Galvo 2D Axis Calibration Module

Use the Galvo 2D Axis Calibration module to create, open, edit, and merge Galvo 2D Axis Calibration files that you can use with an Aerotech controller.

Galvo 2D Axis Calibration Toolbar

Name Type Description
New File (Ctrl+N) Button Makes a new calibration file.
Open File (Ctrl+O) Button Opens a calibration (.cal) file or comma separated value (.csv) file from the MDK file system.
Save File Button Save (Ctrl+S): Saves the changes that you make to an existing file on the MDK file system. The file must be open in the Galvo 2D Axis Calibration module and its tab must be selected.
  Button Save As… (Ctrl+Shift+S): Saves a new file to the MDK File System. You can save it as a calibration (.cal) file or comma separated value (.csv) file.
Merge File Button Merges a file into the selected file. For more information on how to merge two files, refer to the Merge Calibration Files section on this page.
Edit File Properties Button Opens a dialog that lets you edit the properties of the selected file.
Menu Button You can find settings for the Galvo 2D Axis Calibration module. To do this, select the Menu () button and click Settings. In the Settings dialog, make sure the Galvo 2D Axis Calibration section is selected.

Galvo Calibration Files

In the Galvo 2D Axis Calibration module, your Galvo 2D axis calibration files must be associated with galvo scanner axes. You cannot create a calibration file if you do not have configured galvo axes. If your galvo is not configured, visit Machine Setup to configure your galvo axes.

GL4 Scanner Calibration Files

Use the Galvo 2D Axis Calibration module to create and save calibration files into either the .cal or .csv file format. A GL4 calibration file in the .cal format can have up to 138,000 rows and columns. The number of rows and columns must be odd and range from 3 to 32,769. The positions and corrections are stored in either counts, primary units, or secondary units. The field of view can be any size.

Create a File

To create a GL4 calibration file:

  1. Click the New File button. The Create New Galvo 2D Axis Calibration File dialog comes into view.

  2. Select the axes of the GL4 scanner that you want to create a calibration file for. The amplifier type and nominal field size (mm) come into view.

  3. Select the number of rows and columns of the calibration table. The number of rows and columns determined the sample distances.

    The total number of correction values cannot be more than 138,000.

  4. Enter the sample distances for the rows and columns of the calibration table that you want. These values are the distance between each correction position for the rows and columns. This value is specified in units. These distances are automatically calculated if you use primary units that are linear.

  5. Select the units you want to use for the sample distances and corrections.

  6. (Optional) Enter a value in the Correction Divisor value box. The correction divisor changes correction values from units to units / divisor.

  7. Select the OK button.

Use a .CSV File Format for the GL4 Calibration File

If you want to use a .csv file as a GL4 calibration file, the .csv file must obey these guidelines:

  • The number of rows and columns must be odd.

  • The total number of correction values cannot be more than 138,000.

  • Each row must have the same number of entries.

  • Each correction vector must be in the format that follows.

    • "Channel 1 Correction Value, Channel 2 Correction Value, Channel 3 Correction Value"

  • Each subsequent entry must be separated by commas and the entire entry must be inside double quotation marks (""). This is an example of a row from a three-column .csv file:

    • "-3,1,0","-2,0,0","-3,-1,0"

  • The third channel in the .csv file is necessary, but when you import a .csv file as a .cal file, this channel is ignored.

  • The columns and rows must be evenly distributed over the field of view.

GI4 Scanner Calibration Files

Use the Galvo 2D Axis Calibration module to create and save calibration files into either the .cal or .csv file format. A GI4 calibration file in the .cal file format is always 65 x 65 entries. When you save a file that has other dimensions, the table automatically scales to 65 rows by 65 columns. The field of view is stored in counts and the file shows a range of -32768 to 32767 (when 16-bit scanner resolution is used) or -524288 to 524287 (when 20-bit scanner resolution is used).

Create a File

To create a GI4 calibration file:

  1. Click the New File button. The Create New Galvo 2D Axis Calibration File dialog comes into view.

  2. Select the axes of the GI4 scanner that you want to create a calibration file for. The amplifier type and scanner protocol resolution come into view.

