A simple, general, and mathematically tractable sense of depth

In the most general form the defocusing operator is a linear, circularly symmetric, lowpass, and space variant filter. Without any restriction on the general model, the filter´s bandwidth is used as a measure of depth. The paper introduces a simple and efficient way to obtain this measure which has a well founded mathematical tractability. Experimental results indicates its high capability to resolve depth. In the regions of the image with the same texture, this parameter is a good measure of the second derivative of the defocusing filter or depth