Case 1: straight line over the text mark

Abstract: This paper describes a method for marking a line on the text.

1. Description of the problem

The straight line marked on the image of text, text examples are as follows:

2, the protocol described

Straight-line detection of the above image, first think Hough line detection, but so will most of the text contains some fine also detected straight line is not the result we want, therefore, must be pre-image process, and the meaning of the following specific steps:

Binarization process (foundation for the morphological operations)
Morphological operations (to remove text)
Linearly detecting
The straight line marked

3, sample code

. 1  #define _CRT_SECURE_NO_WARNINGS
 2 #include <the iostream>
 . 3 #include <opencv2 / opencv.hpp>
 . 4  
. 5  the using  namespace STD;
 . 6  the using  namespace CV;
 . 7  
. 8  const  char * INPUT = " input image " ;
 . 9  const  char * = OUTPUT1 " binary image " ;
 10  const  char * = Output2 " linear image " ;
 . 11  const  char * = OUTPUT3 "Result image " ;
 12 is  
13 is  Mat the src, src_Threshould, DST, LSRC;
 14  
15  int main ( int Arge, char ** the argv) {
 16      the src = imread ( " C: /Users/Lzy/Desktop/img/word.jpg " );
 . 17      LSRC = imread ( " C: /Users/Lzy/Desktop/img/word.jpg " );
 18 is      IF (src.empty ()) {
 . 19          COUT << " image import failed " << endl;
 20 is          return - . 1 ;
 21      }
22 
23     cvtColor(src, src, COLOR_BGR2GRAY);
24     namedWindow(input, WINDOW_AUTOSIZE);
25     imshow(input, src);
26 
27     adaptiveThreshold(~src,src_Threshould,255,ADAPTIVE_THRESH_MEAN_C,THRESH_BINARY,7,-2);
28     //medianBlur(src_Threshould,src_Threshould,3);
29     namedWindow(output1, WINDOW_AUTOSIZE);
30     imshow(output1,src_Threshould);
31 
32     Mat vline = getStructuringElement(MORPH_RECT,Size(1,src.rows/20),Point(-1,-1));
33     erode(src_Threshould, src_Threshould,vline);
34     dilate(src_Threshould,dst, vline);
35     namedWindow(output2, WINDOW_AUTOSIZE);
36     imshow(output2,dst);
37 
38     vector<Vec4f>lines;
39     HoughLinesP(dst, lines, 1, CV_PI / 180.0, 10, 0, 10);
40     for (int i = 0; i < lines.size(); i++) {
41         Vec4f linep = lines[i];
42         line(lsrc, Point(linep[0], linep[1]), Point(linep[2], linep[3]), Scalar(0,0,255), 3, LINE_AA);
43     }
44     imshow(output3, lsrc); 
45 
46     waitKey(0);
47     return 0;
48 }

4, the operating result

Artwork

Binary image

Morphological operations FIG.

FIG detectable label