参考链接

图片裁剪&矩形复原

• 图片裁剪&矩形复原
• • 实现效果
  • 操作流程
  • • 1.有张照片
    • 2.看看照片
    • 3.选择角点
    • 4.最终结果
  • 代码分析
  • • 懒人一键复制代码

图片裁剪&矩形复原

这篇博文的目的是从图片中提取一定的矩形区域作为新的图片

简单来说：我给我的房间拍了张照片，其中我的桌子上有一个相框，相框里有全家福
现在我的全家福丢了，所以我想从以前的房间照片里，提取出其中的全家福并重新打印一张（忽视画质问题）
现在我就是这么个目的

实现效果

该方法通过鼠标选择四个点，在手动设置生成的矩形长宽后生成变换后的矩形
这篇需要设置矩形长宽，后续的2.0版本不需要设置

操作流程

首先复制代码会吧？

1.有张照片

这是网上随便找的一张照片，自行保存测试

2.看看照片

运行代码，其中show_img函数是展示照片

3.选择角点

按照左上，右上，右下，左下的顺序选择四个角点

如果担心自己选不好，可以直接去除我代码里的points的注释，那是我自己用的原版

4.最终结果

代码分析

import 没什么好说的

#如果python没有安装cv2，那么就安装python-opencv就好
import cv2 as cv
import numpy as np

获取图片的长宽

#输入cv.imread后的图片，通过点击四个点选择要裁剪的部分
def get_window_size(src, bound=600):h,w = src.shape[0], src.shape[1]if h > w:h, w = bound, int(w*bound/h)else:h, w = int(h*bound/w), boundreturn (h, w)

通过鼠标获取图片的坐标点，顺序是左上，右上，右下，左下

class Indexer:def __init__(self, bound=4):self.id = 0self.bound = bounddef get_id(self):self.id = (self.id + 1)return (self.id)def on_EVENT_LBUTTONDOWN(event, x, y, flags, param):if event == cv.EVENT_LBUTTONDOWN:img = param['src']win_name = param['window']indexer = param['indexer']points = param['points']curr_id = indexer.get_id()points.append((x, y))print('第{}个顶点: ({},{})'.format(curr_id, x, y))cv.circle(img, (x, y), 10, (0, 0, 255), thickness=2)cv.putText(img,str(curr_id),  # 文字(x, y),  # 坐标cv.FONT_HERSHEY_PLAIN,5,  # 字号(0, 0, 255),  # 字体颜色thickness=2  # 粗细)cv.imshow(win_name, img)#输入cv.imread后的图片，通过点击四个点选择要裁剪的部分
def get_points(src):points = []indexer = Indexer()h, w=get_window_size(src)win_name = 'get_points'cv.namedWindow(win_name, cv.WINDOW_NORMAL)cv.resizeWindow(win_name, width=w, height=h)cv.imshow(win_name, src)cv.setMouseCallback(win_name, on_EVENT_LBUTTONDOWN,param={'src': src, 'window': win_name, 'indexer': indexer, 'points': points})cv.waitKey(0)cv.destroyAllWindows()if len(points)>4:return points[0:4]# print(points)# points=[(2, 14), (90, 50), (87, 194), (1, 204)]return points#输入cv.imread后的图片，展示图片长什么样
def show_img(src):win_name = 'show_img'h, w=get_window_size(src)cv.namedWindow(win_name, cv.WINDOW_NORMAL)cv.resizeWindow(win_name, width=w, height=h)cv.imshow(win_name, src)cv.waitKey(0)cv.destroyAllWindows()

将图片截取，并按照指定的长宽比恢复成矩形

def photo_cut_restore(src,points,H,W):target_points = [(0, 0), (W, 0), (W, H), (0, H)]points, target_points = np.array(points, dtype=np.float32), np.array(target_points, dtype=np.float32)M = cv.getPerspectiveTransform(points, target_points)# print('透视变换矩阵:', M)result = cv.warpPerspective(src_copy, M, (0, 0))result = result[:H, :W]win_name = 'Result'cv.namedWindow(win_name, cv.WINDOW_NORMAL)cv.resizeWindow(win_name, width=W, height=H)cv.imshow(win_name,result)cv.waitKey(0)cv.destroyAllWindows()return  result

