导向滤波opencv+python版

为接下来的大项目做准备
boxfilter是opencv自带的

import cv2
import numpy as np

# guidefilter : python implementation
# I : guide image
# P : inout image
# rads : the radius of windows
# eps : the regularization parameter
def boxfilter(I,rad):
    N = np.zeros(np.shape(I))
    cv2.boxfilter(I,N,rad)
    return N

def guidefilter(I,P,rads,eps):

    hgt = I.shpae[0]
    wid = I.shpae[1] 
    N = np.ones(np.shape(I))

    meanI = boxfilter(I,rads)
    meanP = boxfilter(P,rads)
    meanIP = boxfilter(I*P,rads)
    covIP = meanIP - meanI * meanP

    meanII = boxfilter(I*I,rads)
    varI = meanII - I*I

    a = covIP / (varI+eps)
    b = meanP - a*meanI

    meanA = boxfilter(a,rads)/N
    meanB = boxfilter(b,rads)/N

    res = meanA * I + meanB
    return res