I didn't know before about artistic or artwork QR codes, while checking some of these codes, they are completely different from the regular standard QR code, but how is it possible to create this kind of QR code without loosing it's value (the scan result is the same) ?
These QR Codes are the most ones that amazed me:
http://www.hongkiat.com/blog/qr-code-artworks/
The only thing in common is the 3 corners, and they're different in style.
So my question is, what are the elements that we should preserve while creating such QR Codes ?
The most important things are:
Dark-on-light
Very nearly square modules
Modest light border
Substantially preserve the three-finder patterns
... and the first line of modules around them, which carries format info
... and the bottom-right alignment pattern, is helpful
The rest, the interior, can be substantially obscured and still be readable, certainly with high error correction. But messing with the elements above will tend to make it unreadable much more rapidly
Related
I've wondered how QR codes are working, so i did a research and tried to paint my own in an table in word.
On Wikipedia I found this picture
I understand the configuration, but how you actually store a letter doesnt make sense to me.
With the example letter w.
On even rows black is 0 and on odd rows 1.
So the example should give this binary number 01110011 which would be 115 but w is number 32.
So how do I get the right number
I dont know much about this topic but I found you a video where dude explains it. And from what I understood, there are those cells that are read in order of numbers depending on arrow (there are 4 options here and you posted those yourself). So you simply follow those numbers and write 1s and 0s on paper which results in 8bit number. That video has much more detail.
It is also worth pointing out that it is MSB, meaning if we follow your example (you just considering numbers, not colors since you mislabeled it), it has arrow pointing up, meaning you write right/down to up/left which leads to number : 01110011 which has most significant bit at the left which means its 115
What do following snippets of code do in Math ML files? I removed those lines and it still worked fine for me.
<mo></mo>
<mo></mo>
<mo></mo>
Answering to any of them or just letting me know what they are would be very much appreciated.
The first two are function application and invisible times. They help indicate semantic information, see this Wikipedia entry
The last one, , could be anything since it lies in the Unicode Private Use Area which is provided so that font developers can store glyphs that do not correspond to regular Unicode positions. (Unless it's a typo and really 6349 in which case it's a a Han character.)
Still include the mode indicator, string length, and data...I was hoping there was an option to just leave the remaining error correction bits as 0's?
I'm making the QR Code in assembly (MIPS) for a class project. Implementing the Reed Solomon Algorithm is becoming quite a bear.
The lowest level of error correction is 7% - see https://en.wikipedia.org/wiki/QR_code#Error_correction
Here's a sample code with "L" level correction. If you cover one or two blocks, the code is still readable. Much more than that and information cannot be recovered.
You could, theoretically, mask out the error corrective bits when you generate the QR code - but I'm not entirely sure why you would do so.
I have a some vector data that has been manually created, it is just a list of x,y values. The coordinate of the points is not perfectly accurate - it can be off by a few pixels and it won't make any perceivable difference.
So now I am looking for some way to watermark this data, so that if someone steal the vector data, I can prove that it's indeed been stolen. I'm looking for some method reliable enough that even if someone take my data and shift all the points by a some small amount, I can still prove that it's been stolen.
Is there any way to do that? I know it exists for bitmap data but how about vector data?
PS: the vector graphic itself is rather random - it cannot be copyrighted.
Is the set of points all you can work with? If, for example, you were dealing with SVG, you could export the file with a certain type of XML formatting, a <!-- generated by thingummy --> comment at the top, IDs generated according to such-and-such a pattern, extra attributes specifically yours, a particular style of applying translations, etc. Just like you can work out from a JPEG what is likely to have been used to create it, you can tell a lot about what produced an SVG file by observation.
On the vectors themselves, you could do something like consider them as an ordered sequence and apply offsets given by the values of two pseudo-random sequences, each starting from a known seed, for X and Y translation, in a certain range (such as [-1, 1]). Even if some points are modified, you should be able to build up an argument from how things match the sequence. How to distinguish precisely what has been shifted could do with a bit more consideration, too; if you were simply doing int(x) + random(-1, 1), then if someone just rounded all values your evidence would be lost. A better way of dealing with this would be to, while still rendering at the same screen size, multiply everything by some constant like 953 (an arbitrary near-1000 prime) and then adjust your values by something in that range (viz, [0, 952]). This base-953 system would be superior to a base-10 system because it's much (much much) harder to see what's happening. If the person changes the scaling, it would require a bit more analysis of values, but it should still be quite possible. I've got a gut feeling that that's where picking a prime number could be a bit helpful, but I haven't thought about it terribly much. If in danger or in doubt in such matters, pick a prime number for the sake of it... you may find out later there are benefits to it!
Combine a number of different techniques for best results, of course.
I have an incomplete QRCode (about 30%). Is it possible to decode just the fragment of it? I would really like a code snippet - the language doesn't matter.
If you mean, can you decode the entire contents of a QR code even if part of the code is obscured or changed, then yes you can -- sometimes.
QR codes can be encoded with varying levels of redundancy, which are known as levels L, M, Q and H, and correspond to about 7%, 15%, 25% and 30% redundancy. This means you can lose up to that much of the barcode and still decode it. The more you lose, the harder it is to decode, but remains possible within those limits.
Note that certain regions of the QR code can't be lost. The finder patterns (squares at corners) must be findable; they can tolerate some distortion but there's no error correction to help that. Also, the regions around the finder patterns encode format and version. They have a different redundancy (2x encoding using BCH, not Reed-Solomon), but, if you lose too much of those tiny areas you'll not be able to decode, regardless of the main error correction.