13 07 20 text and solution part2

Pagina 1

Exercise 1 Consider image A and its corresponding histogram next to it. This image has dimension 100x100. Images B and C have been obtained by applying two separate transformations over image A. 1. Provide a representation of the histogram of images B and C along with brief comments to support your answer. As well, indicate on the axis of the histogram image intensity ranges and an approximate value of the number of countings per bin. 2. Indicate the parameters and provide the graph of the applied transformations between the output and input images. ANSWERS MUST NOT EXCEED ONE PAGE LONG. Exercise 2 1. Report the result of the convolution between the displayed image at pixel location (6, 6) and the prewitt kernel (displayed next to the image) according to the following directions: • direction along x-axis • direction along y-axis • direction along a 45° inclination (counter clock-wise rotation) 2. Pretend that the previous spatial filtering operation is performed for each direction with a stepwise increment of 45° inclination (0°, 45°, 90°, 135°, 180°, ... 315°). At the end, an output image is obtained by summing up the absolute values of all resulting filtered images. Without perfoming any computations, draw a schematic representation of the output image, indicating also a possible range of intensity values it does assume. Provide brief comments about what the resulting image does represent. ANSWERS MUST NOT EXCEED ONE PAGE LONG. Note: for computing the convolution along a 45° direction, approximate the coefficients of the rotated prewitt kernel to [1; 0; -1] and maintain a 3x3 dimensionality.