Threshold Property (Device)

In This Topic

Gets or sets the threshold of black-white images for current scan session.

Syntax

'Declaration

Public Property Threshold As Single

public float Threshold { get; set; }

public: __property float get_Threshold();
public: __property void set_Threshold(
   float value
);

public:
property float Threshold {
   float get();
   void set(float value);
}

Exceptions

Exception	Description
TwainInvalidStateException	Thrown if device is in wrong state.
TwainDeviceCapabilityException	Thrown if device does not support capability.
DebuggerException	Thrown if the .NET debugger is used and the function evaluation requires all threads to run.

Remarks

Call this property only when device is opened (State == DeviceState.Opened).

Supported values of brightness can be received by the GetSupportedThresholdValues method.

Example

This C#/VB.NET code shows how to acquire black-white images from the device.

VB.NET


Public Sub ScanBlackWhiteImageWithBitDepthReductionMode(device As Vintasoft.Twain.Device)
    device.ShowUI = False
    device.DisableAfterAcquire = True

    device.Open()
    device.PixelType = Vintasoft.Twain.PixelType.BW
    device.PixelFlavor = Vintasoft.Twain.PixelFlavor.Chocolate
    device.BitDepthReductionMode = Vintasoft.Twain.BitDepthReductionMode.Threshold
    device.Threshold = 128
    device.UnitOfMeasure = Vintasoft.Twain.UnitOfMeasure.Inches
    device.Resolution = New Vintasoft.Twain.Resolution(200.0F, 200.0F)

    device.Acquire()
End Sub


public void ScanBlackWhiteImageWithBitDepthReductionMode(Vintasoft.Twain.Device device)
{
    device.ShowUI = false;
    device.DisableAfterAcquire = true;

    device.Open();
    device.PixelType = Vintasoft.Twain.PixelType.BW;
    device.PixelFlavor = Vintasoft.Twain.PixelFlavor.Chocolate;
    device.BitDepthReductionMode = Vintasoft.Twain.BitDepthReductionMode.Threshold;
    device.Threshold = 128;
    device.UnitOfMeasure = Vintasoft.Twain.UnitOfMeasure.Inches;
    device.Resolution = new Vintasoft.Twain.Resolution(200f, 200f);

    device.Acquire();
}

Requirements

Target Platforms: .NET 10; .NET 9; .NET 8; .NET 7; .NET 6; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5

Reference

Device Class
Device Members

GetSupportedThresholdValues
Open

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