Android Studio中集成OpenCV

Posted 2022-12-06 粪乧

Demo 下载地址 :https://github.com/hongyang51/OpenCV

近来公司需求需要对图片进行处理,简单的对OpenCV4android进行集成.首先参考前人经验分为三种方式调用 其中开发方式需要使用到 ndk开发 . 我首先记录一下ndk 环境的配置过程.

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Mac下配置Android Studio(AS)NDK环境

1. 首先打开
   
   将Android NDK 勾选上 之后 点击Apply 点OK 之后AS会自动下载 (有的时候google会突破墙 ,有时候就不可以了 发帖时可以直接下载) 如果打开这个页面的时候卡死 那就 赶紧挂上梯子再弄吧…..
2. 下载完成之后创建个项目查看local.properties文件中是否配置ndk目录 一般都是有配置的.
   
3. 打开项目gradle.properties文件, 添加android.useDeprecatedNdk=true
   
   至此NDK环境已经配置完成.

Mac下Android Studio生成jni调用h文件

1. 点击Terminal打开 将终端目录调整到项目的java目录下 例如我的示例目录
   需要输入cd app/src/main/java
   
2. 这个时候需要创建一个java文件 进行jni调用 如例子

/**
 * Created by xyb on 16/2/26 at UHylab
 *
 * @version 1.0
 */
public class OpenCVHelper 
    static 
        System.loadLibrary("opencv_java3");
        System.loadLibrary("OpenCV");
    
    public static native int[] gray(int[] buf, int w, int h);

现在我推荐Clean Project下 之后再 Make Project (哎!挺纠结的一个过程)

1. 在Terminal 中输入
   javah -jni com.uhylab.opencv.OpenCVHelper
2. 查看java目录下生成的.h文件 在main目录下生成jni文件夹将文件放在该目录下
3. 之后就可以开始写牛逼闪闪的C++ 代码了.. 这段俺不会 继续学吧…..
   此时就要在build.gradle文件的android 块下添加

 sourceSets 
        main 
            jni 
                srcDirs = []
            
        
    
    //禁止自带的ndk功能
    sourceSets
        main
            jniLibs
                srcDirs =       ['src/main/libs','src/main/jniLibs']
            
        
    
    //重定向so目录为src/main/libs和src/main/jniLibs，原来为src/main/jniLibs

    task ndkBuild(type: Exec, description: 'Compile JNI source with NDK') 
        Properties properties = new Properties()
        properties.load(project.rootProject.file('local.properties').newDataInputStream())
        def ndkDir = properties.getProperty('ndk.dir')

        if (org.apache.tools.ant.taskdefs.condition.Os.isFamily(org.apache.tools.ant.taskdefs.condition.Os.FAMILY_WINDOWS)) 
            commandLine "$ndkDir/ndk-build.cmd", '-C', file('src/main/jni').absolutePath
         else 
            commandLine "$ndkDir/ndk-build", '-C', file('src/main/jni').absolutePath
        
    

    tasks.withType(JavaCompile) 
        compileTask -> compileTask.dependsOn ndkBuild
    

    task ndkClean(type: Exec, description: 'Clean NDK Binaries') 
        Properties properties = new Properties()
        properties.load(project.rootProject.file('local.properties').newDataInputStream())
        def ndkDir = properties.getProperty('ndk.dir')

        if (org.apache.tools.ant.taskdefs.condition.Os.isFamily(org.apache.tools.ant.taskdefs.condition.Os.FAMILY_WINDOWS)) 
            commandLine "$ndkDir/ndk-build.cmd", 'clean', '-C', file('src/main/jni').absolutePath
         else 
            commandLine "$ndkDir/ndk-build", 'clean', '-C', file('src/main/jni').absolutePath
        
    

    clean.dependsOn 'ndkClean'

