ó  ‰\c@ s¹dZddlmZddlZddlZddlmZmZddl m Z m Z ddl m Z dZe e ƒdd d d „ƒZd d „Zd„Zd„Zd„ZdS(sé Adapted code from "Contrast Limited Adaptive Histogram Equalization" by Karel Zuiderveld , Graphics Gems IV, Academic Press, 1994. http://tog.acm.org/resources/GraphicsGems/ The Graphics Gems code is copyright-protected. In other words, you cannot claim the text of the code as your own and resell it. Using the code is permitted in any program, product, or library, non-commercial or commercial. Giving credit is not required, though is a nice gesture. The code comes as-is, and if there are any flaws or problems with any Gems code, nobody involved with Gems - authors, editors, publishers, or webmasters - are to be held responsible. Basically, don't be a jerk, and remember that anything free comes with no guarantee. iÿÿÿÿ(tdivisionNi(t img_as_floatt img_as_uint(t adapt_rgbt hsv_value(trescale_intensityig{®Gáz„?icC s÷t|ƒ}t|ddtdfƒ}|dkrY|jdd|jddf}nPt|tjƒr~|f|j}n+t |ƒ|jkr©t dj |ƒƒng|D]}t |ƒ^q°}t |||||ƒ}t|ƒ}t|ƒS(s1Contrast Limited Adaptive Histogram Equalization (CLAHE). An algorithm for local contrast enhancement, that uses histograms computed over different tile regions of the image. Local details can therefore be enhanced even in regions that are darker or lighter than most of the image. Parameters ---------- image : (M, N[, C]) ndarray Input image. kernel_size: integer or list-like, optional Defines the shape of contextual regions used in the algorithm. If iterable is passed, it must have the same number of elements as ``image.ndim`` (without color channel). If integer, it is broadcasted to each `image` dimension. By default, ``kernel_size`` is 1/8 of ``image`` height by 1/8 of its width. clip_limit : float, optional Clipping limit, normalized between 0 and 1 (higher values give more contrast). nbins : int, optional Number of gray bins for histogram ("data range"). Returns ------- out : (M, N[, C]) ndarray Equalized image. See Also -------- equalize_hist, rescale_intensity Notes ----- * For color images, the following steps are performed: - The image is converted to HSV color space - The CLAHE algorithm is run on the V (Value) channel - The image is converted back to RGB space and returned * For RGBA images, the original alpha channel is removed. References ---------- .. [1] http://tog.acm.org/resources/GraphicsGems/ .. [2] https://en.wikipedia.org/wiki/CLAHE#CLAHE t out_rangeiiis$Incorrect value of `kernel_size`: {}N(RRt NR_OF_GREYtNonetshapet isinstancetnumberstNumbertndimtlent ValueErrortformattintt_claheR(timaget kernel_sizet clip_limittnbinstk((s:lib/python2.7/site-packages/skimage/exposure/_adapthist.pytequalize_adapthists/  % i€c C s·|dkr|Sttj|jd|dƒƒ}ttj|jd|dƒƒ}ttj|jd|ƒƒ}ttj|jd|ƒƒ}dt|}tjtƒ} | |} tj|||fdtƒ} x"t|ƒD]} x t|ƒD]ý} || || d|…| || d|…f} |dkrrt|| j |ƒ}|dkrxd}qxnt}| | j ƒ}tj |ƒ}tj |tj||j dtƒƒ}t ||ƒ}t|dtd| j ƒ}|| | | fR,tnormtx_coefty_coeft x_inv_coeft y_inv_coeftviewtim_slicetnew((s:lib/python2.7/site-packages/skimage/exposure/_adapthist.pyR&#s;$(  i@(t__doc__t __future__RR tnumpyRtutilRRtcolor.adapt_rgbRRtexposureRRRRRR$R%R&(((s:lib/python2.7/site-packages/skimage/exposure/_adapthist.pyts   > n =