TECH Signal 475
Dithered QR Codes
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Illustration only Photo by Spencer Watson on Unsplash
A technique for embedding low-resolution images into QR codes using two-pass error-diffusion dithering reduces visual noise while preserving scanability.
Engineers building QR-code generators can now produce more aesthetically pleasing codes without sacrificing the robust detection of the finder patterns. The method leverages the QR error-correction capacity but still requires careful limits to avoid rendering the code unreadable.
Written by elseif from the cluster below · every claim links back to a sourceThe three things worth knowing
Data modules can be altered to carry a dithered image, but the functional patterns must stay clear for scanners.
A two-pass error-diffusion algorithm spreads the colour error from forced module colours into surrounding pixels, improving image smoothness.
Excessive modification of data modules or aggressive error diffusion can exceed the QR code's error-correction budget and cause scan failures.
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