我正在Android上爲我的機器人制作線路跟隨者(學習Java/Android編程),目前我正面臨圖像處理問題:攝像頭預覽返回一個名爲YUV的圖像格式,I想要將其轉換爲閾值以便知道線路的位置,那麼該怎麼做?Android上的攝像頭預覽處理
截至目前我已經成功獲得東西,這是我絕對可以從相機的預覽中讀取數據,並通過某種奇蹟,即使知道,如果光強度超過或低於一定值時在一定的區域屏幕。我的目標是將機器人的路徑繪製在相機預覽的疊加層上,這在某種程度上也起作用,但問題在於YUV管理。
正如你不僅可以看到暗區側身拉,但它也重演4倍和預覽圖像被拉伸,我無法弄清楚如何解決這些問題。
這裏的代碼的相關部分:
public void surfaceCreated(SurfaceHolder arg0) {
// TODO Auto-generated method stub
// camera setup
mCamera = Camera.open();
Camera.Parameters parameters = mCamera.getParameters();
List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
for(int i=0; i<sizes.size(); i++)
{
Log.i("CS", i+" - width: "+sizes.get(i).width+" height: "+sizes.get(i).height+" size: "+(sizes.get(i).width*sizes.get(i).height));
}
// change preview size
final Camera.Size cs = sizes.get(8);
parameters.setPreviewSize(cs.width, cs.height);
// initialize image data array
imgData = new int[cs.width*cs.height];
// make picture gray scale
parameters.setColorEffect(Camera.Parameters.EFFECT_MONO);
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
mCamera.setParameters(parameters);
// change display size
LayoutParams params = (LayoutParams) mSurfaceView.getLayoutParams();
params.height = (int) (mSurfaceView.getWidth()*cs.height/cs.width);
mSurfaceView.setLayoutParams(params);
LayoutParams overlayParams = (LayoutParams) swOverlay.getLayoutParams();
overlayParams.width = mSurfaceView.getWidth();
overlayParams.height = mSurfaceView.getHeight();
swOverlay.setLayoutParams(overlayParams);
try
{
mCamera.setPreviewDisplay(mSurfaceHolder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
}
catch (IOException e)
{
e.printStackTrace();
mCamera.stopPreview();
mCamera.release();
}
// callback every time a new frame is available
mCamera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera camera)
{
// create bitmap from camera preview
int pixel, pixVal, frameSize = cs.width*cs.height;
for(int i=0; i<frameSize; i++)
{
pixel = (0xff & ((int) data[i])) - 16;
if(pixel < threshold)
{
pixVal = 0;
}
else
{
pixVal = 1;
}
imgData[i] = pixVal;
}
int cp = imgData[(int) (cs.width*(0.5+(cs.height/2)))];
//Log.i("CAMERA", "Center pixel RGB: "+cp);
debug.setText("Center pixel: "+cp);
// process preview image data
Paint paint = new Paint();
paint.setColor(Color.YELLOW);
int start, finish, last;
start = finish = last = -1;
float x_ratio = mSurfaceView.getWidth()/cs.width;
float y_ratio = mSurfaceView.getHeight()/cs.height;
// display calculated path on overlay using canvas
Canvas overlayCanvas = overlayHolder.lockCanvas();
overlayCanvas.drawColor(0, Mode.CLEAR);
// start by finding the tape from bottom of the screen
for(int y=cs.height; y>0; y--)
{
for(int x=0; x<cs.width; x++)
{
pixel = imgData[y*cs.height+x];
if(pixel == 1 && last == 0 && start == -1)
{
start = x;
}
else if(pixel == 0 && last == 1 && finish == -1)
{
finish = x;
break;
}
last = pixel;
}
//overlayCanvas.drawLine(start*x_ratio, y*y_ratio, finish*x_ratio, y*y_ratio, paint);
//start = finish = last = -1;
}
overlayHolder.unlockCanvasAndPost(overlayCanvas);
}
});
}
此代碼退出應用程序時,有時會產生一個錯誤,由於一些方法release
之後被調用,這是至少我的問題。
UPDATE:
現在的定位問題是固定的(CCD傳感器方向),我仍然面臨重複的問題,這可能與我的YUV數據管理......
謝謝你CCD尖端,這確實是問題,現在重複這個怎麼樣肯定與我的YUV管理有關。一旦我得到它的工作,我會用動態閾值進行優化。 – Solenoid 2012-03-02 11:04:16
...關於liminance問題的介紹 – 2012-03-02 12:40:46