Posts: 3
Joined: Sun May 26, 2019 10:24 pm

Exposure mode for scanning bright phone screens

Sun May 26, 2019 10:34 pm

I'm trying to implement QR reader as it was done by many before me.
I was somewhat successful scanning QR printed on paper, but I need to scan QR from a screen of a phone.
The camera has many exposure modes, but no matter what I choose the exposure set to have a whole picture right. After I put my phone screen in front of the camera, the screen is too bright for the exposure, since it is trying to have the exposure right for the whole image, and content of the screen is overexposed and hardly readable by QR code reader algorithm.
Is something could be done to have an exposure based on the phone's screen brightness instead of the background?

Thank you.

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Posts: 1235
Joined: Fri Jul 22, 2016 9:09 pm
Location: Eberbach, Germany
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Re: Exposure mode for scanning bright phone screens

Mon May 27, 2019 9:15 am

What problem do you have?
I did "raspistill -o file.jpg" of bright android screen.
No problems with daylight, nor problem with room completely dark.


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