Android Studio上使用OpenCV_opencv联级分类训练 android studio-优快云博客

本文介绍在Android环境中使用OpenCV进行图像处理的具体实践，包括如何将彩色图像转换为灰度图像，并提供了完整的代码示例。适用于Android开发者学习OpenCV的集成与应用。

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1、这个链接里讲了Android 里使用OpenCV的第三种方式

我基本上使用也推荐使用第三种方式；

https://cloud.tencent.com/developer/news/48990

2、参考链接：https://blog.youkuaiyun.com/qq_36992688/article/details/79214273

按照上面的这个链接，操作成功了。

我的Android studio的版本是3.2.1

OpenCV版本：openCVLibrary344

MainActivity.Java

package com.example.shengguangyou.opencvtest;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
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.CvType;
import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;

import java.io.InputStream;


public class MainActivity extends AppCompatActivity {

    private double max_size = 1024;
    private int PICK_IMAGE_REQUEST = 1;
    private ImageView myImageView;
    private Bitmap selectbp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        staticLoadCVLibraries();
        myImageView = (ImageView)findViewById(R.id.imageView);
        myImageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
        Button selectImageBtn = (Button)findViewById(R.id.select_btn);
        selectImageBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // makeText(MainActivity.this.getApplicationContext(), "start to browser image", Toast.LENGTH_SHORT).show();
                selectImage();
            }
        });

        Button processBtn = (Button)findViewById(R.id.process_btn);
        processBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // makeText(MainActivity.this.getApplicationContext(), "hello, image process", Toast.LENGTH_SHORT).show();
                convertGray();
            }
        });

    }

    //OpenCV库静态加载并初始化
    private void staticLoadCVLibraries(){
        boolean load = OpenCVLoader.initDebug();
        if(load) {
            Log.i("CV", "Open CV Libraries loaded...");
        }
    }

    private void convertGray() {
        Mat src = new Mat();
        Mat temp = new Mat();
        Mat dst = new Mat();
        Utils.bitmapToMat(selectbp, src);
        Imgproc.cvtColor(src, temp, Imgproc.COLOR_BGRA2BGR);
        Log.i("CV", "image type:" + (temp.type() == CvType.CV_8UC3));
        Imgproc.cvtColor(temp, dst, Imgproc.COLOR_BGR2GRAY);
        Utils.matToBitmap(dst, selectbp);
        myImageView.setImageBitmap(selectbp);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
            Uri uri = data.getData();
            try {
                Log.d("image-tag", "start to decode selected image now...");
                InputStream input = getContentResolver().openInputStream(uri);
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inJustDecodeBounds = true;
                BitmapFactory.decodeStream(input, null, options);
                int raw_width = options.outWidth;
                int raw_height = options.outHeight;
                int max = Math.max(raw_width, raw_height);
                int newWidth = raw_width;
                int newHeight = raw_height;
                int inSampleSize = 1;
                if(max > max_size) {
                    newWidth = raw_width / 2;
                    newHeight = raw_height / 2;
                    while((newWidth/inSampleSize) > max_size || (newHeight/inSampleSize) > max_size) {
                        inSampleSize *=2;
                    }
                }

                options.inSampleSize = inSampleSize;
                options.inJustDecodeBounds = false;
                options.inPreferredConfig = Bitmap.Config.ARGB_8888;
                selectbp = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);

                myImageView.setImageBitmap(selectbp);

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    private void selectImage() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent,"选择图像..."), PICK_IMAGE_REQUEST);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
    >
<Button
    android:id="@+id/select_btn"
    android:text="选择图片"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    />
<Button
    android:id="@+id/process_btn"
    android:text="处理"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    />
<ImageView
    android:id="@+id/imageView"
    android:src="@mipmap/ic_launcher"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    />
</LinearLayout>