Overview
Optimizing image aspect ratios for X/Y scanner pairs requires correct settings for the angular range of each scanner.
These must be specified in the Machine Data File (MDF).
This guide provides information about:
- (left) the relevant MDF settings
- (right) typical MDF values for various market-available scanners
Machine Data File (MDF) Settings
The following key Machine Data File settings affect the image aspect ratio
%% ResScan Section
xGalvoAngularRange
yGalvoAngularRange
galvoVoltsPerOpticalDegreeX
galvoVoltsPerOpticalDegreeY
resonantAngularRange
rScanVoltsPerOpticalDegree
- %% LinScan Section
- xGalvoAngularRange
- yGalvoAngularRange
- galvoVoltsPerOpticalDegreeX
- galvoVoltsPerOpticalDegreeY
Definitions
The Volts Per Optical Degree values specify the amount of control voltage required to drive each scanner to a specified angle deflection from the center
(of which a specified Fill Fraction is imaged, as configured within ScanImage)
These values are in optical degrees - which is 2x the mechanical angular range of the scanner, because of the laser reflection
Angular Ranges at Zoom=1
Zoom 1 is automatically defined as a square scan of the smaller of the two scanner angular ranges
BUT - it is permissible to use the full angular range of the larger of the two angular ranges, via the ROI/Stimulus Group Editor dialog
Typical MDF Settings
Sutter Res Scanner Systems
Typical Sutter resonant scanner system
| Scanner | Optical Angular Range | Volts per Optical Degrees |
|---|---|---|
| Resonant (X) | 26 degrees | 0.1923 |
| Galvo (Y) | 20 degrees | 1.0 |
The license could not be verified: License Certificate has expired!
Cambridge Technologies OEM Resonant Scanners
| Model | Optical Angular Range | Volts per Optical Degrees | Comments |
|---|---|---|---|
| CRS-8 (new driver board) | 26 | 0.1923 | |
| CRS-8 (old driver board) | 15 | 0.33 | |
| CRS-12 |
Cambridge Technologies OEM Galvo Scanners
The specifications for galvo scanners from Cambridge Technologies are listed on specific order sheets when purchased
Below are typical Angular Range & VoltsPerOpticalDegree values for standard X/Y scanner sizes and configurations
Aperture Size | Configuration | Optical Angular Range | Volts per Optical Degrees | Comments |
|---|---|---|---|---|
| 3mm | Standard | 60 degrees | 0.33 | Matched to smaller objective lenses (back focal aperture < 10mm). Typical for slice & fly applications. |
| 5mm | Standard | 40 degrees | 0.5 | |
| 5mm | Reduced Angle | 20 degrees | 1.0 | |
| 6mm | Standard | 40 degrees | 0.5 |
Configurations
Cambridge has 2 types of X/Y scanner configurations
Configuration | Notes |
|---|---|
| Reduced Angle | X & Y scanners are the same size, achieving the best and most uniform speed. The tradeoff is somewhat reduced angular range for the scanner pair. |
| Standard | Y scanner elongated compared to X scanner. This ensures full X scanner range is incident on Y scanner. |