today i read about barcodes and QRcodes . well i see barcodes / QR codes and often see them on almost every product. But as a programming learner , i wanna know about what they represent ?, how they are created(with which information) ?, how they are read by our application ? does any application can read any barcode ?
Edited 2 Years Ago by Learner010
i wanna know about what they represent
Usually a product number, but QR code is designed to contain something larger, like an URL.
how they are read by our application
Usually by an external scanner. These scanners read the image and convert it into plain text, which is often emulated as being keyboard input.
does any application can read any barcode
Mobile application able to integrate with a camera can. So basically, the same is possible when using a webcam. You just need some tools to convert the image into data.
i wanna know about what they represent ?
There are a number of barcode symbologies that have different data restrictions. Here's a quick overview of some common ones:
how they are created(with which information) ?
It depends on the symbology. 1D barcodes could be as simple as placing check characters on the end of the value (
"*12345*" for 3 of 9), or as complex as a thorough compaction, encryption, and encoding scheme typically found in the 2D barcodes.
how they are read by our application ?
There are two options, essentially:
Hardware scanning: A physical device captures an image of the barcode and processes it internally, then passes the extracted value to your application. In terms of using these devices it's often as simple as pulling a string in from standard input.
Image recognition: Using a barcode recognition library, you can open an image file on the hard disk and extract barcode information. This makes up the lion's share of how I handle barcodes at work.
does any application can read any barcode ?
Yes. Barcodes aren't voodoo. With the right library you can do recognition in 10 lines or less. Implementing such a library can be vastly more complex though, especially when it comes to 2D barcodes.
There are many kinds of barcodes -- some contain more information than others. RFID contains the most information, such as nearly everything about the product (manufacturer, dates, shipping info, just to name a few). The person or company generating the barcodes determine what information the barcode contains. The most common -- UPC -- contains just numeric digits. Here is more detailed information about UPC and EAN barcodes.
As previously mentioned, you will need some kind of external scanner to read barcodes -- the scanners I worked with send my programs the barcode info as plain text data, usually by stuffing it into the keyboard buffer, or by making API calls to the barcode reader. Those API calls are totally dependent on the manufacturer of the reader -- there is no industry standard. That means you will have to read the programming docs for the readers you have or will have.
One of the most common industrial style external barcode readers is made by Symbols Technologies -- and they can cost anywhere from $30.00 USD to over $500.00 USD.
Edited 2 Years Ago by Ancient Dragon
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code for the listbox - datagridview interaction
At the top of the code ...
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