public synchronized void requestOcrDecode(Handler handler, int message) {
    Camera theCamera = camera;
    if (theCamera != null && previewing) {
      previewCallback.setHandler(handler, message);
      theCamera.setOneShotPreviewCallback(previewCallback);
    }
  }
A single preview frame will be returned to the handler supplied. The data will arrive as byte[]
in the message.obj field, with width and height encoded as message.arg1 and message.arg2,
respectively.

@param handler The handler to send the message to.
@param message The what field of the message to be sent.
OCRTest/src/main/java/edu/sfsu/cs/orange/ocr/camera/CameraManager.java