Barcodes: These little rectangular blocks containing thin strips of white and black, have become ubiquitous. It has become a deeply integrated component of not only the entire supply chain but our lifestyle. The amount of time this little thing has directly saved for you at no cost and without being thanked for, is huge!
So let’s dive deep into understanding the Barcode!
We will be covering the following two sub-topics.
Need and the origin of barcodes
How does barcode work?
Need and the origin of barcodes
The problem: You would have often seen this happen — you go to a small grocery shop, pick an item and tell the shopkeeper the price. If the product is not very common, he will often check multiple sides or a database for the price of that item.
This method is not very scalable and suitable in stores.
During the early 20th century, the number of products in stores all over the world was increasing rapidly. Not just products, but entire new shelves were being added. What was not increasing at the same rate was — the checkout system.
Food Fair, a large supermarket food chain in the United States was one of the first to realize the severity of the problem! The president of the food chain discussed the problem with one of the deans of Philadelphia's Drexel Institute of Technology. The president attempted to persuade the dean to initiate some research into the problem of capturing product information automatically at checkout. Unfortunately, the dean declined.
But…
Bernard Silver, a 24-year-old graduate student, overheard that conversation.
He explained the problem statement to his friend Norman Joseph Woodland, a twenty-seven-year-old graduate student and teacher at Drexel. The problem fascinated and intrigued Woodland.
First Attempt
They both made their first working system which used patterns of ink that would glow under ultraviolet light. The system worked, but the ink faded too easily and was expensive.
Note: The overall solution for this problem at a basic level, was to have “something” put on the product, that can be read by “some machine (1)”, quickly and accurately. After the machine reads it, another machine (2) maps that reading to pre-stored data (like price, product name, inventory count, etc) and displayed it to the user.
Great, so back to the topic.
Faith, sacrifice and inspiration
Although the ultraviolet ink-based patterns didn’t work out, the problem motivated Woodland enough to seriously pursue finding the solution. He took his stock market savings, quit the institute and moved to his grandfather’s apartment to spend quality time solving the problem.
Once lying on a beach, Woodland drew Morse code on the sand. Then he extended the dots and dashes of the code downwards making it a pattern of parallel lines — the dashes becoming thick lines, and dots becoming thin lines. The resulting pattern left Woodland pondering. After giving a lot of thought, he was sure that this pattern can work in storing information and can be inexpensively made on paper or plastic.
Reading the code
Another insight from a completely different field came that helped in solving the other part of the puzzle, which was reading the code.
Le de Forest had co-invented Phonofilm, which recorded sound directly onto film as parallel lines. The lines varied in their transparency levels. When the film was played, bright light from a 500-watt incandescent light bulb was shone on these parallel lines. The difference in transparency levels of the lines resulted in lights of varying brightness coming on the other side of the film. These were detected by a photo-multiplier tube and converted into electrical waveforms which were then converted to sound by loudspeakers.
Bull’s-eye code
Woodland combined both these ideas — Morse-code-based pattern and Phonofilm-based reading system. He did a modification to the pattern by making them into concentric circles of varying thickness, so that the code can be scanned in any direction. This became known as the bull's-eye code.
Both Woodland and Bernard together filed for the patent for "Classifying Apparatus and Method", in 1949.
Code reader
Remember from our earlier discussion, three things were needed. A code, a machine to read the code, and a machine to process the reading.
Now, the code was ready. The mechanism on how it can be used was ready but on paper. in 1952, Woodland and Silver decided to make their own bull’s eye code reader in the former’s house. The device they came up with was a big desk-size apparatus that had to be wrapped in black oilcloth to keep out the ambient light. Similar to the phonofilm, it also had a 500-watt incandescent light bulb and a photo-multiplier tube, connected to an oscilloscope (an instrument that graphically displays varying electrical voltages).
When Woodland moved the paper with his bar code, the signal on the oscilloscope jumped. He and Silver had created a device that could electronically read printed material.
The machine to read the code, the code-reader was ready!
Now what?
Despite all the success, it was still difficult to convince the world to accept this. And for fair reasons.
First, to process the information coming out from the code-reader, computers would be needed. In those days, computers were big, cumbersome, expensive and could only perform simple calculations. Retail stores are always on the lookout to maximize space utilization. Convincing them to give up some space for a big refrigerator-sized computer, was not going to happen easily.
