How to read A5 sheet with 7mm QR codes?

Discussion related to "under the hood" OpenMV topics.
TedTrippin
Posts: 1
Joined: Thu May 21, 2020 6:22 am

How to read A5 sheet with 7mm QR codes?

Postby TedTrippin » Thu May 21, 2020 7:18 am

Hi,

First off, loving the OpenMV. Installed IDE, plugged in, tried some code -> worked first time!

I'm trying to scan QR codes on an A5 sheet. They are about 7mm x 7mm. Hoping to detect version 1 and 2.

So far I've tried these settings...

sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.VGA)
-> OSError: Image is not mutable!

sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.VGA)
-> MemoryError: Out of fast Frame Buffer Stack Memory! Please reduce the resolution of the image you are running this algorithm on to bypass this issue!

I've got to...
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.CIF)

Unfortunately, this only works for an area less than 10cm x 10cm.

Any way of increasing the area and resolution?
User avatar
kwagyeman
Posts: 4106
Joined: Sun May 24, 2015 2:10 pm

Re: How to read A5 sheet with 7mm QR codes?

Postby kwagyeman » Thu May 21, 2020 8:06 pm

You need the OpenMV Cam H7 Plus. The AprilTag algorithm requires a lot of RAM. If you want VGA resolution you need 8MB of RAM to process that image. The OpenMV Cam H7 Plus has enough to do so. Note that FPS will only be 1. That said, it can do it however. Also, you can probably go up to SXGA before you run out of memory.
Nyamekye,

Return to “Technical Discussion”

Who is online

Users browsing this forum: GL-ITC and 6 guests