``Hysteresis_Threshold'' -- thresholding using hysteresis

purpose:

Thresholds a grayscale volume using hysteresis, based on a scheme by Canny. This function will find all objects satisfying the threshold criteria shown below:

1. The object must contain at least one voxel , where is the high threshold for the hysteresis.
2. All voxels within the object must satisfy , where is the low threshold for the hysteresis.
3. The object must be made up of connected voxels, where S is a minimum allowable component size.

Note that and for this function.

input:

An 8-bit grayscale volume.

output:

An 8-bit binary-valued volume.

parameters:

Default parameters menu is

Upper threshold T1 = 2
* Lower threshold T2 = 2
* (Note: T1 greater than or equal to T2!)
* min component size = 10
* connectivity = 6
* connectivity = no 3-D; 2-D
* input from vol # = 0
* copy output to vol # = 0
*

The ``minimum component size'' parameter sets the value of S described above.
The ``connectivity ='' parameter toggles between 6-- and 26--connectivity.
The second ``connectivity = '' option toggles between ``3-D; no 2-D'' and ``2-D; no 3-D'' and specifies how the operation is done.

comments:

1. This function is comparable in run time to the 2--D conn--comp and 3--D conn--comp operations.

Updated: Fri May 19 14:39:07 CDT