java实现图像处理工具的代码 java图像处理基于opencv与jvm pdf版

submat(int rowStart, int rowEnd, int colStart, int colEnd) 函数的返回值是一个矩阵对象。内容是原图的子矩阵或子区域。

首先我们用imread来读取图片，然后输出矩阵对象本身的一些信息

import org.opencv.core.CvType;
 import org.opencv.core.Mat;
 import org.opencv.core.Core;
 import org.opencv.core.MatOfInt;
 import org.opencv.imgcodecs.Imgcodecs;
 import origami.Origami;public class HelloCv {
     public static void main(String[] args) throws Exception {
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
         Mat mat = Imgcodecs.imread("./images/test.jpg",Imgcodecs.IMREAD_GRAYSCALE);
         System.out.println(mat);
     }
 }

由于这个矩阵是原始图片，所以它的isSubmat是false。

现在我们使用submat函数的第一种形式，输入参数是每一行和每一列的起始和终止值。

 图片裁剪

import org.opencv.core.CvType;
 import org.opencv.core.Mat;
 import org.opencv.core.Core;
 import org.opencv.core.MatOfInt;
 import org.opencv.imgcodecs.Imgcodecs;
 import origami.Origami;public class HelloCv {
     public static void main(String[] args) throws Exception {
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
         Mat mat = Imgcodecs.imread("C:/HWKJ/ZRQ/OpenCv/matrixcv/images/test.jpg");
         System.out.println(mat);
         Mat submat = mat.submat(200, 240, 300, 350);
         System.out.println(submat);
     }
 }

 这里注意submat里的尺寸，尺寸根据原图的尺寸,超出原图的尺寸会报错，报错如下

 然后我们输出裁剪的图片。

那么如何确认你想要截取图片的区域范围呢?也就是说怎么确定这四个参数的填写？我们以下图为例

 截取后的图片

另外两种submat方式

Range(int row,int column)

        row：宽开始结束范围，column：高开始结束范围

Mat submat2 = mat.submat(new Range(20,300),new Range(100,500));
         Imgcodecs.imwrite("./images/output2.png",submat2); 
   Rect(int x, int y,int width, int height)

        x：横坐标，y：纵坐标 ，width ：宽，height：高

Mat submat3 = mat.submat(new Rect(0,200,100,100));
         //submat3.setTo(new Scalar(255,0,0));//将图片绘制为蓝色
         Imgcodecs.imwrite("./images/output3.png",submat3);

 打开setTo如下：

Imgcodecs.imwrite("./images/blurtest.png",mat);

 完整代码：

import org.opencv.core.CvType;
 import org.opencv.core.Scalar;
 import org.opencv.core.Mat;
 import org.opencv.core.Rect;
 import org.opencv.core.Range;
 import org.opencv.core.Core;
 import org.opencv.core.Size;
 import org.opencv.core.MatOfInt;
 import org.opencv.imgcodecs.Imgcodecs;
 import org.opencv.imgproc.Imgproc;
 import origami.Origami;public class HelloCv {
     public static void main(String[] args) throws Exception {
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
         Mat mat = Imgcodecs.imread("C:/HWKJ/ZRQ/OpenCv/matrixcv/images/test.jpg");
         System.out.println(mat);
         Mat submat = mat.submat(200, 400, 200, 550);
         //System.out.println(submat);
         Imgcodecs.imwrite("./images/output.png",submat);
         Mat submat2 = mat.submat(new Range(20,300),new Range(100,500));
         Imgcodecs.imwrite("./images/output2.png",submat2);
         Mat submat3 = mat.submat(new Rect(0,200,400,200));
         submat3.setTo(new Scalar(255,0,0));
         Imgcodecs.imwrite("./images/output3.png",submat3);        //Imgproc.blur(submat,submat,new Size(25.0,25.0));
         Imgcodecs.imwrite("./images/blurtest.png",mat);
     }
 }

 图片模糊处理

import org.opencv.core.CvType;
 import org.opencv.core.Mat;
 import org.opencv.core.Core;
 import org.opencv.core.Size;
 import org.opencv.core.MatOfInt;
 import org.opencv.imgcodecs.Imgcodecs;
 import org.opencv.imgproc.Imgproc;
 import origami.Origami;public class HelloCv {
     public static void main(String[] args) throws Exception {
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
         Mat mat = Imgcodecs.imread("C:/HWKJ/ZRQ/OpenCv/matrixcv/images/test.jpg");
         System.out.println(mat);
         Mat submat = mat.submat(200, 400, 200, 550);
         //System.out.println(submat);
         //Imgcodecs.imwrite("./images/output.png",submat);
         Imgproc.blur(submat,submat,new Size(25.0,25.0));
         System.out.println("after:"+mat);
         Imgcodecs.imwrite("./images/blurtest.png",mat);
     }
 }

子矩阵生成矩阵

setTo和copyTo是OpenCv中两个非常重要的函数。

setTo可以将一个矩阵中的所有像素设置为指定的颜色

copyTo可以将一个已有的矩阵复制到另一个矩阵之中。

第一个颜色值代表蓝色的深度，第二个值代表绿色的深度，最后一个值代表红色的深度。

//获取红绿蓝
         Scalar Red = new Scalar(0,0,255);
         Scalar Green = new Scalar(0,255,0);
         Scalar Blue = new Scalar(255,0,0);

