ImageGear for .NET
INVERSION
| ImageGear for .NET User Guide > Using ImageGear for .NET > Using ImageGear.Recognition Namespace > Preparing the Image for Recognition > Pre-Processing Operations > INVERSION |
Image inversion can be done on any image (bitonal, grayscale, or color) within the recognition engine's memory space. Recognition needs black or dark characters on a white or pale background.
The Invert Method immediately inverts a whole single image - or a specified rectangle within it. This method ignores the image inversion mode setting. The inverted image replaces the original image and is available to the recognition engine and the application.
An image inversion mode setting is made with the ImGearRecPreprocessingSettings.InversionMode Property, taking values from ImGearRecInvertMode Enumeration. These are:
This mode-induced inversion is performed when ImGearRecImage.Preprocess Method is called and always acts on the whole image. The inverted image replaces the original one, it keeps its original type (bitonal, grayscale, or color) and format, and is available to the recognition engine and the application.
If auto-inversion is set (AUTO), grayscale or color images undergo an implicit secondary conversion to create a clean bitonal image. If auto-inversion is set and despeckle mode is ON for a bitonal image with over 280 dpi, a despeckled bitonal image is created. Detecting whether inversion is needed or not is done on the bitonal image - the despeckled image, if available. These bitonal images are not available to the application. If the recognition engine decides inversion is needed, the whole original image is inverted.