Calibration regions contain essential information that enables measurements and calculations in real physical units. If an image does not contain the necessary calibration information from the modality, users must calibrate manually before taking any measurements. If an image needs manual calibration, a Calibrate button displays above the image.
To calibrate:
- Click the Measurement Calibration button.
- Click the Create calibration region button in the top left.
- Click and drag across the image to draw a rectangle.
- Select the Calibration type, Spatial Format, and Data Type to use.
- Calibration type: Horizontal & Vertical or Diagonal. The diagonal metric can be used when both the horizontal and vertical axes are on the same scale.
- Spatial Format: 2D, M-Mode, or Spectral. Choosing Spectral disables the Diagonal Calibration type.
- The default units for 2D and M-Mode are centimeters (cm).
- The default units for Spectral are seconds (sec) for the X-axis and centimeters per second (cm/sec) for the Y-axis.
- Data Type: For 2D and M-Mode, Tissue or Color Flow. For Spectral, CW Spectral Doppler or PW Spectral Doppler.
- Draw a line inside the rectangle. If using Horizontal & Vertical, first draw the horizontal line and then the vertical line.
- In the fields provided at the top, enter values and choose the units for each line and click Done.
- To define a second region, click the Create calibration region button and repeat steps 3 through 6.
To delete calibrations, click Delete calibration region above the viewing pane, and then click on the region to delete.