This tool does a sphere fit to find sphere in 3D data sets  eg Point Cloud 
Scorpion 3D Image

Setup3D
coordinate system
 Reference  select a 3D reference for position
and results
ROI
Fit algorithm
 Fit only  run (possibly multipass  see Advanced) the
fit algorithm given by Method
 RANSAC only  run a single RANSAC fit only
 RANSAC + fit  run a single RANSAC fit, followed by (possibly
multipass  see Advanced) the fit algorithm given by Method
 Exhaustive  run RANSAC followed by a complete iterative fit
based on the algorithm given by Method
 Method 
 Nelder Mead  This algorithm is not based on a gradient or
other derivative of the error function. The method is based on having a simplex in
the search space for which the corners are evaluated. The simplex is
moved and transformed so as to continually shrink simultaneously with
the corner evaluations also decreasing, thus converging on what is hoped
to be a (global) minimum. How this transformation of the simplex is done
is not without freedom, there are some parameters to tweak, giving
variations of the method. With parameters as close to the original work
by Nelder and Mead as we have been able to figure out, we have made a
Classic NelderMead , and with some more recent choices of parameters we
have found published on the internet, we made Variation I.
 Classic (30)  see above
 Variation (31)  see above
 Radius  initial guess
 Tolerance  max deviation from initial guess
 Decimations  max number of iterations (for Exhaustive
search)
 RANSAC count  max RANSAC iterations
 Min dist  minimum distance between points considered for a
RANSAC search
Advanced
Passes
The sphere fit can run a multipass fit procedure. The first option is
used to turn this on or off. (This is not available for the
Exhaustive search.)
 Multipass fit  selects single or multiple passes
 Max iteration count  never exceed this number of passes
 Stop if RMS improvement less than  do not process further if
RMS does not improve more than the threshold
 Stop if RMS less than  do not process further if RMS has
reached the threshold
 Stop if active point count below  do not process further if
less than the specified number of points remain
 Stop if active point percentage below  do not process
further if less than the specified percentage of points within the ROI
remain
 Stop if RMS deteriorates  do not process further, and ignore
last pass, if RMS increases
Constraints
 Point accept distance  used to filter outliers in multipass
fit and for the result (this is not used by the Exhaustive
search)
 Max fit RMS for accept  RMS filter to accept/decline the
result
 Minimum points for accept  point count filter to
accept/decline the result
 Minimum percentage for accept  point percentage filter
(within ROI) to accept/decline the result
Point cloud decimation (x & y)
 Factor  keep only every nth sample in x and y
directions
Point cloud filter
 Contrast  element 4 in a 5element point cloud; set min and
max allowable value
Visualisation
Sphere 
Found sphere 
FittedPoints 
Accepted points within the ROI 
InitialGuess 
Initial cylinder guess 
Points 
All points within the ROI 
ROI 
The ROI cube/cylinder segment/sphere 
Results
Sphere center.x 
The found sphere center 
Sphere center.y 

Sphere center.z 

Sphere radius 
Radius of found sphere 
RMS 
Quality of fit 
Loop count 
Total number of loops 
Point count 
Total number of points within ROI 
Fit count 
Used points 
Fit percent 
Percentage of points used 


