HDR VDP - Frequently Asked Questions

What is the license for the HDR-VDP? Can I used it for my project?

You are free to use and redistribute the HDR-VDP under the GPL v2 license (see COPYING file in the tar distribution). If you would like to use it for your research paper, we would appreciate citing the following paper:

Rafał Mantiuk, Scott Daly, Karol Myszkowski, Hans-Peter Seidel.
Predicting Visible Differences in High Dynamic Range Images - Model and its Calibration
In: Proc. of Human Vision and Electronic Imaging X, IS&T/SPIE's 17th Annual Symposium on Electronic Imaging 2005. pp. 204-214
(bib)

Please write which release of the HDR-VDP you are using. The HDR-VDP predictions may differ slighly depending on its release.

Does HDR VDP work with orinary (LDR) images?

Yes. Low dynamic range image formats, such as JPEG or PNG, are automatically converted to the linear luminance space assuming the sRGB color space and the peak luminance of the display 80 cd/m^2. To the change peak luminance value, use --multiply-lum argument.

Why chrominance differences are not detected?

Current version of HDR VDP compares only luminance values. Chrominance is ignored.

How to measure quality with HDR VDP?

HDR VDP is a near-threshold fidelity metric rather than a quality metric. It can predict if there are visible differences between two images, but it does not tell how these differences affect subjective quality. For more information on quality metrics, check the VQEG web page.

How to compile HDR VDP on Windows?

Teh HDR-VDP makes an extensive use of UNIX features, such as pipes and shell. Therefore, the only way to compile HDR VDP on Windows is to use cygwin for this purpose.

HDR VDP predictions does not seem to be correct?

The human visual system is too complex to model it reliably so it can not be expected that an objective metric will match in 100% our perception. However, the HDR-VDP should make correct predictions in majority of the cases. If it does not, this may indicate that the wrong parameters are used. The default parameters work for natural images and the 19" display of the resolution 1280x1024 observed from 0.5m distance. Check the vdpcmp man page for the list of options that can be user for tuning the HDR-VDP.