A Transformed Domain based Novel Focus Measure for 3D Shape Recovery

This paper introduces a novel focus measure for Shape From Focus (SFF) based on 1-dimensional Discrete Cosine Transform (DCT). Instead of locally computing the focus quality in a window, we constructed a vector consisting of seven pixels for each pixel in the image volume. The new neighborhood incorporates the effect on focus value of pixels from 3-dimensions. In transform domain, to exploit the variation in energy, each AC coefficient is subtracted from the DC component. The focus value is then computed considering the energy of the modified AC components. The proposed method is simple but effective. Experimental results demonstrate the effectiveness of the new focus measure by using two different image sequences.