FRED Knowledge Base

Application Example: Polarizers

The term minimalism is also used to describe a trend in design and architecture where in the subject is reduced to its necessary elements. Minimalist design has been highly influenced by Japanese traditional design and architecture. In addition, the work of De Stijl artists is...

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Spatial Filter

The term minimalism is also used to describe a trend in design and architecture where in the subject is reduced to its necessary elements. Minimalist design has been highly influenced by Japanese traditional design and architecture. In addition, the work of De Stijl artists is...

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Monitoring network license usage

To monitor the usage of a FRED Network license,  open a web browser on the license server computer and go to http://localhost:6002 This opens up the Sentinel License Monitor (will install Java if not already on there) which will allows the viewer to see the available licenses...

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Calculating MTF

The Modulation Transfer function (MTF) is commonly used to describe the performance of an imaging system – specifically how the contrast varies with spatial frequency. It is defined as the normalized Fourier Transform of the Point Spread Function. This stand-alone FRED script can be run after...

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Looping Through Raypaths

FRED has many tools for helping the optical engineer determine the contribution and causes of stray light in an optical system including the Image Artifact Diagnostic Tool and the Stray Light Report. The Stray Light Report, for example, provides a detailed report of system scatter...

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Combining Spectra

The script utility shown in this knowledge base article is intended to serve as a “user tool”, whereby multiple spectra can be multiplied together over a wavelength range and form a unique resultant spectrum.  This knowledge base article also discusses how to add user-tools to...

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Remote Desktop Access

The Safe-Net Sentinel hardware dongles come in both network and single-user formats.  The single-user dongles, however, can also be used to run FRED via Remote Desktop if the dongle is located on the PC which will be running FRED.  Before the dongle will allow you...

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Setting up a Bitmap Source

This knowledge base article describes how to use a bitmap image as an emitter in FRED using the Detailed Source construct.  An example system is included that demonstrates a bitmap source being imaged by an ideal 1:1 relay lens.  The example image is included in...

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First Order Ghost Analysis

FRED is capable of providing the user with detailed information about arbitrary ghost and scatter paths through an opto-mechanical system.  We simply setup the optics and mechanics with physical property attributes (coatings, materials, scatter models, etc.), setup an appropriate source and tell FRED to keep...

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Source Importance Sampling

Setting up a source as a lambertian emitter can be easily done in FRED using the Detailed Source model but often ends up being inefficient for raytracing because the collection optics subtend a small solid angle compared to the emission of the source.  Often, however,...

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