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InvertedPageCommand Class

Summary

Checks and auto-corrects an inverted image.

Syntax

C#
VB
Java
Objective-C
WinRT C#
C++
@interface LTInvertedPageCommand : LTRasterCommand 
public class InvertedPageCommand extends RasterCommand 
function Leadtools.ImageProcessing.Core.InvertedPageCommand() 

Remarks

This command is available in the Document/Medical Toolkits.

An inverted RasterImage is an image that has text or other objects in high contrast color on a low contrast background (for example, white text on black background). This command can determine whether an image is inverted and correct it automatically.

This command can only detect an entire image. To search for and correct specific inverted areas or regions in an image, use the InvertedTextCommand.

A common source of inverted images are black and white images saved with a non-standard palette by some applications.

This command does not support signed data images.

For more information, refer to Cleaning Up 1-Bit Images.

In Silverlight versions of LEADTOOLS, this image processing command will fail if the image data for the RasterImage object is stored internally using a Silverlight WriteableBitmap object. For more information, refer to Image Processing Command Limitations in Silverlight.

Example

This example will show how to use the InvertedPageCommand class to check and auto-correct inverted images.

C#
VB
Silverlight C#
Silverlight VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
 
public void InvertedPageCommandExample() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   // Get an image 
   string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "ocr1.tif"); 
   string invertedImageFileName = Path.Combine(LEAD_VARS.ImagesDir, "ocr1_Inverted.tif"); 
   string nonInvertedImageFileName = Path.Combine(LEAD_VARS.ImagesDir, "ocr1_NonInverted.tif"); 
 
   RasterImage image = codecs.Load(tifFileName); 
 
   // The images should be non-inverted at the beginning, check 
   InvertedPageCommand invertedPage = new InvertedPageCommand(InvertedPageCommandFlags.NoProcess); 
   invertedPage.Run(image); 
   Console.WriteLine("Original image, inverted = {0}", invertedPage.IsInverted); 
 
   // Invert the image 
   InvertCommand invert = new InvertCommand(); 
   invert.Run(image); 
 
   codecs.Save(image, invertedImageFileName, image.OriginalFormat, image.BitsPerPixel); 
 
   // Check again 
   invertedPage.Run(image); 
   Console.WriteLine("After running InvertCommand, inverted = {0}", invertedPage.IsInverted); 
 
   // Now run the command to un-invert the image 
   invertedPage.Flags = InvertedPageCommandFlags.Process; 
   invertedPage.Run(image); 
 
   // Now check the image again 
   invertedPage.Flags = InvertedPageCommandFlags.NoProcess; 
   invertedPage.Run(image); 
   Console.WriteLine("After running InvertedPageCommand, inverted = {0}", invertedPage.IsInverted); 
   codecs.Save(image, nonInvertedImageFileName, image.OriginalFormat, image.BitsPerPixel); 
 
   image.Dispose(); 
 
   codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
} 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
      Leadtools.Examples.Support.SetLicense() 
 
Public Sub InvertedPageCommandExample() 
   Dim codecs As New RasterCodecs() 
 
   ' Get an image 
   Dim tifFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "ocr1.tif") 
   Dim invertedImageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "ocr1_Inverted.tif") 
   Dim nonInvertedImageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "ocr1_NonInverted.tif") 
 
   Dim image As RasterImage = codecs.Load(tifFileName) 
 
   ' The images should be non-inverted at the beginning, check 
   Dim invertedPage As New InvertedPageCommand(InvertedPageCommandFlags.NoProcess) 
   invertedPage.Run(image) 
   Console.WriteLine("Original image, inverted = {0}", invertedPage.IsInverted) 
 
   ' Invert the image 
   Dim invert As New InvertCommand() 
   invert.Run(image) 
 
   codecs.Save(image, invertedImageFileName, image.OriginalFormat, image.BitsPerPixel) 
 
   ' Check again 
   invertedPage.Run(image) 
   Console.WriteLine("After running InvertCommand, inverted = {0}", invertedPage.IsInverted) 
 
