edu.mines.jtk.interp

Class TimeMarker3

java.lang.Object

edu.mines.jtk.interp.TimeMarker3

public class TimeMarker3
extends java.lang.Object

A time and closest-point transform for 3D anisotropic eikonal equations. Transforms an array of times and marks for known samples into an array of times and marks for all samples. Known samples are those for which times are zero, and times and marks for known samples are not modified.

Times for unknown samples are computed by solving an anisotropic eikonal equation grad(t) dot W grad(t) = 1, where W denotes a positive-definite (velocity-squared) metric tensor field. The solution times t represent the traveltimes from one known sample to all unknown samples. Separate solution times t are computed for each known sample that has at least one unknown neighbor. (Such a known sample is sometimes called a "source point.") The output time for each sample is the minimum time computed in this way for all such known samples. Therefore, the times output for unknown samples are the traveltimes to the closest known samples, where "closest" here means least time, not least distance.

As eikonal solutions t are computed for each known sample, the mark for that known sample is used to mark all unknown samples for which the solution time is smaller than the minimum time computed so far. If marks for known samples are distinct, then output marks for unknown samples indicate which known sample is closest. In this way output marks can represent a sampled Voronoi diagram, albeit one that has been generalized by replacing distance with time.

This transform uses an iterative sweeping method to solve for times. Iterations are similar to those described by Jeong and Whitaker (2007). Computational complexity is O(M log K), where M is the number of unknown (missing) samples and K is the number of known samples.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TimeMarker3.Concurrency Type of concurrency used by this transform.

Constructor Summary

Constructors

Constructor and Description
TimeMarker3(int n1, int n2, int n3, Tensors3 tensors) Constructs a time marker for the specified tensor field.

Method Summary

Methods

Modifier and Type	Method and Description
void	apply(float[][][] times, int[][][] marks) Transforms the specified array of times and marks.
void	setConcurrency(TimeMarker3.Concurrency concurrency) Sets the type of concurrency used to solve for times.
void	setTensors(Tensors3 tensors) Sets the tensors used by this time marker.

Methods inherited from class java.lang.Object

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

Constructor Detail

TimeMarker3

public TimeMarker3(int n1,
           int n2,
           int n3,
           Tensors3 tensors)

Constructs a time marker for the specified tensor field.

Parameters:

n1 - number of samples in 1st dimension.

n2 - number of samples in 2nd dimension.

n3 - number of samples in 2nd dimension.

tensors - velocity-squared tensors.

Method Detail

setTensors

public void setTensors(Tensors3 tensors)

Sets the tensors used by this time marker.

Parameters:

tensors - the tensors.

setConcurrency

public void setConcurrency(TimeMarker3.Concurrency concurrency)

Sets the type of concurrency used to solve for times. The default concurrency is parallel.

Parameters:

concurrency - the type of concurrency.

apply

public void apply(float[][][] times,
         int[][][] marks)

Transforms the specified array of times and marks. Known samples are those for which times are zero, and times and marks for these known samples are used to compute times and marks for unknown samples.

Parameters:

times - input/output array of times.

marks - input/output array of marks.