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Centroid Properties (Markers)
The Centroid Properties page page of the
Marker Properties dialog controls how positions are
marked on the image. This page is part of the
Marker Properties dialog which is used by various
drawing commands. The measurement package that opens the page
determines which controls are available.
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Marker Centroid Properties
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 Centroid First Point
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Check this box to centroid the starting point, or
only point, used for locating the marker.
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Centroid Last Point
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Check this box to centroid the ending point used
for locating the marker. This applies to lines
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 Negative
Positive
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Selects whether to centroid on positive-going
values (peaks) or negative-going values (valleys).
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Sample Radius
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Specify the radius, in pixels, used for computing
the centroid (first point and last point).
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Track Centroid
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Check this box to track the centroid position of
the first (or only) point when tracking the marker through an image
set.
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Track Centroid
Endpoint
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Check this box to track the centroid position of
the last point when tracking the marker through an image set.
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Centroid After Move
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Check this box to centroid the marker after
re-positioning it in Move mode.
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Search Radius
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Enter the radius, in pixels, used for tracking the
marker through an image set.
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Using the Centroid properties, the marker can be
centroided at its beginning or ending point, or at both points or
not at all. The meaning if the centroid Properties is as for other
cases where centroiding is used. For example, see the
Centroid Properties for measuring images.
Choosing Sample Radius and Tracking Radius
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The Sample Radius defines the distance from the
target point within which points are used to compute the centroid
position. A reasonable radius value is approximately half
the diameter of a point source, such as a star image.
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The Tracking Radius is used when computing the
centroid of an
Image Set. This value defines the maximum offset
distance Mira will search in the next image to lock onto a new
centroid position.
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The Track Centroids option controls the
duplication of markers when the positions are "tracked" through an
image set. If Track Centroids is checked, the positions are
centroided in every image.
Centroiding on Positive and Negative Points
Centroid positions are computed using image data,
not the screen display. Choose Positive points or Negative points
based upon the type of object to measure rather than the palette or
other image display properties. For modern, inherently digital
images, you will almost always choose Positive points. For scanned
photographs, however, you may be working with a negative image and
would choose the NegativePoints option.
Related Topics
Marker Properties Dialog
Drawing Properties
Command Toolbars
Mira Pro x64 User's Guide, Copyright Ⓒ 2023 Mirametrics, Inc. All
Rights Reserved.
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