Depth from Defocusing

We have developed a new algorithm for \depth from defocusing" (or \depth from blurring") for recovering the depth of objects by measuring the amount of image blur. Compared to earlier algorithms, this method has the following advantages. It gives a unique estimate of depth. It has high accuracy at low computational costs. Easy calibration (only one unknown constant) These advantages are achieved by introducing a \dynamic referencing technique", and taking the focusing position of the lens as a camera parameter rather than the aperture of the lens. The accuracy in the measurement of depth was at worst 8.4 percent and 5.8 percent on the average when the focus length of the lens was 16.7 mm and the distance to the object was varied from 1500 mm to 2500 mm.