Use OpenCv in Android to process images

Recently, I was studying how to use C to process images. Later I went online and found out that some of them used libjpeg and opencv to process images. First, study opencv to process images,

This is a friend on the network to write code http://blogold.chinaunix.net/u1/57901/showart.php? Id = 2512389

 

First compile opencv to get the libandroid-opencv.so library, please refer to the blog http://blog.csdn.net/hellogv/archive/2011/01/21/6157316.aspx of this ox man

 

 

 

1. Create an android project named opencvtest and the package named com. opencvtest

Create a jni folder under the root directory of the project, and then create the Android. mk file and the content of the hello-jni.cpp file Android. mk are as follows: # Date: Summer, 2010 <br/> # author: Ethan Rublee <br/> # contact: ethan.rublee@gmail.com <br/> # <br/> LOCAL_PATH: = $ (call my-dir) </p> <p> include $ (CLEAR_VARS) </p> <p> # OPENCV_ROOT must be defined. <br/> ifndef OPENCV_ROOT <br/> $ (warning Please define OPENCV_ROOT to point to the root folder of opencv, try ndk-build OPENCV_ROOT = .. /.. /opencv) <br/> OPENCV_ROOT = .. /.. /opencv <br/> $ (warning Defaulting to OPENCV_ROOT = $ (OPENCV_ROOT )) <br/> endif </p> <p> # define OPENCV_INCLUDES <br/> include $ (OPENCV_ROOT)/includes. mk <br/> # define OPENCV_LIBS <br/> include $ (OPENCV_ROOT)/libs. mk </p> <p> LOCAL_LDLIBS + = $ (OPENCV_LIBS) </p> <p> LOCAL_C_INCLUDES + = $ (OPENCV_INCLUDES) $ (ANDROID_OPENCV_INCLUDES) </p> <p> LOCAL_MODULE: = hello-jni </p> <p> LOCAL_SRC_FILES: = hello-jni.cpp </p> <p> include $ (BUILD_SHARED_LIBRARY) </p> <p>2. hello-jni.cpp # Include <jni. h> <br/> # include <cstdlib> <br/> # include <stdexcept> <br/> # include <string> </p> <p> # include <opencv2 /core. hpp> <br/> # include <opencv2/features2d/features2d. hpp> <br/> # include <opencv2/highgui. hpp> <br/> # include <opencv2/imgproc. hpp> <br/> # include <opencv2/calib3d/calib3d. hpp> <br/> # include <opencv2/imgproc/imgproc_c.h> </p> <p> static CvScalar colors [] = <br/>{< br/> {{0, 255 }}, <br/>{{ 0,128,255 }}, <br/>{{ 0,255,255 }}, <br/>{{ 0,255, 0 }}, <br/>{{ 255,128, 0 }}, <br/>{{ 255,255, 0 }}, <br/>{{ 255, 0 }}, <br/>{{ 255, 255,255,255 }}, <br/>{{ }}</p> <p> }; </p> <p> extern "C" <br/> jint Java_com_opencv_ActivityMain_getKeypointNum (JNIEnv * env, jobject thiz) <br/>{< br/> IplImage * object = cvLoadImage ("/sdcard/camera.jpg", CV_LOAD_IMAGE_GRAYSCALE); <br/> if (object! = NULL) {<br/> CvSURFParams params = cvSURFParams (500, 1); <br/> CvMemStorage * storage = cvcreatemstorage (0 ); <br/> IplImage * object_color = cvCreateImage (cvGetSize (object), 8, 3); <br/> CvSeq * objectKeypoints = 0; <br/> CvSeq * objectDescriptors = 0; </p> <p> cvCvtColor (object, object_color, CV_GRAY2BGR); <br/> cvExtractSURF (object, 0, & objectKeypoints, & objectDescriptors, storage, params ); </p> <p> for (int I = 0; I <objectKeypoints-> total; I ++) <br/>{< br/> CvSURFPoint * r = (CvSURFPoint *) cvGetSeqElem (objectKeypoints, I); <br/> CvPoint center; <br/> int radius; <br/> center. x = cvRound (r-> pt. x); <br/> center. y = cvRound (r-> pt. y); <br/> radius = cvRound (r-> size * 1.2/9. * 2); <br/> cvCircle (object_color, center, radius, colors [0], 1, 8, 0 ); <br/>}</p> <p> cvSaveImage ("/sdcard/src_surf.jpg", object_color); </p> <p> return objectKeypoints-> total; <br/>}</p> <p> return 0; </p> <p >}</p> <p>3. ActivityMain. java Package com. opencv; </p> <p> import android. app. activity; <br/> import android. OS. bundle; <br/> import android. widget. textView; </p> <p> public class ActivityMain extends Activity {<br/>/** Called when the activity is first created. */</p> <p> private TextView text; </p> <p> @ Override <br/> public void onCreate (Bundle savedInstanceState) {<br/> super. onCreate (savedInstanceState); <br/> setContentView (R. layout. main); </p> <p> text = (TextView) findViewById (R. id. text); <br/> text. setText (Integer. toString (getKeypointNum (); </p> <p >}</p> <p> public native int getKeypointNum (); </p> <p> static <br/> {</p> <p> System. loadLibrary ("hello-jni"); <br/>}</p> <p>}4. compile the project. The project structure is 5. The effect source image is 6. Note that exceptions may occur when processing large images. No response. I don't know what the problem is! Please give answers.