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Merge branch 'master' of https://github.com/xieguigang/sciBASIC 
2 parents c3542a3 + 18c07ec commit 180bdfd

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‎Data_science/Mathematica/SignalProcessing/MachineVision/RANSAC/PointWithDescriptor.vb‎

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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,10 @@
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Imports System.Drawing
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Imports Microsoft.VisualBasic.ApplicationServices.Terminal.ProgressBar
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Imports Microsoft.VisualBasic.Imaging
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Imports Microsoft.VisualBasic.Imaging.Math2D
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Imports Microsoft.VisualBasic.Linq
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Imports Microsoft.VisualBasic.Math.Correlations
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Imports Microsoft.VisualBasic.Serialization.JSON
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Imports std = System.Math
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''' <summary>
@@ -8,11 +13,63 @@ Imports std = System.Math
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Public Structure PointWithDescriptor
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Public Pt As PointF
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''' <summary>
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''' (distance to centroid, angle)
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''' </summary>
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Public Descriptor As (r As Double, theta As Double)
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''' <summary>
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''' other property that used for weight score which is generated from the raw data
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''' </summary>
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Public [properties] As Double()
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Public Overrides Function ToString() As String
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Return $"({Pt.X},{Pt.Y}) radius:{Descriptor.r}, theta:{Descriptor.theta}, properties:{properties.GetJson}"
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End Function
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''' <summary>
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''' Generates a list of candidate matches by finding the nearest neighbor in descriptor space.
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''' </summary>
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Public Shared Function GenerateCandidateMatches(ByRef sourceDesc As PointWithDescriptor(), ByRef targetDesc As PointWithDescriptor()) As List(Of (source As PointF, target As PointF))
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Dim matches As New List(Of (source As PointF, target As PointF))()
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Call $"Generates a list of candidate matches by finding the nearest neighbor in descriptor space.".debug
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Call $"matrix size: [{sourceDesc.Length} x {targetDesc.Length}]".info
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For Each sPt As PointWithDescriptor In Tqdm.Wrap(sourceDesc, wrap_console:=App.EnableTqdm)
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Dim minDist As Double = Double.PositiveInfinity
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Dim bestMatch As PointWithDescriptor
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For Each tPt As PointWithDescriptor In targetDesc
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' Simple Euclidean distance in descriptor space (r, theta)
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' We might want to weight angle more than distance, but this is a start.
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Dim dr = sPt.Descriptor.r - tPt.Descriptor.r
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Dim dtheta = sPt.Descriptor.theta - tPt.Descriptor.theta
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Dim pd As Double = If(sPt.properties.IsNullOrEmpty OrElse tPt.properties.IsNullOrEmpty, 0, sPt.properties.SquareDistance(tPt.properties))
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' Normalize angle difference
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While dtheta > std.PI : dtheta -= 2 * std.PI : End While
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While dtheta < -std.PI : dtheta += 2 * std.PI : End While
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Dim distSq = dr * dr + dtheta * dtheta + pd
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If distSq < minDist Then
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minDist = distSq
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bestMatch = tPt
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End If
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Next
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If minDist <> Double.PositiveInfinity Then
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matches.Add((sPt.Pt, bestMatch.Pt))
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End If
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Next
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Call $"find {matches.Count} candidate matches!".debug
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Return matches
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End Function
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''' <summary>
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''' Computes a simple (distance, angle) descriptor for each point relative to the polygon's centroid.
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''' </summary>
@@ -39,4 +96,31 @@ Public Structure PointWithDescriptor
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}
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Next
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End Function
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Public Shared Iterator Function ComputeDescriptors(Of T As Layout2D)(shape As IEnumerable(Of T), getMetadata As Func(Of T, Double())) As IEnumerable(Of PointWithDescriptor)
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Dim pool As T() = shape.SafeQuery.ToArray
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If pool.Length = 0 Then
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Return
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End If
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Dim poly As New Polygon2D(pool.X, pool.Y)
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' Calculate centroid (using only valid points)
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Dim centroid As PointF = poly.centroid
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' Compute descriptor for each point
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For i As Integer = 0 To poly.length - 1
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Dim pt As PointF = poly(i)
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Dim dx = pt.X - centroid.X
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Dim dy = pt.Y - centroid.Y
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Dim r = std.Sqrt(dx * dx + dy * dy)
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Dim theta = std.Atan2(dy, dx)
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Yield New PointWithDescriptor With {
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.Pt = pt,
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.Descriptor = (r, theta),
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.properties = getMetadata(pool(i))
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}
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Next
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End Function
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End Structure

