A-D converter
AssigneeCanon Kabushiki Kaisha
InventorsTsutomu Takayama, Kan Takaiwa
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Abstract
An A-D converter of an image signal comprises a weighing circuit for performing a different weighing for each quantization step of A/D conversion. The different weighing is performed in accordance with gamma or white compression characteristics of the image signal.
Claims14
An analog to digital converter comprising quantizing means for quantizing an image signal in quantization steps according to the level of the image signal, weighting means for selectively weighting each of the quantization steps, and a digital decoder for producing digital signals corresponding to outputs from the quantizing means,
- wherein said weighting means if structured and arranged to set a weight for each of the quantization steps in accordance with a gamma characteristic and a white compression characteristic of the image signal.
An A/D converter comprising:
- (a) quantizing means for quantizing an analog input signal by predetermined quantization steps, and
- (b) quantization step setting means for setting up the quantization steps,
- wherein weighting of the quantization steps is in successively changing order, and
- wherein the quantization steps for which weighting is performed comprise a portion corresponding to gamma characteristics of an input image signal and a portion corresponding to white compression characteristics.
An image signal processor comprising quantizing means for quantizing an image signal in quantization steps according to the level of the image signal and weighting means for weighting said quantization steps in accordance with a gamma characteristic and a white compression characteristic of the image signal.
Dependencies are inferred from the claim text.