Measuring Focus Quality in Color Space

Shape-from-focus (SFF) has been studied extensively in computer vision for 3D shape reconstruction and depth recovery methods. One of the fundamental stages, in SFF, is to compute the focus value of pixels using one of the many focus measure techniques, which convert the RGB image into gray scale as the first step, and then apply the focus measure operator. Converting RGB image into gray scale may lead to imprecise mapping of pixels of different RGB values into same gray scale value, affecting the overall accuracy of the system. In a colored image, the focused pixels have a considerable color difference from their neighboring pixels as compared to the defocused ones that are blended in their neighborhood. This manuscript presents a new method to measure the degree of focus by directly processing RGB images. Color difference of the adjacent pixels is measured by Euclidean distance formula, and is used to differentiate the focused and defocused pixels.