输入图像f(x,y)，宽、高分别为Width和Height,设置图像中心坐标Center(cx,cy)为缩放中心点，
图像上任意一点到中心点的相对坐标为tx=x-cx,ty=y-cy。
图像拉伸放大
x=(tx/2)*(sqrt(tx*tx+ty*ty)/radius)+cx
y=(ty/2)*(sqrt(tx*tx+ty*ty)/radius)+cy
缩小的函数
x = cos(atan2(ty , tx))* 12*(sqrt(tx*tx + ty*ty))+cx
y = sin(atan2(ty , tx))* 12*(sqrt(tx*tx + ty*ty))+cy
# -*- coding: UTF-8 -*-
import cv2
import numpy as np
import math
def MaxFrame(frame):
height, width, n = frame.shape#得到图片的宽高和维度
# 图像的中心坐标
center_X = width / 2
center_Y = height / 2
radius = 800#图像的变换半径
newX = 0
newY = 0
real_radius =int(radius / 2.0)#设置半径
new_data = frame.copy()
#图像遍历
for i in range(width):
for j in range(height):
#得到图像上任意一点到中心点的相对坐标
tX = i - center_X
tY = j - center_Y
#两点的距离
distance = tX * tX + tY * tY
if distance < radius * radius:
newX = int(tX/ 2.0)
newY = int(tY/ 2.0)
newX = int(newX * (math.sqrt(distance) / real_radius))
newX = int(newX * (math.sqrt(distance)/ real_radius))
#最终变换坐标
newX = int(newX + center_X)
newY = int(newY + center_Y)
if newX<width and newY<height:
new_data[j, i][0] = frame[newY, newX][0]
new_data[j, i][1] = frame[newY, newX][1]
new_data[j, i][2] = frame[newY, newX][2]
else:
new_data[j, i][0] = frame[j, i][0]
new_data[j, i][1] = frame[j, i][1]
new_data[j, i][2] = frame[j, i][2]
return new_data
def MinFrame(frame):
height, width, n = frame.shape
center_X = width / 2
center_Y = height / 2
radius = 800
newX = 0
newY = 0
real_radius =int(radius / 2.0)
new_data = frame.copy()
for i in range(width):
for j in range(height):
tX = i - center_X
tY = j - center_Y
theta = math.atan2(tY, tX)
radius = math.sqrt((tX * tX) + (tY * tY))
newR = math.sqrt(radius) *12
newX = int(center_X + (newR * math.cos(theta)))
newY = int(center_Y + (newR * math.sin(theta)))
if newX < 0 and newX >width:
newX = 0
if newY <0 and newY >height:
newY = 0
if newX<width and newY<height:
new_data[j, i][0] = frame[newY, newX][0]
new_data[j, i][1] = frame[newY, newX][1]
new_data[j, i][2] = frame[newY, newX][2]
else:
new_data[j, i][0] = frame[j, i][0]
new_data[j, i][1] = frame[j, i][1]
new_data[j, i][2] = frame[j, i][2]
return new_data
def main():
img = cv2.imread("5.jpg")
cv2.imshow("original", img)
img2=MaxFrame(img)
cv2.imshow("enlarge", img2)
img3 = MinFrame(img)
cv2.imshow("ensmall", img3)
cv2.waitKey(0)
if __name__ == '__main__':
main()
