Image sensor apparatus and method for scene illuminant estimation

摘要

An image sensor apparatus is disclosed. The image sensor apparatus includes an image sensor for generating pixel data corresponding to a scene under a scene illuminant and a processor. The processor includes an illuminant estimation module for receiving a subset of the pixel data associated with a subset of a color space and finding a chromaticity trend in the pixel data subset to estimate the scene illuminant. A white balance and color correction module in the processor applies white balance and color correction coefficients to the pixel data according to the estimated scene illuminant.

主权项

1. A processor for use in an image sensor device, comprising:
an illuminant characteristic curve generation module adapted to:
measure spectral sensitivities of the image sensor device for at least red, blue, and green color channels,generate a plurality of image sensor device responses to a training set under a plurality of candidate illuminants, the training set including a plurality of natural surfaces,normalize the plurality of image sensor device responses and project the plurality of normalized image sensor devices responses into a color space subset, andapply a statistical trend analysis to the plurality of normalized image sensor device responses in the color space subset to determine a plurality of trend coefficients representing a plurality of illuminant characterization curves; and an illuminant estimation module adapted to:
generate a pixel characteristic curve for a subset of pixel data, captured by the image sensor device under a scene illuminant, in the color space subset, andestimate the scene illuminant based on the pixel characteristic curve and the plurality of illuminant characteristic curves.