import cv2

#载入图片
src=cv2.imread("angle.jpg")

#圆心坐标
center=(float(src.shape[0]/2),float(src.shape[1]/2))
#圆的半径
maxRadius=min(center[0],center[1])

#极坐标变换
lin_polar=cv2.warpPolar(src,None,center,maxRadius,cv2.INTER_LINEAR)
#半对数极坐标变换
log_polar=cv2.warpPolar(src,None,center,maxRadius,cv2.WARP_POLAR_LOG)
#逆变换
i_lin_polar=cv2.warpPolar(lin_polar,(src.shape[0],src.shape[1]),center,
                          maxRadius,cv2.WARP_INVERSE_MAP)
i_log_polar=cv2.warpPolar(log_polar,(src.shape[0],src.shape[1]),center,
                           maxRadius,cv2.WARP_POLAR_LOG|cv2.WARP_INVERSE_MAP)

#旋转输出图像
lin_polar=cv2.rotate(lin_polar,cv2.ROTATE_90_COUNTERCLOCKWISE)
log_polar=cv2.rotate(log_polar,cv2.ROTATE_90_COUNTERCLOCKWISE)

#展示图片
cv2.imshow("src",src)
cv2.imshow("Log-Polar",log_polar)
cv2.imshow("Linear-Polar",lin_polar)
cv2.imshow("Inverese Linear-Polar",i_lin_polar)
cv2.imshow("Inverese-Polar",i_log_polar)
cv2.imwrite("fig5-4a.png",lin_polar)
cv2.imwrite("fig5-4b.png",i_lin_polar)
cv2.imwrite("fig5-4c.png",log_polar)
cv2.imwrite("fig5-4d.png",i_log_polar)
cv2.waitKey(0)