ImageGear for .NET
Preprocess Method
| ImageGear21.Recognition Assembly > ImageGear.Recognition Namespace > ImGearRecImage Class : Preprocess Method |
'Declaration Public Sub Preprocess()
'Usage Dim instance As ImGearRecImage instance.Preprocess()
public void Preprocess()
public: void Preprocess();
public: void Preprocess();
This method performs a series of image pre-processing steps by activating the ImGearRecProcess.IMGPREPROCESS process. Performing these image pre-processing steps may improve the quality of the image from an OCR point of view, which may have an impact on the overall recognition accuracy for the page.
If pre-processing is desired, it should be done before performing auto-zoning and recognition. The available pre-processing steps are image inversion, despeckling, deskewing, and rotation. Also, if the ImGearRecRecognitionSettings.Tradeoff property is set to ImGearRecTradeoff.FAST, a faster, but less accurate deskew, binarization, and despeckle algorithm will be used during pre-processing.
Note: The image resulting from deskewing and rotation are available to the application and can be exported back to an ImGearPage object using the Export method. Inversion and despeckle run on an internal secondary image, and their result is not available for exporting back to the application. Use Invert and Despeckle methods for explicit inversion and despeckling. See The Recognition Process section for explanation of the "secondary image" term.
Whether and how the Preprocess operation does these steps depends on the settings found in the ImGearRecognition.Preprocessing object properties.
The value needed for programmed deskewing, specified with ImGearRecDeskewMode.SET mode, can be detected by DetectSkew method and defined in the ImGearRecPreprocessingSettings.SkewAmount property.
The ImGearRecDeskewMode.AUTO_3D deskewing mode will not be used if an Asian language is set for recognition before pre-processing occurs.