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is it possible to read a bar code displayed on the display of a smartphone by a laser bar code reader in a grocery store?? I know that it is not possible to read it from gallery wich contains a bar code photo. I tried it. So, is there any solution, how can it be done? Thanks

user1408686
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  • Scale your picture to 100% and try it once more. I don't really know *why* you'd need to do this... – Blender May 21 '12 at 19:56
  • Do you want to sort of screen scrape the graphical bars on the screen? Or get the bar code digits as scanned by the bar code reader? If the latter, I'd suggest checking the documentation... perhaps it just functions as a keyboard using a driver and you don't need to do much. Also didn't specify WHAT KIND of smartphone? What operating system? What brand bar code reader?... do you think everybody here has crystal balls? – reiniero May 21 '12 at 19:59
  • I think he wants to display barcodes on the screen for reading by a scanner. The Starbucks application on Android provides this functionality, but solving the problem generically might be pretty tough. – IslandCow May 22 '12 at 08:15
  • @IslandCow: Yes, that is what I wanted. Read a bar code (ean, code 128 ect.) out of display of a smartphone. Starbucks application seems to be it, I havent tried it, because there is no Starbucks near to my place. So you think it is posible to read it from the display? reiniero, I ment any smartphone you can imagine, and any possible bar code reader. I just want to know, if is it possible anyhow. Thanks for the answers. If anybody has something to say about this topic, please do so. – user1408686 May 27 '12 at 14:06
  • Unfortunately, doing this generically might be a challenge. From what I understand, you'd be best off targeting a particular type of barcode and barcode reader first and going from there. If you mention your application domain, somebody may be able to be more helpful. – IslandCow Jun 11 '12 at 20:44

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As far as I know, it's not possible with laser based scanners because they rely on the reflective properties of paper. LCD screens generally reflect too much light, and also emit light, making it hard for the sensor to differentiate the black and white bars.

CMOS and CCD image based scanners, however, should be able to read from mobile phones just fine.

Carson
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  • What about from Ebook readers? or Ebook reader mode on a smartphone? – Karthik Andhamil Nov 01 '13 at 05:10
  • @KarthikPalanivelu The reason it doesn't work is because the screen is reflective and emits light, so if it is a smartphone with a standard screen, I don't think it will matter what mode it is in. As for matte Ebook readers (E Ink?), I am not sure if these will scan with laser scanners. – Carson Nov 05 '13 at 22:07