Trace object in binary image

traces the outline of an object in binary image `B`

= bwtraceboundary(`BW`

,`P`

,`fstep`

)`BW`

. Nonzero
pixels belong to an object and zero-valued pixels constitute the background.
`P`

specifies the row and column coordinates of the point on
the object boundary where you want the tracing to begin. `fstep`

specifies the initial search direction for the next object pixel connected to
`P`

. `B`

holds the row and column
coordinates of the boundary pixels for the region.

The `bwtraceboundary`

function implements the Moore-Neighbor tracing
algorithm modified by Jacob's stopping criteria. This function is based on the
`boundaries`

function presented in the first edition of
*Digital Image Processing Using MATLAB*, by Gonzalez, R. C., R.
E. Woods, and S. L. Eddins, New Jersey, Pearson Prentice Hall, 2004.

[1] Gonzalez, R. C., R. E. Woods, and S. L. Eddins, *Digital Image
Processing Using MATLAB*, New Jersey, Pearson Prentice Hall,
2004.