利用OPENCV为android开发畸变校正的JNI库方法

需要为项目提供一套畸变校正的算法，由于需要大量的矩阵运算，考虑到效率和适时性，使用JNI开发，希望把有关数组短阵的处理的变换全部放入C语言中处理。

主要用于android移动端，大致的数据来源一是从camera直接读取YUV数据，一种是从第三方接读取RGB数据，另一种是直接对BITMAP进行处理。

1.考虑到硬件设备接口，第三方软件接口，图像接口，OPENCV接口，希望能够开发出通用的算法库，一劳永逸的解决各种复杂的使用场景，因此数据要支持YUV，支持ARGB，支持MAT

2android对BITMAP有获取像素点的操作，也有通过象素点生成BITMAP的操作，而且有很多图像处理接口和第三方可以处理RGB矩阵，如

bm.getPixels(pixs, 0, w, 0, 0, w, h);
int[] pixs1 = new int[w*h];
   final Bitmap bm2 = Bitmap.createBitmap(pixs1, w, h, Bitmap.Config.ARGB_8888);

因此设计如下接口，入口为ARGB的整型，输出也是整型

public static native boolean RgbaUndistort(int[] argb, int width, int height, int[] pixels);

3考虑到有些情况需要二维数组，

public static native boolean RgbaUndistort2(int[][] rgb, int width, int height, int[] pixels);

4考虑到OPENCV的MAT结构，由于MAT有matToBitmap可以直接转化为BITMAP，应用MAT 提供

public static native boolean RgbaUndistortMat(int[] argb, int width, int height, long pArgbOutMatAddr);

5考虑到第三方使用MAT的情况，因此输入也可以支持MAT因此设计接口

public static native boolean RgbMatUndistortMat(long pArgbMatAddr, int width, int height, long pArgbOutMatAddr);

6考虑到摄像头输出YUV，提供YUV数据处理， 一个输出RGB， 一个输出MAT

public static native boolean YuvNv21UndistortRgba(byte[] YuvNv21, int width, int height, int[] pixels);
public static native boolean YuvNv21UndistortRgbaMat(byte[] YuvNv21, int width, int height, long pMatAddr);

7考虑到可能有不需要畸变的场合，为YUV设计一个灰度，一个RGB接口

public static native boolean YuvNv21ToGray(byte[] YuvNv21,int width, int height, int[] pixels);
public static native boolean YuvNv21ToRGBA(byte[] YuvNv21, int width, int height, int[] pixels);

8于是编写简单的JAVA头源生类

public class ImageProc3 {
static {
System.loadLibrary("ImgProc3");
}

public static native boolean YuvNv21ToGray(byte[] YuvNv21,int width, int height, int[] pixels);
public static native boolean YuvNv21ToRGBA(byte[] YuvNv21, int width, int height, int[] pixels);

public static native boolean RgbaUndistort(int[] argb, int width, int height, int[] pixels);
public static native boolean RgbaUndistort2(int[][] rgb, int width, int height, int[] pixels);
public static native boolean RgbaUndistortMat(int[] argb, int width, int height, long pArgbOutMatAddr);
public static native boolean RgbMatUndistortMat(long pArgbMatAddr, int width, int height, long pArgbOutMatAddr);

public static native boolean YuvNv21UndistortRgba(byte[] YuvNv21, int width, int height, int[] pixels);
public static native boolean YuvNv21UndistortRgbaMat(byte[] YuvNv21, int width, int height, long pMatAddr);

}

进入BIN目录的classes文件夹使用java -classpath . -jni 生成C头文件

根据头文件编写实现的C代码

#include <stdio.h>
#include <jni.h>
#include<Android/log.h>

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

using namespace std;
using namespace cv;

#define TAG  "Camera XXXXX" // 锟斤拷锟斤拷锟斤拷远锟斤拷锟斤拷LOG锟侥憋拷识
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG,__VA_ARGS__) // 锟斤拷锟斤拷LOGD锟斤拷锟斤拷

#ifdef __cplusplus
extern "C" {
#endif
/*
* Class:   ImgProc_ImageProc3
* Method:  YuvNv21ToGray
* Signature: ([BII[I)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_YuvNv21ToGray
(JNIEnv *jenv, jclass jclassz, jbyteArray YuvNv21, jint width, jint height, jintArray pixels){

jbyte * pNV21FrameData = jenv->GetByteArrayElements(YuvNv21, 0);
jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);

