Perform a Grid Calibration
- Click Image»Image Calibration or select Image Calibration in the Image tab of the Processing Functions palette.
- Select Grid Calibration and click OK.
- Select the type of Distortion that applies to the image.
- Click Next.
- Select Threshold Range values to separate the dots of the grid from the rest of the image. When you select the Threshold Range, the following operations are performed on the image:
- The image is thresholded using the range you provide in Threshold Range.
- Particles that are touching the image borders are removed using the Remove border objects function.
- Particles that are too small or that are larger than the largest dot are rejected using the Particle Filter function.
- Click Next.
- Select the real-world distance between the grid dots in the x and y directions.
If the grid does not cover the entire image, draw a region of interest around the grid or a portion of the grid to learn the calibration information only in this area.
Tip Double-click the last point of the polygonal region of interest to close the region. - Click Next.
- Select the origin of the calibration axis by entering the X- and Y-coordinates or by selecting an Existing Point from the list.
- Select the User-Defined Angle of the calibration or select an Existing Angle. If you choose an Existing Angle from the list, you can add 90°, 180°, or 270° to the value.
- Select an Axis Reference.
- Click OK to learn the calibration.
- Browse to the directory you want to save the calibration information in, enter a File name, and click OK.
- Click OK to save the step in the script and close the Parameter window.
Control Descriptions
- Open Image—Grid image on which to base the calibration. This image must be the same size as the image you want to calibrate.
- Distortion—Type of image distortion.
- Threshold Range—Minimum and maximum intensity values to include in the threshold range.
- X Spacing—Distance between two dots in the x direction.
- Y Spacing—Distance between two dots in the y direction.
- Unit—Real-world unit of the distances.
- Axis Origin
- User Defined—X- and y-coordinates of the pixel that you want to use as the calibration axis origin.
- Existing Point—Point defined in a previous step that you want to use as the calibration axis origin.
- X Axis Angle
- User Defined—Angle you want to use between the x-axis of the calibration axes and the horizontal axis of the image.
- Existing Angle—Angle defined in a previous step that you want to use between the x-axis of the calibration axes and the horizontal axis of the image. You can select a value from the + control to add to the Angle value.
- Axis Reference—Direction of the y-axis.