利用Python将图片中扭曲矩形的复原_Python

前言

日常生活中，手残党们经常会把一些照片拍歪，比如拍个证件、试卷、PPT什么的，

比如下面这本书的封面原本是个矩形，随手一拍就成了不规则四边形

想要把它变成规则的矩形，有什么办法呢？

利用Python将图片中扭曲矩形的复原

你一定想到了 PS，因为网上很多教程就是这么教的

打开PS ⟹\Longrightarrow⟹ 滤镜 ⟹\Longrightarrow⟹镜头校正 ⟹\Longrightarrow⟹自定 ⟹\Longrightarrow⟹变换

可是这样手工的调整数值实在是费劲哟！！

利用Python将图片中扭曲矩形的复原

下面我们来写个程序，自动将图片恢复到任意矩形！

程序实现

1. 打开图片并显示

									import cv2 as cv

									import numpy as np

									path = './book.jpg'

									src = cv.imread(path)

									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), bound

									 return (h, w)

									h, w = get_window_size(src)

									win_name = 'RecAdjust'

									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()

2. 在图片中标记四个角点

利用Python将图片中扭曲矩形的复原

									src_copy = src.copy()

									class Indexer:

									 def __init__(self, bound=4):

									  self.id = 0

									  self.bound=bound

									 def get_id(self):

									  self.id = (self.id+1)%self.bound

									  return (self.id-1)%self.bound+1

									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)

									points = []

									indexer = Indexer()

									win_name = 'RecAdjust'

									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()

									print(points)

3. 设定输出矩形大小

									# W = int(input('输出图片宽度:'))

									# H = int(input('输出图片高度:'))

									W,H = 600, 800

									target_points = [(0,0),(W,0),(W,H),(0,H)]

4. 求解透视变换矩阵

									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)

5. 透视变换并保存图片

									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()

									output_file = 'result.jpg'

									cv.imwrite(output_file, result)