add equalizeHist

data/1.OpenCV初阶/3.图像增强和滤波/2.直方图均衡化/fish.md

+# 浑水摸鱼
+
+通过调整图像的直方图调整图像的整体细节，下图左图是浑水鱼，右边清澈鱼。
+
+![](./fish_enhance.jpeg)
+
+框架代码如下：
+
+```python
+import numpy as np
+import cv2
+
+if __name__ == '__main__':
+    fish = cv2.imread('fish.jpeg', -1)
+
+    # TODO(You): 请正确实现浑水摸鱼代码
+
+    images = np.concatenate((fish, fish_enhance), axis=1)
+    cv2.imwrite('fish_enhance.jpeg', images)
+    cv2.imshow('fish_enhance', images)
+    cv2.waitKey()
+    cv2.destroyAllWindows()
+```
+
+直方图均衡化只能对灰度图使用。下面的实现正确的是？
+
+## 答案
+
+```python
+b, g, r = cv2.split(fish)
+bx, gx, rx = cv2.equalizeHist(b), cv2.equalizeHist(g), cv2.equalizeHist(r)
+fish_enhance = cv2.merge((bx, gx, rx))
+```
+
+## 选项
+
+### 没有分离灰度图
+
+```python
+fish_enhance = cv2.equalizeHist(fish)
+```
+
+### 参数不对
+
+```python
+b, g, r = cv2.split(fish)
+bx, gx, rx = cv2.equalizeHist(b), cv2.equalizeHist(g), cv2.equalizeHist(r)
+fish_enhance = cv2.merge(bx, gx, rx)
+```
+
+### 参数错误
+
+```python
+b, g, r = fish.split()
+bx, gx, rx = cv2.equalizeHist(b), cv2.equalizeHist(g), cv2.equalizeHist(r)
+fish_enhance = cv2.merge((bx, gx, rx))
+```

data/1.OpenCV初阶/3.图像增强和滤波/2.直方图均衡化/fish.py

+import numpy as np
+import cv2
+
+if __name__ == '__main__':
+    fish = cv2.imread('fish.jpeg', -1)
+
+    b, g, r = cv2.split(fish)
+    bx, gx, rx = cv2.equalizeHist(b), cv2.equalizeHist(g), cv2.equalizeHist(r)
+    fish_enhance = cv2.merge((bx, gx, rx))
+
+    images = np.concatenate((fish, fish_enhance), axis=1)
+    cv2.imwrite('fish_enhance.jpeg', images)
+    cv2.imshow('fish_enhance', images)
+    cv2.waitKey()
+    cv2.destroyAllWindows()