Package gov.nih.mipav.model.algorithms.levelset

Class LseFastMarch

  • Direct Known Subclasses:
    LseFastMarch2, LseFastMarch3
    public abstract class LseFastMarch
extends java.lang.Object
    The abstract base class for fast-marching methods of images. This is based on material from J. Sethian's book, Level Set Methods and Fast Marching Methods.
    Version:
    0.1 November 7, 2006
    Author:
    David Eberly

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) float[] m_afInvSpeed
      The inverse speeds associated with the image elements.
      (package private) float[] m_afTime
      The times at which the image elements are visited by moving boundaries.
      (package private) LseMinHeap.Record[] m_akTrial
      Those image elements that are adjacent to the current region boundary points are tracked to allow fast updates of the boundary.
      (package private) float m_fMaxTime
      The maximum time in m_afTime[].
      (package private) float m_fMinTime
      The minimum time in m_afTime[].
      (package private) int m_iQuantity
      The number of image elements.
      (package private) LseMinHeap m_kHeap
      A min-heap data structure used to keep track of the times so that the image element corresponding to the minimum time becomes the next processed boundary point.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected LseFastMarch​(int iQuantity, float[] afSpeed, int[] aiSeeds)
      Create a new fast-marching object, where the speed varies per image element.
      protected LseFastMarch​(int iQuantity, float fSpeed, int[] aiSeeds)
      Create a new fast-marching object, where the speed is constant for all image elements.

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      void computeTimeExtremes()
      Compute the minimum and maximum visitation times for the image elements.
      abstract int[] getBoundary()
      Get the indices of the boundary points of the current region.
      int[] getInterior()
      Get the indices of the interior points of the current region.
      float getMaxTime()
      Get the maximum visitation time for the image elements.
      float getMinTime()
      Get the minimum visitation time for the image elements.
      int getQuantity()
      Get the number of image elements.
      float getTime​(int i)
      Get the time of visitation for an image element.
      protected void initialize​(int iQuantity, int[] aiSeeds)
      Partial initialization of the fast marching object.
      protected void initializeSpeed​(float fSpeed)
      Partial initialization of the fast marching object.
      protected void initializeSpeed​(float[] afSpeed)
      Partial initialization of the fast marching object.
      abstract boolean isBoundary​(int i)
      An image element is a boundary point when it is on the boundary of the current region.
      boolean isFar​(int i)
      An image element is a far element when its visitation time t is infinite: t = Float.MAX_VALUE.
      boolean isInterior​(int i)
      An image element is an interior element when it is valid and not a trial element.
      boolean isTrial​(int i)
      An image element is a trial element when its visitation time t is invalid (t < 0), its inverse speed is finite, and the element is adjacent to the boundary of the current region.
      boolean isValid​(int i)
      An image element is valid whenever its visitation time t satisfies the conditions: 0 ≤ t < Float.MAX_VALUE).
      boolean isZeroSpeed​(int i)
      An image element is never visited when its corresponding speed is zero.
      abstract void iterate()
      Run one iteration of the fast marching algorithm.
      void setTime​(int i, float fTime)
      Set the time of visitation for an image element.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • m_iQuantity

        int m_iQuantity
        The number of image elements.

      • m_afInvSpeed

        float[] m_afInvSpeed
        The inverse speeds associated with the image elements. These are used to control the evolution of region boundaries.

      • m_afTime

        float[] m_afTime
        The times at which the image elements are visited by moving boundaries.

      • m_fMinTime

        float m_fMinTime
        The minimum time in m_afTime[].

      • m_fMaxTime

        float m_fMaxTime
        The maximum time in m_afTime[].

      • m_kHeap

        LseMinHeap m_kHeap
        A min-heap data structure used to keep track of the times so that the image element corresponding to the minimum time becomes the next processed boundary point.

      • m_akTrial

        LseMinHeap.Record[] m_akTrial
        Those image elements that are adjacent to the current region boundary points are tracked to allow fast updates of the boundary.

    • Constructor Detail

      • LseFastMarch

        protected LseFastMarch​(int iQuantity,
                       float[] afSpeed,
                       int[] aiSeeds)
        Create a new fast-marching object, where the speed varies per image element.
        Parameters:
        iQuantity - The number of image elements.
        afSpeed - The array of speeds for the image elements.
        aiSeeds - The initial region points.

