python图像处理：凸透镜效果/鱼眼图像

原理

原理很简单，经过凸透镜放大的区域可以看成一个圆形区域，这个圆形区域是由原始图像一个很小的圆形区域扩展而来。

效果

应用

python图像处理：全景图片转鱼眼图片(鱼眼矫正)

代码

import cv2
import numpy as np 
import math
def transform(img):
    rows,cols,c = img.shape
    center_x,center_y = rows/2,cols/2
    #radius = min(center_x,center_y)
    radius = math.sqrt(rows**2+cols**2)/2
    new_img = img.copy()
    for i in range(rows):
        for j in range(cols):
            dis = math.sqrt((i-center_x)**2+(j-center_y)**2)
            if dis <= radius:
                new_i = np.int(np.round(dis/radius*(i-center_x)+center_x))
                new_j = np.int(np.round(dis/radius*(j-center_y)+center_y))
                new_img[i,j] = img[new_i,new_j]
                #print((i,j),'\t',(new_i,new_j))
    return new_img
    img = cv2.imread('cat.jpg')
img = transform(img)
cv2.imshow('result',img)
cv2.waitKey(0)
cv2.imwrite('result.jpg',img)