1. An apparatus, comprising: a discrete cosine transform (DCT) coder to perform a DCT operation on a set of luminance values associated with a block of pixels selected from an image to obtain a DCT coefficient matrix; and a feature extraction module operatively coupled to the DCT coder to perform operations on a plurality of DCT coefficients selected from low-frequency bands of the DCT coefficient matrix to derive a value of an image feature strength metric associated with the block of pixels.