Sensor Dark Pixel Offset Estimation

A system for correcting for dark current in a sensor comprising a plurality of pixels, the system comprising:

• physical data storage configured to store:
• (i) a scale factor applicable to the plurality of pixels, wherein the plurality of pixels includes all the pixels of the photosensor,
• (ii) a bias factor applicable to the plurality of pixels, and
• (iii) an offset value for each pixel in the plurality of pixels,
• wherein the scale factor and the bias factor depend at least partly on a temperature of the sensor and a gain of the sensor, and the offset value does not depend on the temperature or the gain of the sensor, and the scale factor and the gain factor both contribute to any dark current in the photosensor;
• and
• a physical computer processor in communication with the physical data storage, the physical computer processor configured to:
• access the scale factor and the bias factor;
• access a pixel value representing an output of a pixel in the plurality of pixels;
• access the offset value for the pixel in the plurality of pixels;
• and
• determine a corrected pixel value for the pixel, wherein the corrected pixel value 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.

A computer-implemented method for estimating dark current in a sensor comprising a plurality of pixels, the method comprising:

• under control of one or more computing devices configured with specific computer-executable instructions,
• accessing, by the one or more computing devices, a dark current value for each of the plurality of pixels in the sensor;
• fitting, by the one or more computing devices, the dark current values for the plurality of pixels to a dark current model, wherein the dark current model is based at least partly on:
• a scale factor;
• a bias factor;
• and
• an offset,
• wherein the scale factor and the bias factor depend at least partly on a temperature of the sensor, the scale factor has a first same value for all the pixels in the plurality of pixels, the bias factor has a second same value for all the pixels in the plurality of pixels, the offset is independent of the temperature of the sensor, and the offset has values that can be different for different pixels in the plurality of pixels;
• and
• wherein the fitting first determines the scale factor and the bias factor, and then determines the offset value for a pixel in the plurality of pixels based at least in part on the scale factor, the bias factor, and the dark current value for the pixel;
• and
• providing, by the one or more computing devices the scale factor, the bias factor, and the offset.

A system for estimating dark current in a sensor comprising a plurality of pixels, the system comprising:

• physical data storage configured to store a dark current value for each of the plurality of pixels in the sensor;
• and
• a physical computer processor in communication with the physical data storage, the physical computer processor configured to:
• fit the dark current values for the plurality of pixels to a dark current model,
• wherein the dark current model is based at least partly on a scale factor, a bias factor, and an offset, the scale factor and the bias factor depending at least partly on a temperature of the sensor, the scale factor having a first same value for all the pixels in the plurality of pixels, the bias factor having a second same value for all the pixels in the plurality of pixels, the offset independent of the temperature of the sensor, and the offset having values that can be different for different pixels in the plurality of pixels, and wherein the fitting first determines the scale factor and the bias factor, and then determines the offset value for a pixel in the plurality of pixels based at least in part on the scale factor, the bias factor, and the dark current value for the pixel;
• and
• output the dark current model to the physical data storage.

A method for determining dark current in a second sensor based at least in part on a dark current model for a first sensor that is different from the second sensor, the dark current model for the first sensor comprising a scale factor and a bias factor, the scale factor and the bias factor depending at least partly on temperature, the scale factor and the bias factor each having a respective global value for all the pixels in the first sensor, the method comprising:

• accessing the scale factor and the bias factor for the first sensor;
• accessing dark current values for pixels of the second sensor;
• determining, by execution of instructions by a physical computer processor, offset values for each of the pixels of the second sensor, the offset values based at least in part on the dark current values for the second sensor and the scale factor and the bias factor for the first sensor;
• and
• providing a dark current model for the second sensor based at least partly on the offset values for each of the pixels of the second sensor and the scale factor and the bias factor for the first sensor.