Mat mNV(height, width, CV_8UC1, (unsigned char*) pNV21FrameData);
Mat mBgra(height, width, CV_8UC4, (unsigned char*) poutPixels);

cvtColor(mNV, mBgra, CV_YUV420sp2RGBA);

jenv->ReleaseByteArrayElements(YuvNv21, pNV21FrameData, 0);
jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);

return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  YuvNv21ToRGBA
* Signature: ([BII[I)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_YuvNv21ToRGBA
(JNIEnv *jenv, jclass jclassz, jbyteArray YuvNv21, jint width, jint height, jintArray pixels){
jbyte * pBuf = (jbyte*) jenv->GetByteArrayElements(YuvNv21, 0);
jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);

Mat image(height + height / 2, width, CV_8UC1, (unsigned char *) pBuf);
Mat rgba(height, width, CV_8UC4, (unsigned char*) poutPixels);
Mat tmp(height, width, CV_8UC4);
cvtColor(image, tmp, CV_YUV420sp2RGBA);

vector <Mat> channels;
split(tmp, channels);
Mat r = channels.at(0);
Mat g = channels.at(1);
Mat b = channels.at(2);
Mat a = channels.at(3);

vector <Mat> mbgr(4);
mbgr[0] = b;
mbgr[1] = g;
mbgr[2] = r;
mbgr[3] = a;

merge(mbgr, rgba);

jenv->ReleaseByteArrayElements(YuvNv21, pBuf, 0);
jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);

return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  RgbaUndistort
* Signature: ([III[I)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_RgbaUndistort
(JNIEnv *jenv, jclass jclassz, jintArray argb, jint width, jint height, jintArray pixels){
jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);
jint * pinPixels = jenv->GetIntArrayElements(argb, 0);

Mat out(height, width, CV_8UC4, (unsigned char*) poutPixels);
Mat in(height, width, CV_8UC4, (unsigned char*) pinPixels);

double cam[] = {width, 0, width / 2, 0, height, height / 2, 0, 0, 1 };
double distort[] = { 0.1, 0.35, 0.0, 0.0, 0.01 };

Mat camMat = Mat(3, 3, CV_64FC1, cam);
Mat disMat = Mat(5, 1, CV_64FC1, distort);
undistort(in, out, camMat, disMat);

jenv->ReleaseIntArrayElements(argb, pinPixels, 0);
jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);
return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  RgbaUndistort2
* Signature: ([[III[I)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_RgbaUndistort2(JNIEnv *jenv,
jclass jclassz, jobjectArray argb, jint width, jint height,
jintArray pixels) {

jint i, j;
int row = jenv->GetArrayLength(argb);
jintArray myarray = (jintArray)(jenv->GetObjectArrayElement(argb, 0));
int col = jenv->GetArrayLength(myarray);
jint jniData[row][col];
LOGD("jiaXXX ％s", "Java_ImgProc_ImageProc_convertRGB3");
for (i = 0; i < row; i++) {
myarray = (jintArray)(jenv->GetObjectArrayElement(argb, i));
jint *coldata = jenv->GetIntArrayElements(myarray, 0);

for (j = 0; j < col; j++) {
jniData[i][j] = coldata[j];
LOGD("jiaXXX ％d", jniData[i][j]);
}

jenv->ReleaseIntArrayElements(myarray, coldata, 0);

}

Mat img = Mat(row, col, CV_8UC4, jniData);
LOGD("jiaXXX ％x", img.at<unsigned int>(1, 1));

double cam[] = {width, 0, width / 2, 0, height, height / 2, 0, 0, 1 };
double distort[] = { 0.1, 0.35, 0.0, 0.0, 0.01 };

Mat camMat = Mat(3, 3, CV_64FC1, cam);
Mat disMat = Mat(5, 1, CV_64FC1, distort);

jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);
Mat out(height, width, CV_8UC4, (unsigned char*) poutPixels);
undistort(img, out, camMat, disMat);

jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);

return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  RgbaUndistortMat
* Signature: ([IIIJ)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_RgbaUndistortMat
(JNIEnv *jenv, jclass jclassz, jintArray argb, jint width, jint height, jlong pArgbOutMatAddr){

//jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);
jint * pinPixels = jenv->GetIntArrayElements(argb, 0);

//Mat out(height, width, CV_8UC4, (unsigned char*) poutPixels);
Mat in(height, width, CV_8UC4, (unsigned char*) pinPixels);
Mat out = *((Mat*)pArgbOutMatAddr);

double cam[] = {width, 0, width / 2, 0, height, height / 2, 0, 0, 1 };
double distort[] = { 0.1, 0.35, 0.0, 0.0, 0.01 };

