[英]How to replace cropped rectangle in opencv?
我已经设法用文本裁剪了一个边界框,例如给定这张图片:
我可以准确地说出以下框:
使用此代码:
import re
import shutil
from IPython.display import Image
import requests
import pytesseract, cv2
"""https://www.geeksforgeeks.org/text-detection-and-extraction-using-opencv-and-ocr/"""
# Preprocessing the image starts
# Convert the image to gray scale
img = cv2.imread('img.png')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
# Performing OTSU threshold
ret, thresh1 = cv2.threshold(gray, 0, 255, cv2.THRESH_OTSU | cv2.THRESH_BINARY_INV)
# Specify structure shape and kernel size.
# Kernel size increases or decreases the area
# of the rectangle to be detected.
# A smaller value like (10, 10) will detect
# each word instead of a sentence.
rect_kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (18, 18))
# Applying dilation on the threshold image
dilation = cv2.dilate(thresh1, rect_kernel, iterations = 1)
# Finding contours
contours, hierarchy = cv2.findContours(dilation, cv2.RETR_EXTERNAL,
cv2.CHAIN_APPROX_NONE)
# Creating a copy of image
im2 = img.copy()
for cnt in contours:
x, y, w, h = cv2.boundingRect(cnt)
# Drawing a rectangle on copied image
rect = cv2.rectangle(im2, (x, y), (x + w, y + h), (0, 255, 0), 2)
# Cropping the text block for giving input to OCR
cropped = im2[y:y + h, x:x + w]
cv2.imwrite('image-notxt.png', cropped)
Image(filename='image-notxt.png', width=200)
第 1 部分:如何替换裁剪框并放回明文框? 例如得到类似的东西:
我试过了:
for cnt in contours:
x, y, w, h = cv2.boundingRect(cnt)
# Drawing a rectangle on copied image
rect = cv2.rectangle(im2, (x, y), (x + w, y + h), (0, 255, 0), 2)
# Cropping the text block for giving input to OCR
cropped = im2[y:y + h, x:x + w]
text = pytesseract.image_to_string(cropped).strip('\x0c').strip()
text = re.sub(' +', ' ', text.replace('\n', ' ')).strip()
if text:
# White out the cropped box.
cropped.fill(255)
# Create the image with the translation.
cv2.putText(img=cropped, text="foobar", org=(12, 15), fontFace=cv2.FONT_HERSHEY_TRIPLEX, fontScale=0.3, color=(0, 0, 0),thickness=1)
cv2.imwrite('image-notxt.png', cropped)
Image(filename='image-notxt.png', width=200)
这设法使裁剪框变白并插入如下文本:
第 2 部分:如何创建与裁剪框大小相同的 opencv 文本框矩形? 例如,给定一个字符串foobar
,如何获得这样的最终图像:
在 Python/OpenCV/Numpy 中,使用 Numpy 将颜色写入区域,格式如下:
img[y:y+h, x:x+w] = color tuple
例如:
img[40:40+45, 40:40+150] = (255,255,255)
其中 x,y,w,h = 40,40,150,45
要添加文本,请参阅https://docs.opencv.org/4.1.1/d6/d6e/group__imgproc__draw.html#ga5126f47f883d730f633d74f07456c576上的 cv2.putText()
裁剪框后,填写:
cropped.fill(255)
那会产生
放入文本,它有点细微差别,但首先是步骤:
cv2.putText()
创建包含文本的图像for i, chunk in enumerate(textwrap.wrap(translation, width=20)):
cv2.putText(img=cropped, text=chunk, org=(12, 15+i*10),
fontFace=cv2.FONT_HERSHEY_TRIPLEX, fontScale=0.3,
color=(0, 0, 0),thickness=1)
im2[y:y + h, x:x + w] = cropped
为了处理文本的长度,我必须使用 Python textwrap库将字符串分解为多个子字符串
然后遍历子字符串,我putText
每个子字符串放入cropped
的图像中。
最后,将原始图像的部分替换为编辑后的裁剪图像,并将文本放入其中,如im2[y:y + h, x:x + w] = cropped
可以在https://www.kaggle.com/code/alvations/image-translate上找到一个工作示例
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