What it does ¶
ALBarcodeReader scans an image from the camera and looks for a barcode. If a barcode is found in the image, the module tries to decypher it.
How it works ¶
ALBarcodeReader is a module that regularly queries an image from the camera, converts it to grayscale and processes it in order to find and decode barcodes.
An event is raised whenever a code is read. This event also contains the code data and corner position as depicted in the above image. Note that the first corner (labelled “0”) is always opposite to the corner with no black square. The remaining corners are labelled counter-clockwise.
See BarcodeReader/BarcodeDetected() for a detailed event data description.
Performances and limitations ¶
ALBarcodeReader currently only works with QR Codes. Several codes can be processed in a single image.
Since a barcode is made of small elements (bars, squares...), the image resolution must be set according to the distance between the camera and the code itself. The detection rate also depends on the printed code quality and size.