Gray-world white balance algorithm. This algorithm scales the values of pixels based on a gray-world assumption which states that the average of all channels should result in a gray image. It adds a modification which thresholds pixels based on their saturation value and only uses pixels below the provided threshold in finding average pixel values. Saturation is calculated using the following for a 3-channel RGB image per pixel I and is in the range [0, 1]: Saturation[I]= max(R,G,B)−min(R,G,B) / max(R,G,B) A threshold of 1 means that all pixels are used to white-balance, while a threshold of 0 means no pixels are used. Lower thresholds are useful in white-balancing saturated images. Currently supports images of type CV_8UC3 and CV_16UC3.
More sophisticated learning-based automatic white balance algorithm. As GrayworldWB, this algorithm works by applying different gains to the input image channels, but their computation is a bit more involved compared to the simple gray-world assumption. More details about the algorithm can be found in: Dongliang Cheng, Brian Price, Scott Cohen, and Michael S Brown. Effective learning-based illuminant estimation using simple features. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1000–1008, 2015. To mask out saturated pixels this function uses only pixels that satisfy the following condition: max(R,G,B) / range_max_val < saturation_thresh Currently supports images of type CV_8UC3 and CV_16UC3.
A simple white balance algorithm that works by independently stretching each of the input image channels to the specified range. For increased robustness it ignores the top and bottom p% of pixel values.
The base class for auto white balance algorithms.
Class that contains entry points for the XPhoto module.