Prerequisites:
- Image Processing in Java – Read and Write
- Image Processing In Java – Get and Set Pixels
- Image Processing in Java – Colored Image to Grayscale Image Conversion
- Image Processing in Java – Colored Image to Negative Image Conversion
- Image Processing in Java – Colored to Red Green Blue Image Conversion
- Image Processing in Java – Colored Image to Sepia Image Conversion
- Image Processing in Java – Creating a Random Pixel Image
- Image Processing in Java – Creating a Mirror Image
- Image Processing in Java – Face Detection
- Image Processing in Java – Watermarking an Image
- Image Processing in Java – Changing Orientation of Image
Contrast Enhancement
At first, we need to set up OpenCV for Java, we recommend using eclipse for the same since it is easy to use and set up. Now let us understand some of the methods required for enhancing the color of an image. Now let us understand some of the methods required for contrast enhancement.
Method 1: equalizeHist(source, destination): This method resides in Imgproc package of opencv.source parameter is an 8-bit single-channel source image, and the destination parameter is the destination image
Method 2: Imcodecs.imread() or Imcodecs.imwrite(): These methods are used to read and write images as Mat objects which are rendered by OpenCV.
Implementation: Let us take an arbitrary input image which is as follows:
Example:
Java
// Java Program to Demonstrate Contrast Enhancement// Using OpenCV Library// Importing package modulepackage ocv;// Importing required classesimport org.opencv.core.Core;import org.opencv.core.Mat;import org.opencv.imgcodecs.Imgcodecs;import org.opencv.imgproc.Imgproc;// Main classpublic class GFG { // Try block to check for exceptions public static void main(String[] args) { // Try block to check for exceptions try { // For proper execution of native libraries // Core.NATIVE_LIBRARY_NAME must be loaded // before calling any of the opencv methods System.loadLibrary(Core.NATIVE_LIBRARY_NAME); // Reading image from local directory by // creating object of Mat class Mat source = Imgcodecs.imread( "E:\\input.jpg", Imgcodecs.CV_LOAD_IMAGE_GRAYSCALE); Mat destination = new Mat(source.rows(), source.cols(), source.type()); // Applying histogram equalization Imgproc.equalizeHist(source, destination); // Writing output image to some other directory // in local system Imgcodecs.imwrite("E:\\output.jpg", destination); // Display message on console for successful // execution of program System.out.print( "Image Successfully Contrasted"); } // Catch block to handle exceptions catch (Exception e) { // Print the exception on the console // using getMessage() method System.out.println("error: " + e.getMessage()); } }} |
Output: On console
Image Successfully Contrasted
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