鱼眼镜头效果

import cv2
import numpy as np 
import math
def transform1(img):
    rows,cols,c=img.shape
    R=np.int(cols/2/math.pi)
    D=R*2
    cx=R
    cy=R
    print(rows,cols,c,R,D,cx,cy)
    new_img=np.zeros((D,D,c),dtype=np.uint8) 
    new_img1=np.zeros((D,D,c),dtype=np.uint8)
    for i in range(D):
        for j in range(D):
            r=math.sqrt((i-cx)**2+(j-cy)**2)
            if r>R:
                continue
            tan_inv=np.arctan((j-cy)/(i-cx+1e-10))
            if(i<cx):
                theta=math.pi/2+tan_inv
            else:
                theta=math.pi*3/2+tan_inv  
            xp=np.int(np.floor(theta/2/math.pi*cols))
            yp=np.int(np.floor(r/R*rows))
            new_img[j,i]=img[rows-yp-1,xp]
    return new_img
def transform2(img):
    rows,cols,c=img.shape
    R=np.int(cols/2/math.pi)
    D=R*2
    cx=R
    cy=R
    print(rows,cols,c,R,D,cx,cy)
    new_img=np.zeros((D,D,c),dtype=np.uint8) 
    new_img1=np.zeros((D,D,c),dtype=np.uint8)
    for i in range(D):
        for j in range(D):
            r=math.sqrt((i-cx)**2+(j-cy)**2)
            if r>R:
                continue
            tan_inv=np.arctan((j-cy)/(i-cx+1e-10))
            if(i<cx):
                theta=math.pi/2+tan_inv
            else:
                theta=math.pi*3/2+tan_inv  
            xp=np.int(np.floor(theta/2/math.pi*cols))
            yp=np.int(np.floor(r/R*rows)-1)
            new_img[j,i]=img[yp,xp]
    return new_img
img=cv2.imread('C:/Users/xpp/Desktop/Lena.png')
img1=transform1(img)
img2=transform2(img)
cv2.imshow('C:/Users/xpp/Desktop/result1',img1)
cv2.imshow('C:/Users/xpp/Desktop/result2',img2)
cv2.waitKey(0)
cv2.imwrite('C:/Users/xpp/Desktop/result1.jpg',img1)
cv2.imwrite('C:/Users/xpp/Desktop/result2.jpg',img2)