Second, the large light source was another expensive thing to deal with. Additionally it created lots of waste heat and could cause eye damage. The worst thing was that only a very small fraction of the emitted light was to be used. A system to focus a large amounts of light into a small space was needed. Lasers were not there!
In retrospect, bar codes were clearly a technology ahead of its time.
In 1952, the patent was granted. Woodland was working at IBM at this time. As a result of Woodland’s persuasion, IBM hired a consultant to evaluate the potential of his invention. The consultant praised but reached the same conclusion that the technology was at least 5 years ahead.
IBM offered to buy the patent, which Woodland declined due to the low price offer. In 1962, Philco (an electronics manufacturer) bought the patent for $15,000 and then later sold it on to RCA, another electronics company.
Not only a “checkout” problem
The need for fast and accurate identification was not limited to only supermarkets and grocery stores. Another industry was facing this problem all over the country — Freight cars. The railroad industry wanted to have a system to track freight cars all over the country. Track a large vehicle moving at high speed, across the country. This was the problem that attracted the attention of David J. Collins who got his master's degree from MIT in 1959.
Collins was working at Sylvania Electric Products, who had build its own computer. What this meant was, that Collins need one machine less! He only now needed the right form of code and a method to scan it.
Collins came up with labels that used groups of orange and blue stripes made of reflective material. Each strip represented a number from 0 to 9. A four-digit number identified the railroad that owned the freight car, and a 6 digit number identified the car itself. It was read using a flash of beam and interpreting the reflection. The system was called “KarTrak ACI (Automatic Car Identification) system.”
The Boston & Maine conducted the first test of this system in 1961, and by 1967 a nationwide code had been adopted. By 1975, a full 90% of US rail cars carried KarTrak labels.
But… it was short-lived.
In just 3 years, KarTrak was abandoned. Lack of consistency, high maintenance requirements, the need for expensive computers and multiple bankruptcies in the industry were the top reasons. Up to 20% of the cars were not read correctly. It was replaced by Automatic equipment identification (AEI) which used Radio Frequency based tags.
New Developments
Collins tried to convince senior management at Sylvania to take the KarTrak system to other fields. Realizing they won’t budge, Collins quit his job at Sylvania and started his own firm Computer Identics Corporation. Within a few years, new technologies started coming into place. Lasers became affordable. Now instead of 500-watt bulbs, a milliwatt helium-neon laser beam could do the job.
Computer Identics installed the first barcode systems at two places. One was at the General Motors plant in Pontiac, Michigan. Here it was used to track the production and distribution of car axles. The second system was installed at General Trading Company in Carlsbad, New Jersey where it was used for directing the shipments to the right channels. Both systems used extremely simple barcodes that required just 2 digits.
The utility of barcodes in industrial settings was proved!
Back to Grocery Industry
Remember from our earlier discussion that the patent for Bull’s eye code of Woodland was ultimately purchased by RCA. In 1966, the National Association of Food Chains, held a meeting on the idea of automated checkout systems, after which RCA started developing a robust system based on Woodland’s code. Kroger grocery chain came forward and volunteered to test it.
Within a few years, a committee was established to set guidelines and also select the optimum code type. Some of the guidelines were —
Bar codes have to be readable from almost any angle and a good range of distance.
The code labels should be cheap and easy to print.
The checkout systems would have to pay for themselves in two and a half years.
The last point was based on a 1970 study by McKinsey & Co, which predicted that the industry would save $150 million a year by adopting the systems. Further, a standardized 11-digit code was developed for identifying products.
The request to design the optimum code was sent to many firms, of which prominent ones were RCA and IBM.
RCA vs IBM: Circle vs Bar
In 1972, RCA did an 18-month test with Krogers in Cincinnati, with their bull’s eye code. Very soon a problem was observed. Printing presses often smeared the ink in the direction of the movement of paper. When this happened to the bull’s eye code, the different concentric circles would get merged, making the code unreadable in multiple directions or sometimes in all directions.
In 1973, IBM with the help of Woodland (the original inventor of the bull’s eye code) developed the UPC (Universal Product Code) which had a rectangular bar code. These codes were printed in the direction of paper movement, so the extra ink would simply make the bars taller, without affecting readability. Murray Eden, another consultant at IBM, added the numbers to the bottom, making it a fail-safe system, to help in case the barcode reader failed to read correctly.
