Where does DilateFilter live in the IronBarcode API?

DilateFilter is a class in the IronBarCode namespace, shipped in IronBarCode.dll. It derives from Object and implements IImageFilter, so it can be added to the ImageFilterCollection assigned to BarcodeReaderOptions.ImageFilters.

How do you make DilateFilter grow the bars more aggressively?

Raise KernelSize above its default of 3, either through the DilateFilter(int kernelSize) constructor or by setting the KernelSize property. A larger kernel grows the dark regions further, closing wider gaps in a fragmented barcode.

Class DilateFilter

A filter to apply dilation to an image.

Inheritance

System.Object

DilateFilter

Implements

IImageFilter

Namespace: IronBarCode

Assembly: IronBarCode.dll

Syntax

public class DilateFilter : Object, IImageFilter

DilateFilter thickens the dark regions of a barcode image so thin or broken bars join into a solid, readable shape. Dilation is a morphological operation that grows the foreground pixels, which closes small gaps and reconnects a pattern that printing, faxing, or low-resolution scanning has eroded into fragments. Reach for it when a code reads as a scatter of disconnected marks rather than continuous bars; for the opposite problem, where bars have bled together, the erosion filter shrinks them back.

The filter implements IImageFilter and is added to the ImageFilterCollection on BarcodeReaderOptions.ImageFilters, where filters run in collection order before the read. A developer constructs it, adds it to the collection, and passes the options to BarcodeReader.Read. The parameterless constructor uses a KernelSize of 3, the length of one side of the square kernel that controls how aggressively the bars are grown. The DilateFilter(int kernelSize) overload or the KernelSize property raises that value for heavier dilation when the gaps are wide.

using IronBarCode;

var options = new BarcodeReaderOptions
{
    ImageFilters = new ImageFilterCollection { new DilateFilter() }
};
var results = BarcodeReader.Read("faded.png", options);

The image correction how-to walks through filter selection on a sample barcode, and the imperfect barcode example reads a degraded image through a filter pipeline.

Constructors

DilateFilter()

Initializes a new instance of the DilateFilter class.

Declaration

public DilateFilter()

DilateFilter(Int32)

Initializes a new instance of the DilateFilter class.

Declaration

public DilateFilter(int kernelSize)

Parameters

Type	Name	Description
System.Int32	kernelSize	Size of the kernel used to apply dilation, expressed as the length of one side of a square kernel of ones.

Fields

KernelSize

Size of the kernel used to apply dilation, expressed as the length of one side of a square kernel of ones. Default = 3.

Declaration

public int KernelSize

Field Value

Type	Description
System.Int32

Remarks

The greater the size of the kernel, the more the low color intensity regions grow.

Implements

IImageFilter