- (nullable LTRasterImage *)rasterImageForPageType:(LTOcrPageType)pageType error:(NSError **)error
public RasterImage getRasterImage(OcrPageType pageType)
The page type to get.
A RasterImage object that represent the current or processing image data of this page.
Each IOcrPage contains two versions of the image used to create it: an original (current) and an optional processing version. The processing version usually black/white and has uniform resolution (if the original image is FAX for example) and it gets passed to the internal OCR engine during the zoning and recognition process. The AutoPreprocess method also uses the B/W image to determine if the page is inverted, skewed or has an orientation; however, it applies the correction to both the current and processing images.
You can use GetRasterImage(OcrPageType) to get a copy of either of these images.
You cannot set the processing image of a page; it is created automatically by the engine. This is why there is no IOcrPage.SetRasterImage(OcrPageType pageType) method.
If the original image is black and white and has uniform vertical and horizontal resolution, then the engine will not create a processing image, in other words, GetRasterImage(OcrPageType.Current) and GetRasterImage(OcrPageType.Processing) will return identical RasterImage objects.
If the original image has different horizontal and vertical resolution, such as a FAX image, the processing page will be have be resized to have uniform resolution.
The LEADTOOLS C# and VB .NET Main OCR demos (Examples\DotNet\CS\OcrMainDemo and Examples\DotNet\VB\OcrMainDemo) have an option in the page menu to toggle between showing the current (default) or processing image of each page.
For an example, refer to OcrPageType.
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