OpenCV with PHP - recognize text

Question

I need to recognize text in an image and then crop out the rectangle with the text to reduce the image size

The first step is to recognize the text and I have found a solution here

But how to compile and run this from PHP? I'm not familiar with C

How to compile the code so you can pass arguments to the program like exec('opencv_test input.jpg output.jpg')

Instead of drawing rectangles around each text block the program should analyse all text blocks and get the two coordinates where the image should be cropped.. And then crop the image an write the output file to the output destination

code

#include "stdafx.h"

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>

using namespace cv;
using namespace std;

#define INPUT_FILE              "1.jpg"
#define OUTPUT_FOLDER_PATH      string("")

int _tmain(int argc, _TCHAR* argv[])
{
    Mat large = imread(INPUT_FILE);
    Mat rgb;
    // downsample and use it for processing
    pyrDown(large, rgb);
    Mat small;
    cvtColor(rgb, small, CV_BGR2GRAY);
    // morphological gradient
    Mat grad;
    Mat morphKernel = getStructuringElement(MORPH_ELLIPSE, Size(3, 3));
    morphologyEx(small, grad, MORPH_GRADIENT, morphKernel);
    // binarize
    Mat bw;
    threshold(grad, bw, 0.0, 255.0, THRESH_BINARY | THRESH_OTSU);
    // connect horizontally oriented regions
    Mat connected;
    morphKernel = getStructuringElement(MORPH_RECT, Size(9, 1));
    morphologyEx(bw, connected, MORPH_CLOSE, morphKernel);
    // find contours
    Mat mask = Mat::zeros(bw.size(), CV_8UC1);
    vector<vector<Point>> contours;
    vector<Vec4i> hierarchy;
    findContours(connected, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));
    // filter contours
    for(int idx = 0; idx >= 0; idx = hierarchy[idx][0])
    {
        Rect rect = boundingRect(contours[idx]);
        Mat maskROI(mask, rect);
        maskROI = Scalar(0, 0, 0);
        // fill the contour
        drawContours(mask, contours, idx, Scalar(255, 255, 255), CV_FILLED);
        // ratio of non-zero pixels in the filled region
        double r = (double)countNonZero(maskROI)/(rect.width*rect.height);

        if (r > .45 /* assume at least 45% of the area is filled if it contains text */
            && 
            (rect.height > 8 && rect.width > 8) /* constraints on region size */
            /* these two conditions alone are not very robust. better to use something 
            like the number of significant peaks in a horizontal projection as a third condition */
            )
        {
            rectangle(rgb, rect, Scalar(0, 255, 0), 2);
        }
    }
    imwrite(OUTPUT_FOLDER_PATH + string("rgb.jpg"), rgb);

    return 0;
}

You'll need to write your own wrappers. http://www.xarg.org/project/php-facedetect/ — GPPK, Dec 09 '15 at 12:02
I am surprised with 5 downvotes! question is not bad at all and asks for how to call c++ code from php! — Humam Helfawi, Dec 09 '15 at 12:25

score 0 · Accepted Answer · answered Dec 09 '15 at 12:29

You can see GPPK comment. It should work for you. However, if you need some fast way without so much additional libraries and wrappers. Just compile your c++ code into an executable file (such as exe or whatever in your platform) and put an argument possibilities (passing image path as argument). Then, I think you can call it from your PHP code. As far as I know PHP is server-side so it should be an easy task. However, You may ask for permission from your hosting service or the server administrator to give you the possibility of running exe file on server.

By any C++ compiler for your platform. tell any C++ developer where you work and he will do it for you in 5 minutes — Humam Helfawi, Dec 09 '15 at 15:44

OpenCV with PHP - recognize text

code

1 Answers1