Question

Is it possible by using the Zbar API, that one can check if the image consists of barcode or not?
This is as a backup measure, so that if the application is unable to get barcode value, let it check if it might contain a barcode, if so user can later manually verify it.

I have explored quite a bit but with no major success. If not ZBar, any other open source library that can do it well?

Thanks

Answer 1

What you need is a detector, i.e. the ability to locate the barcode (if any), and thus just return yes or no according to the detection result.

IMHO Zbar does not provide a versatile enough API to do so since it exposes a high-level scanner interface (zbar_scan_image) that combines detection & decoding on one hand, and a pure decoder interface on the other hand.

You should definitely refer to this paper: Robust 1D Barcode Recognition on Mobile Devices. It contains an entire section related to the detection step including pseudo-algorithms [1] – see 4. Locating the barcode. But there is no ready-to-use open source library: you would have to implement your own detector based on the described techniques.

At last, more pragmatic/simple techniques may be used depending on the kind of input images you plan to work with (is there any rotation? blur? is it about processing images or the video stream in real-time?).

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[1] In addition I would say that it’s a good idea to use a different kind of algorithm within this fallback step than the one used within the first step.