Image hashes tell whether two images look nearly identical. This is different from cryptographic hashing algorithms (like MD5, SHA-1) where tiny changes in the image give completely different hashes. In image fingerprinting, we actually want our similar inputs to have similar output hashes as well. The image hash algorithms (average, perceptual, difference, wavelet) analyse the image structure on luminance (without colo…
Image hashes tell whether two images look nearly identical. This is different from cryptographic hashing algorithms (like MD5, SHA-1) where tiny changes in the image give completely different hashes. In image fingerprinting, we actually want our similar inputs to have similar output hashes as well. The image hash algorithms (average, perceptual, difference, wavelet) analyse the image structure on luminance (without color information). The color hash algorithm analyses the color distribution and black & gray fractions (without position information).