assertion failed

asked 2015-08-18 13:44:33 -0500

Salman gravatar image

updated 2015-08-18 14:22:47 -0500

on running this code an assertion failed error occurred on cmd line window

OPENCV Error : Assertion Failed <scn =="3" ||="" scn="4"> in cv::cvtColor,file:C:(address)

#include <stdio.h>
#include <iostream>

#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/nonfree/nonfree.hpp"
#include "opencv2/calib3d/calib3d.hpp"
#include "opencv2/imgproc/imgproc.hpp"

using namespace cv;

/** @function main */
int main()
{


    // Load the images
    Mat image1 = imread("scene11.jpeg");
    Mat image2 = imread("scene21.jpeg");
    Mat gray_image1;
    Mat gray_image2;
    // Convert to Grayscale
    cvtColor(image1, gray_image1, CV_RGB2GRAY);
    cvtColor(image2, gray_image2, CV_RGB2GRAY);

    imshow("image1", image2);
    imshow("image2", image1);

    if (!gray_image1.data || !gray_image2.data)
    {
        std::cout << " --(!) Error reading images " << std::endl; return -1;
    }

    //-- Step 1: Detect the keypoints using SURF Detector
    int minHessian = 400;

    SurfFeatureDetector detector(minHessian);

    std::vector< KeyPoint > keypoints_object, keypoints_scene;

    detector.detect(gray_image1, keypoints_object);
    detector.detect(gray_image2, keypoints_scene);

    //-- Step 2: Calculate descriptors (feature vectors)
    SurfDescriptorExtractor extractor;

    Mat descriptors_object, descriptors_scene;

    extractor.compute(gray_image1, keypoints_object, descriptors_object);
    extractor.compute(gray_image2, keypoints_scene, descriptors_scene);

    //-- Step 3: Matching descriptor vectors using FLANN matcher
    FlannBasedMatcher matcher;
    std::vector< DMatch > matches;
    matcher.match(descriptors_object, descriptors_scene, matches);

    double max_dist = 0; double min_dist = 100;

    //-- Quick calculation of max and min distances between keypoints
    for (int i = 0; i < descriptors_object.rows; i++)
    {
        double dist = matches[i].distance;
        if (dist < min_dist) min_dist = dist;
        if (dist > max_dist) max_dist = dist;
    }

    printf("-- Max dist : %f \n", max_dist);
    printf("-- Min dist : %f \n", min_dist);

    //-- Use only "good" matches (i.e. whose distance is less than 3*min_dist )
    std::vector< DMatch > good_matches;

    for (int i = 0; i < descriptors_object.rows; i++)
    {
        if (matches[i].distance < 3 * min_dist)
        {
            good_matches.push_back(matches[i]);
        }
    }
    std::vector< Point2f > obj;
    std::vector< Point2f > scene;

    for (size_t i = 0; i < good_matches.size(); i++)
    {
        //-- Get the keypoints from the good matches
        obj.push_back(keypoints_object[good_matches[i].queryIdx].pt);
        scene.push_back(keypoints_scene[good_matches[i].trainIdx].pt);
    }

    // Find the Homography Matrix
    Mat H = findHomography(obj, scene, CV_RANSAC);
    // Use the Homography Matrix to warp the images
    cv::Mat result;
    warpPerspective(image1, result, H, cv::Size(image1.cols + image2.cols, image1.rows));
    cv::Mat half(result, cv::Rect(0, 0, image2.cols, image2.rows));
    image2.copyTo(half);
    imshow("Result", result);

    waitKey(0);
    return 0;
}
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Comments

1

The error indicates your Mat image1 and/or Mat image2 does not have the required 3 channels to convert from RGB. Probably the problem is you didn't read the images correctly with imread and the matrices are empty. Try using full paths of the images

LorenaGdL gravatar imageLorenaGdL ( 2015-08-18 13:56:11 -0500 )edit

as @LorenaGdL stated you must correct your code as below to be sure your source images successfully loaded

// Load the images
Mat image1 = imread("scene11.jpeg");
Mat image2 = imread("scene21.jpeg");

if (!image1.data || !image2.data)
{
    std::cout << " --(!) Error reading images " << std::endl; return -1;
}
Mat gray_image1;
Mat gray_image2;
// Convert to Grayscale
cvtColor(image1, gray_image1, CV_RGB2GRAY);
cvtColor(image2, gray_image2, CV_RGB2GRAY);

imshow("image1", image2);
imshow("image2", image1);



//-- Step 1: Detect the keypoints using SURF Detector
int minHessian = 400;
sturkmen gravatar imagesturkmen ( 2015-08-18 14:26:51 -0500 )edit

you were right, images were not uploaded. I've restored the original version of the code that passes command line argument. However this doesn't work too :/ I'm using VC13 and i've given the arguments to properties of solution explorer -> debugging -> command argument -> "C:/image1.jpeg" "C:/image2.jpeg"

using namespace std; using namespace cv;

int main(int argc, char* argv[]) { Mat img;

img = imread(argv[1], CV_LOAD_IMAGE_COLOR);

if (img.empty())
{
    cout << "Error: Image cannot be loaded!" << endl;
    system("pause");
    return -1;
}

namedWindow("Image", CV_WINDOW_AUTOSIZE);
imshow("Image", img);

waitKey(0);
destroyWindow("Image");

return 0;
Salman gravatar imageSalman ( 2015-08-19 06:21:07 -0500 )edit

Weren't your images named scene11.jpeg and scene21.jpeg? Anyway, try first to use your previous version with full paths, i.e., Mat image1 = imread("C:/scene11.jpeg");

LorenaGdL gravatar imageLorenaGdL ( 2015-08-19 06:54:21 -0500 )edit