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Open Source Computer Vision Library
https://opencv.org/
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75 lines
2.2 KiB
75 lines
2.2 KiB
5 years ago
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/*
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This tutorial demonstrates how to correct the skewness in a text.
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The program takes as input a skewed source image and shows non skewed text.
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*/
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#include <opencv2/core.hpp>
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#include <opencv2/imgcodecs.hpp>
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#include <opencv2/highgui.hpp>
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#include <opencv2/imgproc.hpp>
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#include <iostream>
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#include <iomanip>
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#include <string>
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using namespace cv;
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using namespace std;
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int main( int argc, char** argv )
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{
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CommandLineParser parser(argc, argv, "{@input | imageTextR.png | input image}");
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// Load image from the disk
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Mat image = imread( samples::findFile( parser.get<String>("@input") ), IMREAD_COLOR);
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if (image.empty())
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{
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cout << "Cannot load the image " + parser.get<String>("@input") << endl;
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return -1;
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}
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Mat gray;
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cvtColor(image, gray, COLOR_BGR2GRAY);
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//Threshold the image, setting all foreground pixels to 255 and all background pixels to 0
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Mat thresh;
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threshold(gray, thresh, 0, 255, THRESH_BINARY_INV | THRESH_OTSU);
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// Applying erode filter to remove random noise
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int erosion_size = 1;
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Mat element = getStructuringElement( MORPH_RECT, Size(2*erosion_size+1, 2*erosion_size+1), Point(erosion_size, erosion_size) );
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erode(thresh, thresh, element);
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cv::Mat coords;
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findNonZero(thresh, coords);
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RotatedRect box = minAreaRect(coords);
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float angle = box.angle;
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// The cv::minAreaRect function returns values in the range [-90, 0)
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// if the angle is less than -45 we need to add 90 to it
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if (angle < -45.0f)
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{
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angle = (90.0f + angle);
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}
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//Obtaining the rotation matrix
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Point2f center((image.cols) / 2.0f, (image.rows) / 2.0f);
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Mat M = getRotationMatrix2D(center, angle, 1.0f);
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Mat rotated;
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// Rotating the image by required angle
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stringstream angle_to_str;
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angle_to_str << fixed << setprecision(2) << angle;
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warpAffine(image, rotated, M, image.size(), INTER_CUBIC, BORDER_REPLICATE);
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putText(rotated, "Angle " + angle_to_str.str() + " degrees", Point(10, 30), FONT_HERSHEY_SIMPLEX, 0.7, Scalar(0, 0, 255), 2);
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cout << "[INFO] angle: " << angle_to_str.str() << endl;
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//Show the image
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imshow("Input", image);
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imshow("Rotated", rotated);
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waitKey(0);
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return 0;
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}
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