我们把这些颜色当作RGB的补充色。因此把其他通道设置为最大值255，主通道设置为0。蓝绿色是红色的补充色，所以红色值通道被设为0，而另外两个通道为255；

        定义蓝绿色、品红色和黄色

Scalar cyan = new Scalar(255,255,0);
         Scalar  magena= new Scalar(255,0,255);
         Scalar yellow = new Scalar(0,255,255);

下面我们使用setTo将子矩阵设置为给定的Scalar颜色

private void setColors(Mat mat ,boolean comp,int row){
       for (int i = 0; i <3 ; i++) {
           Mat sub = mat.submat(row*100,row*100+100,i*100,i*100+100);
           if(comp){
              //RGB
              if (i==0){
                  sub.setTo(Red);
              }if (i==1){
                   sub.setTo(Green);
               }if (i==2){
                   sub.setTo(Blue);
               }
           }else {
               //cmy
               if (i==0){
                   sub.setTo(cyan);
               }if (i==1){
                   sub.setTo(magena);
               }if (i==2){
                   sub.setTo(yellow);
               }
           }
       }
   }

接下来，我们创建一个包含三个颜色通道矩阵，并且填充它的第一行和第二行

完整代码：

import org.opencv.core.CvType;
 import org.opencv.core.Scalar;
 import org.opencv.core.Mat;
 import org.opencv.core.Rect;
 import org.opencv.core.Range;
 import org.opencv.core.Core;
 import org.opencv.core.Size;
 import org.opencv.core.MatOfInt;
 import org.opencv.imgcodecs.Imgcodecs;
 import org.opencv.imgproc.Imgproc;
 import origami.Origami;public class HelloCv1 {
 public static  Scalar Red = new Scalar(0,0,255);
 public static   Scalar Green = new Scalar(0,255,0);
 public static   Scalar Blue = new Scalar(255,0,0);
 public static   Scalar cyan = new Scalar(255,255,0);
 public static   Scalar  magena= new Scalar(255,0,255);
 public static   Scalar yellow = new Scalar(0,255,255);
     public static void main(String[] args) throws Exception {
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
         Mat mat = new Mat(200,300,CvType.CV_8UC3);
         setColors(mat,false,1);
         setColors(mat,true,0);
         Imgcodecs.imwrite("./images/rgbcmy.png",mat);    }
    static void setColors(Mat mat ,boolean comp,int row){
       for (int i = 0; i <3 ; i++) {
           Mat submat = mat.submat(row*100,row*100+100,i*100,i*100+100);
           if(comp){
              //RGB
              if (i==0){
                submat.setTo(Red);
              }if (i==1){
                submat.setTo(Green);
               }if (i==2){
                 submat.setTo(Blue);
               }
           }else {
               //cmy
               if (i==0){
                 submat.setTo(cyan);
               }if (i==1){
                 submat.setTo(magena);
               }if (i==2){
                 submat.setTo(yellow);
               }
           }
       }
   }
 }

 从图片子矩阵生成矩阵

        首先创建一个大小为200x200的矩阵和子矩阵：一个是主矩阵的上部，一个是主矩阵的下部

int width = 200,height = 200;
         Mat mat1 = new Mat(height,width,CvType.CV_8UC3);
         Mat top = mat.submat(0,height/2,0,width);
         Mat bottom = mat.submat(height/2,height,0,width);

然后加载一个图片以创建另一个小矩阵，并把它的大小调整为上部（或下部）的子矩阵大小。这里会引入Imgproc类中的resize函数。

完整代码：

import org.opencv.core.CvType;
 import org.opencv.core.Scalar;
 import org.opencv.core.Mat;
 import org.opencv.core.Rect;
 import org.opencv.core.Range;
 import org.opencv.core.Core;
 import org.opencv.core.Size;
 import org.opencv.core.MatOfInt;
 import org.opencv.imgcodecs.Imgcodecs;
 import org.opencv.imgproc.Imgproc;
 import origami.Origami;public class HelloCv1 {
 public static  Scalar Red = new Scalar(0,0,255);
 public static   Scalar Green = new Scalar(0,255,0);
 public static   Scalar Blue = new Scalar(255,0,0);
 public static   Scalar cyan = new Scalar(255,255,0);
 public static   Scalar  magena= new Scalar(255,0,255);
 public static   Scalar yellow = new Scalar(0,255,255);
     public static void main(String[] args) throws Exception {
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);        int width = 200,height = 300;
         Mat mat1 = new Mat(height,width,CvType.CV_8UC3);
         Mat top = mat1.submat(0,height/2,0,width);
         Mat bottom = mat1.submat(height/2,height,0,width);        Mat small = Imgcodecs.imread("./images/test.jpg");
         Imgproc.resize(small,small,top.size());
         small.copyTo(top);
         small.copyTo(bottom);
         Imgcodecs.imwrite("./images/matofpictures.png",mat1);
     }

注意：设置大小的步骤很关键。复制能够成功，是因为小矩阵和子矩阵的大小是完全相同的，因此复制的时候没有出现任何问题