The CenterLineFromLines tool can be used to first locate the center line of an object.

Setup

Reference - Reference system selection

Baseline - input line

Point & Click Clipboard Support

The ROI can be managed by the buttons

• Paste - paste the ROI from the image to the scorpion clipboard
• Copy - copy the ROI to the image from the scorpion clipboard

Point & Click Clipboard Support

The line defines the baseline of the traceline. The line defines the width and the center of the tracecomb. To edit length of tracecomb used the tool's length field.

One point will change the ROI center point.

Trace lines - describing the edge search area 

• Number of trace lines - Number of trace lines in search comb
• Trace line, positive side - start - start point relative to center line - stop -  stop point relative to center line
• Trace line, negative side - start - start point relative to center line - stop -  stop point relative to center line
• Trace step - sample step along each traceline
• Trace line width - number of pixel in each trace line

Note: A trace line width equal 3 means that each point of the trace line is calculated using the pixel value. It is recommended to increase the trace line width to improve edge detection in low contrast conditions

Advanced

Edge Detection

• Smooth base - 3 is normally a good value
• Smooth counter - 1 default - given i pixels
  • The smoothing increasing with higher values
• Differentiation
  • 0 - give threshold
  • 1 - 1. order differentiation - the derivative - default normally used
  • 2 - 2. order differentiation
• Mode - Peaks are default. Threshold is only used when Differentiation is set to 0.

More information - see Normalisation

Note: Combining 2. order differentiation and polarity are used to find the center position of light or dark stripes

• Polarity - Dark to light | Light to dark | All transitions
• Threshold - value lower values means more sensitivity
• Edge Choice - First | Last | Largest

Trace line samples dialog - a helper window to set trace line filter parameters and thresholds

• Middle - show the middle traceline
• Middle+edges - shows the first, middle and last traceline
• Selection - show the selected tracelines
• Line indices - traceline selection
  • example: 2,3,12-15
  • example: 1 3 5 7
• Show trace line popup - activates a modeless traceline window

Example tracelines - Middle+edges is selected

 

Constraints

Results

PosSideMin	minmium length positive side
PosSideMax	maximum length positive side
PosSideMean	mean length
PosSideStd	standard deviation
PosSideCount	number of edge points negative side
NegSideMin	minmium length negative side
NegSideMax	maximum length negative side
NegSideMean	mean length
NegSideStd	standard deviation
NegSideCount	number of edge points negative side
WidthSideMin	minmium width
WidthSideMax	maximum width
WidthSideMean	mean width
WidthSideStd	standard deviation width
WidthSideCount	number of edge points width

Visualisation

Baseline
Edge points
Max Distance
Mean lines	Mean width lines
Min Distance
Trace lines

ExecuteCmd support (see also executeCmd)

Command	Parameters	Return values	Comments
Set	Object=ROI;Value=<point/line>	ok,res	Sets the tool's ROI. See Copy/paste ROIs for details.
Get	Object=ROI	ok,<line>	Current ROI as tool's baseline