字母模糊/裁剪功能模糊 [英] Letters blurry / fuzzy after crop function

问题描述

尝试通过将坐标列表保存到数组来在多个位置裁剪图像后，裁剪区域中的字母变得非常模糊，我无法弄清原因。

after attempting to crop my image in several locations by saving the list of coordinates to an array the letters in the cropped area become extremely blurry and I cannot figure out why.

原始图片如下

裁剪后的图像看起来像

问题代码如下：

import numpy as np
import cv2

im2 = cv2.imread('1.jpg')
im = im2.copy()

gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray,(5,5),0)
thresh = cv2.adaptiveThreshold(blur,255,1,1,11,2)


contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)


squares = []

for cnt in contours:
    if cv2.contourArea(cnt)>50:
        [x,y,w,h] = cv2.boundingRect(cnt)

        if  h>28 and h<34:
            rect = (cv2.rectangle(im,(x,y),(x+w,y+h),(255,255,255),3))
            squares.append(cv2.boundingRect(cnt))
            cv2.imwrite('norm1.jpg',im)

crop_img = [[[255, 255, 255] for x in xrange(377)] for x in xrange(377) ]

for s in squares:
    x = s[0]
    y = s[1]
    w = s[2]
    h = s[3]
    img = im[y:y+h,x:x+w]
    for col in range(y,y+h):
        for row in range(x,x+w):
            if img[col - y][row - x].tolist() == [0,0,0]:
                crop_img[col][row] = [0,0,0]
cv2.imwrite("cropped.jpg", np.array(crop_img))

任何帮助将不胜感激！

推荐答案

import numpy as np
import cv2
import matplotlib.pyplot as plt

im2 = cv2.imread('norm1_zps89266edb.jpg')
im = im2.copy()

gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray,(5,5),0)
ret3,thresh = cv2.threshold(blur,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)

#we ony want the external contours
contours,hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE) 
#extract the countours with area > 50
squares = [cnt for cnt in contours if cv2.contourArea(cnt) > 50]

#mask array with the same shape as img (but only 1 channel)
mask = np.zeros((im.shape[0], im.shape[1]))
#draw the contours filled with 255 values. 
cv2.drawContours(mask,squares,-1,255,-1)

newImage = np.where(mask==255, thresh, 255)

plt.imshow(newImage)
plt.show()

cv2.imwrite("cropped.jpg", newImage)

输出：

output:

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