ScanImage 2019 : Calibration of the resonant scanner's amplitude at different zoom levels


This feature is only available in ResScan (Resonant Scanning)

The amplitude of a resonant scanner does not always change linearly with the control voltage. Since the galvanometric mirror for the scan in y-direction has a linear response, this can lead to an image distorton in x-direction at different zoom levels.

ScanImage has a built in tool to correct for the non-linear amplitude of the resonant scanner. To access this feature, execute the following command in the Matlab command prompt:

>> hSI.hScan2D.plotFov2VoltageCurve();

This will show the Resonant FOV to Voltage Calibration Curve, which allows you to manipulate the zoom-to-voltage lookup table for the resonant mirror. After enabling the feature with the checkbox in the lower left corner, start a focus and adjust the zoom level until the distortion becomes visible. In the calibration window, add a control point and adjust the control point's position using the arrow buttons until the distortion is removed. Repeat the process for multiple zoom levels.


In older versions of ScanImage 2015, no controls are available in the calibration window. Use the following commands to manipulate the lookup table:

hSI.hScan2D.useNonlinearResonantFov2VoltsCurve = true; % this will bring up the calibration window
hSI.hScan2D.adjustResVoltageCal(0.1); % increase the voltage of the current point by 0.1%; use negative values to decrease the voltage
% additional commands
hSI.hScan2D.removeResFov2VoltsCalControlPoint(); % remove a calibration point at the current zoom level
hSI.hScan2D.plotFov2VoltageCurve(); % show the calibration curve again after the window was closed
hSI.hScan2D.clearResFov2VoltsCal(); % reset the calibration curve
Resonant Scanner Lookup Table Adjustment


The two knees in the lookup table adjust the voltage for zoom levels 2x and 3x to compensate for the non-linear amplitude response of the resonant mirror.