bwselect3

Select objects in binary volume

Syntax

J = bwselect3(V,c,r,p)

J = bwselect3(V,c,r,p,n)

[J,idx] = bwselect3(___)

[x,y,z,J,idx,xi,yi,zi] = bwselect3(___)

[___] = bwselect3(x,y,z,V,xi,yi,zi)

Description

J = bwselect3(V,c,r,p) returns the binary volume J containing the objects that overlap the voxel (r,c,p). Objects are connected sets of voxels with the value 1.

J = bwselect3(V,c,r,p,n) also specifies the connectivity, n, used to define objects.

[J,idx] = bwselect3(___) returns in idx the linear indices of voxels belonging to the selected objects.

[x,y,z,J,idx,xi,yi,zi] = bwselect3(___) also returns the x, y, and z extents of the binary volume and the (xi,yi,zi) coordinates of selected voxels. By default, bwselect3 uses the intrinsic coordinate system so that x,y, and z are the volume XData, YData, and ZData.

[___] = bwselect3(x,y,z,V,xi,yi,zi) establishes a nondefault world coordinate system for V from the vectors x, y, and z. The arguments xi, yi, and zi specify voxel coordinates in the world coordinate system.

Examples

Find Objects in Volume

Load a volume and change its name to V.

load mristack;
V = mristack;

Define a set of points in the volume.

C = [126 87 11];
R = [34 120 20];
P = [20 2 12];

Return a volume that contains objects that intersect with the points specified.

J = bwselect3(V,C,R,P);

Input Arguments

V — Binary volume

3-D numeric array | 3-D logical array

Binary volume, specified as a 3-D numeric array or 3-D logical array.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical

r — Row index of voxels

numeric scalar | numeric vector

Row index of voxels in objects of interest, specified as a numeric scalar or numeric vector. If you specify a vector, then r must be the same length as c and p. The output binary volume J contains the sets of objects overlapping with any of the voxels (r(k), c(k), p(k)), where k is an index into the vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

c — Column index of object

numeric scalar | numeric vector

Column index of voxels in objects of interest, specified as a numeric scalar or numeric vector. If you specify a vector, then c must be the same length as r and p. The output binary volume J contains the sets of objects overlapping with any of the voxels (r(k), c(k), p(k)), where k is an index into the vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

p — Plane index of object

numeric scalar | numeric vector

Plane index of voxels in objects of interest, specified as a numeric scalar or numeric vector. If you specify a vector, then p must be the same length as r and c. The output binary volume J contains the sets of objects overlapping with any of the voxels (r(k), c(k), p(k)), where k is an index into the vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

n — Connectivity

26 (default) | 6 | 18

Connectivity, specified as one of these values.

Connectivities

Value	Connectivity
6	6-connected objects (Face-Face)
18	18-connected objects (Face-Face and Edge-Edge)
26	26-connected objects (Face-Face, Edge-Edge, and Vertex-Vertex)

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

x — World x-axis coordinates

numeric scalar | numeric vector

World x-axis coordinates, specified as a numeric scalar or numeric vector of the same length as y and z. Use x, y, and z to establish a nondefault spatial coordinate system. If you do not specify a coordinate system, then by default bwselect3 uses the intrinsic coordinate system in which x is [1, size(J,2)].

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

y — World y-axis coordinates

numeric scalar | numeric vector

World y-axis coordinates, specified as a numeric scalar or numeric vector of the same length as x and z. Use x, y, and z to establish a nondefault spatial coordinate system. If you do not specify a coordinate system, then by default bwselect3 uses the intrinsic coordinate system in which y is [1, size(J,1)].

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

z — World z-axis coordinates

numeric scalar | numeric vector

World z-axis coordinates, specified as a numeric scalar or numeric vector of the same length as x and y. Use x, y, and z to establish a nondefault spatial coordinate system. If you do not specify a coordinate system, then by default bwselect3 uses the intrinsic coordinate system in which z is [1, size(J,3)].

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

xi — x-coordinates of voxels

numeric scalar | numeric vector

x-coordinates of voxels in the world coordinate system, specified as a numeric scalar or numeric vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

yi — y-coordinates of voxels

numeric scalar | numeric vector

y-coordinates of voxels in the world coordinate system, specified as a numeric scalar or numeric vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

zi — z-coordinates of voxels

numeric scalar | numeric vector

z-coordinates of voxels in the world coordinate system, specified as a numeric scalar or numeric vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Output Arguments

J — Binary volume containing objects that overlap specified voxels

3-D logical array

Binary volume containing objects that overlap specified voxels, returned as a 3-D logical array. J contains the set of objects overlapping with any of the voxels specified by r,c, and p, or xi,yi, and zi.

idx — Linear indices of voxels belonging to selected objects

numeric vector

Linear indices of the voxels belonging to the selected objects, returned as a numeric vector.

Version History

Introduced in R2017b