  3. Select the number of rows and columns of the calibration table.

  4. Select the OK button.

Use a .CSV File Format for the GI4 Calibration File

If you want to use a .csv file as a GI4 calibration file, the .csv file must obey these guidelines:

  • Each row must have the same number of entries.

  • Each correction vector must be in the format that follows:

    • "Channel 1 Correction Value, Channel 2 Correction Value, Channel 3 Correction Value"

  • Each subsequent entry must be separated by commas and all of the entry must be inside double quotation marks (""). This is an example of a row from a three-column .csv file:

    • "-3,1,0","-2,0,0","-3,-1,0"

  • The third channel in the .csv file is necessary, but when you import a .csv file as a .cal file, this channel is ignored.

  • The columns and rows must be evenly distributed over the field of view.

  • The field of view is determined by the scanner protocol resolution:

    • In a file with 16-bit scanner protocol resolution, the first entry corresponds to the point (-32768, -32768). The last entry corresponds to the point (32767, 32767). Each intermediate entry evenly divides this range.

    • In a file with 20-bit scanner protocol resolution, the first entry corresponds to the point (-524288, -524288). The last entry corresponds to the point (524287, 524287). Each intermediate entry evenly divides this range.

    • In the .csv file, as you read the rows from top to bottom, the entries correspond to an increase in the Axis 2 position. As you read the columns from left to right, the entries correspond to an increase in the Axis 1 position.

Interpolation

When you scale a galvo calibration file, the application uses bicubic interpolation to calculate the new correction values. In general, bicubic interpolation makes accurate corrections for the galvo lens.

Change Precision in Calibration Files

To adjust the number of decimal places of precision in your calibration files, use the Precision settings. To do this, select the Menu () button and click Settings. In the Settings dialog, make sure the Galvo 2D Axis Calibration tab is selected.

Display Precision

Display Precision is the number of decimal places that the application shows for a correction value. You can specify a value from 0 to 15. If you decrease the display precision, the application shows the values rounded to fewer decimal places. Display precision only changes how the application shows the value. It does not have an effect on the precision of the values in your calibration file.

Output Precision

Output Precision is the number of decimal places that the application applies to a correction value when you save the calibration file.

To have access to edit the Output Precision box, you must enable the Use output precision when saving files toggle. When you save the calibration file, correction values that have more decimal places than the specified output precision value are rounded. Correction values with fewer decimal places than the specified value are zero-padded.

If the Use output precision when saving files toggle is off, when you save the calibration file, the correction values are written to the file with as many or as few decimal places as are necessary for the full correction value.

IMPORTANT: If you use fixed precision when you save a calibration file, the correction values can lose precision. You will overwrite the original full-precision correction values with the rounded correction values.

Merge Calibration Files

You can merge two calibration files to get one calibration file with the corrections from both files. Typically, you merge files to improve calibration by merging measured corrections with the corrections that are active on the controller.

To merge calibration files, use the procedure that follows.

  1. Open one of the calibration files that you want to merge.

    1. Click the Open File button on the toolbar. The Open dialog comes into view.

    2. Select the file you want and click the Open button.

  2. Click the Merge File button on the toolbar. The Open dialog comes into view.

    1. Select the file you want to merge into the current file and click the Open button.

The corrections from the file that you selected are added to the corrections of the file that is currently open.

Rules for Merging Files

When you merge files, you must obey the rules that follow: 

  • You cannot merge a file with itself.

  • Corrections in the open file that are outside of the field of view of the file you selected to merge do not change.

  • Corrections in the open file that do not align with corrections in the file you selected to merge are interpolated.

  • These rules apply to existing GL4 calibration files:

    • The file being merged cannot have a row or column dimension larger than 45,999.

    • The units of both files must be the same.

  • These rules apply to existing GI4 calibration files:

    • The file being merged must have dimensions of 65 rows by 65 columns.

    • The file being merged must have corrections in counts.

    • The file being merged must use the same scanner protocol resolution.

Related Topics 

Axis Calibration