Decoder Class Reference

Class for decoding. More...

Inherits INativeHandle.

Public Member Functions
void	Dispose ()
	IDisposable implementation.
T	GetConfig< T > ()
	Retrieves the typed configuration for the decoder.
IEnumerable< Result >	Execute (ImagePlane imagePlane, int numMaxCodes=0)
	Executes the decoding process on the specified image plane.
IEnumerable< Result >	Execute (ImagePlane imagePlane, Rect aoi, int numMaxCodes=0)
	Executes the decoding process on the specified image plane inside area of interest.
TimeLimitedResult	ExecuteFor (ImagePlane imagePlane, TimeSpan timeSpan, int numMaxCodes=0)
	Executes the decoding process within a specified time limit.
TimeLimitedResult	ExecuteFor (ImagePlane imagePlane, Rect aoi, TimeSpan timeSpan, int numMaxCodes=0)
	Executes the decoding process within a specified time limit.

Static Public Member Functions
static Decoder	Create ()
	Creates a decoder object.
static Decoder	FromHandle (IntPtr handle)
	Creates a decoder object from a handle.

Protected Member Functions
virtual void	Dispose (bool disposing)
	IDisposable helper function.

Properties
bool	BasicInkjetDPMEnabled [get, set]
	Enable/disable reading of Basic Inkjet DPM (Direct Part Marking). This mode can read poor quality inkjet images.
CustomPerformance	CustomPerformance [get, set]
	The custom image processing method to improve decoding robustness and performance.
CodeSearchSpeed	CodeSearchSpeed [get, set]
	Adjusts the trade-off between decoding speed, damage tolerance, and required code contrast. The default value (CodeSearchSpeed.Speed0) provides maximum damage tolerance allows detection of high-contrast codes. Higher values increase search speed but reduce damage tolerance and require higher code contrast: 0 - Maximum damage tolerance, detects low-contrast codes (default). 1 - Faster, reduced damage tolerance, detects low-contrast codes. 2 - Faster, further reduced damage tolerance, detects medium-contrast codes. 3 - Fastest, same damage tolerance as level 2, detects high-contrast codes only.
int	DetectorDensity [get, set]
	Sets detector density to increase or decrease the search aggressiveness for small barcodes.
IntPtr	Handle [get]
	Native handle of the Decoder.
bool	IsDisposed [get]
	Gets if the native handle has been disposed.

Events
NativeHandleEventDelegate	ObjectDisposing
	Raised when this object is about to be disposed via the IDisposable.Dispose method.
Events inherited from INativeHandle
NativeHandleEventDelegate	ObjectDisposing
	Raised when this object is about to be disposed via the IDisposable.Dispose method.

Detailed Description

Class for decoding.

This class provides the core functionality for detecting and decoding codes in images. Each code type can be configured using its corresponding configuration class.

To decode an image containing a supported code, start by creating a decoder. You can configure your decoder using the member function Decoder.GetConfig<T> which returns a reference to the desired configuration class.

After configuring the decoder, load an image containing the code(s) and execute the decoding process.The following code snippet demonstrates how to decode an image containing Data Matrix and QR codes:

using Stemmer.Cvb.CodeReader.Config;
 
// Create a decoder.
using (var decoder = Decoder.Create())
{
    var config = decoder.GetConfig<DataMatrix>();
 
    // Enable decoding for the selected symbology and configure additional (optional) parameters.
    config.SetEnabled(true).SetPolarity(Config.Polarity.DarkOnLight);
 
    // Alternatively, the configuration can be performed in a more concise manner:
    decoder.GetConfig<DataMatrix>().SetEnabled(true).SetPolarity(Config.Polarity.DarkOnLight);
 
    // Load the image and decode.
    using (var image = Image.FromFile("your_image_with_code.bmp"))
    {
        var results = decoder.Execute(image.Planes[0]);
    }
 }

Member Function Documentation

Create()

static Decoder Create ( )

static

Creates a decoder object.

Returns

Decoder object

Dispose()

virtual void Dispose ( bool disposing )

protectedvirtual

IDisposable helper function.

Parameters

disposing

Execute() [1/2]

IEnumerable< Result > Execute	(	ImagePlane	imagePlane,
		int	numMaxCodes = 0 )

Executes the decoding process on the specified image plane.

Before execution, ensure that you have configured the decoder using Decoder.GetConfig<T>. If you wish to restrict the search area, you can utilize the overloaded function Execute(ImagePlane, Rect, int).

Note

Up to 256 codes can be detected.

