CMOS active pixel with memory for imaging sensors

An imaging sensor comprising:

• a monolithic semiconductor substrate;
• a matrix of pixels located on said monolithic semiconductor substrate, each pixel including a photodetector and an array of memory cells, said memory cells being dual port memory cells having a storage device that is isolated by said at least two switches;
• and
• peripheral circuitry means connected to said pixels for providing control and timing signals to said pixels and for processing signals received from said pixels.

A method of capturing, digitizing, and storing an image using an image sensor having a plurality of pixels on a monolithic structure, said method comprising steps of:

• generating a photo signal in an analog format at each pixel of said plurality of pixels, said photo signal being responsive to an intensity of incident light sensed at said each pixel;
• converting said photo signal into a digital photo signal word at each of said plurality of pixels;
• storing said digital photo signal word in a memory array located within each of said plurality of pixels;
• generating a reference signal in an analog format at each of said pixels, said reference signal being representative of a dark frame;
• converting said reference signal into a digital reference signal word at each of said pixels;
• and
• storing said digital reference signal word in said memory array located within each of said pixels, including using separate portions of said memory array to store said digital reference signal word and said digital photo signal word.

An imaging apparatus having a photosensitive area formed by a matrix of pixels in which incident light is captured, digitized, and stored, said pixels being formed on a monolithic chip, each particular pixel comprising:

• photodetecting means located within a pixel region of said particular pixel of said monolithic chip for generating an analog photo signal that is representative to an intensity of said incident light on said particular pixel;
• analog-to-digital converting means located within said pixel region and operatively connected to said photodetecting means for transforming said analog photo signal to a digital photo signal word, said digital photo signal word being indicative of incident light intensity information;
• and
• memory having a first multi-bit storage connected to said analog-to-digital means to receive and store said digital photo signal word, said memory having a second multi-bit storage connected to store a digital reference signal word that is representative of noise associated with said particular pixel, said memory being memory cells located within said pixel region of said particular pixel.