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To
avoid
errors
caused
by
the
discrepancy
between
the
image
size
and
the
real
size,
Calibration
tool
should
be
used
when
working
with
projection
images
(e.g.
X-ray
images)
(see
Section 2.29). |
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The
measurement
accuracy
is
up
to
one
screen
pixel.
As
a
screen
pixel
is
smaller
than
a
source
image
pixel,
the
true
linear
measurement
accuracy
is
up
to
one
source
image
pixel.
Errors
may
also
occur
in
density
measurements.
The
most
accurate
measurements
are
performed
with
bilinear
interpolation
(see
Section 2.4). |
|
The following tools are used to measure various parameters: Ruler, Polygonal Ruler, Corner
meter, Kobb angle, Point value, ROI rectangle tool, ROI ellipse tool, ROI polygon tool.
To select one of these tools, click on the arrow on the right side of the tool selection button. The
button will look different depending on the selected tool:
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Ruler
(selected
by
default) |
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Polygonal
Ruler |
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Corner
meter |
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Cobb
angle
measurement |
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Intensity
value
at
point |
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ROI
rectangle
tool |
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ROI
ellipse
tool |
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ROI
polygon
tool |
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To activate or deactivate the tool that is currently selected, just click on the left side of the tool
selection button. If some tool is activated, the button is highlighted. The drawn objects will be
displayed in the window while it is open, and you can pan, zoom or rotate them together with the
image.
If the series is open in multiple windows or tabs, the measurements made in any window, appear
in all the other windows.
2.15.1 Ruler
To measure distance in an image:
- Activate the Ruler
tool on the toolbar by clicking the left/right/middle mouse
button. To continue work with this tool, use the button with which the tool was activated.
To learn more about tool control, see Section 1.14.
- Click the mouse button on the image to mark the first point.
- Move the cursor over the screen. The distance from the first point to the current point
will be displayed next to the line.
- Click the mouse button to fix the current point.
- To cancel an incomplete measurement, press Esc.
This tool is also available from the image context menu and from the Image main menu item.
Activation is only possible with the left mouse button.
2.15.2 Polygonal Ruler
To perform plygonal linear measurements:
- Activate the Polygonal ruler
tool by clicking the left/right/middle mouse button.
To continue work with this tool, use the button with which the tool was activated. To
learn more about tool control, see Section 1.14.
- Mark the first point on the toolbar by clicking the mouse button.
- Drag the cursor over the screen. The distance from the first point to the current point
will be displayed beside the line.
- To fix the current point, click the mouse button.
- Repeat Steps 3 and 4 until the last but one point is fixed.
- Fix the last point by double-clicking the mouse.
- To cancel an incomplete measurement, press Esc.
To move the linear measurement point:
- Locate the cursor on the point to be moved.
- Drag the point, holding down the left mouse button or the button to which this tool is
assigned;
- Release the mouse button.
To delete a point:
- Locate the cursor on the point to be deleted.
- Right-click the mouse and select the Remove point command.
To insert a point:
- Locate the cursor on the ruler where you want to insert a point.
- Right-click the mouse and select the Insert point command.
This tool is also available from the image context menu and from the Image main menu item.
Activation is only possible with the left mouse button.
2.15.3 Corner meter
To measure an angle:
- Activate the Corner meter
tool from the toolbar by clicking the left/right/middle
mouse button. To continue work with this tool, use the button with which the tool was
activated. To learn more about tool control, see Section 1.14.
- Put two points on the image, clicking the mouse button. The second point is the angle
apex.
- Move the cursor over the screen to set the other side of the angle.
- Click the mouse button to fix the second side of the angle.
- To cancel an incomplete measurement, press Esc.
The DICOM Viewer allows you to build as many angles as you need. To deactivate the tool, click
on the left side of the tool selection button.
This tool is also available from the image context menu and from the Image main menu item.
Activation is only possible with the left mouse button.
2.15.4 Cobb angle meter
To measure a Cobb angle:
- Activate the Cobb angle
tool from the toolbar by clicking the left/right/middle
mouse button. To continue work with this tool, use the button with which the tool was
activated. To learn more about tool control, see Section 1.14.
- Draw a line that runs along the border of one of the vertebrae. To do this, click the mouse
button to set two points through which the line must pass.
- Likewise, construct a line for the second vertebra.
