> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# LearnCheckmarks Method of the FRPage Object

This method trains FineReader Engine to recognize checkmarks of a custom type. As the result of training, the method fills in the training data ([ICheckmarkBlock::TrainingData](/fine-reader/engine/api-reference/layout-related-objects/checkmarkblock#trainingdata)) for each checkmark block on the page. See details on how to use this method in [Recognizing Checkmarks](/fine-reader/engine/guided-tour/advanced-techniques/recognizing-checkmarks#custom).

## Syntax

### C++

```cpp theme={null}
HRESULT LearnCheckmarks( IObjectsExtractionParams* ExtractionParams );
```

### C\#

```csharp theme={null}
void LearnCheckmarks( IObjectsExtractionParams ExtractionParams );
```

### Visual Basic .NET

```vb theme={null}
Sub LearnCheckmarks( ExtractionParams As IObjectsExtractionParams )
```

## Parameters

ExtractionParams

\[in] The [ObjectsExtractionParams](/fine-reader/engine/api-reference/parameter-objects/preprocessing-analysis-recognition-and-synthesis-parameters/objectsextractionparams) object that stores parameters of objects extraction. This parameter may be 0. In this case, the objects are extracted with default parameters, or, if a [profile](/fine-reader/engine/guided-tour/advanced-techniques/working-with-profiles) has been loaded, the parameters set by this profile are used.

## Return values

This method has no specific return values. It returns [standard return codes of ABBYY FineReader Engine functions](/fine-reader/engine/api-reference/return-codes).

## See also

[FRPage](/fine-reader/engine/api-reference/document-related-objects/frpage)

[Recognizing Checkmarks](/fine-reader/engine/guided-tour/advanced-techniques/recognizing-checkmarks)

[Working with Profiles](/fine-reader/engine/guided-tour/advanced-techniques/working-with-profiles)

[Tuning Analysis, Recognition, and Synthesis Parameters](/fine-reader/engine/guided-tour/advanced-techniques/tuning-parameters-of-preprocessing-analysis-recognition-and-synthesis)