Sensor dark pixel offset estimation

Abstract

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit under 35 U.S.C. §119(e) of U.S. Patent Application No. 61 / 625,322, filed Apr. 17, 2012, entitled “Sensor Dark Pixel Offset Estimation;” the entire disclosure of which is hereby incorporated by reference herein so as to form part of this specification.BACKGROUND[0002]1. Field[0003]The present disclosure relates generally to calibrating sensors such as, for example, photosensors, which have pixel-dependent noise or bias.[0004]2. Description of Related Art[0005]Photosensors can be used to detect the amount of light incident on the image sensor. Photosensors include, for example, devices such as charge-coupled devices (CCDs) in which each pixel includes a photoactive capacitor, and active pixel image sensors in which each pixel includes a light sensor and an active amplifier. The amplifier can provide a programmable or switchable gain for each pixel. Active pixel image sensors produced by complementary meta...

AI Technical Summary

Benefits of technology

[0027]An implementation of a method for calibrating a plurality of pixels on a sensor is provided. The method is performed under control of one or more physical computing devices configured with specific computer-executable instructions. The method comprises accessing a global factor that is the same for each of the plurality of pixels, accessing a local factor for each of the plurality of pixels, the l

Problems solved by technology

When an image is taken with a photosensor, dark curren

Images