- To cancel an incomplete measurement, press Esc.
This tool is also available from the image context menu and from the Image main menu item.
Activation is only possible with the left mouse button.
2.15.5 Measure Intensity at a Point
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If
non-bilinear
interpolation
filters
are
used,
significant
errors
may
occur
when
intensity
is
measured
in
a
certain
point.
In
this
case,
the
intensity
value
will
be
marked
by
an
asterisk
in
the
top
right-hand
corner.
For
accurate
measurements,
use
the
bilinear
interpolation
filter
(see
Section 2.4). |
|
To measure intensity at some point:
- Activate the Intensity value at point
tool from the toolbar by clicking the
left/right/middle mouse button. To continue work with this tool, use the button with
which the tool was activated. To learn more about tool control, see Section 1.14.
- Click the mouse button on the target point.
The point will be highlighted at the image, and the intensity value will be displayed next to
it.
This tool is also available from the image context menu and from the Image main menu item.
Activation is only possible with the left mouse button.
2.15.6 Measure the Intensity Average and Standard Deviation in an Area
To measure the average intensity value and standard deviation in a particular area:
- Activate one of the ROI ... tools (rectangle
, ellipse
, or polygon
)
from the toolbar by clicking the left/right/middle mouse button. To continue work with
this tool, use the button with which the tool was activated. To learn more about tool
control, see Section 1.14.
- To draw a rectangle, click the mouse button in its top left-hand and bottom right-hand
corners.
- To draw an ellipse, just draw the rectangle the ellipse is inscribed in.
- To draw a polygon, click the mouse button to mark each apex and then double-click the
mouse to finish.
- To cancel an incomplete measurement, press Esc.
These tools are also available from the image context menu and from the Image main menu item.
Activation is only possible with the left mouse button.
The following parameters will be displayed next to the highlighted area:
- minimum intensity value;
- maximum intensity value;
- average intensity value;
- standard deviation;
- area perimeter;
- area space.
2.15.7 Drawing Parameters
To set the default drawing parameters for measurement tools:
- Click on the arrow on the right side of the measurement tool selection button.
- Select the item Set default ROI render params....
- In the dialog box that appears, set the color by clicking on the color box.
- Set the line thickness and the font size.
- Set length and area units (millimetres or centimetres).
- To connect the footnote and the measurement of the dotted line, check the box Footline.
- To apply the settings, click OK. To cancel the settings, click Cancel.
Drawing parameters are available as well from the image context menu and from the Image main
menu item.
The settings will be applied only to the measurements conducted in the flat image view window.
For multiplanar reconstruction, similar settings should be saved separately.
To edit the drawing parameters of an existing measurement:
- Locate the cursor on the measurement to highlight a line or a point.
- Right-click the mouse.
- Select the Set render params item from the context menu.
- In the dialog box that appears, set the parameters in the same way as the default drawing
parameters.
- To use these parameters by default, check the box Set as default. Set the measurement
name if necessary.
2.15.8 Move Measurements
To move a measurement:
- Locate the cursor on the measurement to highlight the line or point or to magnify the
cross, marking the angular point. Do not locate the cursor on angle points.
- Move the measurement, holding any mouse button.
2.15.9 Move Measurement Results
To move a measurement result:
- Locate the cursor on the measurement so that it is highlighted by a dotted frame.
- Move the measurement result, holding down the left mouse button or the button to which
this tool is assigned;
If the cursor is located on the measurement, the corresponding measurement result will be
highlighted, and vice versa.
2.15.10 Delete all Annotations and Measurements
To delete annotations and measurements:
- Locate the cursor on the measurement to highlight a line or a point.
- Right-click the mouse.
- Select the Remove object item from the context menu.
To delete all annotaions and measurements, click the Delete all Annotations and
Measurements
button on the toolbar or select the corresponding item from the image
context menu. In the dialog box that appears, Click Yes to delete or No to cancel. If you want the
DICOM Viewer to always delete annotations and measurements without this confirmation, check the
box Don‘t show this dialog again and click Yes. If you want the DICOM Viewer to show the
confirmation dialog, check the box Ask before deleting all annotations and measurements (see
Section 14.5.1). Please note that all other graphic objects created manually will be deleted
as well.
This tool is also available from the image context menu and from the Image main menu
item.