Abstract: A method for reading a pixel, the method includes: (i) generating a first signal responsive to light sensed by the pixel during a first exposure period; (ii) comparing a first threshold to a first value of the first signal; (iii) writing a second value to the pixel; wherein the second value equals the first threshold if the first value exceeds the first threshold; wherein the second value equals the first value is the first signal is below the first threshold; (iv) generating a third signal responsive to the second value and to light sensed by the pixel during a second exposure period; (v) reading the third signal; and (vi) calculating a digital detection signal in response to a value of the third signal and in response to a first threshold.

Abstract: An image is generated by receiving a first image that is acquired during a first exposure period and defining the first image as a reference image; defining multiple reference regions of interest within the reference image, wherein an aggregate number of pixels within the multiple reference regions of interest is substantially smaller than a number of pixels of the first image; receiving a second image that is acquired during a second exposure period; and updating the reference image in response to a content of the reference image, content of the second image and a first type of spatial relationship (e.g., a shift) defined between the reference image and the second image, wherein the shift is defined in response to multiple spatial relationships between the multiple reference regions of interest and between multiple regions of interest of the second image.

Abstract: An image is generated by receiving a first image that is acquired during a first exposure period and defining the first image as a reference image; defining multiple reference regions of interest within the reference image, wherein an aggregate number of pixels within the multiple reference regions of interest is substantially smaller than a number of pixels of the first image; receiving a second image that is acquired during a second exposure period; and updating the reference image in response to a content of the reference image, content of the second image and a first type of spatial relationship (e.g., a shift) defined between the reference image and the second image, wherein the shift is defined in response to multiple spatial relationships between the multiple reference regions of interest and between multiple regions of interest of the second image.