2019独角兽企业重金招聘Python工程师标准>>> 
在android上实现 基于肤色的皮肤检测的几个技术要点：
（1）android上使用相机预览，包括相机api的使用和surfaceview的应用。
（2）android上相机使用的色彩空间NV12.
(3)NV12是YCrCb的色彩空间，了解YCrCb色彩空间。YCrCb和YUV之间的转换。
yuv色彩模型来源于rgb模型，该模型的特点是将亮度和色度分离开，从而适合于图像处理领域。YCbCr模型来源于yuv模型.
（4）YCrCb色彩空间表示的人类肤色的特征。这个特征是133≤Cr≤173，77≤Cb≤127.实验表明Cr在[140,160]区间是符合黄种人的肤色。
YUV和RGB的转换:
★这里是不是不是yuv而是Y Cb Cr？？？★
Y = 0.299 R + 0.587 G + 0.114 B
U = -0.1687 R - 0.3313 G + 0.5 B + 128
V = 0.5 R - 0.4187 G - 0.0813 B + 128
R = Y + 1.402 (V-128)
G = Y - 0.34414 (U-128) - 0.71414 (V-128)
B = Y + 1.772 (U-128)
以前，一直没明白yuv和YcbCr之间的差异，想必有些朋友也会有同样的疑惑。
所以，我看完之后就记载下来了。
一、和rgb之间换算公式的差异
yuv<-->rgb
Y'= 0.299*R' + 0.587*G' + 0.114*B'
U'= -0.147*R' - 0.289*G' + 0.436*B' = 0.492*(B'- Y')
V'= 0.615*R' - 0.515*G' - 0.100*B' = 0.877*(R'- Y')
R' = Y' + 1.140*V'
G' = Y' - 0.394*U' - 0.581*V'
B' = Y' + 2.032*U'
yCbCr<-->rgb
Y’ = 0.257*R' + 0.504*G' + 0.098*B' + 16
Cb' = -0.148*R' - 0.291*G' + 0.439*B' + 128
Cr' = 0.439*R' - 0.368*G' - 0.071*B' + 128
R' = 1.164*(Y’-16) + 1.596*(Cr'-128)
G' = 1.164*(Y’-16) - 0.813*(Cr'-128) - 0.392*(Cb'-128)
B' = 1.164*(Y’-16) + 2.017*(Cb'-128)
Note: 上面各个符号都带了一撇，表示该符号在原值基础上进行了gamma correction
源代码如下：
package com.example.hearrate;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Size;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.res.Configuration;
import android.util.Log;
import android.view.Menu;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.graphics.PorterDuff;
import android.graphics.PorterDuff.Mode;
public class MainActivity extends Activity implements SurfaceHolder.Callback ,Camera.PreviewCallback{
SurfaceHolder mHolder;
SurfaceView mView;
SurfaceView mLayer;
SurfaceHolder mLayerHolder;
private Camera mCamera =null;
private boolean bIfPreview =false;
private int mPreviewHeight;
private int mPreviewWidth;
private Canvas canvas;
private Paint paint;
private int facex=0,facey=0;
private boolean bprocessing=false;
private int[] RGBData;
private byte[] mYUVData;
private boolean bfront=false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mView=(SurfaceView)findViewById(R.id.layer0);
paint = new Paint();
paint.setColor(Color.RED);
paint.setAntiAlias(true);
mPreviewWidth=320;
mPreviewHeight=400;
mHolder=mView.getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
mLayer=(SurfaceView)findViewById(R.id.layer1);
mLayer.setZOrderOnTop(true);
//mLayer.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
mLayerHolder=mLayer.getHolder();
mLayerHolder.setFormat(PixelFormat.TRANSPARENT);
mLayerHolder.addCallback(this);
mLayerHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
void drawlayer1()
{
canvas=mLayerHolder.lockCanvas();
// canvas.drawRGB(0, 0, 0);
// canvas.save();
Bitmap bmp=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
//绘制
// canvas.drawBitmap(bmp, null, paint);
drawImage(canvas,bmp,facex,facex,72,72,0,0);
canvas.restore();
bmp=null;
mLayerHolder.unlockCanvasAndPost(canvas);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int width, int height) {
// TODO Auto-generated method stub
mPreviewWidth=width;
mPreviewHeight=height;
if(arg0.equals(mLayerHolder))
{
//drawlayer1();
return;
}
RGBData= new int[mPreviewHeight* mPreviewWidth];
mYUVData= new byte[mPreviewHeight* mPreviewWidth+(mPreviewHeight/2)* (mPreviewWidth/2)+(mPreviewHeight/2)* (mPreviewWidth/2)];
