I have just added two new scripts.
The first, phashes, computes and stores one or more perceptual hashes for all provided images. Any or all of four different binary string perceptual hashes are available: block mean hash (bmh), block difference hash (bdh), Annular Variance Hash (avh) and Polar FFT Hash (pfh). The hashes may be stored in 1) the image's comment field, 2) the image's label field, 3) a JSON file or 4) just redirected from the terminal session to a simple text file.
The second, hamming, computes the percent hamming distance between two binary strings of equal length. The perceptual hash strings may be automatically extracted from the two images' comment or label field or the two string may be provided as arguments.