開發的基礎是首先配置好各種開發環境,過程很複雜,這裏先不具體介紹了,整個過程中遇到了很多問題,主要步驟參考這幾篇博客
http://blog.csdn.net/pwh0996/article/details/8957764
下面直接介紹同時實現兩個功能的app,這裏採用的是利用C++來實現,至於直接利用JAVA來實現灰度化的過程,可以參考這裏http://blog.csdn.net/yanzi1225627/article/details/16917961
使用java API開發android:
創建工程
(1) 打開eclipse,創建android應用工程Img;
(2) 將測試圖像lena.jpg添加到資源目錄res/drawable-hdpi中;
(3) 在Package Explorer中選擇項目Img,單擊右鍵在彈出菜單中選擇Properties,然後在彈出的Properties窗口中左側選擇Android,然後點擊右下方的Add按鈕,選擇OpenCV Library 2.4.9並點擊OK,操作完成後,會將OpenCV類庫添加到Img的Android Dependencies中.
工程代碼:
(1) 佈局文件:activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<Button
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:id="@+id/btnNDK"
android:text="Canny檢測" />
<Button
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:id="@+id/btnGray"
android:text="灰度化" />
<Button
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:id="@+id/btnRestore"
android:text="還原" />
<ImageView
android:id="@+id/ImageView01"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</LinearLayout>
2、MainActivity.java文件
package com.iipc.img;
import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.widget.Button;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
public class MainActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
ImageView imgView;
Bitmap resultImg;
Bitmap img;
Button btnNDK, btnRestore,btnGray;
private static final String TAG="MainActivity";
//OpenCV類庫加載並初始化成功後的回調函數,在此我們不進行任何操作
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS:{
Log.i(TAG,"成功加載");
System.loadLibrary("Image_proc");
} break;
default:{
super.onManagerConnected(status);
Log.i(TAG,"加載失敗");
} break;
}
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.setTitle("應用NDK轉換灰度圖");
btnRestore = (Button) findViewById(R.id.btnRestore);
btnNDK = (Button) findViewById(R.id.btnNDK);
btnGray = (Button) findViewById(R.id.btnGray);
imgView = (ImageView) findViewById(R.id.ImageView01);
img = ((BitmapDrawable) getResources().getDrawable( R.drawable.lena)).getBitmap();
imgView.setImageBitmap(img);
btnRestore.setOnClickListener(this);
btnNDK.setOnClickListener(this);
btnGray.setOnClickListener(this);
}
public void procSrc2Gray(){
int w = img.getWidth();
int h = img.getHeight();
int[] pixels = new int[w*h];
img.getPixels(pixels, 0, w, 0, 0, w, h);
int[] resultInt = LibImgFun.grayProc(pixels, w, h);
resultImg = Bitmap.createBitmap(w, h, Config.ARGB_8888);
resultImg.setPixels(resultInt, 0, w, 0, 0, w, h);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (v == btnNDK) {
// long current = System.currentTimeMillis();
Bitmap img1 = ((BitmapDrawable) getResources().getDrawable( R.drawable.lena)).getBitmap();
int w = img1.getWidth(), h = img1.getHeight();
int[] pix = new int[w * h];
img1.getPixels(pix, 0, w, 0, 0, w, h);
int[] resultInt = LibImgFun.imgFun(pix, w, h);
Bitmap resultImg = Bitmap.createBitmap(w, h, Config.ARGB_8888);
resultImg.setPixels(resultInt, 0, w, 0, 0, w, h);
// long performance = System.currentTimeMillis() - current;
imgView.setImageBitmap(resultImg);
// MainActivity.this.setTitle("w:" + String.valueOf(img1.getWidth()) + ",h:" + String.valueOf(img1.getHeight()) + "NDK耗時" + String.valueOf(performance) + " 毫秒");
MainActivity.this.setTitle("OpenCV的Canny檢測圖");
}
else if (v == btnGray) {
procSrc2Gray();
imgView.setImageBitmap(resultImg);
MainActivity.this.setTitle("OpenCV灰度化");
