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This documentation is for a legacy ScanImage version. The current documentation is ScanImage 2019.

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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

  • %% ResScanCtrl Section
    • galvoVoltsPerOpticalDegree
    • rScanVoltsPerOpticalDegree 
    • refAngularRange 

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


The Angular Range values specify the peak-to-peak angular range of each scanner
(of which a specified Fill Fraction is imaged, as configured within ScanImage)

(tick) These values are in optical degrees - which is 2x the mechanical angular range of the scanner, because of the laser reflection

The Ref Angular Range specifies the angular range to scan both scanners at Zoom = 1 

 

 

Typical MDF Settings

Sutter Res Scanner Systems

Typical Sutter resonant scanner system

Scanner
Optical Angular Range
Volts per Optical Degrees
Resonant (X)26 degrees0.1923
Galvo (Y)20 degrees1.0

Cambridge Technologies OEM Resonant Scanners

 

Model
Optical Angular Range
Volts per Optical Degrees
CRS-8 (new driver board)260.1923
CRS-8 (old driver board)150.33
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
3mmStandard60 degrees0.33Matched to smaller objective lenses (back focal aperture < 10mm). Typical for slice & fly applications.
5mmStandard40 degrees0.5 
5mmReduced Angle20 degrees1.0 
6mmStandard40 degrees0.5 

 

Configurations

Cambridge has 2 types of X/Y scanner configurations

Configuration
Sample Image
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.
StandardY scanner elongated compared to X scanner. 
This ensures full X scanner range is incident on Y scanner.

 

 

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