Signal processing apparatus, signal processing method, program, and storage medium employing random number generation
AssigneeCanon Kabushiki Kaisha
InventorYusuke Shirakawa
Life of this patent
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Abstract
An object of this invention is to prevent an increase in image data while preventing degradation of the image quality caused by an image process in a digital image processing system. To achieve this object, a signal processing apparatus which quantizes pixel values within a pixel area having M (M is an integer of 2 or more) pixels into data of 2N steps by N bits (N is a positive integer) expresses a decimal part of data in the entire pixel area by increasing or decreasing by one a predetermined number of pixel values among the M pixels on the basis of the decimal part of the data in the entire pixel area.
Claims5
A signal processing apparatus comprising:
- an image sensing element which senses an object image;
- a random number generating unit which generates, from lower bits of data of input pixel values, random numbers;
- and
- a digital clamping circuit which digitally clamps a signal from a photoelectric conversion portion of an area not shielded from light, on the basis of a signal from a photoelectrical conversion portion of a light-shielded area of said image sensing element,
- wherein a clamping level is calculated at a precision higher than a quantization step of image data, and
- one quantization step is subtracted from each pixel data of target pixels selected in accordance with a probability corresponding to data of the clamping level that is lower than the quantization step and the random numbers generated by said random number generating unit.
A signal processing method of calculating a clamping level at a precision higher than a quantization step of image data, wherein one quantization step is subtracted from each pixel data of target pixels selected in accordance with a probability corresponding to data of the clamping level that is lower than the quantization step and random numbers generated by a random number generating unit, wherein the random number generating unit generates, from lower bits of data of input pixel values, the random numbers.
Dependencies are inferred from the claim text.