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The cvtColor() method of the Imgproc class changes/converts the color of the image from one to another. This method accepts three parameters −src − A Matrix object representing source.dst − A Matrix object representing the destination.code − An integer value representing the color of the destination image.To convert an HSV image to BGR you need to pass Imgproc.COLOR_HSV2BGR as the 3rd parameter to the cvtColor() method.Examplepublic class HSV2RGB { public static void main(String args[]) throws Exception { System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); Mat src = Imgcodecs.imread("D:\images\hsvimage2.jpg"); Mat dst = new Mat(); ... Read More
The cvtColor() method of the Imgproc class changes/converts the color of the image from one to another. This method accepts three parameters −src − A Matrix object representing source.dst − A Matrix object representing the destination.code − An integer value representing the color of the destination image.To convert an HSV image to RGB you need to pass Imgproc.COLOR_HSV2RGB as the third parameter to this method.Exampleimport org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class HSV2RGB { public static void main(String args[]) throws Exception { //Loading the OpenCV core library System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); ... Read More
The cvtColor() method of the Imgproc class changes/converts the color of the image from one to another. This method accepts three parameters −src − A Matrix object representing source.dst − A Matrix object representing the destination.code − An integer value representing the color of the destination image.To convert an RGB image to HSV you need to pass Imgproc.COLOR_RGB2HSV as the third parameter to this method.Exampleimport org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class RGB2HSV { public static void main(String args[]) throws Exception { //Loading the OpenCV core library System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); ... Read More
Sharpening an image is the opposite of blur. To alter the sharpness of an image using the OpenCV library, you need to smooth/blur it using the Gaussian filter and subtract the smoothed version from the original image.ExampleFollowing is a JavaFX program with two sliders representing the alpha and beta values.import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import javafx.application.Application; import javafx.beans.value.ChangeListener; import javafx.beans.value.ObservableValue; import javafx.embed.swing.SwingFXUtils; import javafx.geometry.Insets; import javafx.scene.Scene; import javafx.scene.control.Label; import javafx.scene.control.Slider; import javafx.scene.image.ImageView; import javafx.scene.image.WritableImage; import javafx.scene.layout.VBox; import javafx.stage.Stage; import javax.imageio.ImageIO; import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.MatOfByte; import org.opencv.core.Size; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class SharpnessJavaFX extends Application ... Read More
The convertTo() method of the org.opencv.core.Mat class accepts 4 parameters namely: mat(empty matrix), rtype(integer), alpha(integer), beta(integer), in the same order.To increase the brightness − You need to reduce the beta value from 0 towards -255(keeping alpha value 1).To decrease the brightness − You need to increase the beta value from 0 towards 255(keeping alpha value 1).To increase the contrast − You need to increase the alpha value from 1 towards 100(keeping beta value 0).To decrease the contrast − You need to decrease the alpha value from 1 to 0 (keeping beta value 0).ExampleFollowing is a JavaFX program with two slide ... Read More
One way to alter the brightness of an image using Java is to use the convertTo() method. This method performs the required calculations on the given matrix to alter the contrast and brightness of an image. This method accepts 4 parameters −mat − Empty matrix to hold the result with the same size and type as the source matrix.rtype − integer value specifying the type of the output matrix. If this value is negative, the type will be same as the source.alpha − Gain value, which must be greater than 0 (default value 1).beta − Bias value (default value 0).if ... Read More
Sharpening an image is the opposite of blur. To alter the sharpness of an image using the OpenCV library, you need to smooth/blur it using the Gaussian filter and subtract the smoothed version from the original image.Exampleimport org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.Size; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class AlteringSharpness { public static void main (String[] args) { //Loading the OpenCV core library System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); //Reading the Image from the file String file ="D:\Image\lamma1.jpg"; Mat src = Imgcodecs.imread(file, Imgcodecs.IMREAD_COLOR); //Creating an ... Read More
The convertTo() method of the org.opencv.core.Mat class performs the required calculations on the given matrix to alter the contrast and brightness of an image. This method accepts 4 parameters −mat − Empty matrix to hold the result with the same size and type as the source matrix.rtype − integer value specifying the type of the output matrix. If this value is negative, the type will be the same as the source.alpha − Gain value, which must be greater than 0 (default value 1).beta − Bias value (default value 0).Altering the brightness of an image using OpenCV Java libraryAs mentioned the ... Read More
The increasing/decreasing of brightness and contrast of an image are the operations that can be achieved by transforming the pixels of the image. this can be expressed in the form of an equation as −g(i, j) = α . f(i, j)+ βWhere, (i, j) are the positions of the pixels.α (gain) and β (bias) are the parameters of the transformation.At times the gain parameter controls the contrast of an image and the bias parameter controls the brightness of an image.The convertTo() method of the org.opencv.core.Mat class performs the required calculations on the given matrix to alter the contrast and brightness ... Read More
To compare two images −Read Both of them using the Image.IO.read() method.Get the height and width of both of them to make sure they are equal.Get the pixel values and, get the RGB values of both of the images.Get the sum of the differences between the RGB values of these two images.Calculate the percentage of the difference using the following formula −Average = difference/weight*height*3; Percentage = (Average/255)*100;Exampleimport java.awt.Color; import java.awt.image.BufferedImage; import javax.imageio.ImageIO; import java.io.File; public class ComparingImages { public static void main(String[] args) throws Exception { BufferedImage img1 = ImageIO.read(new File("D:\Images\test1.jpg")); BufferedImage img2 ... Read More