主程序

if __name__ == '__main__':path = './1.jpg'src = cv.imread(path)src_copy = src.copy()show_img(src)W = 20H = 20# points=[(112, 308), (175, 310), (176, 369), (113, 369)]points=get_points(src)n = 20W = int(W * n)H = int(H * n)result=photo_cut_restore(src_copy,points,H,W)output_file = 'result.jpg'cv.imwrite(output_file, result)

懒人一键复制代码

诶，气不气，好不容易一段段复制完，结果最后居然有一键复制的地方

import cv2 as cv
import numpy as np#输入cv.imread后的图片，通过点击四个点选择要裁剪的部分
def get_window_size(src, bound=600):h,w = src.shape[0], src.shape[1]if h > w:h, w = bound, int(w*bound/h)else:h, w = int(h*bound/w), boundreturn (h, w)class Indexer:def __init__(self):self.id = 0def get_id(self):self.id = (self.id + 1)return (self.id)def on_EVENT_LBUTTONDOWN(event, x, y, flags, param):if event == cv.EVENT_LBUTTONDOWN:img = param['src']win_name = param['window']indexer = param['indexer']points = param['points']curr_id = indexer.get_id()points.append((x, y))print('第{}个顶点: ({},{})'.format(curr_id, x, y))cv.circle(img, (x, y), 10, (0, 0, 255), thickness=2)cv.putText(img,str(curr_id),  # 文字(x, y),  # 坐标cv.FONT_HERSHEY_PLAIN,5,  # 字号(0, 0, 255),  # 字体颜色thickness=2  # 粗细)cv.imshow(win_name, img)#输入cv.imread后的图片，通过点击四个点选择要裁剪的部分
def get_points(src):points = []indexer = Indexer()h, w=get_window_size(src)win_name = 'get_points'cv.namedWindow(win_name, cv.WINDOW_NORMAL)cv.resizeWindow(win_name, width=w, height=h)cv.imshow(win_name, src)cv.setMouseCallback(win_name, on_EVENT_LBUTTONDOWN,param={'src': src, 'window': win_name, 'indexer': indexer, 'points': points})cv.waitKey(0)cv.destroyAllWindows()if len(points)>4:return points[0:4]# print(points)# points=[(2, 14), (90, 50), (87, 194), (1, 204)]return points#输入cv.imread后的图片，展示图片长什么样
def show_img(src):win_name = 'show_img'h, w=get_window_size(src)cv.namedWindow(win_name, cv.WINDOW_NORMAL)cv.resizeWindow(win_name, width=w, height=h)cv.imshow(win_name, src)cv.waitKey(0)cv.destroyAllWindows()def photo_cut_restore(src,points,H,W):target_points = [(0, 0), (W, 0), (W, H), (0, H)]points, target_points = np.array(points, dtype=np.float32), np.array(target_points, dtype=np.float32)M = cv.getPerspectiveTransform(points, target_points)# print('透视变换矩阵:', M)result = cv.warpPerspective(src_copy, M, (0, 0))result = result[:H, :W]win_name = 'Result'cv.namedWindow(win_name, cv.WINDOW_NORMAL)cv.resizeWindow(win_name, width=W, height=H)cv.imshow(win_name,result)cv.waitKey(0)cv.destroyAllWindows()return  resultif __name__ == '__main__':path = './3.jpg'src = cv.imread(path)src_copy = src.copy()# show_img(src)W = 20H = 20# points=[(124, 182), (181, 177), (180, 243), (125, 266)]points=get_points(src)print(points)n = 20W = int(W * n)H = int(H * n)result=photo_cut_restore(src_copy,points,H,W)output_file = 'result.jpg'cv.imwrite(output_file, result)

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