opencv3.0线性极坐标变换，python

对数极坐标变换：

import math
import numpy as np
import cv2


def print_hi(str):
    print('hi,'+str)


def print_3(str):
    print('hi3,'+str)


def polar2(I, center, r, theta=(0, 360), rstep=0.52, thetastep=360.0/(180*8)):
#def polar2(I, center, r, theta=(0, 360), rstep=0.5, thetastep=1.0/4):
    """
    最近邻插值方法
    """
    cx, cy = center

    minr, maxr = r
    mintheta, maxtheta = theta
    h = int((maxr-minr)/rstep)+1
    w = int((maxtheta-mintheta)/thetastep)+1
    O33 = 125*np.ones((h, w), I.dtype)
    #cv2.imshow('i',O33)
    # 极坐标变换
    r = np.linspace(minr, maxr, h)  # 生成等差数列，minr起始，maxr终止，生成h个
    r = np.tile(r, (w, 1))
    r = np.transpose(r)#转置
    theta = np.linspace(mintheta, maxtheta, w)
    theta = np.tile(theta, (h, 1))
    x1, y1 = cv2.polarToCart(r, theta, angleInDegrees=True)  # 默认是角度表示，也可以幅度表示
    # 最近邻插值
    for i in range(h):
        for j in range(w):
            px = int(round(x1[i][j])+cx) #近邻
            py = int(round(y1[i][j])+cy) #近邻
            if ((px >= 0 and px <= w-1) and (py >= 0 and py <= h-1)):
                O33[i][j] = I[py][px]
    return O33


if __name__ == "__main__":
    print_hi('极坐标')
    print('坐标11,13以0,0为中心极坐标转换')

    I = cv2.imread(r'clock2.png', cv2.IMREAD_GRAYSCALE)
    #dst = cv2.linearPolar(I,(390,370),390,cv2.INTER_LINEAR) #opencv3.0线性极坐标变换，
    M = 100 #系数，越大越好
    dst  = cv2.logPolar(I,(390,370),M,cv2.WARP_FILL_OUTLIERS) #opencv3.0对数极坐标变换
    
    dst = cv2.rotate(dst,2) # 0:0度，1:90度
    cv2.imwrite('duishu.jpg',dst)
    cv2.imshow('O33', dst)
    cv2.waitKey(0)
    cv2.destroyAllWindows()