Mat camMat = Mat(3, 3, CV_64FC1, cam);
Mat disMat = Mat(5, 1, CV_64FC1, distort);
undistort(in, out, camMat, disMat);

jenv->ReleaseIntArrayElements(argb, pinPixels, 0);
//jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);

return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  RgbMatUndistortMat
* Signature: (JIIJ)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_RgbMatUndistortMat
(JNIEnv *jenv, jclass jclassz, jlong pArgbMatAddr, jint width, jint height, jlong pArgbOutMatAddr){

Mat in=*((Mat*)pArgbMatAddr);
Mat out = *((Mat*)pArgbOutMatAddr);

double cam[] = {width, 0, width / 2, 0, height, height / 2, 0, 0, 1 };
double distort[] = { 0.1, 0.35, 0.0, 0.0, 0.01 };

Mat camMat = Mat(3, 3, CV_64FC1, cam);
Mat disMat = Mat(5, 1, CV_64FC1, distort);
undistort(in, out, camMat, disMat);

return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  YuvNv21UndistortRgba
* Signature: ([BII[I)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_YuvNv21UndistortRgba
(JNIEnv *jenv, jclass jclassz, jbyteArray YuvNv21, jint width, jint height, jintArray pixels){

jbyte * pBuf = (jbyte*) jenv->GetByteArrayElements(YuvNv21, 0);
jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);

Mat image(height + height / 2, width, CV_8UC1, (unsigned char *) pBuf);
Mat rgba(height, width, CV_8UC4, (unsigned char*) poutPixels);
Mat tmp(height, width, CV_8UC4);
cvtColor(image, tmp, CV_YUV420sp2RGBA);

double cam[] = { width, 0, width / 2, 0, height, height / 2, 0, 0, 1 };
double distort[] = { 0.1, 0.35, 0.0, 0.0, 0.01 };

Mat camMat = Mat(3, 3, CV_64FC1, cam);
Mat disMat = Mat(5, 1, CV_64FC1, distort);
undistort(tmp, tmp, camMat, disMat);

vector < Mat > channels;
split(tmp, channels);
Mat r = channels.at(0);
Mat g = channels.at(1);
Mat b = channels.at(2);
Mat a = channels.at(3);

vector < Mat > mbgr(4);
mbgr[0] = b;
mbgr[1] = g;
mbgr[2] = r;
mbgr[3] = a;

merge(mbgr, rgba);

jenv->ReleaseByteArrayElements(YuvNv21, pBuf, 0);
jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);

return true;
}

/*
* Class:   ImgProc_ImageProc3
* Method:  YuvNv21UndistortRgbaMat
* Signature: ([BIIJ)Z
*/
JNIEXPORT jboolean JNICALL Java_ImgProc_ImageProc3_YuvNv21UndistortRgbaMat
(JNIEnv *jenv, jclass jclassz, jbyteArray YuvNv21, jint width, jint height, jlong pMatAddr){

jbyte * pBuf = (jbyte*) jenv->GetByteArrayElements(YuvNv21, 0);
//jint * poutPixels = jenv->GetIntArrayElements(pixels, 0);

Mat image(height + height / 2, width, CV_8UC1, (unsigned char *) pBuf);
//Mat rgba(height, width, CV_8UC4, (unsigned char*) poutPixels);
Mat rgba = *((Mat*) pMatAddr);
Mat tmp(height, width, CV_8UC4);
cvtColor(image, tmp, CV_YUV420sp2RGBA);

double cam[] = { width, 0, width / 2, 0, height, height / 2, 0, 0, 1 };
double distort[] = { 0.1, 0.35, 0.0, 0.0, 0.01 };

Mat camMat = Mat(3, 3, CV_64FC1, cam);
Mat disMat = Mat(5, 1, CV_64FC1, distort);
undistort(tmp, tmp, camMat, disMat);

vector < Mat > channels;
split(tmp, channels);
Mat r = channels.at(0);
Mat g = channels.at(1);
Mat b = channels.at(2);
Mat a = channels.at(3);

vector < Mat > mbgr(4);
mbgr[0] = b;
mbgr[1] = g;
mbgr[2] = r;
mbgr[3] = a;

merge(mbgr, rgba);

jenv->ReleaseByteArrayElements(YuvNv21, pBuf, 0);
//jenv->ReleaseIntArrayElements(pixels, poutPixels, 0);

return true;
}

#ifdef __cplusplus
}
#endif

来源：https://blog.csdn.net/cnbloger/article/details/78256086