In OpenCV, images are stored in Using Mat object. It is nothing but an n-dimensional array and is used to store image data of grayscale or color images, voxel volumes, vector fields, point clouds, tensors, histograms, etc.If you try to read an image using the OpenCV library it will be read to a Mat object.Mat matrix = Imgcodecs.imread(filePath);You can instantiate this class manually using one of the following constructors −Mat() − A no-arg constructor, used to create an empty matrix and pass this to other OpenCV methods.Mat(int rows, int cols, int type) − This constructor accepts three parameters of integer ... Read More

The applyColorMap() method of the Imgproc class applies specified color map to the given image. This method accepts three parameters −Two Mat objects representing the source and destination images.An integer variable representing the type of the color map to be applied.You can pass any of the following as color map value to this method.COLORMAP_AUTUMN, COLORMAP_BONE, COLORMAP_COOL, COLORMAP_HOT, COLORMAP_HSV, COLORMAP_JET, COLORMAP_OCEAN , COLORMAP_PARULA, COLORMAP_PINK, COLORMAP_RAINBOW, COLORMAP_SPRING, COLORMAP_SUMMER, COLORMAP_WINTER.Exampleimport org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class CustomColorMaps {    public static void main(String args[]) {       // Loading the OpenCV core library       System.loadLibrary(Core.NATIVE_LIBRARY_NAME);     ... Read More

The equalizeHist() method of the Imgproc class accepts a greyscale image and equalizes its histogram, which will, in turn, normalizes the brightness and increases the contrast of the given image. This method accepts two parameters −A Mat object representing the source image (greyscale).A Mat object to save the result.ExampleFollowing Java program reads a colored image as greyscale, saves it, normalizes the brightness and increases the contrast of the given image and saves it.import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.highgui.HighGui; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class HstExample {    public static void main(String args[]) {       //Loading the OpenCV core ... Read More

JavaFX provides a class known as Slider, this represents a slider component that displays a continuous range of values. This contains a track on which the numerical values are displayed. Along the track, there is a thumb pointing to the numbers. You can provide the maximum, minimum and initial values of the slider. To create a slider you need to instantiate the Slider class, set the required properties and, add it to the scene.Exampleimport javafx.application.Application; import javafx.geometry.Insets; import javafx.scene.Scene; import javafx.scene.control.Slider; import javafx.scene.layout.VBox; import javafx.stage.Stage;         public class SliderExample extends Application {    public void start(Stage stage) ... Read More

In general, a slider is a component that displays a continuous range of values. This contains a track on which the numerical values are displayed. Along the track, there is a thumb pointing to the numbers. You can provide the maximum, minimum and initial values of the slider.The slider JavaFX provides contains only one thumb if you want to create a slider with two thumbs you need to rely on an external library named org.controlsfx.control.Following is the maven dependency for this library −    org.controlsfx    controlsfx    11.0.1 The RangeSlider class of this package is the JavaFXSlider but with ... Read More

To add noise to a given image using OpenCV −Read the contents of the given image to a Mat object.Create two more empty matrices to store the noise and the resultant matrices.Create two MatOfDouble matrices to store mean and standard deviation.Get the mean and standard deviation values using the meanStdDev() method.Create a matrix with random elements (to store the noise) using the randn() method.To this method pass the above-created source, mean and standard deviation objects.Finally, add the noise matrix and source matrix and save as destination.Exampleimport java.awt.Image; import java.awt.image.BufferedImage; import java.io.IOException; import javafx.application.Application; import javafx.embed.swing.SwingFXUtils; import javafx.scene.Group; import javafx.scene.Scene; import ... Read More

The resize() method of the Imgproc class resizes the specified image. This method accepts −Two Mat objects representing the source and destination images.A Size object representing the size of the output image.A double variable representing the scale factor along the horizontal axis.A double variable representing the scale factor along the vertical axis.An integer variable representing the interpolation method to be used in the operation.Exampleimport java.awt.Image; import java.awt.image.BufferedImage; import java.io.IOException; import javafx.application.Application; import javafx.embed.swing.SwingFXUtils; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.ImageView; import javafx.scene.image.WritableImage; import javafx.stage.Stage; import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.Size; import org.opencv.highgui.HighGui; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class ScalingAnImage extends Application { ... Read More

JShell has introduced in Java 9 and is a command-line tool that allows us to enter simple statements, expressions, methods, and classes without a main () method.When we can enter code in JShell, the code has assigned a unique ID. This ID starts at 1 and has incremented for each command entered in JShell. The same can be true for libraries loaded at startup. For each of these imports, a unique ID has been assigned. It starts with $1 and is incremented for each code loaded ($2, $3 and etc). There is an internal command to list all code loaded, and ... Read More

The warpAffine() method of the Imgproc class applies an affine transformation to the specified image. This method accepts −Three Mat objects representing the source, destination, and transformation matrices.An integer value representing the size of the output image.To translate an image Create a translation matrix and pass it as a transformation matrix to this method along with the other parameters.Exampleimport java.awt.Image; import java.awt.image.BufferedImage; import java.io.IOException; import javafx.application.Application; import javafx.embed.swing.SwingFXUtils; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.ImageView; import javafx.scene.image.WritableImage; import javafx.stage.Stage; import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.MatOfPoint2f; import org.opencv.core.Point; import org.opencv.core.Size; import org.opencv.highgui.HighGui; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class TranslatingAnImage extends Application { ... Read More

The warpAffine() method of the Imgproc class applies an affine transformation to the specified image. This method accepts −Three Mat objects representing the source, destination, and transformation matrices.An integer value representing the size of the output image.To rotate an image Create a rotation matrix and pass it as a transformation matrix to this method along with the other parameters.Exampleimport java.awt.Image; import java.awt.image.BufferedImage; import java.io.IOException; import javafx.application.Application; import javafx.embed.swing.SwingFXUtils; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.ImageView; import javafx.scene.image.WritableImage; import javafx.stage.Stage; import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.Point; import org.opencv.core.Size; import org.opencv.highgui.HighGui; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class RotatingAnImage extends Application {    public ... Read More