Spatial measurements of Object and Field parameters are made in pixels by default. It is useful to calibrate these measurements into more convenient units for real-world comparisons. This option allows the operator to calibrate the image using a microscope reticule or macroscopic scale ruler. A typical use of multiple calibration files is to store calibrations for each objective of a microscope nosepiece, for each zoom factor if there is an optical zoom attachment, and for each capture device used.
The Calibration list displays the title and details of the current calibration. Clicking in the lower list will select a different calibration to be displayed for modification. Any of the entries can be edited by clicking on the slot and typing the new values, notice the blinking cursor, it indicates which slot you are currently editing. The calibration units and calibration symbol are displayed in the status bar and when measurements are displayed. The Calibration Factor can be entered numerically if required, or measured from a known distance in the image using the Calibrate button. It may also be necessary to check the accuracy of the calibration, and an option is given to make linear measurements in calibrated units to verify the calibration factor, the Measure button.
The Title of the current calibration. Typically this would be set to indicate the objective magnification, and perhaps an intermediate turret mounted magnifier - "10x obj. + 1.5x Mag". Visible in various data displays to show the current calibration selected as a reminder.
The Spatial units of the current calibration. Typically this would be set to some normal spatial units e.g., "Microns", but can be set to any arbitrary scale. Visible in various data displays to show the current calibration units selected as a reminder.
The Scale Factor of the current calibration: the number of units per pixel in both the horizontal and vertical screen directions. Used when measuring spatial parameters, e.g., Length or Area. Visible in various data displays to show the current calibration selected as a reminder. This can be entered directly or computed using the Calibrate By Pointing button.
Note: The Scale Factor value should be set within the range 0.01 to 100. Other values can be used, but may create too many decimal places for accurate viewing when viewing Area or Volume measurement. If the value is outside this range, use different units, e.g., Millimeters instead of Microns.
The default size (calibrated in Units) of the Calibration Scalebar created in the right-click Context Menu. A Scalebar of pre-determined size can be saved and recalled easily according to the magnification selected. The value used should create a Scalebar that has enough pixels to be recognizable, and not extend greater than the maximum size of the current selected Capture Device.
Note: This is only the default Scalebar value, and does not restrict the Scalebar sizes that can be created.
A two character symbol used in various data displays to show the current calibration selected as a reminder. Typically this would be set to match the Units selected above, e.g. "um" for microns.
Spatial
Select to Calibrate an image from pixels to another spatial unit. Click Calibrate and move the cursor to the start of a known distance; then click and drag a line to span the distance to measure.
Click Measure to confirm that the calibrating is accurate. Move the cursor to the start of a known distance; then click and drag a line to span the distance to measure.
Multiple calibrations can be computed and stored at one time. These calibrations are saved with the extension .CAL; the default name for the file is "HCImage.CAL". Any of the different calibrations in the current file can be selected at any time from this form. The name of the currently selected calibration file is stored in the current profile file at the end of the program, and will be reloaded when the program is executed the next time.
The Load button allows a calibration file to be loaded from disk. A list of the available calibration files is displayed. Select one of the files and click OK to load this file into the Spatial Calibration Menu on display. Select Cancel if you change your mind. All Spatial Calibration files have the suffix ".CAL".
The Save button allows a calibration file to be stored to disk. The File Type should always be ".CAL", which is an ASCII text file and can be viewed with the NOTEPAD utility.
Save the calibration options in the "HCImage.CAL" file, and save the current calibration in the Workfile being created or modified.
