Technical Memorandum: Ray File Format for Description of the Emission Properties of Light Sources

Ray File Format for Description of the Emission Properties of Light Sources

$90.00

Member Price: $70.00

ANSI/IES TM-25-20
Document Type: Technical Memorandum (TM)

Available as a downloadable secure PDF only.

To stay current with all IES standards, we recommend subscribing to the The Lighting Library as an Individual or through your company as a Sustaining Member.

In stock

SKU: ANSI/IES TM-25-20 Category: Tag:

Product Description

Approved American National StandardMany commercially available ray-tracing optical design and simulation software programs have been developed to support a wide variety of optical design tasks. All of these software packages can use ray files as source models. Ray files are typically generated by light source manufacturers using either an optical simulation or physical measurements using near field goniometers. These ray files are then put in a specific format for each optical design program, which allows optical engineers to integrate the light source characteristics into their optical system design simulations. Ray files describe light sources by a large number of rays with individual start location, direction, flux, and optional spectral and/or polarization data. Ray files are mainly intended for optical engineers, who are designing optical systems using light sources. Ray files are a characterization of the near field characteristics of a light source. This document provides recommendations for a standard ray file format to describe the emission properties of light sources. The ray file format contains information necessary to interface between ray tracing or other optical design, simulation, analysis and metrology software used in lighting applications.

Page count: 33 pages
Publisher: Illuminating Engineering Society (2020)
SKU: ANSI/IES TM-25-20
ISBN-13: 978-0-87995-222-8

Chapters:

  • 1.0 Introduction and Scope
  • 2.0 Normative References
  • 3.0 Definitions and Nomenclature
  • 4.0 Ray File Format
  • 5.0 Branding – Logo and Name
  • 6.0 Maintenance and Design
  • Annex A – File Format Selection
  • Annex B – Spectral Data Commentary
  • Annex C – Future Revisions and Compatibility

CONTENTS

  • 1.0 Introduction and Scope
  • 1.1 Introduction
  • 1.2 Scope
  • 2.0 Normative References
  • 2.1 ANSI/IES LS-1-20
  • 2.2 ISO 8601
  • 2.3 IEEE 754-2008
  • 2.4 The Unicode Standard
  • 2.5 The International System of Units (SI)
  • 2.6 ISO/IEC 8859-1:1998
  • 3.0 Definitions and Nomenclature
  • 3.1 ASCII
  • 3.2 binary
  • 3.3 binary32
  • 3.4 byte
  • 3.5 denormalized real
  • 3.6 direction cosine
  • 3.7 fatal error
  • 3.8 light source
  • 3.9 Little Endian
  • 3.10 lumen
  • 3.11 luminous flux, Φv
  • 3.12 NAN (Quiet NAN, Signaling NAN)
  • 3.13 normalized real
  • 3.14 parser
  • 3.15 radiant flux
  • 3.16 ray
  • 3.17 ray direction
  • 3.18 ray start position
  • 3.19 ray file
  • 3.20 signaling NAN
  • 3.21 Stokes Parameters
  • 4.0 Ray File Format
  • 4.1 File Type and Extension
  • 4.2 Overall File Structure
  • 4.3 Ray Ordering and Sampling
  • 4.4 Units in File
  • 4.5 Data Types in File
    4.5.1 ASCII
    4.5.2 Int
    4.5.3 Float
    4.5.4 String
    4.5.5 Unsigned Long Int

  • 4.6 Section and Block Breakdown
  • 4.7 Header Section
    4.7.1 File Header Block
    4.7.1.1 File Type
    4.7.1.2 File Version
    4.7.1.3 Creation Method
    4.7.1.4 Total Luminous Flux
    4.7.1.5 Total Radiant Flux
    4.7.1.6 Number of Rays
    4.7.1.7 File Creation Date and Time
    4.7.1.8 Ray Start Position
    4.7.1.9 Spectral Data Identifier
    4.7.1.10 Single Wavelength
    4.7.1.11 Minimum Wavelength
    4.7.1.12 Maximum Wavelength
    4.7.1.13 Number of Spectral Tables
    4.7.1.14 Number of Additional Ray Data Items per Ray
    4.7.1.15 Size of Additional Text Block
    4.7.1.16 Reserved for Future Use
    4.7.2 Known Data Flags Block
    4.7.2.1 Position Flag
    4.7.2.2 Direction Flag
    4.7.2.3 Radiant Flux Flag / Stokes S0 Vector Flag
    4.7.2.4 Wavelength Flag
    4.7.2.5 Luminous Flux / Y Tristimulus Flag
    4.7.2.6 Stokes Flag
    4.7.2.7 Tristimulus Flag
    4.7.2.8 Spectrum Index Flag
    4.7.3 Description Header Block
    4.7.3.1 Name of Light Source
    4.7.3.2 Manufacturer of Light Source
    4.7.3.3 Creator of Optical Light Source Model
    4.7.3.4 Creator of the Ray File
    4.7.3.5 Measurement Equipment / Simulation Software
    4.7.3.6 Camera Information
    4.7.3.7 Light Source Operation Information
    4.7.3.8 Additional Information
    4.7.3.9 Data Reference to Light Source Geometry
    4.7.4 Spectral Tables Block
    4.7.4.1 Data Types
    4.7.4.2 Error Conditions
    4.7.5 Additional Ray Data Column Labels Block
    4.7.6 Additional Text Block

  • 4.8 Ray Data Section
    4.8.1 Ray Data Lines Block
    4.8.1.1 X Position
    4.8.1.2 Y Position
    4.8.1.3 Z Position
    4.8.1.4 X Direction Cosine
    4.8.1.5 Y Direction Cosine
    4.8.1.6 Z Direction Cosine
    4.8.1.7 Radiant Flux, Stokes S0
    4.8.1.8 Wavelength
    4.8.1.9 Luminous Flux, Y Tristimulus
    4.8.1.10 Stokes S1
    4.8.1.11 Stokes S2
    4.8.1.12 Stokes S3
    4.8.1.13 Polarization Ellipse Major Axis X Direction Cosine
    4.8.1.14 Polarization Ellipse Major Axis Y Direction Cosine
    4.8.1.15 Polarization Ellipse Major Axis Z Direction Cosine
    4.8.1.16 X Tristimulus
    4.8.1.17 Z Tristimulus
    4.8.1.18 Spectrum Index
    4.8.1.19 Additional User Defined Data

  • 5.0 Branding – Logo and Name
  • Annex A – File Format Selection
  • Annex B – Spectral Data Commentary
  • Annex C – Future Revisions and Compatibility