Extending Image Sensor Dynamic Range by Scene-aware Pixelwise-adaptive Coded Exposure

Abstract

We present a method for extending the dynamic range of an image sensor by frame-to-frame adaptive adjustment of exposure of every pixel based on changes in the brightness of the scene for that pixel. The method employs an image sensor with a coded-exposure-pixel (CEP), where the exposure time of each frame is divided into Nsubframes, each of unary or binary-weighted duration. In each subframe, the pixel is re-programmed with a 1-bit binary code to be either on (code 1) or off (code 0), depending on the light flux captured by that pixel in the previous frame. The photo-generated charge is integrated across all subframes. The proposed technique analyzes light flux in each pixel in the captured frame and makes dynamic adjustments to the exposure times in the next frame.