   ' Now run the command to un-invert the image 
   invertedPage.Flags = InvertedPageCommandFlags.Process 
   invertedPage.Run(image) 
 
   ' Now check the image again 
   invertedPage.Flags = InvertedPageCommandFlags.NoProcess 
   invertedPage.Run(image) 
   Console.WriteLine("After running InvertedPageCommand, inverted = {0}", invertedPage.IsInverted) 
   codecs.Save(image, nonInvertedImageFileName, image.OriginalFormat, image.BitsPerPixel) 
 
   image.Dispose() 
 
   codecs.Dispose() 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class 
using Leadtools; 
using Leadtools.ImageProcessing; 
using Leadtools.Examples; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
 
public void InvertedPageCommandExample(RasterImage image, Stream outStream1, Stream outStream2) 
{ 
   // The images should be non-inverted at the beginning, check 
   InvertedPageCommand invertedPage = new InvertedPageCommand(InvertedPageCommandFlags.NoProcess); 
   invertedPage.Run(image); 
   Debug.WriteLine("Original image, inverted = {0}", invertedPage.IsInverted); 
 
   // Invert the image 
   InvertCommand invert = new InvertCommand(); 
   invert.Run(image); 
 
   RasterCodecs codecs = new RasterCodecs(); 
   // save image to "ocr1_Inverted.tif"; 
   codecs.Save(image, outStream1, image.OriginalFormat, image.BitsPerPixel); 
 
   // Check again 
   invertedPage.Run(image); 
   Debug.WriteLine("After running InvertCommand, inverted = {0}", invertedPage.IsInverted); 
 
   // Now run the command to un-invert the image 
   invertedPage.Flags = InvertedPageCommandFlags.Process; 
   invertedPage.Run(image); 
 
   // Now check the image again 
   invertedPage.Flags = InvertedPageCommandFlags.NoProcess; 
   invertedPage.Run(image); 
   Debug.WriteLine("After running InvertedPageCommand, inverted = {0}", invertedPage.IsInverted); 
 
   // save result image to "ocr1_NonInverted.tif" 
   codecs.Save(image, outStream2, RasterImageFormat.CcittGroup4, 1); 
 
   image.Dispose(); 
} 
Imports Leadtools 
Imports Leadtools.ImageProcessing 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
 
Public Sub InvertedPageCommandExample(ByVal image As RasterImage, ByVal outStream1 As Stream, ByVal outStream2 As Stream) 
   ' The images should be non-inverted at the beginning, check 
   Dim invertedPage As InvertedPageCommand = New InvertedPageCommand(InvertedPageCommandFlags.NoProcess) 
   invertedPage.Run(image) 
   Debug.WriteLine("Original image, inverted = {0}", invertedPage.IsInverted) 
 
   ' Invert the image 
   Dim invert As InvertCommand = New InvertCommand() 
   invert.Run(image) 
 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   ' save image to "ocr1_Inverted.tif"; 
   codecs.Save(image, outStream1, image.OriginalFormat, image.BitsPerPixel) 
 
   ' Check again 
   invertedPage.Run(image) 
   Debug.WriteLine("After running InvertCommand, inverted = {0}", invertedPage.IsInverted) 
 
   ' Now run the command to un-invert the image 
   invertedPage.Flags = InvertedPageCommandFlags.Process 
   invertedPage.Run(image) 
 
   ' Now check the image again 
   invertedPage.Flags = InvertedPageCommandFlags.NoProcess 
   invertedPage.Run(image) 
   Debug.WriteLine("After running InvertedPageCommand, inverted = {0}", invertedPage.IsInverted) 
 
   ' save result image to "ocr1_NonInverted.tif" 
   codecs.Save(image, outStream2, RasterImageFormat.CcittGroup4, 1) 
 
   image.Dispose() 
End Sub 

Requirements

Target Platforms

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Leadtools.ImageProcessing.Core Assembly
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