For a given scan speed (ms/Line), ScanImage should 'know' the mirror servo controller's phase delay – the time lag between the command signal and the actual miror position – in order for acquired image data to be correctly 'aligned' with the laser scan. This value was referred to as Cusp Delay in ScanImage 3.0, and is referred to now in ScanImage 3.5 controls as the Servo Delay. As in ScanImage 3.0, this parameter can be adjusted in the Advanced Configuration... dialog box:
The Servo Delay control is renamed from Cusp Delay in ScanImage 3.0
As in ScanImage 3.0, the Servo Delay value is specified as a fraction of the Seconds / Line value displayed in the dialog box (which is determined by the ms/Line and Fill Fraction controls in the Advanced Configuration... dialog)
As in ScanImage 3.0, the Configuration... dialog box, is accessed via Settings >> Edit >> Configuration... from the window. The Advanced Configuration... dialog box is accessed from the Configuration... menubar via Settings >> Advanced....
ScanImage 3.5 additionally allows the Servo Delay to be adjusted via new controls which now appear on the window:
New Servo Delay controls (at bottom right) allow adjustment of mirror servo controller's phase delay value, including during live (FOCUS) imaging. Selecting the Fine? checkbox causes arrow controls to increment/decrement value in fine steps.
The Servo Delay value on the Main Controls window is linked to the value in the Advanced Configuration... dialog box. Either updates the other.
Usage Notes
The effect of adjusting the Servo Delay is to shift the imaged area left or right. When the servo delay is too (small/large), a 'reflected' image will appear on the (right/left) side of the image. The optimal servo delay value is exactly between the values where these reflected images become apparent on either side.
If it is not possible to eliminate the 'reflected' image with any value of the servo delay, try reducing the Fill Fraction value in the dialog box.
The Servo Delay should be re-optimized if either ms/Line or Fill Fraction is modified. It is generally advised to save the three parameters together as part of a saved configuration (CFG) file. If users are frequently changing their ms/Line and/or Fill Fraction variables in the midst of an experimental session, the use of fast configurations is strongly recommended.
ScanImage 3.6 will more completely address issues related to optimizing scan parameters