Imaging apparatus, imaging circuit and imaging method

An imaging circuit for taking an image, said imaging circuit having a structure created on a single chip as a structure comprising:

• a solid-state imaging sensor configured to convert incoming light into an electrical imaging analog signal;
• an analog-to-digital conversion circuit configured to convert said electrical imaging analog signal generated by said solid-state imaging sensor into a digital image signal;
• and
• a compression circuit configured to compress said digital image signal, which is generated by said analog-to-digital conversion circuit, by dividing said digital image signal into blocks each composed of a fixed number of same color component pixels adjacent to each other and taking each of said blocks as a unit of compression,
• wherein each of said blocks is split in advance into two quantization-subject areas each composed of one or more pixels adjacent to each other,
• a plurality of block types are defined in advance for each of said blocks,
• said block types defined for any individual one of said blocks are distinguished from each other by the position of the inter-area boundary between said two quantization-subject areas in said individual block, and
• said compression circuit has
• a dynamic-range computation section configured to compute a dynamic range of pixel data of pixels in each of said quantization-subject areas for each of said quantization-subject areas in each of said blocks,
• a block-type select section configured to compute a sum of said dynamic ranges, which are each computed by said dynamic-range computation section for one of said quantization-subject areas in any individual one of said blocks, for each of said block types defined for said individual block on the assumption that each of said block types has been selected for said individual block and to select said block type having a smallest sum of said dynamic ranges among all said block types defined for said individual block as a proper block type for said individual block, and
• a quantization processing section configured to quantize a difference, which is obtained as a result of subtracting the smallest pixel data among all pixels in any individual one of said quantization-subject areas from the pixel data of each of said pixels in said individual quantization-subject area, in accordance with said dynamic range, which is computed by said dynamic-range computation section for said individual quantization-subject area, for every pixel in said quantization-subject areas which are included in any individual one of said blocks as quantization-subject areas having an inter-area boundary conforming to said proper block type selected by said block-type select section for said individual block.

An imaging method for taking an image by making use of a solid-state imaging sensor, said imaging method comprising:

• compressing, performed by a compression section, image data, which is generated by said solid-state imaging sensor as a result of an imaging process, by dividing said image data into blocks each composed of a fixed number of same color component pixels adjacent to each other and by taking each of said blocks as a unit of compression and storing compressed image data obtained as a result of said compression process;
• decompressing, performed by a decompression section, compressed image data read out from said memory;
• and
• correcting, performed by a signal processing section, image-quality of decompressed image data produced by said decompression section,
• wherein each of said blocks is split in advance into two quantization-subject areas each composed of one or more pixels adjacent to each other,
• a plurality of block types are defined in advance for each of said blocks,
• said block types defined for any individual one of said blocks are distinguished from each other by the position of the inter-area boundary between said two quantization-subject areas in said individual block, and
• said compression step is carried out by executing the steps of
• computing a dynamic range of pixel data of pixels in each of said quantization-subject areas for each of said quantization-subject areas in each of said blocks,
• computing a sum of said dynamic ranges, which are each computed at said dynamic-range computation sub-step for one of said quantization-subject areas in any individual one of said blocks, for each of said block types defined for said individual block on the assumption that each of said block types has been selected for said individual block and selecting said block type having a smallest sum of said dynamic ranges among all said block types defined for said individual block as a proper block type for said individual block, and
• quantizing a difference, which is obtained as a result of subtracting the smallest pixel data among all pixels in any individual one of said quantization-subject areas from the pixel data of each of said pixels in said individual quantization-subject area, in accordance with said dynamic range, which is computed at said dynamic-range computation sub-step for said individual quantization-subject area, for every pixel in said quantization-subject areas which are included in any individual one of said blocks as quantization-subject areas having an inter-area boundary conforming to said proper block type selected at said block-type select sub-step for said individual block.