Compression method and apparatus for single-sensor color imaging systems
First Claim
Patent Images
1. A color imaging apparatus, comprising:
- an electronic camera, said electronic camera comprised of;
image sensing means having a discrete array of image sensing elements each representing a pixel of image data, said image sensing elements each providing an analog output signal value indicative of the intensity of incident light sensed thereby;
a color filter pattern means for separating an incident light beam into at least three different colors;
means for converting the sensor analog output signal values into digital signal values;
means for separating and forming the digital signal values into a plurality of signals according to the color of the pixels represented by the digital signal values;
means for processing and compressing the plurality of signals including means for forming interpolated values for at least one of said color signals at the same positions as the pixels of a second of said color signals;
means for digitally recording or transmitting the compressed color signals;
a playback device, said playback device comprised of;
means for recovering the recorded or transmitted compressed color signals;
means for decompressing the compressed color signals;
means for interpolating the missing colored pixel values from the decompressed color signals; and
means for interfacing the interpolated color image to a device for displaying or printing the image.
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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/Gmissing and log R/Gmissing 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.
42 Citations
15 Claims
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1. A color imaging apparatus, comprising:
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an electronic camera, said electronic camera comprised of; image sensing means having a discrete array of image sensing elements each representing a pixel of image data, said image sensing elements each providing an analog output signal value indicative of the intensity of incident light sensed thereby; a color filter pattern means for separating an incident light beam into at least three different colors; means for converting the sensor analog output signal values into digital signal values; means for separating and forming the digital signal values into a plurality of signals according to the color of the pixels represented by the digital signal values; means for processing and compressing the plurality of signals including means for forming interpolated values for at least one of said color signals at the same positions as the pixels of a second of said color signals; means for digitally recording or transmitting the compressed color signals;
a playback device, said playback device comprised of;means for recovering the recorded or transmitted compressed color signals; means for decompressing the compressed color signals; means for interpolating the missing colored pixel values from the decompressed color signals; and means for interfacing the interpolated color image to a device for displaying or printing the image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 13, 14, 15)
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8. A color imaging apparatus comprising:
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a color image sensor for providing an output signal; means for separating the sensor output signal into at least three signals according to color; means for preprocessing at least two of said signals prior to data compression wherein said preprocessing means operates on at least two of said signals to form at least one preprocessed signal which is a function of interpolated signal values computed using one of said color signals; data compression means for compressing the preprocessed signals; means for storing or transmitting the compressed signals; means for decompressing the compressed color signals; and means for interpolating the missing colored pixels from the decompressed color signals. - View Dependent Claims (9, 10, 11)
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12. A color imaging apparatus comprising:
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a color image sensor for providing an output signal; means for digitizing the sensor output signal; means for separating the digitized sensor output signal into at least three signals wherein one signal is a highly sampled luminance and the remainder are sparsely sampled color signals formed as the ratio of a color pixel to an interpolated luminance pixel corresponding to the same spatial position as the said colored pixel; means for preprocessing at least two of said signals prior to data compression; data compression means for compressing each signal; means for storing or transmitting the compressed signals; means for decompressing the compressed color signals; means for interpolating the missing colored pixels from the decompressed color signals; and means for interfacing the interpolated color image to a device for displaying or printing the image.
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Specification