GetTransformationParameters Method

Summary

Computes the rotation angle, XY scaling, and XY translation of the transformed image with comparison to the reference image. These are the transformations that would have to be performed to the reference image to have it match the current image. This method is available in the Document/Medical Toolkits.

Syntax

Objective-C

C++

Java

public static TransformationParameters GetTransformationParameters( 
   RasterImage image, 
   LeadPoint[] referencePoints, 
   LeadPoint[] transformedPoints 
)

Public Shared Function GetTransformationParameters( _ 
   ByVal image As RasterImage, _ 
   ByVal referencePoints() As LeadPoint, _ 
   ByVal transformedPoints() As LeadPoint _ 
) As TransformationParameters

+ (nullable LTTransformationParameters *)getTransformationParameters:(LTRasterImage *)image 
                                                     referencePoints:(nullable NSArray<NSValue *> *)referencePoints /*LeadPoint*/ 
                                                   transformedPoints:(nullable NSArray<NSValue *> *)transformedPoints /*LeadPoint*/ 
                                                               error:(NSError **)error

public static TransformationParameters getTransformationParameters( 
   RasterImage image,  
   LeadPoint[] referencePoints,  
   LeadPoint[] transformedPoints 
)

public: 
static TransformationParameters GetTransformationParameters(  
   RasterImage^ image, 
   array<LeadPoint>^ referencePoints, 
   array<LeadPoint>^ transformedPoints 
)

Parameters

image
RasterImage object that references the transformed image.

referencePoints
Pointer to an array of reference points. These points represent the center of mass points for the registration marks in the reference image. You have to provide this information.

transformedPoints
Pointer to an array of transformed points. These points are the center of mass points in the image. You have to provide this information.

Return Value

TransformationParameters

Remarks

This method detects transformation parameters of the transformed image by comparing it with the reference image. The number of reference and detected points must be three.
Use GetRegistrationMarksCenterMass to fill the referencePoints array with the points representing the center of masses for each of the reference marks from the reference image.
Fill the transformedPoints array by performing the following steps:
- Use SearchRegistrationMarksCommand to find the new positions for the reference marks.
- Using GetRegistrationMarksCenterMass to fill the transformedPoints array with points representing the center of masses for each of the transformed reference marks.
The properties of TransformationParameters which are: XTranslation, YTranslation, Angle, XScale and YScale are internally divided by 100. For example, an Angle of 500 would mean to rotate the image 5 degrees clockwise.
The results of this method must be sent without any modification to the ApplyTransformationParameters method in order to correct the image.
If you want to correct the image yourself, you have to perform the inverse operations in this order:
- Shift the image by (-TransformationParameters.XTranslation / 100, -TransformationParameters.YTranslation / 100) using CombineCommand
- Rotate without resizing by - (TransformationParameters.Angle)
- Resize using scaling factors of (100 / TransformationParameters.XScale, 100 / TransformationParameters.YScale) using SizeCommand or ResizeCommand.
If you simply want to automatically straighten the image, use the DeskewCommand.
This method supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical toolkits.
This command does not support signed images.

For more information, refer to Detecting Registration Marks.

Example

This example computes the translation parameters. The example makes the assumption that you have saved the position of the registration marks of the reference image in a file. You should modify this example and replace the manual assignment of the rmData with your own code to load the reference registration mark data before testing this example.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using LeadtoolsExamples.Common; 
 
public void GetTransformationParametersExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "RGSRef.cmp")); 
 
   // Prepare the command 
   SearchRegistrationMarksCommandData[] rmData = new SearchRegistrationMarksCommandData[3]; 
 
   //Mark1 
   rmData[0] = new SearchRegistrationMarksCommandData(); 
   rmData[0].Rectangle = new LeadRect(680, 20, 941 - 680, 218 - 20); 
   rmData[0].MarkDetectedPoints = new LeadPoint[1]; 
   rmData[0].Width = 31; 
   rmData[0].Height = 29; 
   rmData[0].Type = RegistrationMarkCommandType.TShape; 
   rmData[0].MinimumScale = 90; 
   rmData[0].MaximumScale = 110; 
   rmData[0].SearchMarkCount = 1; 
 
   //Mark2 
   rmData[1] = new SearchRegistrationMarksCommandData(); 
   rmData[1].Rectangle = new LeadRect(665, 790, 899 - 665, 961 - 790); 
   rmData[1].MarkDetectedPoints = new LeadPoint[1]; 
   rmData[1].Width = 31; 
   rmData[1].Height = 29; 
   rmData[1].Type = RegistrationMarkCommandType.TShape; 
   rmData[1].MinimumScale = 90; 
   rmData[1].MaximumScale = 110; 
   rmData[1].SearchMarkCount = 1; 
 