}
else if (v == btnRestore) {
Bitmap img2 = ((BitmapDrawable) getResources().getDrawable( R.drawable.lena)).getBitmap();
imgView.setImageBitmap(img2);
MainActivity.this.setTitle("原始圖像");
}
}
@Override
public void onResume(){
super.onResume();
//通過OpenCV引擎服務加載並初始化OpenCV類庫,所謂OpenCV引擎服務即是
//OpenCV_2.4.3.2_Manager_2.4_*.apk程序包,存在於OpenCV安裝包的apk目錄中
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9, this, mLoaderCallback);
}
}
3、LibImgFun.java文件
package com.iipc.img;
public class LibImgFun {
public static native int[] imgFun(int[] buf, int w, int h);
public static native int[] grayProc(int[] buf, int w, int h);
}
4、Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
include ../OpenCV-SDK/native/jni/OpenCV.mk
LOCAL_SRC_FILES := LibImgFun.cpp
LOCAL_MODULE := Image_proc
include $(BUILD_SHARED_LIBRARY)
5、 Application.mk(配置文件)
APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-8
6、LibImgFun.cpp文件#include <LibImgFun.h>
#include <opencv2/opencv.hpp>
#include<highgui.h>
#include <string>
#include <vector>
#include<stdio.h>
#include<stdlib.h>
#include<iostream>
using namespace cv;
using namespace std;
//改寫的canny檢測代碼,返回值爲存儲canny檢測圖像數據的int數組jintArray,傳遞的參數存儲原始圖像數據的int數組,以及w和h
JNIEXPORT jintArray JNICALL Java_com_iipc_img_LibImgFun_imgFun(JNIEnv* env, jclass obj, jintArray buf, jint w, jint h){
jint *cbuf; cbuf = env->GetIntArrayElements(buf, false);//JNI傳遞int數組的方法
if (cbuf == NULL)
{
return 0;
}
Mat myimg(h, w, CV_8UC4, (unsigned char*) cbuf);//java中讀入的圖像都是4通道的,所以這裏myimg聲明定義爲CV_8UC4,以一個數組中的數據來建立Mat
Mat grayimg;
cvtColor(myimg,grayimg,CV_BGRA2GRAY);//將4通道的彩色圖轉爲灰度圖
Mat pCannyImage;
Canny(grayimg,pCannyImage,50,150,3);//canny檢測
uchar* ptr = myimg.ptr(0);//因爲灰度圖最終以4通道bmp形式顯示,所以將得到的灰度圖grayimg的數據賦值到4通道的imageData中,
for(int i = 0; i < w*h; i ++){
//得到的canny圖像原本是單通道,但java中顯示bmp時只能4通道或三通道,爲了使顯示的圖像時灰度的,把canny圖像的數據值賦給一個4通道的myimg
//對於一個int四字節,其彩色值存儲方式爲:BGRA
ptr[4*i+1] = pCannyImage.data[i];
ptr[4*i+2] = pCannyImage.data[i];
ptr[4*i+0] = pCannyImage.data[i];
}
//以下部分是將得到canny圖像存在數組中,以數組的形式返回
int size = w * h;
jintArray result = env->NewIntArray(size);
env->SetIntArrayRegion(result, 0, size, cbuf);
env->ReleaseIntArrayElements(buf, cbuf, 0);
return result;
}
JNIEXPORT jintArray JNICALL Java_com_iipc_img_LibImgFun_grayProc(JNIEnv* env, jclass obj, jintArray buf, jint w, jint h){
jint *cbuf;
cbuf = env->GetIntArrayElements(buf, false);
if(cbuf == NULL){
return 0;
}
Mat imgData(h, w, CV_8UC4, (unsigned char*)cbuf);
Mat grayimg;
cvtColor(imgData,grayimg,CV_BGRA2GRAY);//將4通道的彩色圖轉爲灰度圖
uchar* ptr = imgData.ptr(0);//因爲灰度圖最終以4通道bmp形式顯示,所以將得到的灰度圖grayimg的數據賦值到4通道的imageData中,
for(int i = 0; i < w*h; i ++){
//計算公式:Y(亮度) = 0.299*R + 0.587*G + 0.114*B//去掉了原始程序中轉換的公式
//對於一個int四字節,其彩色值存儲方式爲:BGRA
ptr[4*i+1] = grayimg.data[i];
ptr[4*i+2] = grayimg.data[i];
ptr[4*i+0] = grayimg.data[i];
}
//以下部分是將得到canny圖像存在數組中,以數組的形式返回
int size = w * h;
jintArray result = env->NewIntArray(size);
env->SetIntArrayRegion(result, 0, size, cbuf);
env->ReleaseIntArrayElements(buf, cbuf, 0);
return result;
}
7、LibImgFun.h文件
#include <jni.h>
extern "C" {
JNIEXPORT jintArray JNICALL Java_com_iipc_img_LibImgFun_imgFun
(JNIEnv *, jclass, jintArray, jint, jint);
JNIEXPORT jintArray JNICALL Java_com_iipc_img_LibImgFun_grayProc
(JNIEnv *, jclass, jintArray, jint, jint);
}
8、結果
1、原圖
2、灰度化
3、Canny檢測