DropOutMethod Property

Visual Basic
C#
C++/CLI

'Declaration
 
Public Property DropOutMethod As DropOutMethod

'Usage
 
Dim instance As DropOutProcessor
Dim value As DropOutMethod
 
instance.DropOutMethod = value
 
value = instance.DropOutMethod

public DropOutMethod DropOutMethod {get; set;}

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

This property tells the object how to drop out the form. You must set this value before you call the CreateImageOfField method.

There are three methods for creating field images: DropOut, Clip, and ClipWithoutRescaling.

Normally, you should use the DropOut method, which will compare the filled and model images, then create an output image that contains the content that was added to the form. Ideally, the output image will not contain any part of the form model; however it is sometimes impossible to determine what is part of the form and what was added by a user.

However, when you are processing OMR fields, you should use the ClipWithoutRescaling method. The OmrProcessor object requires its input images to contain both the marks and the original bubbles. It is okay to use the Clip method for OMR but the ClipWithoutRescaling method will generally perform better.

There are also a few non-OMR situations where you should use the Clip method:

There is no form content near the field. In this case, the Clip method will run faster.
Comparison to the model form is useless. For example, a form may have a region reserved for a stick-on barcode label. In this case, the model has text instructions for attaching the label and the filled image has a barcode. Using the DropOut method will probably leave holes in the barcode wherever a character was present in the model image.
You wish to include part of the form. For example, you may wish to double-check form identification by reading a page number or form revision number. The DropOut method would discard the data you wish to process.

If your images do not drop well, you should try using the line removal and comb removal feature in ScanFix. Make sure you set this property to Clip before you use line or comb removal.

Note: when you set this property to Clip or ClipWithoutRescaling, the resulting confidence of the operation will always be 100.

Default value: Clip

Reference

DropOutProcessor Class
DropOutProcessor Members