Inspired by the Japanese board game Go, he thought of extending barcodes into two dimensions, making a grid of data instead of lines. This new grid format allows for far more data storage in less space and can be scanned from different angles, leading to the creation of QR codes.

Chinese x Japanese x Korean

In essence, QR codes are pivotal as they have bridged the gap between human needs and machine efficiency, simplifying many processes in our digital worldRemember, a fellow human like me and you invented it from something unlikely. So stay motivated and curious! DYOR <a href="https://youtu.be/w5ebcowAJD8?si=GQkT-3kAdaZsCQr-">YouTube</a> <a href="https://x.com/Xhesra/status/1839722220962103359">BFT</a><a href="https://en.m.wikipedia.org/wiki/QR_code">WIKIPEDIA</a>

Special thanks to Veritasium for making this informative video. Veritasium is a YouTube channel that is geared at finding out the truth about concepts, phenomena, and whatever there is in the world, one at a time. Do well to check it out, and subscribe—you'll surely not regret it. Quick Response (QR) codes are a type of two-dimensional barcode that store information in a grid of black and white squares.

An Element Of Truth

Now, this is the technical part of QR codes. Let's see the basic components of any QR code: The three large squares in the corners, which help the scanner know the orientation of the code, making it readable from any angle. They are called the POSITION MARKERS. The lines connecting the position squares (like zebra crossings), which help the scanner detect how large the grid is; they are called TIMING STRIPS. Small squares within the code, which help adjust for distortion when the QR code is viewed from different angles, called the ALIGNMENT PATTERNS.

Parts?

The Data consists of the rest of the small squares (black = 1, white = 0), which encode the actual information in binary (1s and 0s).

QR codes can be set to four different hierarchies of error correction:Low (7%): Up to 7% of the code can be damaged. Medium (15%): 15% of the code can be damaged. Quartile (25%): 25% of the code can be damaged. High (30%): Up to 30% of the code can be damaged or obscured, but it will still work. This system is what makes it possible for logos or designs to be incorporated into QR codes. If a portion of a QR code becomes unreadable (due to damage or a misprint), error correction kicks in.

Echelons Of Tolerated Errors

Since we have understood that QR codes store more data than barcodes, how much data can they store? The amount of data a QR code stores depends on the size since they come in different sizes. Version 1 QR code is a 21x21 grid, capable of holding about 25 alphanumeric characters. Version 40, the largest-sized QR code, has a 177x177 grid and can hold about 4,296 alphanumeric characters or 3 kilobytes of data. For an IRL instance, you can store an entire URL, a small document, or even a simple game within a QR code!

Data Capacity

Countries like China use QR codes widely to make purchases through their indigenous apps like WeChat and others like Alipay. I can't relate to this though, lol. Accessing links is now easier with QR codes. You don't necessarily need to type it in. I have actually done this a whole lot of times. Physical menus and tickets have been replaced with QR codes in many restaurants and event venues. I once registered for an event and received a QR code as my ticket. Manufacturers can use QR codes to track product history, origin, or even shipping routes, as well as monitor the authenticity of products.

Use Cases

Unlike traditional barcodes that only store data horizontally, QR codes store data both horizontally and vertically, giving them a much higher capacity to hold information—up to thousands of characters in comparison to the 12 digits a barcode can hold. The origin of QR codes can be traced to Morse codes. Morse codes were created in the 1800s, using dots and dashes to communicate letters through electrical pulses. This basic idea of encoding information into symbols birthed barcodes in the 1950s, which used lines of varying widths to encode numbers.

Morse

When you scan a QR code, the camera breaks it down into ones and zeros (binary code). This binary sequence is then decoded to reveal the text, link, or other information stored within the code. Each character in a QR code is encoded using an ASCII encoding system, similar to how Morse code assigns a number to each letter. For example, the word “HELLO” would be broken down into binary like this: H = 72 (in binary: 01001000) E = 69 (in binary: 01000101) L = 76 (in binary: 01001100) O = 79 (in binary: 01001111) These binary codes are then arranged in the grid of the QR code.

WHAT HAPPENS WHEN YOU SCAN A QR CODE?

It's worth noting that a mathematical technique known as the Reed-Solomon error correction is used to design QR codes to be error-tolerant. (Have you read about BFT? Does this ring a bell?)This is to say that a QR code can still be scanned successfully, even if part of the code is damaged or dirty.

You Could Read About BFT, I Wrote About

As time went on, barcodes became essential for tracking and identifying products. But there was a problem… Companies that wanted to store and track more information, such as tracking where products come from or embedding URLs, couldn't do that because barcodes had limited storage capacity. Now, we will see why QR codes were invented. Sometime in the 1990s, someone became frustrated with scanning multiple barcodes on auto parts, as that was a slow and inefficient repetitive process. That individual is the enigmatic Engineer Masahiro Hara, who at the time worked in the Japanese company DENSO.

Barcodes → QR Codes

Analogically, imagine you send a message that includes numbers. Before sending it, you also add a few extra numbers (just like adding spare parts) that allow the receiver to double-check if there were any mistakes. When the receiver gets your message, they can use these extra numbers to detect errors (wrong numbers or missing numbers) and even fix them. In QR codes, the error correction system allows the missing or incorrect parts of the grid to be recrafted. This is why you can scan a QR code that’s partially damaged or dirty.

Error Correction

When Veritasium uploaded the video on YT, I was amazed. I thought it best to write about it.

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