最近需要将Python人证对比模型移植安卓端.安卓端需要使用openCV简单的人像提取处理.在配置openCV前首先需要配置NDK环境.
NDK的介绍(http://www.cnblogs.com/leaven/archive/2010/05/27/1744855.html)
JNI与NDK详细介绍: http://blog.csdn.net/carson_ho/article/details/73250163
一 NDK在Ubuntu的配置
参考: http://blog.csdn.net/jq_ak47/article/details/52349189
二 NDK在IntelliJ IDEA中的配置
参考: http://blog.csdn.net/yipatshi/article/details/54585049
三 NDK开发实例
参考: http://www.cnblogs.com/xiaoxiaoqingyi/p/6524165.html
在main/java下创建创建一个NDKUtils.Java类:
public class NDKUtils {
public native String invokeCmethod();
static {
System.loadLibrary("NDKUtils");
}
}
右键选择 External Tools ---> javah
会在app目录下生成jni目录和目录内一个com_**_demo_utils_NDKUtils.h文件
复制.h 文件修改后缀名为 .c (该文件就是C 语言的实现文件)
修改com_**_demo_utils_NDKUtils.c内容:
JNIEXPORT jstring JNICALL Java_com_**_demo_utils_NDKUtils_jniInit
(JNIEnv *env, jobject obj){
return (*env)->NewStringUTF(env,"NDK 获取Native 字符串");
}
将jni目录拷贝至main/java目录下.
在jni目录下新建Android.mk和Application.mk:
Android.mk:
LOCAL_PATH:=$(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := NDKUtils
LOCAL_SRC_FILES := com_**_demo_utils_NDKUtils.c
include $(BUILD_SHARED_LIBRARY)
Application.mk:
APP_PLATFORM := android-23
APP_ABI := armeabi
在IntelliJ IDEA的命令窗口(Terminal)执行:
cd app/src/main/
继续输入:
ndk-build
该命令是编译C文件，然后生成 .so 文件，生成在 app\src\main\libs 目录下。
完成后会在main目录下生成libs和obj两个目录.
配置build.gradle 文件,在android {}中添加:
sourceSets{
main{
jni.srcDirs = [] // disable automatic ndk-build call, which ignore our Android.mk
jniLibs.srcDir 'src/main/libs'
}
}
在MainActivity中使用:
package com.***.opencvdemo; import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView; public class MainOpencvActivity extends AppCompatActivity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_opencv); NDKUtils ndk = new NDKUtils(); TextView text = (TextView) findViewById(R.id.tv);
text.setText(ndk.invokeCmethod()); }
}
运行程序会输出字符串: NDK 获取Native 字符串
以上测试成功.
四 Android+openCV
首先下载openCV包,地址:http://opencv.org/
最新的3.3,我下载了3.2
opencv配置参考: http://www.cnblogs.com/xiaoxiaoqingyi/p/6676096.html
NDKUtils.Java代码:
package com.***.opencvdemo;
public class NDKUtils {
//public native String invokeCmethod();
public static native int[] gray(int[] buf, int w, int h);
static {
//System.loadLibrary("NDKUtils");
System.loadLibrary("OpenCV");//导入生成的链接库文件
}
}
右键选择 External Tools ---> javah 同上,把生成目录jni拷贝到 src/main.
复制.h文件 修改后缀名为 .cpp (.c文件编译会报错) 参考: https://*.com/questions/30219754/ubuntu-no-such-file-or-directory-include-string
编辑 com_***_opencvdemo_NDKUtils.cpp:
#include <jni.h>
#include <string>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <opencv2/opencv.hpp> using namespace cv; extern "C" JNIEXPORT jintArray JNICALL Java_com_***_opencvdemo_NDKUtils_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;
}
把 sdk/native 目录 拷贝到 项目的 jni 目录下.
修改:
Android.mk:
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 $(LOCAL_PATH)/native/jni/OpenCV.mk
else
include $(OPENCV_MK_PATH)
endif
LOCAL_MODULE := OpenCV
LOCAL_SRC_FILES := com_***_opencvdemo_NDKUtils.cpp
LOCAL_LDLIBS += -lm -llog
include $(BUILD_SHARED_LIBRARY)
Application.mk:
APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_PLATFORM := android-9
ndk-build:生成.so文件
MainOpencvActivity:
package com.***.opencvdemo; import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView; public class MainOpencvActivity extends AppCompatActivity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_opencv); Bitmap bitmap = ((BitmapDrawable) getResources().getDrawable(
R.mipmap.aaa)).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= NDKUtils.gray(pix,w,h);
Bitmap result = Bitmap.createBitmap(w,h, Bitmap.Config.RGB_565);
result.setPixels(resultPixes, 0, w, 0, 0,w, h); ImageView img = (ImageView)findViewById(R.id.image2);
img.setImageBitmap(result); }
}
附加 activity_main_opencv.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.***.opencvdemo.MainOpencvActivity"> <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="调用openCV灰度化"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"/> <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv"
android:text="原图"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.1"/> <ImageView
android:scaleType="centerInside"
android:layout_width="0dp"
android:layout_height="180dp"
android:id="@+id/image1"
android:src="@mipmap/aaa"
android:layout_margin="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.2" /> <ImageView
android:scaleType="centerInside"
android:layout_width="0dp"
android:layout_height="180dp"
android:id="@+id/image2"
android:src="@mipmap/aaa"
android:layout_margin="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.8" /> </android.support.constraint.ConstraintLayout>
运行效果:
