如何在Google Vision Camera Source上设置矩形对焦区域？

Question

I'm currently having problems with Google vision. There is nothing wrong with the library actually, its works great. All what I'm trying to accomplish now is set a rectangular area where the CameraSource will focus only on. The aim is try to capture text within that particular rectangular box only. I've tried many examples on StackOverflow but they all didn't seem to work. My current working code with the Google Vision ( 11.8.0 ) is

cameraView = findViewById(R.id.surfaceview);
        output = findViewById(R.id.output);

        TextRecognizer textRecognizer = new TextRecognizer.Builder(ScanVoucher.this).build();

        if(!textRecognizer.isOperational()) {
            show_alert("Text Recognition not supported on this device");
        } else {

            cameraSource = new CameraSource.Builder(ScanVoucher.this, textRecognizer)
                    .setAutoFocusEnabled(true)
                    .setFacing(CameraSource.CAMERA_FACING_BACK)
                    .setRequestedFps(2.0f)
                    .setRequestedPreviewSize(300, 300)
                    .build();

            cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
                @Override
                public void surfaceCreated(SurfaceHolder surfaceHolder) {
                    try {
                        cameraSource.start(cameraView.getHolder());
                    } catch (IOException e) {
                        show_alert("Unable to access camera");
                    } catch (SecurityException e) {
                        finish();
                    } catch(Exception e) {
                        //Kill
                        finish();
                    }
                }

                @Override
                public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

                }

                @Override
                public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
                    cameraSource.stop();
                }
            });

            textRecognizer.setProcessor(new Detector.Processor<TextBlock>() {
                @Override
                public void release() {

                }

                @Override
                public void receiveDetections(Detector.Detections<TextBlock> detections) {
                    final SparseArray<TextBlock> items = detections.getDetectedItems();

                    if(items.size() != 0) {
                        output.post(new Runnable() {
                            @Override
                            public void run() {
                                StringBuilder builder = new StringBuilder();

                                for(int i = 0; i < items.size(); i++) {
                                    TextBlock item = items.valueAt(i);
                                    builder.append(item.getValue());
                                }

                                try {
                                    output.setText(builder.toString());
                                } catch (Exception e) {
                                    output.setText(e.getMessage());
                                }

                            }
                        });
                    }
                }
            });
        }

As I said, everything works great. Wondering how I could set the rectangular box like preview area so that the camera only captures text with the box just like the QR or bar code scanner apps. Thanks in advance.

Answer 1

Please dont abandon project.. You can Reset your .setRequestedPreviewSize(80, 24) to fit. for me, this only captures the first text line. i hope you see this