‎Data_science/Mathematica/SignalProcessing/MachineVision/RANSAC/RANSACPointAlignment.vb‎

Lines changed: 59 additions & 49 deletions
Original file line numberDiff line numberDiff line change
@@ -58,9 +58,11 @@
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#End Region
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Imports System.Drawing
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Imports System.Runtime.CompilerServices
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Imports Microsoft.VisualBasic.ApplicationServices.Terminal.ProgressBar
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Imports Microsoft.VisualBasic.ApplicationServices.Terminal.ProgressBar.Tqdm
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Imports Microsoft.VisualBasic.ComponentModel.Algorithm.base
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Imports Microsoft.VisualBasic.Imaging
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Imports Microsoft.VisualBasic.Imaging.Math2D
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Imports Microsoft.VisualBasic.Language
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Imports Microsoft.VisualBasic.Linq
@@ -81,6 +83,41 @@ Public Module RANSACPointAlignment
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Return assignMap
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End Function
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''' <summary>
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''' Aligns a source polygon to a target polygon using RANSAC.
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''' </summary>
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''' <param name="sourcePoly">The polygon to be transformed.</param>
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''' <param name="targetPoly">The polygon to align to.</param>
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''' <param name="iterations">The number of RANSAC iterations.</param>
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''' <param name="distanceThreshold">The distance threshold to consider a point an inlier.</param>
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''' <returns>The best-fit Transform object.</returns>
94+
Public Function AlignPolygons(Of T As Layout2D)(sourcePoly As T(),
95+
targetPoly As T(),
96+
properties As Func(Of T, Double()),
97+
Optional iterations As Integer = 1000,
98+
Optional distanceThreshold As Double = 0.1) As AffineTransform
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' Pre-check: need at least 3 points
100+
If sourcePoly.Length < 2 OrElse targetPoly.Length < 2 Then
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Return New AffineTransform
102+
End If
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' 1. Compute descriptors for all points in both polygons
105+
Dim sourceDescriptors = PointWithDescriptor.ComputeDescriptors(sourcePoly, properties).ToArray
106+
Dim targetDescriptors = PointWithDescriptor.ComputeDescriptors(targetPoly, properties).ToArray
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108+
' 2. Generate candidate matches based on descriptor similarity
109+
Dim candidateMatches As (source As PointF, target As PointF)() = PointWithDescriptor _
110+
.GenerateCandidateMatches(sourceDescriptors, targetDescriptors) _
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.ToArray
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113+
If candidateMatches.Length < 3 Then
114+
' Not enough candidate matches to proceed
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Return New AffineTransform
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Else
117+
Return candidateMatches.MakeAlignment(iterations, distanceThreshold)
118+
End If
119+
End Function
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''' <summary>
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''' Aligns a source polygon to a target polygon using RANSAC.
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''' </summary>
@@ -104,13 +141,26 @@ Public Module RANSACPointAlignment
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Dim targetDescriptors = PointWithDescriptor.ComputeDescriptors(targetPoly).ToArray
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' 2. Generate candidate matches based on descriptor similarity
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Dim candidateMatches = GenerateCandidateMatches(sourceDescriptors, targetDescriptors)
144+
Dim candidateMatches As (source As PointF, target As PointF)() = PointWithDescriptor _
145+
.GenerateCandidateMatches(sourceDescriptors, targetDescriptors) _
146+
.ToArray
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109-
If candidateMatches.Count < 3 Then
148+
If candidateMatches.Length < 3 Then
110149
' Not enough candidate matches to proceed
111150
Return New AffineTransform
151+
Else
152+
Return candidateMatches.MakeAlignment(iterations, distanceThreshold)
112153
End If
154+
End Function
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156+
''' <summary>
157+
''' Aligns a source polygon to a target polygon using RANSAC.
158+
''' </summary>
159+
''' <param name="iterations">The number of RANSAC iterations.</param>
160+
''' <param name="distanceThreshold">The distance threshold to consider a point an inlier.</param>
161+
''' <returns>The best-fit Transform object.</returns>
162+
<Extension>
163+
Private Function MakeAlignment(candidateMatches As (source As PointF, target As PointF)(), iterations As Integer, distanceThreshold As Double) As AffineTransform
114164
