图像滤波操作

package com.example.opencvapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import org.opencv.android.OpenCVLoader;
import org.opencv.android.Utils;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.Size;
import org.opencv.imgproc.Imgproc;

public class Expt_4 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_expt4);
        //初始化加载OpenCV
        OpenCVLoader.initDebug();

        //通过id查找按钮
        Button button_go_home4 = findViewById(R.id.go_home4);

        //添加按钮点击响应
        button_go_home4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //界面跳转
                startActivity(new Intent(Expt_4.this,MainActivity.class));
            }
        });//
        Button btn_mean_filter = findViewById(R.id.btn_mean_filter);
        Button btn_gaussian_filter = findViewById(R.id.btn_gaussian_filter);
        Button btn_median_filter = findViewById(R.id.btn_median_filter);
        Button btn_custom_filter = findViewById(R.id.btn_custom_filter);
        Button btn_restore_4 = findViewById(R.id.btn_restore_4);
        ImageView img_expt_4 =findViewById(R.id.img_expt_4);

        btn_mean_filter.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.noise);
                Mat src = new Mat();
                Utils.bitmapToMat(bitmap,src);
                Mat dst = new Mat();
                Imgproc.blur(src,dst,new Size(30,30));
                Utils.matToBitmap(dst,bitmap);
                img_expt_4.setImageBitmap(bitmap);
                dst.release();
                src.release();
            }
        });


        btn_gaussian_filter.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.noise);
                Mat src = new Mat();
                Utils.bitmapToMat(bitmap,src);
                Mat dst = new Mat();
                Imgproc.GaussianBlur(src,dst,new Size(0,0),
                        15,0, Core.BORDER_DEFAULT);
                Utils.matToBitmap(dst,bitmap);
                img_expt_4.setImageBitmap(bitmap);
                dst.release();
                src.release();
            }
        });

        btn_median_filter.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.noise);
                Mat src = new Mat();
                Utils.bitmapToMat(bitmap,src);
                Mat dst = new Mat();
                Imgproc.medianBlur(src,dst,11);
                Utils.matToBitmap(dst,bitmap);
                img_expt_4.setImageBitmap(bitmap);
                dst.release();
                src.release();
            }
        });
        btn_custom_filter.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.original);
                Mat src = new Mat();
                Utils.bitmapToMat(bitmap,src);

                Imgproc.cvtColor(src,src,Imgproc.COLOR_RGBA2GRAY);

                //定义X和Y方向的模板，计算梯度
                Mat temp_x = new Mat(3,3,CvType.CV_32F);
                Mat temp_y = new Mat(3,3,CvType.CV_32F);
                float [] gradient_x = new float [] {-3,0,3,-10,0,10,-3,0,3};
                float [] gradient_y = new float [] {-3,-10,-3,0,0,3,10,3};
                temp_x.put(0,0,gradient_x);
                temp_y.put(0,0,gradient_y);

                Mat dst_x = new Mat();
                Mat dst_y = new Mat();

                Imgproc.filter2D(src,dst_x, CvType.CV_32F,temp_x);
                Core.convertScaleAbs(dst_x,dst_x);

                Imgproc.filter2D(src,dst_y, CvType.CV_32F,temp_y);
                Core.convertScaleAbs(dst_y,dst_y);

                Mat dst = new Mat();
                Core.addWeighted(dst_x,0.5,dst_y,0.5,0,dst);
                dst.convertTo(dst,CvType.CV_8U);
                Imgproc.threshold(dst,dst,60,255,Imgproc.THRESH_BINARY);

                Utils.matToBitmap(dst,bitmap);

                img_expt_4.setImageBitmap(bitmap);
                src.release();
                dst.release();
                temp_x.release();
                temp_y.release();
                dst_x.release();
                dst_y.release();
            }
        });

        btn_restore_4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.noise);
                img_expt_4.setImageBitmap(bitmap);
            }
        });
    }
}