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 Angle
Measurements
The Angle Measurement tool measures the
included angle and base angle between two intersecting angles. The
vertex and endpoint coordinates are reported in both (column,row)
and world coordinates for images having a world coordinate
calibration. Coordinates are marked using the mouse crosshair and
may be refined using precision centroid coordinates computed near
the clicked point. Angles drawn on the image are persistent until
you leave Angles mode by closing the toolbar. Results are reported
in the Angles Measurement Pane or Angle Measurements
report window. The toolbar opens with Marking Mode (top button)
active. Angles may also be measured using the CMeasureAngles
class in the Pro Script Module. See the
Mira Pro x64 Script User's Guide.
The picture below shows several angles marked on an
image. The results may be directed to a measurement pane or report
window, as described below.
Procedure
The basic procedure for drawing angles is as
follows:
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Mouse down at the vertex.
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Holding the mouse down, move to the endpoint of
the first line and release.
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Without pressing the mouse buttons, move to the
end of the second line.
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Click the mouse at the endpoint of the second
line.
Here a more detailed procedure:
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Adjust the image to the desired magnification,
image position, palette, and other attributes.
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Click the  button on the
Image Measurements Toolbar or use the
Measure > Angles Toolbar menu
command to open the toolbar. Marking mode is automatically enabled
when the toolbar is opened. If marking mode has been disabled by
prior commands, activate it by clicking the button.
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Move the mouse to the vertex point where both
lines will intersect. At the vertex point, press and hold down the
left mouse button. If  Centroid First Point
is checked on the
Centroid Properties (Markers) page, the
position will lock onto the local centroid near where the mouse is
released.
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With the left button down, drag the cursor to
the endpoint of the first side. Release the button at the endpoint
to draw the first side. If Centroid Last Point is checked on the
Centroid Properties (Markers) page, the
position will lock onto the local centroid near where the mouse is
released.
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Move the mouse to the endpoint of the other side
of the angle marker. Click the mouse to mark the endpoint. The
angle measurement is reported in the Angle Measurements
window or Angles measurement pane in the Image Window. If
Centroid Last Point is checked on the
Centroid Properties (Markers) page, the
position will lock onto the local centroid near where the mouse is
released. The results are reported in the measurement pane or
window.
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To measure other angles, repeat steps 3 though
5.
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When finished you can disable marking mode by
clicking  on the toolbar.
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TIP
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Before tracking through an image set, be sure
Centroid
First Point and Centroid Last Point are set as desired on the
Centroid Properties (Markers) page.
 If checked, the centroid coordinates
will be computed for every member of the image set.
If unchecked, the current coordinates
will be duplicated to each member of the image set.
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Measurement Results
Measurements are tabulated in either the Angle
Measurements measurement pane owned by the Image Window as
shown above, or a Report Window as shown below. The difference
between the two output options is that the Angles
measurement pane receives only measurements of that Image Window
whereas the Angle Measurements window is global and receives
measurements from all Image Windows.
If the image has a World Coordinate System ("WCS")
calibration, then X1, X2, Y1, and Y2 give the WCS values
corresponding to listed column,row coordinates.
Column data in the Angles pane and Angle
Measurements report are described in the table below. The last
few columns from the table below are not scrolled into view in the
picture above.
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Angle Measurements Column Data
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#
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The sequence number of the measurement.
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Image
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The name of the image that was measured.
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Index
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The marker index for the particular image.
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Angle
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The "included" angle in degrees measured between
the two line segments.
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Base Angle
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The angle between horizontal and the line segment
drawn first. This is calculated between the vertex Col1,Row1 (or
X1, Y1 in world coordinates) and Col2, Row2.
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X
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The World (or pixel) X coordinate at the vertex of
the angle marker. This is the point where the 2 side vectors
intersect. If the image has no WCS calibration, this is the column
coordinate.
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Y
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The World (or pixel) Y coordinate at the vertex of
the angle marker. This is the point where the 2 side vectors
intersect. If the image has no WCS calibration, this is the row
coordinate.
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Col 1
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The column coordinate of the starting point
(vertex).
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Row 1
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The row coordinate of the starting point
(vertex).
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Col 2
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The column coordinate of the ending point of the
first side drawn (ending at Col2, Row1).
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Row 2
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The row coordinate of the ending point of the
first side drawn (ending at Col2, Row2).
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Col 3
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The column coordinate of the ending point of the
last side drawn (ending at Col3, Row3).
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Row 3
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The row coordinate of the ending point of the last
side drawn (ending at Col3, Row3).
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Notes
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Space to add comments about the measurements.
These will be included if you export the table to a text file.
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Marking Endpoints
As with other interactive marking commands, the
Angle Measurements command can use the exact marked
coordinates or it can compute the coordinates as a precise centroid
positions. To set these options, click  on the toolbar to open the Marker
Properties dialog for this command, then set Centroid First Point
or Centroid Last Point accordingly.
Related Topics
Measuring Images
World Coordinate System
Distance and Angle
Angle Measurement Definition
Measurement Panes
Report Windows
Marker Properties
Mira Pro x64 User's Guide, Copyright Ⓒ 2023 Mirametrics, Inc. All
Rights Reserved.
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