The backlight of the masked SLA resin printers isn't perfect and it can affect the dimensional accuracy.
This device allows you to measure the backlight and compensate for the defects:
It does so via a moving a sensor over the printer's LCD:
You can learn more in the corresponding blog post.
The repository contains a Marlin-based firmware in the fw directory and
command line control app that allows you to acquire data and process them in the
drlcd directory.
# Installation
$ pip install git+https://github.com/yaqwsx/DrLCD.git@master
# Acquire data
$ drlcd measurelcd --size <display_size_in_mm> --resolution <number_of_samples> --fast <output_file>
# E.g. drlcd measurelcd --size 202x130 --resolution 202x130 --fast frist-saturn2-mesurement.json
# Visualize measurement
$ drlcd visualize --show --title "<graph name>" <measurement file> <output HTML>
# Create compensation map
$ drlcd compensate --measurement <measurement file> --min <low value to compensate> --max <high value to compensate> --by <amount of dimming> --screen <resolution in px> --cutoff <black value for screen detection> <output PNG file>