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This is the Wiki for HDRI Calibration Tool.

The HDRI Calibration Tool was designed to automate the process of merging multiple LDR images together and generating a calibrated HDR image using the tool Radiance. This is an entirely free, open-sourced application developed by a small group of undergraduate Computer Science students at Oregon State University.

To read more about the process of generating an HDR image from LDR image input, see the research paper by Clotilde Pierson here.

To read more about how our application interacts with Radiance (Back-End), please visit the page here.

Motivation

In the field of Architectural Design, researchers use High-Dynamic Range (HDR) images to learn more about lighting in an environment. HDR cameras are very expensive, but there is also a way to merge and calibrate multiple Low-Dynamic Range (LDR) images of varying exposures into a single HDR image using free software called Radiance.

Currently, the way to utilize Radiance for this process is through the Command-Line Interface, which can be intimidating for those who are unfamiliar with it.

Our tool serves as a user-friendly GUI that runs a pipeline of Radiance commands so that people of varying technological experiences can generate their own HDR images.

Purpose

Our tool is fully open-source and free to use. It performs HDR image merging according to the validated process outlined in [0]. In addition, it has been user tested by 3 user evaluation studies, with volunteers ranging from graduate students in the field, familiar with this process, to undergraduate students who were brand new to this scope. With their input, we were able to adjust our design to be clear and simple to use for many.

While other HDR image merge apps exist, they do not calibrate the image according to the camera settings. HDR cameras do, but those require expensive specialized equipment. Our tool is unique in that it is a free way to get HDR images through a verified rendering process.

Tech Stack

  • Python 3.11.1
  • Front end: PySide6, PyQt6
  • Back end: Radiance, HDRGen

Architecture

HDRI Calibration tool architecture diagram

Contact Information

Use the issues tab to submit an issue.

If an issue is more pertinent to the back-end of the project, submit a Radiance Pipeline issue.

If necessary, you can contact the author Clotilde Pierson via email here:

clotilde.pierson (at) oregonstate.edu

Wiki

This wiki has other pages that you can utilize to learn more about the app:

  • See the "Install and Run" section for Windows, MacOS, and Linux installation guides and general troubleshooting.
  • Our "Step by Step Guide" section has more info for each step of the user input, as well as where to find the output HDR image
  • The "Making Changes" section is for developers who wish to contribute to the project, and how they can set up the same build environment. For Windows users, it explains how to re-bundle the changed application using PyInstaller to create an updated executable.
  • See the "About Development" section to learn more about how this application was created, documentation, and what went into the design.

Credits

Author: Dr. Clotilde Pierson

Contributors:

  • Liam Zimmermann
  • Xiangyu Li
  • Nathaniel Klump

References

[0]Luminance Maps for Daylighting Studies from High Dynamic Range Photography