Storage - What would the ratio be in terms of storage capability between a normal QR Code and a RBG (Red, Blue & Green) colour coded QR Code, assuming that a colour coded QR Code is practical to use.
QR Codes
- Thread starter Hankie Vogel
- Start date
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DelJo63
Have no idea there's any difference -- also never seen a colored version.
There isn’t but it was a theoretical question: QR codes used use 1 bit colour pixels in a maximum of 177 x 177 resolution. So this gives a total of 177 x 177 x 1 = 31329 bits of data or 3.8 kB. If colour was used, it would have to be very simple, e.g. just black, white, pure red, blue, and green, to make detection as simple as possible. This would give you 5 states for each pixel, which equates to 2 bits, plus one extra state. So it wouldn’t give much of a boost to the data storage limit; less than 10 kB in total. Even if QR scanning system could accurately and consistently identify a huge range of colours (such 8 bit per colour channel), the data limit would still be no more than 92 kB. It’s the resolution of the QR code that’s the biggest restriction, and not really the colour.
Appreciate the view... Can I check once again. Can combinations of black, white, red, blue and green per pixel, given that there are 31 329 combinations, not be better utilised to improve the storage capability. Agreed that it is of little use if it can't be scanned effectively with the current standard equipment. Although there are no copyrights as such there are standards that must be adhered to when making use of QR Codes. Question: Can the current storage capability significantly improved by making use of the colour combinations as well.
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DelJo63
Short answer is *only if everyone elected to follow suite*
As noted, it's a B&W screen scraping and no amount of color is/will be beneficial.
As noted, it's a B&W screen scraping and no amount of color is/will be beneficial.
cliffordcooley
Posts: 13,141 +6,441
Calibrating the QR Code reader to correctly read color shading would prove just as difficult, as calibrating colors of monitor and/or printers. The fewer shades of each color makes calibration easier. Especially if there is only one shade of each color. Having color shades would be a major problem as colors tend to fade over time.
No, not with 5 colours, not with millions of colours. The normal 2 colour system (black or white) provides 1 bit of data per pixel; 5 colours doesn't quite fit (4 colours = 2 bits, 8 colours = 3 bits) so it's really only a 2 bit system with such colours. Thus 31 329 x 2 bits = 62 658 bits of data. But even going with 16 777 216 possible colours (I.e. using 8 bit per channel RGB) only raises this to 24 bits per pixel . Then the data limit becomes just 31 329 x 24 = 751 896 bits.
Of course, such a system, regardless of how good the scanner is, would be crippled by a single pixel colour being wrong - e.g. dirty on the image, sunlight changing the viewed colour, QR code printed incorrectly. The latter is especially significant as printers are notoriously poor at replicating desired colours correctly.
This is why all optical storage systems are just 1 bit data streams; the black & white aspect of QR codes is replicated by CD, DVD, Blu-ray discs using 'no interference' & 'destructive interference'. The binary nature of such systems makes them very robust.
Lastly, QR codes do follow a standard - ISO/IEC 18004:2015 .
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