Text recognition app - computer-vision

Question

now i`m trying to make camera app which can recognize text. For this I use the information from guides by google. This site describes how to make a full-screen reader. But i need to set Mobile Vision text scanner active in small rectangle(like in picture).Screenshot of barcode reader app(i need the same solution for text). Please help me).
required result

Answer 1

I have implemented this feature by integrating "filter" in front of the detector which crops the image (in my case a line of text from the center of image). Look at the code below:
public class LineDetector extends Detector {
Detector mDelegate;
public LineDetector(Detector delegate) {
mDelegate = delegate;
}
#Override
public SparseArray detect(Frame frame) {
int width = frame.getMetadata().getWidth();
int height = frame.getMetadata().getHeight();
int mBoxHeight = height;
int mBoxWidth = Math.toIntExact(Math.round(mBoxHeight * ConstantsPool.CROP_BOX_ASPECT_RATIO));
int right = (width / 2) + (mBoxWidth / 2);
int left = (width / 2) - (mBoxWidth / 2);
int bottom = height;
int top = 0;
YuvImage yuvImage = new YuvImage(frame.getGrayscaleImageData().array(), ImageFormat.NV21, width, height, null);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
yuvImage.compressToJpeg(new Rect(left, top, right, bottom), 100, byteArrayOutputStream);
byte[] jpegArray = byteArrayOutputStream.toByteArray();
Bitmap bitmap = BitmapFactory.decodeByteArray(jpegArray, 0, jpegArray.length);
Frame croppedFrame = new Frame.Builder()
.setBitmap(bitmap)
.setRotation(frame.getMetadata().getRotation())
.build();
return mDelegate.detect(croppedFrame);
}
#Override
public boolean isOperational() {
return mDelegate.isOperational();
}
#Override
public boolean setFocus(int id) {
return mDelegate.setFocus(id);
}
}
And then you can use it in a following way:
TextRecognizer textRecognizer = new TextRecognizer.Builder(this).build();
LineDetector lineDetector = new LineDetector(textRecognizer);
lineDetector.setProcessor(...);
...
Camera2Source camera2Source = new Camera2Source.Builder(getContext(), lineDetector).build();
If you have any questions, just ask
Tom