Mac下配置Android Studio(AS)OpenCV环境

1. 首先使用OpenCV需要去下载库文件 OpenCV4Android
   

2. 将下载的文件解压后 在sdk目录下有个native文件夹 将该文件夹复制到工程的根目录下.如图
   

3. 在jni文件夹下面创建Android.mk 与 Application.mk 文件

   Android.mk文件内容为

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
OpenCV_INSTALL_MODULES := on
OpenCV_CAMERA_MODULES := off
OPENCV_LIB_TYPE :=STATIC
ifeq ("$(wildcard $(OPENCV_MK_PATH))","")
include ../../../../native/jni/OpenCV.mk
else
include $(OPENCV_MK_PATH)
endif
LOCAL_MODULE := OpenCV
LOCAL_SRC_FILES := com_uhylab_opencv_OpenCVHelper.cpp
LOCAL_LDLIBS +=  -lm -llog
include $(BUILD_SHARED_LIBRARY)

Application.mk 内容为

APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi armeabi-v7a
APP_PLATFORM := android-15

再创建C++代码文件
我的为com_uhylab_opencv_OpenCVHelper.cpp

//
// Created by xyb on 16/2/26.
//

#include "com_uhylab_opencv_OpenCVHelper.h"
#include <stdio.h>
#include <stdlib.h>
#include <opencv2/opencv.hpp>

using namespace cv;

extern "C" 

JNIEXPORT jintArray JNICALL Java_com_uhylab_opencv_OpenCVHelper_gray(
        JNIEnv *env, jclass obj, jintArray buf, int w, int h);



JNIEXPORT jintArray JNICALL Java_com_uhylab_opencv_OpenCVHelper_gray(
        JNIEnv *env, jclass obj, jintArray buf, int w, int h) 

    jint *cbuf;
    cbuf = env->GetIntArrayElements(buf, JNI_FALSE );
    if (cbuf == NULL) 
        return 0;
    

    Mat imgData(h, w, CV_8UC4, (unsigned char *) cbuf);

    uchar* ptr = imgData.ptr(0);
    for(int i = 0; i < w*h; i ++)
        //计算公式：Y(亮度) = 0.299*R + 0.587*G + 0.114*B
        //对于一个int四字节，其彩色值存储方式为：BGRA
        int grayScale = (int)(ptr[4*i+2]*0.299 + ptr[4*i+1]*0.587 + ptr[4*i+0]*0.114);
        ptr[4*i+1] = grayScale;
        ptr[4*i+2] = grayScale;
        ptr[4*i+0] = grayScale;
    

    int size = w * h;
    jintArray result = env->NewIntArray(size);
    env->SetIntArrayRegion(result, 0, size, cbuf);
    env->ReleaseIntArrayElements(buf, cbuf, 0);
    return result;

ndkBuild创建so文件

此时 在Activity中调用方式测试成功.

MainActivity.java

package com.uhylab.opencv;

import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity 

    private ImageView img;
    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        img = (ImageView) findViewById(R.id.img);
        Bitmap bitmap = ((BitmapDrawable) getResources().getDrawable(
                R.mipmap.ic_launcher)).getBitmap();
        int w = bitmap.getWidth(), h = bitmap.getHeight();
        int[] pix = new int[w * h];
        bitmap.getPixels(pix, 0, w, 0, 0, w, h);
        int [] resultPixes=OpenCVHelper.gray(pix,w,h);
        Bitmap result = Bitmap.createBitmap(w,h, Bitmap.Config.RGB_565);
        result.setPixels(resultPixes, 0, w, 0, 0,w, h);
        img.setImageBitmap(result);

    

再次 感谢yanzi
http://blog.csdn.net/yanzi1225627/article/details/27863615;
安卓弟 http://blog.csdn.net/sbsujjbcy/article/details/49520791 还有各位大神.!
菜鸟敬上!有错误恳请提醒修正 谢谢!
Demo 下载地址 :https://github.com/hongyang51/OpenCV