low resolution preview luminance component, the chrominance component, and the full resolution luminance component; and b. the means at the receiver displays the low resolution preview luminance component, adds the chrominance component block-by-block to the low resolution luminance component, and replaces block-by-block the low resolution luminance component with the full resolution luminance component.

Claim 5

The color still image communication system claimed in claim 3, wherein the full resolution luminance component of the image is a 512×512 array of luminance (Y) values, the chrominance component is a 128×128 array of red minus luminance (R-Y) values and a 128×128 array of blue minus luminance (B-Y) values, and the low resolution preview luminance component is a 128×128 array of luminance values.

Claim 6

A communication system for communicating a full resolution digital image over a limited bandwidth communication channel, comprising: a. means for compressing and transmitting a digital image, including; (1) means for subsampling said full resolution digital image to produce a low resolution preview image, (2) means for compressing said preview image or said full resolution by block cosine transformation and Huffman and run-length coding of transform coefficients, (3) means for transmitting a compressed image block-by-block, and (4) transmitter control means operative in a preview mode for affecting compression and transmission of said preview image and operative in a full resolution mode for effecting compression and transmission of said preview image followed by said full resolution image, and responsive to a terminate transmission signal for terminating transmission of an image, and b. receiver means for receiving, expanding, and displaying a digital image including; (1) means for receiving a compressed image, block-by-block, (2) means for expanding a received image block-by-block, (3) means for displaying an expanded image block-by-block, (4) control means for affecting display of a preview image, and for replacing said preview image on said display means with a full resolution image block-by-block, as said full resolution image is received, and (5) means responsive to an operator input for generating and transmitting a terminate transmission signal.

Claim 7

A communication system for communicating a full resolution digital image over a limited bandwidth communication channel, comprising: a. means for compressing and transmitting a digital image, including; (1) means for subsampling said full resolution digital image to produce a low resolution preview image, (2) means for compressing said preview image or said full resolution by block cosine transformation and Huffman and run-length coding of transform coefficients, (3) means for transmitting a compressed image block-by-block, and (4) transmitter control means operative in a preview mode for affecting compression and transmission of said preview image and operative in a full resolution mode for effecting compression and transmission of said preview image followed by said full resolution image, and responsive to a terminate transmission signal for terminating transmission of an image, and b. receiver means for receiving, expanding, and displaying a digital image including; (1) means for receiving a compressed image, block-by-block, (2) means for expanding a received image block-by-block, (3) means for displaying an expanded image block-by-block, (4) control means for affecting display of a preview image, and for replacing said preview image on said display means with a full resolution image block-by-block, as said full resolution image is received, and (5) means responsive to an operator input for generating and transmitting a terminate transmission signal.

Claim 8

The communication system claimed in claim 5 wherein said full resolution digital image is a color digital image having a full resolution luminance component, and a chrominance component; said means for subsampling said image, subsamples said full resolution luminance component to produce a low resolution preview luminance component; said means for compressing, compresses said luminance component, and said chrominance component; said transmitter control means operates in said preview mode to compress and transmit a preview luminance component and said chrominance sequentially; and said control means operates in said full resolution mode to compress and transmit said preview luminance component, said chrominance component, and said full resolution luminance component sequentially; and said receiver control means effects display of said low resolution preview luminance component, adds said chrominance component block-by-block to said preview luminance component to produce a low resolution color preview image, and replaces said low resolution preview-luminance component block-by-block with said full resolution luminance component.

Claim 9

The communication system claimed in claim 6 wherein said full resolution luminance component is a 512×512 array of luminance (Y) values, said chrominance component is 128×128 array or red minus luminance (R-Y) values and 128×128 array of blue minus luminance (B-Y) values and said means for subsampling said image subsamples saaid array of luminance component values to an array of 128×128 luminance values.