High Dynamic Range Imaging Sensor Array

Abstract

The present invention discloses a device with a rectangular imaging array, characterized by a plurality of pixel sensors and a plurality of readout lines. The device has a plurality of column processing circuits, each column processing circuit connected to a corresponding one of the readout lines and a plurality of signal injectors, one signal injector connected to each readout line. Each signal injector couples one of a predetermined number of voltages to the sense line. The exposure of each pixel sensor is determined during an image recording cycle. The signal injector injects a plurality of calibration voltages into the readout lines and determines a gain function of amplifiers in a column processing circuit by measuring the outputs of the amplifiers for the plurality of calibration voltages during calibration periods between imaging recording periods.

Description

technical field [0001] The present invention relates to high dynamic range imaging sensor arrays. Background technique [0002] CMOS cameras typically form an image of a scene by imaging light from the scene onto an array of pixel sensors. Typically, each pixel sensor has one or more photodetectors. Each photodetector converts light received during exposure into an electrical signal. The electrical signal is then digitized by an analog-to-digital converter (ADC) to produce a digital value representing the amount of light received during the exposure period. The array is typically a two-dimensional array of pixels with thousands of columns and rows. The array is read out one row at a time using a separate column amplifier and ADC for each row. [0003] Typically, photodiodes have some range where the signal from the photodiode is a monotonically increasing function of the light received during the exposure period. At the bottom of the range, the accuracy of determining l...

AI Technical Summary

Problems solved by technology

[0005] While providing a second photodiode in each pixel sensor extends the high-intensity response of the pixel sensor, various noise sources limit how well low-light areas can be imaged with reasonable exposure times

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