initCamera();
}
@SuppressLint("NewApi")
@Override
public void surfaceCreated(SurfaceHolder arg0) {
// TODO Auto-generated method stub
// TODO Auto-generated method stub
if(arg0.equals(mLayerHolder))
return;
if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.GINGERBREAD)
{
for(int i=0;i>1)*w+j;
// canvas=mLayerHolder.lockCanvas();
// canvas.drawRGB(0, 0, 0);
// canvas.save();
// Bitmap bmp=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
//绘制
// canvas.drawBitmap(bmp, null, paint);
// drawImage(canvas,bmp,facex,facex,72,72,0,0);
// bmp=null;
// int RGBData[] = new int[mPreviewHeight* mPreviewWidth];
// byte[] mYUVData = new byte[mYUV420sp.length];
// System.arraycopy(mYUV420sp, 0, mYUVData, 0, mYUV420sp.length);
/*
for( i=0,yp = 0;i>1)*mPreviewWidth;
for( j=0;j133&&v<173)
canvas.drawPoint(j, i, paint);
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0) r = 0; else if (r > 262143) r = 262143;
if (g < 0) g = 0; else if (g > 262143) g = 262143;
if (b < 0) b = 0; else if (b > 262143) b = 262143;
// int rgb=0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
//r=(rgb&0x00ff0000)>>4;
// g=(rgb&0x0000ff00)>>2;
// b=(rgb&0x000000ff);
// if(r>200&&g>200&&b>200)
// canvas.drawPoint(j, i, paint);
// rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
}
}
canvas.restore();
mLayerHolder.unlockCanvasAndPost(canvas);
*/
/*
* framesize=w*h;
* yp=0;
* for (int i=0;i>1)*w;
* for(int j=0;j> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp]));
if (y < 0) y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]);;
u = (0xff & yuv420sp[uvp++]);
}
///133≤Cr≤173，77≤Cb≤127
if(y>250)
{
RGBData[yp]=Color.RED;
// canvas.drawPoint(i, j, paint);
}else
{
RGBData[yp]=Color.TRANSPARENT;
}
}
}
}
public void detectface(byte[] yuv420sp, int width, int height)
{
final int frameSize = width * height;
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]);;
u = (0xff & yuv420sp[uvp++]);
}
///133≤Cr≤173，77≤Cb≤127
if((v)>133&&(v)<160&&(u>77)&&(u<127))
{
RGBData[yp]=Color.RED;
// canvas.drawPoint(i, j, paint);
}else
{
RGBData[yp]=Color.TRANSPARENT;
}
}
}
}
public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) {
final int frameSize = width * height;
canvas=mLayerHolder.lockCanvas();
Paint paint1 = new Paint();
paint1.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
canvas.drawPaint(paint1);
canvas.save();
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0) y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
///133≤Cr≤173，77≤Cb≤127
if((v)>133&&(v)<160&&(u>77)&&(u<127))
{
canvas.drawPoint(i, j, paint);
}
/*
* 这个是yuv转RGB的处理
* */
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0) r = 0; else if (r > 262143) r = 262143;
if (g < 0) g = 0; else if (g > 262143) g = 262143;
if (b < 0) b = 0; else if (b > 262143) b = 262143;
rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
r = (rgb[yp] >> 16)&0xff;
g = (rgb[yp] >> 8) & 0xff;
b = rgb[yp] & 0xff;
// if(r==255&&g==255&&b==255)
// canvas.drawPoint(i, j, paint);
}
}
canvas.restore();
mLayerHolder.unlockCanvasAndPost(canvas);
}
private void initCamera()
{
if (bIfPreview)
{
mCamera.stopPreview();
}
if(null != mCamera)
{
try{
Camera.Parameters parameters = mCamera.getParameters();
// parameters.setFlashMode("off"); // 无闪光灯
