Image Processing in Java | Set 11 (Changing orientation of image)

In this article we will use opencv to change orientation of any input image, by using the CORE.flip() method of OpenCV library.

The main idea is that an input buffered image object will be converted to a mat object and then a new mat object will be created in which the original mat object values are put after orientation modification.

For achieving the above result, we will be requiring some of the OpenCV methods:

• getRaster() – The method returns a writable raster which in turn is used to get the raw data from input image.
• put(int row, int column, byte[] data) / get(int row, int column, byte[] data) – used to read/write the raw data into a mat object.
• flip(mat mat1, mat mat2, int flip_value) – mat1 and mat2 corresponds to input and output mat objects and the flip_value decides the orientation type.flip_value can be either 0 (flipping along x-axis), 1 (flipping along y-axis), -1 (flipping along both the axis).

// Java program to illustrate orientation modification of image
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;

public class OrientingImage
{
  public static void main( String[] args ) throws IOException
  {
    // loads methods of the opencv library
    System.loadLibrary( Core.NATIVE_LIBRARY_NAME );

    // input buffered image object
    File input = new File("E:\\test.jpg");
    BufferedImage image = ImageIO.read(input);

    // converting buffered image object to mat object
    byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
    Mat mat = new Mat(image.getHeight(),image.getWidth(),CvType.CV_8UC3);
    mat.put(0, 0, data);

    // creating a new mat object and putting the modified input mat object by using flip()
    Mat newMat = new Mat(image.getHeight(),image.getWidth(),CvType.CV_8UC3);
    Core.flip(mat, newMat, -1);  //flipping the image about both axis

    // converting the newly created mat object to buffered image object
    byte[] newData = new byte[newMat.rows()*newMat.cols()*(int)(newMat.elemSize())];
    newMat.get(0, 0, newData);
    BufferedImage image1 = new BufferedImage(newMat.cols(), newMat.rows(), 5);
    image1.getRaster().setDataElements(0,0,newMat.cols(),newMat.rows(),newData);

    File ouptut = new File("E:\\result.jpg");
    ImageIO.write(image1, "jpg", ouptut);
  }
}

Output:

test.jpg


result.jpg

This article is contributed by Pratik Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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