The pyradi radiometry toolkit

Modeling and designing in electro-optical systems entails the calculation of several (often interrelated) parameters. Many of these calculations are repetitive, suitable for including in a generic toolkit. A well-designed kit would facilitate work flow and increase productivity during the modeling and design process. The concept of an extendable toolkit lends itself naturally to the open-source philosophy, where users cooperatively develop new tools to add to an ever-expanding set for the mutual benefit of all. The pyradi toolkit is an extendable, integrated and coherent collection of basic functions that can be applied towards diverse calculations in the electro-optics domain.1 The name pyradi is derived from the combination of ‘Python’ and ‘Radiometry.’ We initially considered two candidate languages for pyradi, MATLAB and Python. MATLAB has a strong following in the scientific community. In recent years Python and associated modules have beenwell tested, and have stabilized andmatured sufficiently to support mainstream tool development. But after extensive use of both languages for radiometric calculation and modeling, we decided to continue only with Python. With this application and its features in mind, Python provides better capability as a general purpose language, and its data visualization tools, Matplotlib and Mayavi, are the most powerful available today. While the wider range of toolboxes (including Simulink) might be a compelling reason to use MATLAB, those capabilities are not required here. We have already designed a number of pyradi modules covering basic electro-optical system calculations. For instance, the ryplanck module provides functions for Planck Law emittance calculations, as well as the Planck Law temperature derivative functions. Given the temperature and spectral vector, the functions provide spectral emittance in W/(m2 ) or q/(s m2 ), with spectral variable * in wavelength, Figure 1. Example polar plots: note axes conventions and yellow/red highlight of negative values.