OpenCV 对图片亮度增强或减弱

Posted 2021-05-24 ʚVVcatɞ

对每个像素点的三通道值进行同步放大，同时保持通道值在0-255之间

将图像中的像素限制在最小值和最大值之间，超过此区间的值赋值为最小值或最大值

图片亮度增强

import cv2
import numpy as np
import matplotlib.pyplot as plt

img = cv2.imread('1.png', 1)
height, width = img.shape[:2]

dst = np.zeros((height, width, 3), np.uint8)
for i in range(0, height):
    for j in range(0, width):
        (b, g, r) = img[i, j]
        bb = int(b) + 50
        gg = int(g) + 50
        rr = int(r) + 50
        if bb > 255:
            bb = 255
        if gg > 255:
            gg = 255
        if rr > 255:
            rr = 255
        dst[i, j] = (bb, gg, rr)

img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
dst = cv2.cvtColor(dst, cv2.COLOR_BGR2RGB)
plt.figure(figsize=(14, 6), dpi=100)  # 设置绘图区域的大小和像素
plt.subplot(121)
plt.imshow(img)
plt.subplot(122)
plt.imshow(dst)
plt.show()

运行结果：

import cv2
import numpy as np
import matplotlib.pyplot as plt

img = cv2.imread('1.png', 1)
height, width = img.shape[:2]

dst = np.zeros((height, width, 3), np.uint8)
for i in range(0, height):
    for j in range(0, width):
        (b, g, r) = img[i, j]
        bb = int(b * 1.3) + 10
        gg = int(g * 1.2) + 15
        if bb > 255:
            bb = 255
        if gg > 255:
            gg = 255
        dst[i, j] = (bb, gg, r)

img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
dst = cv2.cvtColor(dst, cv2.COLOR_BGR2RGB)
plt.figure(figsize=(14, 6), dpi=100)  # 设置绘图区域的大小和像素
plt.subplot(121)
plt.imshow(img)
plt.subplot(122)
plt.imshow(dst)
plt.show()

运行结果：

图片亮度减弱

import cv2
import numpy as np
import matplotlib.pyplot as plt

img = cv2.imread('1.png', 1)
height, width = img.shape[:2]

dst = np.zeros((height, width, 3), np.uint8)
for i in range(0, height):
    for j in range(0, width):
        (b, g, r) = img[i, j]
        bb = int(b) - 50
        gg = int(g) - 50
        rr = int(r) - 50
        if bb < 0:
            bb = 0
        if gg < 0:
            gg = 0
        if rr < 0:
            rr = 0
        dst[i, j] = (bb, gg, rr)

img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
dst = cv2.cvtColor(dst, cv2.COLOR_BGR2RGB)
plt.figure(figsize=(14, 6), dpi=100)  # 设置绘图区域的大小和像素
plt.subplot(121)
plt.imshow(img)
plt.subplot(122)
plt.imshow(dst)
plt.show()

运行结果：