System and method for using filtering and pixel correlation to increase sensitivity in image sensors

摘要

An over sampled image sensor in which the pixel size is small enough to provide spatial oversampling of the minimum blur size of the sensor optics is disclosed. Image processing to detect targets below the typical limit of 6× the temporal noise floor is also disclosed. The apparatus is useful in detecting dimmer targets and targets at a longer range from the sensors. The inventions exploits signal processing, which allows spatial temporal filtering of the superpixel image in such manner that the Noise Equivalent Power is reduced by a means of Superpixel Filtering and Pooling, which increases the sensitivity far beyond a non-oversampled imager. Overall visual acuity is improved due to the ability to detect dimmer targets, provide better resolution of low intensity targets, and improvements in false alarm rejection.

主权项

1. An imaging system comprising:
optics including a limiting aperture and a focal length, said limiting aperture and said focal length defining a diffraction limited minimum blur of the system for electromagnetic radiation of a particular wavelength (λ); a sensor array including a plurality of individual pixels disposed in a focal plane defined by said optics and sensitive to said particular wavelength of electromagnetic radiation, each of said pixels having a surface area smaller than one-ninth ( 1/9) of the surface area of said diffraction limited minimum blur; and a noise suppresser operative to identify false positive noise signals from properly operating ones of said individual pixels by correlating the signal from a particular pixel with at least one other of said pixels within a predetermined area associated with said particular pixel; and wherein a false positive noise signal is a signal from a particular pixel indicative of light incident on said particular pixel when no light is being focused on said particular pixel by said optics.