After lots of design discussions and testing, on 3 April 1973, the IBM UPC bar code designed by George Laurer, was selected as the NAFC standard.
The First Scan
National Cash Register (NCR) installed the UPC bar code scanning system at Marsh's Supermarket in Troy, Ohio. At 8:01 a.m. on June 26, 1974, a single pack of Wrigley's Juicy Fruit chewing gum became the first retail product sold with the help of a scanner. The NCR cash register rang up 67 cents.
In 1978 less than one percent of grocery stores nationwide had scanners. By mid-1981, the figure was 10 percent and 8,000 stores per year were converting. Three years later it was 33 percent. And, today more than 60 percent are equipped.
Impact
It was found that the return on investment for a barcode scanner was 41.5%. Within 5 weeks after installing barcode scanners, sales in grocery stores increased by 10–12%. This was happening because the barcode system provided stores with lots of sales data that enabled them to have greater responsiveness to customer habits, needs and preferences. There was also a 1–2% decrease in operating costs for those stores, and this enabled them to lower prices and thereby to increase market share.
The popularity of barcodes took them outside US and Sims Supermarkets was the first location in Australia to use barcodes, starting in 1979.
Now we have many types and variants of barcodes adopted across industries globally. Two-dimensional QR codes which can store much more data have also become common. They have enhanced properties like, readability even if a good portion of the code is damaged.
How barcodes work?
Time to decode the Barcode!
Let's start with something which you would already be knowing. All Barcodes look similar - at least when viewed from distance. They have the same alternating black and white lines (always). Plus there is one more similarity - there are exactly 95 lines of those.
So let's build on from here. There are 95 columns evenly spaced. Some columns appear thicker when a group of columns is of the same color, both black and white. See the top of the barcode below.
Next, when the laser light falls on this set of parallel lines the white lines reflect most of the light while the black lines don't. Now a computer can understand only two numbers - either 0 or 1. So it treats dark lines as 1s and white lines as os - ya it is not so intuitive, but it is so.
Time to go into more detail now.
The first line reflects none of the light (or very less light) - Hence assigned the digit 1. The next line reflects almost all light - hence assigned 0. In the same manner, all columns are assigned the numbers. Total assignations - 95. Note that these numbers are different from the one actually put below. After this, these 95 numbers are grouped into 15 different sections. 12 of these sections are used for the actual visible numbers and the remaining 3 act as guards - Left Guard, Center Guard and Right Guard. You can see that in each bar code the left, the right and the center sections are similar.
The patterns for the left side code are shown below -
The pattern for the right side is similar except that it has an even number of 1s. This helps the computer to figure out which side is left/right, in case the product has been turned upside down! There is one more check for this. All the codes for the left side begin with a 0 while those for the right side begin with a 1, leaving the guards.
Okay now we have got the numbers, what do they actually mean?
The very first number decides the type of product - Standard, weighted items, pharmacy, coupons etc.
The next 5 sets of numbers tell who the manufacturer of the product is.
The next 5 sets of numbers tell the product code.
Finally the final digit is called Modulo check character. It is used for error checking. It is an important number, and its functioning is explained below.
To get the Modulo check character:
Add all the digits at odd places. There are 11 digits (leaving the Modulo number)
So for the above figure it is—
0+6+0+2+1+5 = 14 : Multiply it by 3 to get 42
Now add the even digits: 3 +0+0+9+4 = 16
Add both: 42 + 16 = 58.
Now the modulo check number is obtained by subtracting this from the next higher multiple of 10. Here 60 - 58 = 2 --> The Modulo number.
This is how the scanner verifies that the code is correct or not.
Now do barcodes have information on price?
Yes, but not directly. After scanning the barcodes, the scanner sends the code to a central computer and from there it fetches the price. By this the price of the product can be changed accordingly at the central Point of Sale computer.
So, that was the journey taken by multiple industries to make the life of the cashier easy. To create a simple looking black and white stripes of code. The Barcode.
Next time you see a barcode try remembering this story, try decoding it and try sharing it with your friends.
Feel free to ask any questions or share your thoughts on this article or any feedback you have. This publication is for made for you!