由于您的问题并不完全清楚您是想提取单个字符还是整个单词,因此以下是同时执行这两种操作的方法。
个别字符
这里的主要思想是
- 将图像转换为灰度和高斯模糊
- 执行精明的边缘检测
- 查找轮廓
- 迭代轮廓并使用最小面积进行过滤
- 获取边界框并提取ROI
Canny 边缘检测使用cv2.Canny()
Now we iterate through contours using cv2.findContours()
and filter using cv2.contourArea()
then draw bounding boxes
这是其他一些输入图像的结果
import cv2
image = cv2.imread('1.png')
original = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray, (3,3), 0)
canny = cv2.Canny(blur, 120, 255, 1)
cnts = cv2.findContours(canny, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
min_area = 100
image_number = 0
for c in cnts:
area = cv2.contourArea(c)
if area > min_area:
x,y,w,h = cv2.boundingRect(c)
cv2.rectangle(image, (x, y), (x + w, y + h), (36,255,12), 2)
ROI = original[y:y+h, x:x+w]
cv2.imwrite("ROI_{}.png".format(image_number), ROI)
image_number += 1
cv2.imshow('blur', blur)
cv2.imshow('canny', canny)
cv2.imshow('image', image)
cv2.waitKey(0)
整个词
现在如果你想提取整个单词,你必须稍微修改一下策略
- 将图像转换为灰度和高斯模糊
- 执行精明的边缘检测
- 扩张以获得单个轮廓
- 查找轮廓
- 迭代轮廓并使用最小面积进行过滤
- 获取边界框并提取ROI
Canny 边缘检测
使用扩张cv2.dilate()
连接轮廓
查找边界框并使用轮廓区域进行过滤
提取的投资回报率
注意:如果您尝试查找整个单词,则可能必须更改最小面积值,因为它取决于您正在分析的图像。
import cv2
image = cv2.imread('1.png')
original = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray, (3,3), 0)
canny = cv2.Canny(blur, 120, 255, 1)
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (9,9))
dilate = cv2.dilate(canny, kernel, iterations=5)
cnts = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
min_area = 5000
image_number = 0
for c in cnts:
area = cv2.contourArea(c)
if area > min_area:
x,y,w,h = cv2.boundingRect(c)
cv2.rectangle(image, (x, y), (x + w, y + h), (36,255,12), 2)
ROI = original[y:y+h, x:x+w]
cv2.imwrite("ROI_{}.png".format(image_number), ROI)
image_number += 1
cv2.imshow('blur', blur)
cv2.imshow('dilate', dilate)
cv2.imshow('canny', canny)
cv2.imshow('image', image)
cv2.waitKey(0)