Method of processing three-dimensional image data by up-sampling low resolution depth data, wherein said depth data is registered to a colour data of a high resolution colour image by homograph mapping, comprising the following successive steps: - up-scaling the low resolution depth data to resolution of said high resolution colour image using a nearest neighbour interpolation to obtain an up-scaled disparity map, - detecting the horizontal and vertical bounds for each pixel of said high resolution colour image based on intensity differences, wherein in said detection, a search is performed for each pixel in four directions and said search continues until a first pixel which defines said horizontal or vertical bound in corresponding direction and whose absolute intensity difference with the centre pixel is above a predetermined threshold is reached, - combining the up-scaled disparity map and the detected vertical and horizontal bounds by applying an averaging filter among an arbitrary shaped region which is determined by vertical and horizontal bound search which limits the colour variation within the predetermined threshold, by the utilization of horizontal and vertical integral data of the up-scaled disparity map to obtain a high resolution disparity map, wherein said averaging filter performs a filtering among the nearest neighbour up-scaled disparity map by utilizing adaptive support windows detected through processing of the high resolution colour images, wherein the adaptive support windows are determined by detecting the vertical and horizontal bounds for each pixel, wherein then for each pixel the averaging of the disparity values among the detected bounds of the neighbouring pixels located within the bounds of the corresponding pixels is performed. - up-scaling the low resolution depth data to resolution of said high resolution colour image using a nearest neighbour interpolation to obtain an up-scaled disparity map, - detecting the horizontal and vertical bounds for each pixel of said high resolution colour image based on intensity differences, wherein in said detection, a search is performed for each pixel in four directions and said search continues until a first pixel which defines said horizontal or vertical bound in corresponding direction and whose absolute intensity difference with the centre pixel is above a predetermined threshold is reached, - combining the up-scaled disparity map and the detected vertical and horizontal bounds by applying an averaging filter among an arbitrary shaped region which is determined by vertical and horizontal bound search which limits the colour variation within the predetermined threshold, by the utilization of horizontal and vertical integral data of the up-scaled disparity map to obtain a high resolution disparity map, wherein said averaging filter performs a filtering among the nearest neighbour up-scaled disparity map by utilizing adaptive support windows detected through processing of the high resolution colour images, wherein the adaptive support windows are determined by detecting the vertical and horizontal bounds for each pixel, wherein then for each pixel the averaging of the disparity values among the detected bounds of the neighbouring pixels located within the bounds of the corresponding pixels is performed.