RAM line storage for fixed pattern noise correction

A fixed pattern noise reducing image sensing apparatus, comprising:

• an array of image obtaining elements obtaining values indicating an image;
• a plurality of image processing circuit elements, respectively processing said values, said elements including a plurality of analog-to-digital converters;
• a memory, storing information indicating fixed pattern noise in said value indicating the image, said fixed pattern noise being at least in part due to variations in response of at two of said analog-to-digital converters;
• and
• an arithmetic device, operating to change said values by a value stored in said memory, to thereby compensate for said fixed pattern noise.

An image sensing device, comprising:

• a plurality of image sensing elements producing an output indicating elements of an image;
• a plurality of analog-to-digital converters operative to digitize said output;
• a circuit which adds different offsets to different ones of said output indicating image sensing elements;
• an offset detecting element, detecting said offsets due to device variations in said plurality of analog-to-digital converters for a plurality of said image sensing elements;
• and
• an offset compensator, operating to change said output indicating said image sensing elements in a way that tends to reduce said offsets.

A method of acquiring an image, comprising:

• determining fixed pattern noise for a plurality of substantially simultaneously-obtained pixel values, said fixed pattern noise representing some offset in a plurality of analog-to-digital converters used to obtain said values;
• storing a value indicating said fixed pattern noise;
• and
• adding the value indicating said fixed pattern noise to the pixel values to compensate he pixel value for the fixed pattern