      • LseFastMarch

        protected LseFastMarch​(int iQuantity,
                       float fSpeed,
                       int[] aiSeeds)
        Create a new fast-marching object, where the speed is constant for all image elements.
        Parameters:
        iQuantity - The number of image elements.
        fSpeed - The common speed for the image elements.
        aiSeeds - The initial region points.

    • Method Detail

      • getQuantity

        public final int getQuantity()
        Get the number of image elements.
        Returns:
        The number of image elements.

      • setTime

        public final void setTime​(int i,
                          float fTime)
        Set the time of visitation for an image element.
        Parameters:
        i - The index of the image element.
        fTime - The time of visitation for the image element.

      • getTime

        public final float getTime​(int i)
        Get the time of visitation for an image element.
        Parameters:
        i - The index of the image element.
        Returns:
        The time of visitation for the image element.

      • computeTimeExtremes

        public final void computeTimeExtremes()
        Compute the minimum and maximum visitation times for the image elements. The extreme values may be retrieved via calls to getMinTime() and getMaxTime().

      • getMinTime

        public final float getMinTime()
        Get the minimum visitation time for the image elements.
        Returns:
        The minimum visitation time.

      • getMaxTime

        public final float getMaxTime()
        Get the maximum visitation time for the image elements.
        Returns:
        The maximum visitation time.

      • isValid

        public final boolean isValid​(int i)
        An image element is valid whenever its visitation time t satisfies the conditions: 0 ≤ t < Float.MAX_VALUE).
        Parameters:
        i - The index of the image element.
        Returns:
        The Boolean result of the t-constraints.

      • isTrial

        public final boolean isTrial​(int i)
        An image element is a trial element when its visitation time t is invalid (t < 0), its inverse speed is finite, and the element is adjacent to the boundary of the current region.
        Parameters:
        i - The index of the image element.
        Returns:
        The Boolean result of the t-constraints.

      • isFar

        public final boolean isFar​(int i)
        An image element is a far element when its visitation time t is infinite: t = Float.MAX_VALUE. Such elements are not considered when searching the heap for the next element to visit.
        Parameters:
        i - The index of the image element.
        Returns:

      • isZeroSpeed

        public final boolean isZeroSpeed​(int i)
        An image element is never visited when its corresponding speed is zero. Such elements are preprocessed initially so that there visitation times are t = -Float.MAX_VALUE.
        Parameters:
        i - The index of the image element.
        Returns:

      • isInterior

        public final boolean isInterior​(int i)
        An image element is an interior element when it is valid and not a trial element. Effectively, these are interior points of the current region.
        Parameters:
        i - The index of the image element.
        Returns:

      • getInterior

        public int[] getInterior()
        Get the indices of the interior points of the current region.
        Returns:
        The array of indices of the interior points.

      • getBoundary

        public abstract int[] getBoundary()
        Get the indices of the boundary points of the current region. This is an abstract function, because the identification of such points depends on the dimensionality of the image.
        Returns:
        The array of indices of the boundary points.

      • isBoundary

        public abstract boolean isBoundary​(int i)
        An image element is a boundary point when it is on the boundary of the current region. This is an abstract function, because the identification of such points depends on the dimensionality of the image.
        Parameters:
        i - The index of the image element.
        Returns:
        The Boolean result indicating whether or not the image element is a boundary point.

      • iterate

        public abstract void iterate()
        Run one iteration of the fast marching algorithm. This is an abstract function, because the identification of such points depends on the dimensionality of the image.

      • initialize

        protected void initialize​(int iQuantity,
                          int[] aiSeeds)
        Partial initialization of the fast marching object. The visitation times are set to zero for the initial region (the seeds) but to Float.MAX_VALUE for all other points. Initially, none of the points are trial points.
        Parameters:
        iQuantity - The number of image elements.
        aiSeeds - The initial region points.

      • initializeSpeed

        protected void initializeSpeed​(float[] afSpeed)
        Partial initialization of the fast marching object. The inverse speeds are computed for those speeds that are positive. If an input speed is zero, the inverse speed is set to Float.MAX_VALUE and the visitation time is set to -Float.MAX_VALUE as a flag that the corresponding image element should never be visited.
        Parameters:
        afSpeed - The speeds for the image elements.

      • initializeSpeed

        protected void initializeSpeed​(float fSpeed)
        Partial initialization of the fast marching object. The inverse speed is constnnt for all image elements and must be positive.
        Parameters:
        fSpeed - The common speed for the image elements.