calculation of the 'phash' of an image
This function calculates the phash of an image
phash( gray_image, hash_size = 8, highfreq_factor = 4, MODE = "hash", resize = "nearest" )
gray_image |
a (2-dimensional) matrix or data frame |
hash_size |
an integer specifying the hash size (hash_size * highfreq_factor should be less than number of rows or columns of the gray_image) |
highfreq_factor |
an integer specyfing the highfrequency factor (hash_size * highfreq_factor should be less than number of rows or columns of the gray_image) |
MODE |
one of 'hash' (returns the hash of the image), 'binary' (returns binary identifier of the image) |
resize |
corresponds to one of 'nearest', 'bilinear' (resizing method) |
The function is a modification of the 'phash' function of the imagehash package [ please consult the COPYRIGHT file ]. The phash algorithm extends the average_hash by using the discrete cosine transform.
either a hash-string or a binary vector
image = readImage(system.file("tmp_images", "2.jpg", package = "OpenImageR"))
image = rgb_2gray(image)
res_hash = phash(image, hash_size = 6, highfreq_factor = 3, MODE = 'hash')
res_binary = phash(image, hash_size = 6, highfreq_factor = 3, MODE = 'binary')Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.