Comparing Mat types

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Hello.

I am attempting to use open cv to compare the Mat representations of a local image versus an image extracted via URL. I'm interested in getting a binary output, true if the web image matches in every way with the local image, false otherwise.

To test, I downloaded a web image locally, and attempted to compare the original web image against the local copy using the overloaded equals method of the Mat type.

The dimensions of both Mat objects appear to be the same in the output, but the equals method reports that the two Mat objects are not the same.

I'm kind of at a loss. Was I using the Mat.equals method outside the context it was intended?

Source code follows:

public static void main (String args[]) throws IOException { ImageExtractor imageRepository = new ImageExtractor("filepath", "urlPath");

System.out.println(imageRepository.getLocalImage()); System.out.println(imageRepository.getWebImage());

System.out.println(imageRepository.getLocalImage().equals(imageRepository.getWebImage())); }

public class ImageExtractor { private Mat webImage; private Mat localImage;

public ImageExtractor(String filepath, String urlPath) throws IOException
{
    localImage = convertLocalImageToMat(filepath);
    webImage = convertWebImageToMat(urlPath);

}


// webimage conversion 
private Mat convertWebImageToMat(String url) throws IOException
{
    InputStream input = new URL(url).openStream();

    Mat resultImage = readInputStreamIntoMat(input);
    return resultImage;
}

private Mat readInputStreamIntoMat(InputStream inputStream) throws IOException {
    // Read into byte-array
    byte[] temporaryImageInMemory = readStream(inputStream);

    // Decode into mat. Use any IMREAD_ option that describes your image appropriately
    Mat outputImage = Imgcodecs.imdecode(new MatOfByte(temporaryImageInMemory), Imgcodecs.IMREAD_ANYCOLOR);

    return outputImage;
}

private byte[] readStream(InputStream stream) throws IOException {
    // Copy content of the image to byte-array
    ByteArrayOutputStream buffer = new ByteArrayOutputStream();
    int nRead;
    byte[] data = new byte[16384];

    while ((nRead = stream.read(data, 0, data.length)) != -1) {
        buffer.write(data, 0, nRead);
    }

    buffer.flush();
    byte[] temporaryImageInMemory = buffer.toByteArray();
    buffer.close();
    stream.close();
    return temporaryImageInMemory;
}

// local image conversion
private Mat convertLocalImageToMat(String filepath)
{
    return Imgcodecs.imread(filepath);
}

public Mat getWebImage()
{
    return webImage;
}

public Mat getLocalImage()
{
    return localImage;
}

}