在Android中使用OpenCv 来处理图片

最近在研究在用C来处理图片，后来再网上找了一下，有的说用libjpeg和opencv来处理图片。先研究一下，opencv来处理图片，

这是网上一位友人写的代码http://blogold.chinaunix.net/u1/57901/showart.php?id=2512389

 

开始之前，先编译opencv得到 libandroid-opencv.so库 ，请参考这位牛人的博客http://blog.youkuaiyun.com/hellogv/archive/2011/01/21/6157316.aspx

 

 

 

1、创建一个android工程,工程名为opencvtest,包名为com.opencvtest

在工程的根目录下创建一个jni文件夹,然后分别创建Android.mk和hello-jni.cpp两个文件

Android.mk的内容如下:

  # date: Summer, 2010 # author: Ethan Rublee # contact: ethan.rublee@gmail.com # LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) #OPENCV_ROOT must be defined. ifndef OPENCV_ROOT $(warning Please define OPENCV_ROOT to point to the root folder of opencv, try ndk-build OPENCV_ROOT=../../opencv) OPENCV_ROOT=../../opencv $(warning Defaulting to OPENCV_ROOT=$(OPENCV_ROOT)) endif #define OPENCV_INCLUDES include $(OPENCV_ROOT)/includes.mk #define OPENCV_LIBS include $(OPENCV_ROOT)/libs.mk LOCAL_LDLIBS += $(OPENCV_LIBS) LOCAL_C_INCLUDES += $(OPENCV_INCLUDES) $(ANDROID_OPENCV_INCLUDES) LOCAL_MODULE := hello-jni LOCAL_SRC_FILES := hello-jni.cpp include $(BUILD_SHARED_LIBRARY)

2、hello-jni.cpp

#include <jni.h> #include <cstdlib> #include <stdexcept> #include <string> #include <opencv2/core/core.hpp> #include <opencv2/features2d/features2d.hpp> #include <opencv2/highgui/highgui.hpp> #include <opencv2/imgproc/imgproc.hpp> #include <opencv2/calib3d/calib3d.hpp> #include <opencv2/imgproc/imgproc_c.h> static CvScalar colors[]= { {​{0,0,255}}, {​{0,128,255}}, {​{0,255,255}}, {​{0,255,0}}, {​{255,128,0}}, {​{255,255,0}}, {​{255,0,0}}, {​{255,0,255}}, {​{255,255,255}} }; extern "C" jint Java_com_opencv_ActivityMain_getKeypointNum(JNIEnv* env,jobject thiz) { IplImage* object = cvLoadImage("/sdcard/camera.jpg",CV_LOAD_IMAGE_GRAYSCALE); if(object != NULL){ CvSURFParams params = cvSURFParams(500, 1); CvMemStorage* storage = cvCreateMemStorage(0); IplImage* object_color = cvCreateImage(cvGetSize(object), 8, 3); CvSeq *objectKeypoints = 0; CvSeq *objectDescriptors = 0; cvCvtColor( object, object_color, CV_GRAY2BGR ); cvExtractSURF( object, 0, &objectKeypoints, &objectDescriptors, storage, params); for( int i = 0; i < objectKeypoints->total; i++ ) { CvSURFPoint* r = (CvSURFPoint*)cvGetSeqElem( objectKeypoints, i ); CvPoint center; int radius; center.x = cvRound(r->pt.x); center.y = cvRound(r->pt.y); radius = cvRound(r->size*1.2/9.*2); cvCircle( object_color, center, radius, colors[0], 1, 8, 0 ); } cvSaveImage( "/sdcard/src_surf.jpg" , object_color); return objectKeypoints->total; } return 0; }

3、ActivityMain.java

  package com.opencv; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class ActivityMain extends Activity { /** Called when the activity is first created. */ private TextView text; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); text = (TextView) findViewById(R.id.text); text.setText(Integer.toString(getKeypointNum())); } public native int getKeypointNum(); static { System.loadLibrary("hello-jni"); } }

4、把这个工程编译了,工程结构

 

5、效果如图：原图

效果图：

6、注意，如果处理大的图片的时候会出现异常。没有响应，不知道是什么问题！求高手解答。