
Paper Title:

    Dirty Glass: Rendering Contamination on Transparent Surfaces


Online Submission ID:

    paper_123

Date:   04/11/2007




Description
===================


This folder contains the rendering results shown in the paper
(Section 6, Figs.13-20) in their full resolutions. All the images
are in PNG format. The examples and their brief descriptions are
listed as below. Please refer to our paper for more details. For the
animation for some of the results, please refer to our supplemental
video. Thanks for reviewing.



Section 6.1 Rendering of 3D scenes
----------------------------------

Fig13-dusty-sphere/:
        A glass sphere rendered with different thickness of a
        uniform layer of dust. As the optical thickness increases,
        both the transmission and the reflection become smooth to
        give the sphere a more velvety appearance, especially near
        the boundary of the sphere.


Fig14-window/:
        A contaminated window rendered with a background that
        changes with time of day. Note how the contaminants appear
        very different for the different illuminations of the background.


Fig15-monitor/:
        A monitor screen rendered with dust and fingerprints when
        the monitor is turned on and off as well as the view angle
        is changing. The contaminants become more clearly visible
        when the monitor is off. Their brightness increases as the
        viewing angle approaches the grazing angles.


Fig16-cognac/:
        A cognac glass rendered with different thickness of a
        uniform dust layer. The caustics and the base of the cognac
        glass become dimmer and smoother as the dust thickness increases.


Fig17-cognac/:
        A cognac glass with stains, rendered with/without the
        scattering from the stains. Notice the subtle visual effects 
        produced by the scattering of the contaminant, including the 
        vertical "shadows" on the glass body, the contrast reversals of 
        the contaminant against the background, and the increased 
        scattering effects at grazing angles. As shown, correctly 
        modeling the scattering is essential to rendering quality.




Section 6.2 Creating Contamination Effects on 2D Photographs
------------------------------------------------------------

Fig18-lens/:
        This example shows that our model can be used to modify a
        photograph of the scene taken with a clean camera lens to
        create the effects of an image as if it were taken with a
        dirty camera lens.


Fig19-seawater-spray/:
        Based on our model, we can also generate the contamination
        effect for this 2D photograph as if it were taken through a
        glass that had been sprayed by sea water.


Fig20-make-window-dirty/:
        Given a photograph with a clean window, we can make the
        window "dirty" based on our model. Notice the brighter
        appearance of the window on the bottom right and the darker
        appearance in the top regions.



Credits
================

1. The photograph in Fig.19 is from http://www.flickr.com

2. The photograph in Fig.20 is from
        http://people.csail.mit.edu/fredo/PUBLI/Siggraph2002/index.html#hdr

3. Most of the 3D scenes are rendered with PBRT with our own extensions
        http://www.pbrt.org