parameters.setPictureFormat(PixelFormat.JPEG); //Sets the image format for picture 设定相片格式为JPEG，默认为NV21
parameters.setPreviewFormat(PixelFormat.YCbCr_420_SP); //Sets the image format for preview picture，默认为NV21
mCamera.setPreviewCallback(this);
// 【调试】获取caera支持的PictrueSize，看看能否设置？？
List pictureSizes = mCamera.getParameters().getSupportedPictureSizes();
List previewSizes = mCamera.getParameters().getSupportedPreviewSizes();
List previewFormats = mCamera.getParameters().getSupportedPreviewFormats();
List previewFrameRates = mCamera.getParameters().getSupportedPreviewFrameRates();
Size psize = null;
for (int i = 0; i < pictureSizes.size(); i++)
{
psize = (Size) pictureSizes.get(i);
}
for (int i = 0; i < previewSizes.size(); i++)
{
psize = (Size) previewSizes.get(i);
}
Integer pf = null;
for (int i = 0; i < previewFormats.size(); i++)
{
pf = (Integer) previewFormats.get(i);
}
// 设置拍照和预览图片大小
parameters.setPictureSize(640, 480); //指定拍照图片的大小
parameters.setPreviewSize(mPreviewWidth, mPreviewHeight); // 指定preview的大小
//这两个属性 如果这两个属性设置的和真实手机的不一样时，就会报错
if(bfront)
{
parameters.set("orientation", "landscape"); //
parameters.set("rotation", 0); // 镜头角度转90度（默认摄像头是横拍）
mCamera.setDisplayOrientation(0); // 在2.2以上可以使用
}
// 横竖屏镜头自动调整
/* if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE)
{
parameters.set("orientation", "portrait"); //
parameters.set("rotation", 90); // 镜头角度转90度（默认摄像头是横拍）
mCamera.setDisplayOrientation(90); // 在2.2以上可以使用
} else// 如果是横屏
{
parameters.set("orientation", "landscape"); //
mCamera.setDisplayOrientation(0); // 在2.2以上可以使用
}
*/
//添加对视频流处理函数
// 设定配置参数并开启预览
mCamera.setParameters(parameters); // 将Camera.Parameters设定予Camera
mCamera.startPreview(); // 打开预览画面
bIfPreview = true;
// 【调试】设置后的图片大小和预览大小以及帧率
Camera.Size csize = mCamera.getParameters().getPreviewSize();
mPreviewHeight = csize.height; //
mPreviewWidth = csize.width;
csize = mCamera.getParameters().getPictureSize();
}catch(Exception e)
{
Log(e.getMessage());
}
}
}
void Log(String msg)
{
System.out.println("LOG:"+msg);
}
int[] g_v_table,g_u_table,y_table;
int[][] r_yv_table,b_yu_table;
int inited = 0;
void initTable()
{
g_v_table=new int[256];
g_u_table=new int[256];
y_table=new int[256];
r_yv_table=new int[256][256];
b_yu_table=new int[256][256];
if (inited == 0)
{
inited = 1;
int m = 0,n=0;
for (; m < 256; m++)
{
g_v_table[m] = 833 * (m - 128);
g_u_table[m] = 400 * (m - 128);
y_table[m] = 1192 * (m - 16);
}
int temp = 0;
for (m = 0; m < 256; m++)
for (n = 0; n < 256; n++)
{
temp = 1192 * (m - 16) + 1634 * (n - 128);
if (temp < 0) temp = 0; else if (temp > 262143) temp = 262143;
r_yv_table[m][n] = temp;
temp = 1192 * (m - 16) + 2066 * (n - 128);
if (temp < 0) temp = 0; else if (temp > 262143) temp = 262143;
b_yu_table[m][n] = temp;
}
}
}
public class ProcessTask extends AsyncTask
{
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
drawdetect();
bprocessing=false;
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
if(bprocessing)
this.cancel(true);
}
@Override
protected Void doInBackground(byte[]... params) {
// TODO Auto-generated method stub
bprocessing=true;
byte[] data= params[0];
//皮肤检测
detectface(data,mPreviewWidth, mPreviewHeight);
//白色检测
//detectwhite(data,mPreviewWidth, mPreviewHeight);
// publishProgress(null);
return null;
}
}
} 以下是layout
以下是manifest