opencv_tutorials/python/code_017/opencv_017.py at master · HZHCoder1990/opencv_tutorials · GitHub

45 lines (34 loc) · 1.01 KB

import cv2 as cv

import numpy as np

from matplotlib import pyplot as plt

def custom_hist(gray):

h, w = gray.shape

hist = np.zeros([256], dtype=np.int32)

for row in range(h):

for col in range(w):

pv = gray[row, col]

hist[pv] += 1

y_pos = np.arange(0, 256, 1, dtype=np.int32)

plt.bar(y_pos, hist, align='center', color='r', alpha=0.5)

plt.xticks(y_pos, y_pos)

plt.ylabel('Frequency')

plt.title('Histogram')

# plt.plot(hist, color='r')

# plt.xlim([0, 256])

plt.show()

def image_hist(image):

cv.imshow("input", image)

color = ('blue', 'green', 'red')

for i, color in enumerate(color):

hist = cv.calcHist([image], [i], None, [256], [0, 256])

plt.plot(hist, color=color)

plt.xlim([0, 256])

plt.show()

src = cv.imread("./test.png")

cv.namedWindow("input", cv.WINDOW_AUTOSIZE)

gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)

cv.imshow("input", gray)

# custom_hist(gray)

image_hist(src)

cv.waitKey(0)

cv.destroyAllWindows()

Expand file tree