Alleviating dominant color failure in automatic white balance using histogram trimming

Patent metadata

Field	Value
Publication number	US-9007484-B2
Application number	US-201213349090-A
Country	US
Kind code	B2
Filing date	Jan 12, 2012
Priority date	Oct 12, 2011
Publication date	Apr 14, 2015
Grant date	Apr 14, 2015

Abstract

Methods, devices and computer readable media for implementing novel dominant color alleviation techniques for color balancing are described. The techniques take advantage of unique properties of 2D image data histograms accumulated in a chromaticity space, along with other factors such as estimated scene lux and knowledge of plausible scene illuminant white point values within the chromaticity space. The accumulated 2D image data histograms may be refined and “trimmed,” such that the resultant image data passed to an auto white balance solution has much less influence from the dominant colors in the image, even those that overlap the plausible scene illuminant color region. The described techniques provide for white point estimates that are much less prone to dominant color failures.

First claim

What is claimed is:

1. A non-transitory program storage device, readable by a programmable control device comprising instructions stored thereon for causing the programmable control device to:
store image pixel data in a memory, wherein the image pixel data is obtained from an image sensor;
transform the image pixel data into a two-dimensional image histogram of values over a color space, wherein the values correspond to a distribution of the image pixel data in the color space,…

Assignees

• Zhang Xuemei
• Bai Yingjun
• Hubel Paul
• Apple Inc

Inventors

• Zhang Xuemei
• Bai Yingjun
• Hubel Paul

Classifications

• H04N1/6041 Primary

  Electricity · mapped topic

• H04N23/88 Primary

  Electricity · mapped topic

• H04N9/73 Primary

  Electricity · mapped topic