Method and appartus for increasing resolution of digital color images using correlated decoding

A decoder capable of decoding a multi-spectral image wherein said multi-spectral image is represented as a spatially multiplexed image plane comprising:

• an image store capable of capturing the multi-spectral image as a single spatially-multiplexed digitized image plane, said image plane comprising at each pixel location a representation of a single spectral component;
• a processor comprising:
• an image expander capable of expanding said spatially-multiplexed digitized image plane into a plurality of separable component planes, said separable component planes initially comprised of a plurality of pixels of known value and a plurality of pixels with missing values;
• a pixel correlater capable of determining a missing pixel value in one of said plurality of component planes wherein said missing pixel value is set so that a first difference value between said missing pixel value and a local average value in one of said reconstructed separable planes is correlated to a second difference value between a known pixel value at a corresponding pixel location in a different reconstructed plane and a local average in said different reconstructed plane;
• and
• an image combiner/driver capable of combining said reconstructed separable planes into a composite visual image.

An apparatus for decoding a multi-spectral image wherein said multi-spectral image is represented as a spatially multiplexed image plane comprising:

• means for capturing the multi-spectral image as a single spatially-multiplexer digitized image plane, said image plane comprising at each pixel location a representation of a single spectral component;
• means for expanding said spatially-multiplexed digitized image plane into a plurality of separable component planes, said separable component planes initially comprised of a plurality of pixels of known value and a plurality of pixels with missing values;
• correlated decoding means capable of determining a missing pixel value in one of said plurality of component planes wherein said missing pixel value is set so that a first difference value between said missing pixel value and a local average value in one of said reconstructed separable planes is correlated to a second difference value between a known pixel value at a corresponding pixel location in a different reconstructed plane and a local average in said different reconstructed plane;
• and
• means for presenting said plurality of reconstructed separable planes as a visual image.

A method for increasing the pixel density of a multi-spectral image comprising:

• capturing a multi-spectral image in at least two separable digitized planes suited to be combined to form said multi-spectral image, said separable planes comprising known and missing pixel values;
• decoding said separable planes by a method of correlated decoding comprising setting a missing pixel value so that a first difference value between said missing pixel value and a local average value in one of said separable planes is correlated to a second difference value between a known pixel value at a corresponding pixel location in a different separable plane and a local average in said different separable plane;
• combining said separable planes after decoding to produce a multi-spectral image with increased pixel density from said captured multi-spectral image;
• and
• presenting said multi-spectral image with increased pixel density.

In a digital camera comprising a plurality of spectral sensors, each sensor comprised of an array of pixel detectors, a method for enhancing image resolution comprising:

• offsetting each sensor a fraction of a pixel in a lateral direction from each other sensor;
• capturing a multi-spectral image in at least two separable digitized planes using said offset sensors, said separable digitized planes having a number of pixel storage locations greater than the number of pixel detectors in said sensors, said separable planes only partially filled by pixel values from said sensors;
• determining missing pixel values in said separable planes by a method of correlated decoding comprising setting a missing pixel value so that a first difference value between said missing pixel value and a local average value in one of said separable planes is correlated to a second difference value between a known pixel value at a corresponding pixel location in a different separable plane and a local average in said different separable plane;
• and
• presenting said plurality of reconstructed planes as a visual image whereby said visual image has enhanced image resolution from that achievable with non-offset sensors of the same pixel density.

An apparatus for increasing the pixel density of a multi-spectral image comprising:

• means for capturing the multi-spectral image in at least two captured planes of digitized separable multi-spectral components;
• averaging means coupled to said image capturing means for determining local average digital values in one of said planes thereby creating an averaged plane;
• selecting means coupled to said averaging means and to said image capturing means for spatially multiplexing said captured plane values and said average plane values in order to generate a single-plane spatially-multiplexed digital plane such that said spatially-multiplexed digital plane contains, at each pixel location, a pixel value from one of said captured planes or from said averaged plane;
• means for expanding said spatially-multiplexed digitized image plane into a plurality of expanded component planes, said expanded component planes initially comprised of a plurality of pixels of known value and a plurality of pixels with missing values;
• correlated decoding means capable of determining a missing pixel value in one of said plurality of component planes wherein said missing pixel value is set so that a first difference value between said missing pixel value and a local average value in one of said reconstructed separable planes is correlated to a second difference value between a known pixel value at a corresponding pixel location in a different reconstructed plane and a local average in said different reconstructed plane;
• and
• means for presenting said plurality of reconstructed separable planes as a visual image.

A camera system with enhanced resolution comprising:

• a plurality of spectral component sensors, each sensor comprising an array of pixel detectors;
• an image splitter capable of splitting spectral energy from an image source such that said spectral energy reaches each of said spectral component sensors, said sensors and said image splitter arranged so that spectral energy falling on at least one such sensor is offset a fraction of a pixel from the spectral energy falling on another such sensor;
• and
• a decoder capable of decoding digital pixel information generated by said offset component sensors using a method of correlated decoding whereby resolution is enhanced in at least one spectral component plane by correlating the difference between an interstitial pixel value in said plane and a local average value in said plane to a second difference value in a second spectral component plane said second difference being the difference between a known pixel value at that location in said second plane and a local average in said second plane.

A camera system with enhanced resolution comprising:

• a plurality of spectral component sensors, each sensor comprising an array of pixel detectors, one sensor being a red sensor, one sensor being a green sensor, and one sensor being a blue sensor;
• an image splitter capable of splitting light from an image source such that said light reaches each of said spectral component sensors, said sensors and said image splitter arranged so that spectral energy falling on at least one such sensor is offset a fraction of a pixel from the spectral energy falling on another such sensor;
• a pixel memory capable of storing pixel information from said sensors and capable of holding a representation of said image comprising for at least one spectral component a number of pixels that is a multiple of the number of pixels in said sensor array said pixel memory being only partly filled by data from said component sensors;
• a decoder capable of decoding digital pixel information generated by said component sensors using a method of correlated decoding whereby resolution is enhanced in at least one spectral component plane by correlating the difference between an interstitial pixel value in said plane and a local average value in said plane to a second difference value in a second spectral component plane said second difference being the difference between a known pixel value at the interstitial location in said second plane and a local average value in said second plane.

A method for enhancing image resolution in a digital camera comprising a plurality of spectral sensors, each sensor comprised of an array of pixel detectors, comprising:

• offsetting laterally each sensor a fraction of a pixel from each other sensor;
• capturing a multi-spectral image in three separable digitized planes, a red plane, a green plane, and a blue plane, using said offset sensors, said separable digitized planes having a pixel size that is a fraction of the pixel size of said sensors, said separable planes only partially filled by pixel values from said sensors;
• producing at least a fourth separable digitized image plane from one of said red, blue, or green planes, said fourth plane comprising a pixel value at each pixel location that corresponds to a location where there is no detected red, green, or blue value;
• determining missing pixel values in said separable planes by a method of correlated decoding comprising setting a missing pixel value so that a first difference value between said missing pixel value and a local average value in one of said separable planes is correlated at least to a second difference value between a known pixel value at a corresponding pixel location in a different separable plane and a local average in said different separable plane;
• and
• presenting said plurality of reconstructed planes as a visual image whereby said visual image has enhanced resolution from that obtainable from a digital camera with the same size pixel detectors not employing said capturing, said offsetting, said producing, and said determining steps.