   //Mark3 
   rmData[2] = new SearchRegistrationMarksCommandData(); 
   rmData[2].Rectangle = new LeadRect(7, 1073, 298 - 7, 1246 - 1073); 
   rmData[2].MarkDetectedPoints = new LeadPoint[1]; 
   rmData[2].Width = 31; 
   rmData[2].Height = 29; 
   rmData[2].Type = RegistrationMarkCommandType.TShape; 
   rmData[2].MinimumScale = 90; 
   rmData[2].MaximumScale = 110; 
   rmData[2].SearchMarkCount = 1; 
   SearchRegistrationMarksCommand command1 = new SearchRegistrationMarksCommand(rmData); 
   command1.Run(image); 
   if ((rmData[2].MarkDetectedCount != 1) || (rmData[1].MarkDetectedCount != 1) || (rmData[0].MarkDetectedCount != 1)) 
      return; 
 
   LeadPoint[] original = 
   { 
      new LeadPoint(81400, 11300), 
      new LeadPoint(78600, 87400), 
      new LeadPoint(14300, 115400) 
   }; 
 
   LeadPoint[] detected = 
   { 
      rmData[0].MarkDetectedPoints[0], 
      rmData[1].MarkDetectedPoints[0], 
      rmData[2].MarkDetectedPoints[0] 
   }; 
 
   //Find center of mass for detected registration marks in the transformed image 
   LeadPoint[] transformed = CoreUtilities.GetRegistrationMarksCenterMass(image, detected); 
   //Find transformation parameters 
   TransformationParameters parameters = CoreUtilities.GetTransformationParameters(image, original, transformed); 
   //Apply transformation parameters to correct the image 
   ApplyTransformationParametersCommand applyCommand = new ApplyTransformationParametersCommand(parameters.XTranslation, parameters.YTranslation, parameters.Angle, parameters.XScale, parameters.YScale, 
         ApplyTransformationParametersCommandFlags.Normal); 
   applyCommand.Run(image); 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS21\Resources\Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Core 
 
Public Sub GetTransformationParametersExample() 
   Dim codecs As New RasterCodecs() 
   codecs.ThrowExceptionsOnInvalidImages = True 
 
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "RGSRef.cmp")) 
 
   ' Prepare the command 
   Dim rmData(2) As SearchRegistrationMarksCommandData 
   ' Mark1 
   rmData(0) = New SearchRegistrationMarksCommandData 
   rmData(0).Rectangle = New LeadRect(680, 20, 941 - 680, 218 - 20) 
   Dim pt0(0) As LeadPoint 
   rmData(0).MarkDetectedPoints = pt0 
   rmData(0).Width = 31 
   rmData(0).Height = 29 
   rmData(0).Type = RegistrationMarkCommandType.TShape 
   rmData(0).MinimumScale = 90 
   rmData(0).MaximumScale = 110 
   rmData(0).SearchMarkCount = 1 
 
   ' Mark2 
   rmData(1) = New SearchRegistrationMarksCommandData 
   rmData(1).Rectangle = New LeadRect(665, 790, 899 - 665, 961 - 790) 
   Dim pt1(0) As LeadPoint 
   rmData(1).MarkDetectedPoints = pt1 
   rmData(1).Width = 31 
   rmData(1).Height = 29 
   rmData(1).Type = RegistrationMarkCommandType.TShape 
   rmData(1).MinimumScale = 90 
   rmData(1).MaximumScale = 110 
   rmData(1).SearchMarkCount = 1 
 
   ' Mark3 
   rmData(2) = New SearchRegistrationMarksCommandData 
   rmData(2).Rectangle = New LeadRect(7, 1073, 298 - 7, 1246 - 1073) 
   Dim pt2(0) As LeadPoint 
   rmData(2).MarkDetectedPoints = pt2 
   rmData(2).Width = 31 
   rmData(2).Height = 29 
   rmData(2).Type = RegistrationMarkCommandType.TShape 
   rmData(2).MinimumScale = 90 
   rmData(2).MaximumScale = 110 
   rmData(2).SearchMarkCount = 1 
   Dim command1 As New SearchRegistrationMarksCommand(rmData) 
   command1.Run(leadImage) 
 
   If ((rmData(2).MarkDetectedCount <> 1) OrElse (rmData(1).MarkDetectedCount <> 1) OrElse (rmData(0).MarkDetectedCount <> 1)) Then 
      Return 
   End If 
 
   Dim original() As LeadPoint = 
   { 
      New LeadPoint(81400, 11300), 
      New LeadPoint(78600, 87400), 
      New LeadPoint(14300, 115400) 
   } 
 
   Dim detected() As LeadPoint = 
   { 
      rmData(0).MarkDetectedPoints(0), 
      rmData(1).MarkDetectedPoints(0), 
      rmData(2).MarkDetectedPoints(0) 
   } 
 
   ' Find center of mass for detected registration marks in the transformed image 
   Dim transformed() As LeadPoint = CoreUtilities.GetRegistrationMarksCenterMass(leadImage, detected) 
   ' Find transformation parameters 
   Dim parameters As TransformationParameters = CoreUtilities.GetTransformationParameters(leadImage, original, transformed) 
   ' Apply transformatin parameters to correct the image 
   Dim applyCommand As New ApplyTransformationParametersCommand(parameters.XTranslation, parameters.YTranslation, 
                                                                parameters.Angle, parameters.XScale, 
                                                                parameters.YScale, ApplyTransformationParametersCommandFlags.Normal) 
 
   applyCommand.Run(leadImage) 
 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\LEADTOOLS21\Resources\Images" 
End Class