1 /*
2  * Medical Image Registration ToolKit (MIRTK)
3  *
4  * Copyright 2013-2015 Imperial College London
5  * Copyright 2013-2015 Andreas Schuh
6  *
7  * Licensed under the Apache License, Version 2.0 (the "License");
8  * you may not use this file except in compliance with the License.
9  * You may obtain a copy of the License at
10  *
11  *     http://www.apache.org/licenses/LICENSE-2.0
12  *
13  * Unless required by applicable law or agreed to in writing, software
14  * distributed under the License is distributed on an "AS IS" BASIS,
15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  * See the License for the specific language governing permissions and
17  * limitations under the License.
18  */
19 
20 #ifndef MIRTK_SumOfSquaredIntensityDifferences_H
21 #define MIRTK_SumOfSquaredIntensityDifferences_H
22 
23 #include "mirtk/ImageSimilarity.h"
24 
25 
26 namespace mirtk {
27 
28 
29 /**
30  * Sum of squared differences image similarity measure
31  */
32 class SumOfSquaredIntensityDifferences : public ImageSimilarity
33 {
34   mirtkEnergyTermMacro(SumOfSquaredIntensityDifferences, EM_SSD);
35 
36   // ---------------------------------------------------------------------------
37   // Attributes
38 
39   /// Minimum input target image intensity value
40   mirtkReadOnlyAttributeMacro(double, MinTargetIntensity);
41 
42   /// Maximum input target image intensity value
43   mirtkReadOnlyAttributeMacro(double, MaxTargetIntensity);
44 
45   /// Minimum input source image intensity value
46   mirtkReadOnlyAttributeMacro(double, MinSourceIntensity);
47 
48   /// Maximum input source image intensity value
49   mirtkReadOnlyAttributeMacro(double, MaxSourceIntensity);
50 
51   /// Maximum squared intensity difference used for normalization
52   mirtkReadOnlyAttributeMacro(double, MaxSqDiff);
53 
54   /// Sum of squared intensity difference value
55   mirtkReadOnlyAttributeMacro(double, SumSqDiff);
56 
57   /// Number of foreground voxels for which similarity is evaluated
58   mirtkReadOnlyAttributeMacro(int, NumberOfForegroundVoxels);
59 
60   /// Copy attributes of this class from another instance
61   void CopyAttributes(const SumOfSquaredIntensityDifferences &);
62 
63   // ---------------------------------------------------------------------------
64   // Construction/Destruction
65 public:
66 
67   /// Constructor
68   SumOfSquaredIntensityDifferences(const char * = "");
69 
70   /// Copy constructor
71   SumOfSquaredIntensityDifferences(const SumOfSquaredIntensityDifferences &);
72 
73   /// Assignment operator
74   SumOfSquaredIntensityDifferences &operator =(const SumOfSquaredIntensityDifferences &);
75 
76   /// Destructor
77   ~SumOfSquaredIntensityDifferences();
78 
79   // ---------------------------------------------------------------------------
80   // Initialization
81 
82   /// Initialize similarity measure
83   virtual void Initialize();
84 
85   /// Update moving input image(s) and internal state of similarity measure
86   virtual void Update(bool = true);
87 
88   // ---------------------------------------------------------------------------
89   // Evaluation
90 protected:
91 
92   /// Exclude region from similarity evaluation
93   ///
94   /// Called by ApproximateGradient \b before the registered image region of
95   /// the transformed image is updated.
96   virtual void Exclude(const blocked_range3d<int> &);
97 
98   /// Include region in similarity evaluation
99   ///
100   /// Called by ApproximateGradient \b after the registered image region of
101   /// the transformed image is updated.
102   virtual void Include(const blocked_range3d<int> &);
103 
104   /// Evaluate similarity of images
105   virtual double Evaluate();
106 
107   /// Evaluate non-parametric similarity gradient w.r.t the given image
108   virtual bool NonParametricGradient(const RegisteredImage *, GradientImageType *);
109 
110 };
111 
112 
113 } // namespace mirtk
114 
115 #endif // MIRTK_SumOfSquaredIntensityDifferences_H
116