Main Page

About HDR-VDP

HDR-VDP is a visual metric that compares a pair of images, a reference and a test image, and predicts:

• Visibility - what is the probability that the differences between both images are visible for an average observer;
• Quality - what is the quality degradation with the respect to the reference image, expressed as a mean-opinion-score.

What is new in HDR-VDP-2

HDR-VDP-2 is a major revision of the original HDR-VDP. The entire architecture of the metric and the visual model has been changed to improve accuracy of the predictions. The most important changes are:

• The metric predicts both visibility (detection/decrimination) and image quality (mean-opinion-score).
• The metric is based on new CSF measurements, made in the consistent viewing conditions for a large variation of background luminance and spatial frequencies.
• The new metric models L-, M-, S- and rod sensitivities and is sensitive to different spectral characteristic of the incoming light.
• Photoreceptor light sensitivity is modelled separately for cones and rods, though L and M cones share the same characteristic.
• The intra-ocular light scatter function (glare) has been improved by fitting to the experimental data.
• The metric uses a steerable pyramid rather than cortex transform to decompose image into spatially- and orientation-selective bands. Steerable filter introduces less ringing and in general case is computationally more efficient.
• The new model of contrast masking introduces inter-band masking and the effect of CSF flattening.
• A simple spatial-integration formula using probability summation is used to account for the effect of a stimuli size.

The previous version of the HDR-VDP can be still found at the MPI web-pages and in the !SourceForge file archive.

News

• 28 April 2011 - Together with the release of HDR-VDP-2, the project home page was moved to Trac wiki. Wiki will hopefully be easier to maintain.

Documentation

Check first the Frequently Asked Questions.

The best forum to ask questions is the HDR-VDP Google group. You can also contact the author directly.

Literature

The architecture of the HDR-VDP-2 is described in the paper:

HDR-VDP-2: A calibrated visual metric for visibility and quality predictions in all luminance conditions
Rafał Mantiuk, Kil Joong Kim, Allan G. Rempel and Wolfgang Heidrich.
In: ACM Transactions on Graphics (Proc. of SIGGRAPH'11), 30(4), article no. 40, 2011
DOI 10.1145/1964921.1964935 pre-print PDF

Abstract:

Visual metrics can play an important role in the evaluation of novel lighting, rendering, and imaging algorithms. Unfortunately, current metrics only work well for narrow intensity ranges, and do not correlate well with experimental data outside these ranges. To address these issues, we propose a visual metric for predicting visibility (discrimination) and quality (mean-opinion-score). The metric is based on a new visual model for all luminance conditions, which has been derived from new contrast sensitivity measurements. The model is calibrated and validated against several contrast discrimination data sets, and image quality databases (LIVE and TID2008). The visibility metric is shown to provide much improved predictions as compared to the original HDR-VDP and VDP metrics, especially for low luminance conditions. The image quality predictions are comparable to or better than for the MS-SSIM, which is considered one of the most successful quality metrics. The code of the proposed metric is available on-line.

Download

The Matlab code with the HDR-VDP-2 will be available for download in the next few weeks.

hddrvdp-2 code requires Eero Simoncelli's matlabPyrTools, which can be downloaded from here. Note that when using matlabPyrTools version 1.4 (2009-12-17), a MatlabPyrTools patch must be applied.

Calibration datasets and reports

The great care was taken to calibrate the HDR-VDP-2 with the experimental data. Check the calibration reports for the current release of the metric.

We plan to release selected data sets so that others can benchmark their metrics against HDR-VDP-2. The data sets will be available before August 2011.