Constructor

obj = cv.ImgHash(alg)
obj = cv.ImgHash(alg, 'OptionName',optionValue, ...)

Input

• alg image hash algorithm, one of:
  • AverageHash Computes average hash value of the input image. This is a fast image hashing algorithm, but only work on simple case. For more details, please refer to [lookslikeit].
  • BlockMeanHash Image hash based on block mean. See [zauner2010implementation] for details.
  • ColorMomentHash Image hash based on color moments. See [tang2012perceptual] for details.
  • MarrHildrethHash Marr-Hildreth Operator Based Hash, slowest but more discriminative. See [zauner2010implementation] for details.
  • PHash Slower than average_hash, but tolerant of minor modifications. This algorithm can combat more variation than than AverageHash, for more details please refer to [lookslikeit].
  • RadialVarianceHash Image hash based on Radon transform. See [tang2012perceptual] for details.

Options

The following are options for the various algorithms:

BlockMeanHash

• Mode block mean hash mode. default 'Mode0'

MarrHildrethHash

• Alpha scale factor for marr wavelet. default 2
• Scale level of scale factor. default 1

RadialVarianceHash

• Sigma Gaussian kernel standard deviation. default 1
• NumOfAngleLine Number of angles to consider. default 180