What's the Difference Between Barcodes and That Square Pattern? - The Worlds of One and Two Dimensions

Barcodes Are "Stripes," the Square Pattern Is a "Go Board Grid"

The barcode that is read with a "beep" at supermarket and convenience store checkouts is a "striped pattern" of black lines of different thicknesses and white gaps lined up in a single horizontal row. Because the information runs only in the horizontal direction, it is called a "one-dimensional code." The black-and-white square pattern, on the other hand, is a "two-dimensional code" with information stored both vertically and horizontally. Like the grid of a Go board, it represents information by whether each individual cell is white or black.

This difference is directly linked to the amount of information. The information a barcode can store is, depending on the format, a short string of digits or characters. A JAN code used on products can hold little more than the product's identification number. The square pattern can store up to 7,089 numeric digits or 4,296 alphanumeric characters, so it can pack in far more information, such as URLs, contact details, and Wi-Fi passwords.

The Way They Are Read Is Completely Different

At checkouts, the typical method is to read barcodes with a "laser scanner." A red laser beam sweeps sideways, and when it hits a black line the light is absorbed, while when it hits a white gap the light is reflected. This reflection pattern is converted into digits. With a scanner whose laser sweeps in only one horizontal direction, you need to line up the orientation of the barcode. If you hold it at an angle, it may fail to read.

The square pattern is read with a "camera." The whole pattern is captured at once, and image processing software analyzes the white and black cells. Thanks to the large square markers in three corners (finder patterns), it can be read even at an angle or upside down. It is thanks to this mechanism that a smartphone camera can read it. Barcodes can be hard to read with a smartphone in some cases, but the square pattern can be read quickly.

Why Barcodes Are Still in Use Today

If the square pattern is superior, why haven't barcodes disappeared? There are three reasons. First, there is the existing infrastructure. The barcode readers installed in supermarkets, convenience stores, and warehouses around the world are enormous in number. Replacing them all is not realistic.

Second, there are many situations where a barcode is enough. If all you need is to read a product's identification number (13 digits), a barcode does the job. Third, there is the printing cost. Because barcodes are long and narrow horizontally, they fit even into the tight spaces on product packaging. Because the square pattern is a square, it can be hard to fit into long, narrow spaces. In other words, barcodes and the square pattern are not "competitors" but are in a relationship of "dividing up the roles."

Look Around You - Which One Is Where?

Barcodes and the square pattern are actually everywhere around us. Let's look for them. Barcodes can be found on food and drink packaging, on the back covers of books (ISBN codes), on parcel delivery slips, and on labels stuck to library books.

The square pattern can be found on restaurant tables (for showing menus), in train advertisements, on business cards, on event tickets, and on product packaging (as links to detailed information). What is interesting is that sometimes both are printed on the same product. The barcode is for payment at the checkout, and the square pattern is for consumers to view detailed information. Two technologies coexist on a single product.

How to Think About Which One to Choose

Barcodes and the square pattern are not a matter of better or worse, but each is good at different things. In situations where there is little information to handle and you want to read fixed content such as a product number at high speed, the simple barcode still plays an active role today. On the other hand, in situations where you want to hold a URL or several pieces of information together, or want it to stay readable even when dirty, the square pattern is the better fit. Which one to choose is determined by what you want to convey and how much, and in what environment it will be read. Choosing the one that fits your purpose leads to building a system without waste.

What Does the Future Hold? - The Arrival of GS1 Digital Link

There is a movement to merge the "division of roles" between barcodes and the square pattern into one. In a standard called GS1 Digital Link, the same product identification number as a barcode is stored in the square pattern in URL format. A compatible checkout scanner reads it as a product number, and a consumer's smartphone reads it as a URL. A single code can fulfill two roles.

If this standard spreads, barcodes may be replaced by the square pattern in the future. However, updating checkout systems around the world is expected to take many years, and the complete disappearance of barcodes is still a long way off. For now, we are in a transition period in which the two technologies coexist.