Method and system for automatic exposure and white balance correction

A method for an image acquisition system for automatic exposure correction, the image acquisition system including an image sensor, and an auto exposure module operatively connected to the image sensor to control the exposure of images acquired by the image sensor, the method comprising:

• determining, by the auto-exposure module, a first set of exposure parameters to acquire at least a first image, said first set of exposure parameters comprising at least an exposure time in combination with a gain;
• acquiring the first image using said first set of exposure parameters;
• determining a target image histogram;
• calculating a first image histogram based on the intensity values of the pixels of the first image;
• determining an integral of the first image histogram and of the target image histogram for a range of pixel intensity values;
• calculating a first transfer curve for transforming the integral of the first image histogram to match the integral of the target image histogram;
• calculating a first slope of a first line fitting at least a portion of the first transfer curve;
• determining an auto-exposure correction factor based on the calculated first slope;
• adjusting said first set of exposure parameters according to said auto-exposure correction factor;
• and
• acquiring at least one second image using the adjusted first set of exposure parameters.

A method for an image acquisition system for automatic white balance correction, the image acquisition system including an image sensor, an auto exposure module operatively connected to the image sensor to control the exposure of images acquired by the image sensor, and a plurality of color channels operatively connected to the image sensor and configured to provide respective image planes, the method comprising:

• determining, by the auto-exposure module, a first set of exposure parameters to acquire at least a plurality of image planes via the color channels, wherein said first set of exposure parameters includes at least a plurality of first channel gains, each of the first channel gains being associated with a corresponding one of a plurality of color channels;
• determining a target image histogram;
• calculating a plurality of first image histograms, each first image histogram being calculated based on the intensity values of the pixels of a corresponding one of the image planes;
• determining an integral of each of the first image histograms;
• calculating a plurality of first transfer curves for transforming the integrals of the first image histograms to match the integral of the target image histogram;
• calculating a plurality of first slopes of first lines fitting at least a portion of the first transfer curves;
• determining a plurality of white balance correction factors for the first channel gains based on the calculated first slopes;
• adjusting each of the first channel gains according to a corresponding one of the plurality of the white balance correction factors;
• and
• acquiring at least one second image using the adjusted first channel gains.