Dim bestTransform As New AffineTransform
115165
Dim maxInliers As Integer = 0
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Dim thresholdSq = distanceThreshold * distanceThreshold
@@ -119,24 +169,23 @@ Public Module RANSACPointAlignment
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120170
' RANSAC 迭代
121171
For Each iter As Integer In TqdmWrapper.Range(0, iterations, bar:=bar, wrap_console:=App.EnableTqdm)
122-
' Randomly select 3 different matches from the candidate list
123-
If candidateMatches.Count < 3 Then Exit For
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172+
' make sampling of 3 data points from the generated candidate matches
125173
Dim matches = candidateMatches.OrderBy(Function(x) rand.NextDouble()).Take(3).ToArray()
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Dim p1 = matches(0).source, q1 = matches(0).target
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Dim p2 = matches(1).source, q2 = matches(1).target
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Dim p3 = matches(2).source, q3 = matches(2).target
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131179
' Compute a transform hypothesis from these 3 matches
132-
Dim hypothesisTransform = ComputeAffineFrom3Pairs(p1, p2, p3, q1, q2, q3)
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180+
Dim hypothesisTransform As AffineTransform = ComputeAffineFrom3Pairs(p1, p2, p3, q1, q2, q3)
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' Count inliers for this hypothesis across ALL candidate matches
135182
Dim currentInliers As Integer = 0
136-
For Each pair In candidateMatches
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184+
For Each pair As (source As PointF, target As PointF) In candidateMatches
137185
Dim transformedSourcePt = hypothesisTransform.ApplyToPoint(pair.source)
138186
Dim dx = transformedSourcePt.X - pair.target.X
139187
Dim dy = transformedSourcePt.Y - pair.target.Y
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140189
If dx * dx + dy * dy <= thresholdSq Then
141190
currentInliers += 1
142191
End If
@@ -159,45 +208,6 @@ Public Module RANSACPointAlignment
159208
Return bestTransform
160209
End Function
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162-
''' <summary>
163-
''' Generates a list of candidate matches by finding the nearest neighbor in descriptor space.
164-
''' </summary>
165-
Private Function GenerateCandidateMatches(ByRef sourceDesc As PointWithDescriptor(), ByRef targetDesc As PointWithDescriptor()) As List(Of (source As PointF, target As PointF))
166-
Dim matches As New List(Of (source As PointF, target As PointF))()
167-
168-
Call $"Generates a list of candidate matches by finding the nearest neighbor in descriptor space.".debug
169-
Call $"matrix size: {sourceDesc.Length}x{targetDesc.Length}".info
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171-
For Each sPt As PointWithDescriptor In Tqdm.Wrap(sourceDesc, wrap_console:=App.EnableTqdm)
172-
Dim minDist As Double = Double.PositiveInfinity
173-
Dim bestMatch As PointWithDescriptor
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175-
For Each tPt As PointWithDescriptor In targetDesc
176-
' Simple Euclidean distance in descriptor space (r, theta)
177-
' We might want to weight angle more than distance, but this is a start.
178-
Dim dr = sPt.Descriptor.r - tPt.Descriptor.r
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Dim dtheta = sPt.Descriptor.theta - tPt.Descriptor.theta
180-
' Normalize angle difference
181-
While dtheta > std.PI : dtheta -= 2 * std.PI : End While
182-
While dtheta < -std.PI : dtheta += 2 * std.PI : End While
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184-
Dim distSq = dr * dr + dtheta * dtheta
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If distSq < minDist Then
186-
minDist = distSq
187-
bestMatch = tPt
188-
End If
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Next
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191-
If minDist <> Double.PositiveInfinity Then
192-
matches.Add((sPt.Pt, bestMatch.Pt))
193-
End If
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Next
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196-
Call $"find {matches.Count} candidate matches!".debug
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198-
Return matches
199-
End Function
200-
201211
''' <summary>
202212
''' Computes an affine transform from exactly three point pairs.
203213
''' </summary>
@@ -235,12 +245,12 @@ Public Module RANSACPointAlignment
235245
''' <summary>
236246
''' Refines the transformation using all inliers with a least-squares fit for an affine transform.
237247
''' </summary>
238-
Private Function RefineTransformWithLeastSquares(candidateMatches As List(Of (source As PointF, target As PointF)), initialTransform As AffineTransform, threshold As Double) As AffineTransform
248+
Private Function RefineTransformWithLeastSquares(candidateMatches As (source As PointF, target As PointF)(), initialTransform As AffineTransform, threshold As Double) As AffineTransform
239249
Dim inlierPairs As New List(Of (source As PointF, target As PointF))
240250
Dim thresholdSq = threshold * threshold
241251
Dim errors As New List(Of Double)
242252

243-
For Each pair In candidateMatches
253+
For Each pair As (source As PointF, target As PointF) In candidateMatches
244254
Dim transformedSourcePt = initialTransform.ApplyToPoint(pair.source)
245255
Dim dx = transformedSourcePt.X - pair.target.X
246256
Dim dy = transformedSourcePt.Y - pair.target.Y

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