J4L-QRCode Vision for .NET

• Introduction
• Installation
• Examples

Installation

J4L QRCode Vision is a .NET component which can read (scan) QRCode barcodes images. It support the following features:

• Finding all barcodes in large images (for example in a scanned page or document)
• Supports byte, alpha , numeric and Kanji encoding.
• Supports all formats.

The requirements are:

• .NET 1.0 or later

Known limitations are:

• Best result are achieved with black barcodes on white background.
• Shadowed or blurred barcodes can be unreadable.
• Barcodes can be rotated but only 90, 180 or 270 degrees.

Installation

In order to use the component you only need to add rvisionQR*.dll to your project.

Examples

The delivered ZIP file includes a sample applicaion (QRCodeSample*.exe) that scans all images in the "qrimages" subdirectory and displays the result in the standard output (MSDOS console).

The use of the component is very simple. You must follow these steps:

1. Create a QRCodeReader instance:
   
   [c#]
   QRCodeReader reader=new QRCodeReader();
   
   
   
2. Load your image into an Image class (format must be PixelFormat.Format24bppRgb). The application QRCodeSample.cs includes a method called loadImage() you can use for this purpose.
   
   [c#]
   Image image=loadImage("myFile.gif"); // see loadImage method in QRCodeSample.cs
   
   
3. Create a RImage instance and call the read() method of the QRCodeReader
   
   [c#]
   QRCodeData[] barcodes=reader.read(new RImage(im));
   
   
4. Read the result. The QRCodeData objects contain the following information: Value ( of the barcode) and position ( x , y).
   
   If no barcode has been found the array returned by read() will be empty.

You can optimize the scanning process by setting some system properties:

• J4L.Vision.Util.SystemProperties.setProperty("maxArea","90000");. Ignore objects larger than 90000 pixels.
  
  

• J4L.Vision.Util.SystemProperties.setProperty("minArea","30");. Ignore objects smaller than 30 pixels.

Depending on the size of the object and the image resolution you use, you can modify these values to speed up the scanning process.