Parameters

imagePlane	The image plane containing the code.
numMaxCodes	Maximum number of codes to detect. 0 for no limit (up to 256).

Returns

A collection of detected codes.

Exceptions

ObjectDisposedException	When this decoder or the parent of the imagePlane is disposed.
ArgumentNullException	When parent of imagePlane is null.

Execute() [2/2]

IEnumerable< Result > Execute	(	ImagePlane	imagePlane,
		Rect	aoi,
		int	numMaxCodes = 0 )

Executes the decoding process on the specified image plane inside area of interest.

Detailed information can be found in the description of function Execute(ImagePlane, int).

Parameters

imagePlane	The image plane containing the code.
aoi	Area of interest.
numMaxCodes	Maximum number of codes to detect. 0 for no limit (up to 256).

Returns

A collection of detected codes.

Exceptions

ObjectDisposedException	When this decoder or the parent of the imagePlane is disposed.
ArgumentNullException	When parent of imagePlane is null.

ExecuteFor() [1/2]

TimeLimitedResult ExecuteFor	(	ImagePlane	imagePlane,
		Rect	aoi,
		TimeSpan	timeSpan,
		int	numMaxCodes = 0 )

Executes the decoding process within a specified time limit.

Parameters

imagePlane	The image plane containing the code.
aoi	Area of interest.
timeSpan	The maximum decoding time (max 60 seconds).
numMaxCodes	Maximum number of codes to detect. 0 for no limit (up to 256).

Returns

TimeLimitedResult, containing the results for the found codes and an info about wether the decoding finished within the given timeSpan .

Exceptions

ObjectDisposedException	When this decoder or the parent of the imagePlane is disposed.
ArgumentNullException	When parent of imagePlane is null.
CvbException	When an error during decoding occurs.

ExecuteFor() [2/2]

TimeLimitedResult ExecuteFor	(	ImagePlane	imagePlane,
		TimeSpan	timeSpan,
		int	numMaxCodes = 0 )

Executes the decoding process within a specified time limit.

Parameters

imagePlane	The image plane containing the code.
timeSpan	The maximum decoding time (max 60 seconds).
numMaxCodes	Maximum number of codes to detect. 0 for no limit (up to 256).

Returns

TimeLimitedResult, containing the results for the found codes and an info about wether the decoding finished within the given timeSpan .

Exceptions

ObjectDisposedException	When this decoder or the parent of the imagePlane is disposed.
ArgumentNullException	When parent of imagePlane is null.
CvbException	When an error during decoding occurs.

FromHandle()

static Decoder FromHandle ( IntPtr handle )

static

Creates a decoder object from a handle.

Parameters

handle

The decoder handle.

Returns

Decoder object

GetConfig< T >()

T GetConfig< T >

(

)

Retrieves the typed configuration for the decoder.

After a decoder is created with Create and before starting the decoding process with Execute, you should configure your decoder. The following code snippet shows exemplarily how to enable and configure the decoding of Data Matrix codes:

var config = decoder.GetConfig<DataMatrix>();
config.IsEnabled = true;
config.Polarity = Polarity.DarkOnLight;

Note that you can enable and configure multiple code types simultaneously. The classes for all supported code types can be found within the Config namespace.

Alternatively, you can utilize the fluent interface pattern for seamless configuration:

decoder.GetConfig<DataMatrix>().SetEnabled(true).SetPolarity(Polarity.DarkOnLight);

Template Parameters

T	The class representing the code type.

Returns

The configuration object.

Type Constraints

T

:

ConfigBase

Property Documentation

BasicInkjetDPMEnabled

bool BasicInkjetDPMEnabled

getset

Enable/disable reading of Basic Inkjet DPM (Direct Part Marking). This mode can read poor quality inkjet images.

Attention

If you enable this mode, the following image requirements have to be met: Width <= 1280 and Width x Height <= 1280x1024 = 1310720 pixels

DetectorDensity

int DetectorDensity

getset

Sets detector density to increase or decrease the search aggressiveness for small barcodes.

Setting it to a lower value can improve robustness of decoding smaller barcodes or poorly formed 2D codes, but will also increase the decoding time. Setting to a higher value will speed up decoding with reduced robustness for decoding smaller barcodes. The default setting is 3. Value must be between 1 and 4 (inclusive).

Exceptions

ArgumentOutOfRangeException

If value not between 1 and 4 (inclusive).>

Event Documentation

ObjectDisposing

NativeHandleEventDelegate ObjectDisposing

Raised when this object is about to be disposed via the IDisposable.Dispose method.

This event is raised right before this object is disposed. The dispose itself cannot be canceled.