Allow external barcode scanner app => improve camera/scanner handling

[stacsk]

Hello. My camera is not detecting the barcodes for some reason but I could easily scan with Atharok's Barcode Scanner, for instance, when I used Book Catalogue. Could you maybe add external app support for scanning?

Thank you for your work.

[tfonteyn]

Atharok is using the same barcode scanner library as I do: zxing version "3.3.3" while I'm using the latest version '3.5.3'
We're using the same Android CameraX library, same version.

While technically possible to call an external app, I see no point doing so if we're using the same libs anyhow.

What I can do however is review my use of camera settings and see if I can improve on them.
Give me some time to review the Atharok parameter usage in depth and I'll see if/how I can improve mine.

One tip (which I really should add to my docs) is to switch on the "torch" using the icon at the bottom of the scan screen. I find lack of light the biggest issue when scanning; specially when I'm in a brick-and-mortar bookshop.

I'll get back to you in a bit.

[tfonteyn]

the actual decoding is by and large the same. Not much of a surprise, as we both interface with Zxing after all.

Th biggest difference I can find is that I depend on the camera doing the focusing on its own, while Atharok uses a specific auto-focusing helper. He also supports zooming, but that is really just a matter of holding the camera closer to the code.

I've added auto-focussing to my scanner code and will run some tests on a real device.

[tfonteyn]

I don't see any difference on my test device, but obviously it will all depend on the camera.

My scanner code is a separate module/project to facilitate testing.
I've pushed a build of my scanner library/test project here:

https://github.com/tfonteyn/TinyZXingWrapper/releases/tag/v1.1.1

If you could install that apk, you'll get a basic scanner example.

The main thing to test using the "Generic" scan, but do it with the auto-focus switch ON (default) and OFF.

Let me know if you get a different result when it's ON.

Likewise, play with switching the torch OF/OFF.

I presume when you said "My camera is not detecting the barcodes" you mean it just never detects/scans a number, and NOT that it scans it but delivers a wrong result? Can you confirm this presumption?

Does it scan no codes at all, or is it a matter that some work, other not?
If the latter, can you upload a picture of such a failing scan?

[stacsk]

My camera is not detecting the barcodes

Hi. I meant it never detects anything.

I tried it with several books/magazines now. The main app and the separate scanner detects barcodes wider than 2.5 cm at 10 cm length between the camera and the book, however it's very slow and sometimes it can't detect the same barcode at the same settings, also it sometimes gives the wrong barcode, sometimes the right one for the same book. Also, barcodes with 2cm width can't be scanned at all.

I've tried it with auto-focus on and off and it's pretty much the same. Both apps perform similarly. Meanwhile with Atharok's scanner it takes less than half a second.

I think it could be related to the lack of zoom, the camera has just too much space to study and when you bring the camera closer, the barcode naturally gets blurred and becomes unreadable.

[tfonteyn]

10 cm length between the camera and the book

to b honest, that's the distance I tend to scan my own books. At home I'm typically using a tablet with a single lens.

bring the camera closer, the barcode naturally gets blurred and becomes unreadable.

yes, this bit is normal, the camera can't focus when it's too close, or is brought too close too fast.

it's very slow

That I have come across myself; not too often, but I have not investigated really. I'll add this to the to-do.

sometimes gives the wrong barcode

personal experience that's almost always down to lightning. Enabling the torch rectifies this.

auto-focus on and off

yes, didn't make any difference for me either.

the camera has just too much space to study

quite possible.

ok - this was good feedback. I've got work to do, that's clear :)

Could you please provide:

• brand/model of the device you're using? I tend to check specs on https://www.gsmarena.com
• can you upload a picture of a book (the barcode) which totally fails to scan

My scanner code is quite some years old and at the time I might not have done a good job of optimizing. I'll revisit and see what I can do this week.

[stacsk]

• brand/model of the device you're using? I tend to check specs on https://www.gsmarena.com

I'm using Xiaomi Note 12 Pro+, Android 13.

* can you upload a picture of a book (the barcode) which totally fails to scan

This book is from a series that have the same barcode width for every book. I couldn't scan this until just now when I tried for one more time, and it gave me the correct barcode. It's difficult to scan the book in this series. This one is Emile Zola - Nana (publisher: Türkiye İş Bankası Kültür Yayınları). Mind you that it scans perfectly fine on these photos since the pictures are bigger, and so are the barcodes.

The dimensions of the book are 12.5 x 20.5 cm if you wanna scale the pictures to your screen.
Thanks again for your good work.

[tfonteyn]

I may unexpectedly already have some news... it's not the zoom, but it's related.

It's the size of the preview. Mine: full screen; Atharok's a small rectangle.

Funnily enough I had already implemented most/all of the code to use an embedded preview/scanner. i.e. pretty much like what that app does. I just had not enabled it in a release build.

I ran a quick test with the embedded preview and it's already much faster.

If you're into the tech/code bits, take a look here and the use of that embeddedBarcodeScanner switch.

So.... I'll likely enable that embedded preview permanently and run my usual tests. I may have to tweak the screen layouts a bit for smaller devices. No promise on a release date, but it shouldn't take too long providing I hit no major issues.

[stacsk]

That's what I was actually trying to say when I said zoom. I'm glad you worked it out. I don't know how to code/compile but I'll keep an eye out for the next update. Yay!

[tfonteyn]

yes - that's what put me on the right track.

One thing the embedded scanner code is still missing is the torch-button. I'll need to do that first, then start the tests.

But enough for today - dinner time :)

[tfonteyn]

I've wrapped up a new version of the scanner example, can you please give this a try to see if your issues are indeed fixed?

https://github.com/tfonteyn/TinyZXingWrapper/releases/download/v1.2.0-beta/example-1.2.0-beta.apk

Test using the "Generic" scan button.