Histogram equalization (source)

# Of gray levels is calculated cumulative probability, then: current = current pixel value of the accumulated probability of the pixel 255 * 
Import CV2 
Import numpy AS NP 
IMG = cv2.imread ( 'D: /pythonob/imageinpaint/img/flower.jpg',1 ) 
imgInfo img.shape = 
height = imgInfo [0] 
width = imgInfo [. 1] 
Gray = cv2.cvtColor (IMG, cv2.COLOR_BGR2GRAY) 
cv2.imshow ( 'Gray', Gray) 
COUNT = np.zeros (256, NP. a float) 
for I in Range (0, height): 
    for J in Range (0, width): 
        Pixel = Gray [I, J] 
        index = int (Pixel) 
        COUNT [index] = COUNT [index] + 1'd 
for I in Range (0,256): 
    COUNT [I] = COUNT [I] / (height * width) 
# calculates cumulative probability 
SUM = a float (0) 
for I in Range (0,256): 
    SUM = SUM + COUNT [I] 
    COUNT [I] = sum
#计算映射表
map = np.zeros(256,np.uint16)
for i in range(0,256):
    map[i] = count[i]*255
for i in range(0,height):
    for j in range(0,width):
        index = gray[i,j]
        gray[i,j] = map[index]
cv2.imshow('aftergGray',gray)
cv2.waitKey(0)

效果图：