Sensor Dark Pixel Offset Estimation

摘要

Examples of systems and methods to provide estimates of dark current for pixels of a photosensor as a function of the temperature of the sensor and the gain applied to the photosensor are described. In various implementations, the dark current estimated for each pixel can depend at least partly on a global scale factor and a global bias that depend on temperature and gain and a temperature-independent and gain-independent offset value for each pixel. The scale, bias, and offsets may be determined from multiple dark field images taken by the sensor over a range of operating temperatures. In some cases, the scale and bias can be determined using a subset of less than all the image pixels. Scale and bias derived for a particular sensor can be used in the calibration of different sensors.

主权项

1. A computer-implemented method for correcting for dark current in a photosensor comprising a plurality of pixels, the method comprising:
under control of one or more physical computing devices configured with specific computer-executable instructions, accessing, by the one or more physical devices, a scale factor and a bias factor for the plurality of pixels of the photosensor, wherein the plurality of pixels includes all the pixels of the photosensor, the scale factor and the bias factor depending at least partly on a temperature of the photosensor and a gain of the photosensor, and the scale factor and the gain factor both contributing to any dark current in the photosensor, the scale factor having the same value for each pixel in the plurality of pixels, and the bias factor having the same value for each pixel in the plurality of pixels; for each pixel in the plurality of pixels of the photosensor:
accessing, by the one or more physical computing devices, a pixel value that represents a response of the pixel to receipt of light;accessing, by the one or more physical computing devices, an offset value for the pixel, the offset value not dependent on the temperature or the gain of the photosensor;determining, by the one or more physical computing devices, a corrected pixel value that depends at least partly on the pixel value, the scale factor, the bias factor, and the offset value, wherein the scale factor and the bias factor are global factors that are the same for each pixel in the plurality of pixels, and wherein the pixel value and the offset value are local factors capable of having values that are different for different pixels in the plurality of pixels; andproviding, by the one or more physical computing devices, the corrected pixel value.