Image Processing Class (EGBE443) #3 — Point Operation

These point operations map the intensity by the mapping function contained the constant which is image content such as the highest intensity and the lowest intensity.Automatic Contrast AdjustmentAuto-contrast modification is the method to map the lowest intensity and highest intensity which found in the image to the minimum and maximum intensity of the full intensity range respectively (in case of 8 bits gray-scale image, the full range is 0–255)..The mapping function of Auto-contrast adjustment is defined asFrom the equation, a min, a max, a low and a high are minimum value intensity, maximum value intensity in the range, lowest intensity and highest intensity respectively..In case of 8 bit image, a min=0 and a max=255 so the mapping function is defined asModify Auto-ContrastThe highest intensity and the lowest intensity may be the noise of the image, We exclude these noise by saturate intensity of the image using quantile..The mapping function is defined as:Where H(a) is the cumulative histogram of pixel value a, K is maximum intensity value and MN is the lastest cumulative intensity.You can apply it to your python code using OpenCV moduleequ = cv2.equalizeHist(img)And here is the result of histogram equalization process.Histogram SpecificationThis task is similar to histogram equalization but the aim of this process is mapping distribution function of histogram to the reference distribution.. More details

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