基本上我正在尝试使用OpenCV Android进行面部识别。
我需要通过inputFrame.gray();
中的CvCameraViewFrame
将面部检测期间收到的Mat图像转换为byte[]
的blob,以保存到SQLite数据库中。然后,在识别过程中,将此byte[]
转换回可以在jni文件夹中的.cpp文件中使用的Mat文件,因为识别代码是本机代码。
答案 0 :(得分:1)
import org.opencv.core.Mat;
import android.content.Context;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
class SqTable extends SQLiteOpenHelper {
String table = "mydb";
public SqlTable(Context context, String name, CursorFactory factory, int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table "+table+" (name TEXT UNIQUE, t INTEGER, w INTEGER, h INTEGER, pix BLOB);");
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
}
public void dbput(String name, Mat m) {
long nbytes = m.total() * m.elemSize();
byte[] bytes = new byte[ (int)nbytes ];
m.get(0, 0,bytes);
dbput(name, m.type(), m.cols(), m.rows(), bytes);
}
public void dbput(String name, int t, int w, int h, byte[] bytes) {
Log.d("dbput", name + " " + t + " " + w + "x" + h);
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("name", name);
values.put("t", t);
values.put("w", w);
values.put("h", h);
values.put("pix", bytes);
db.insert(table, null, values);
db.close();
}
public Mat dbget(String name) {
SQLiteDatabase db = this.getReadableDatabase();
String [] columns = {"t","w","h","pix"};
Cursor cursor = db.query(table,columns," name = ?",
new String[] { name }, // d. selections args
null, // e. group by
null, // f. having
null, // g. order by
null); // h. limit
if (cursor != null)
cursor.moveToFirst();
int t = cursor.getInt(0);
int w = cursor.getInt(1);
int h = cursor.getInt(2);
byte[] p = cursor.getBlob(3);
Mat m = new Mat(h,w,t);
m.put(0,0,p);
Log.d("dbget("+name+")", m.toString());
return m;
}
};
// later use in your Activity:
SqlTable sql = new SqlTable(this,"imgs",null,1);
Mat m = new Mat(200,400, CvType.CV_8UC3,new Scalar(0,100,0));
Core.putText(m, "world (~)", new Point(30,80), Core.FONT_HERSHEY_SCRIPT_SIMPLEX, 2.2, new Scalar(200,200,200));
sql.dbput("hello",m);
// Mat m = sql.dbget("hello");