Java中使用OpenCV进行图像处理|S13（增亮）

在本文中, 我们将学习如何使用OpenCv库增强图像的亮度。可以通过将图像的每个像素与alpha值相乘, 然后向其添加beta值来增强图像的亮度。

首先, 我们需要为Java设置OpenCV, 我们建议使用eclipse来实现, 因为它易于使用和设置。有关安装, 请参阅这里

亮度增强所需的方法：

convertTo(目标, rtype, alpha, beta)：此方法位于OpenCv的Mat包中。

语法如下：

sourceImage.convertTo(destination, rtype, alpha, beta);
parameters:
destination: is the destination image
rtype:  is the desired output matrix type
alpha:  is optional scale factor multiplied 
to each pixel of source image
beta:  it is optional beta value added to the scaled values.

imread()–此方法用于将图像读取为由OpenCV渲染的Mat对象。

语法如下：

Imgcodecs.imread(filename);
parameters:
filename: filename of the image file.If the image is 
in another directory whole path of image must be mentioned.

imwrite()–此方法用于将Mat对象写入图像文件。

语法如下：

Imgcodecs.imwrite(filename, mat_img);
parameters:
filename: filename of the image file.If the image is 
in another directory whole path of image must be mentioned.
mat_img: resultant mat object.

package ocv;
  
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
  
public class Main {
    static int width;
    static int height;
    static double alpha = 1 ;
    static double beta = 50 ;
     
    public static void main( String[] args ) {
     
       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 );
  
          //input image
          Mat source =  
           Imgcodecs.imread( "E://input.jpg" , Imgcodecs.CV_LOAD_IMAGE_COLOR);
          Mat destination = new Mat(source.rows(), source.cols(), source.type());
  
          //applying brightness enhacement
          source.convertTo(destination, - 1 , alpha, beta);
  
          //output image
          Imgcodecs.imwrite( "E://output.jpg" , destination);
           
       } catch (Exception e) {
          System.out.println( "error: " + e.getMessage());
       }
    }
}

注意：该代码无法在在线IDE中使用, 因为它需要硬盘中的图像。

Input.jpg