Chris Hawley

Hi, I'm Chris. (View my resume)

I develop software for RADAR. I'm a backend engineer primarily focusing on building large scale systems, but am also interested in many computer vision topics.

Recent News

2017.03.17 - New job!

Started as a Software Engineer at RADAR!

2015.05.11 - New job!

Started as a Software Engineer at Spotify!

2015.01.06 - Promotion!

Promoted to Software Development Engineer II at!

2014.01.06 - Started work!

Started full time as a Software Development Engineer I at!

2013.12.18 - Graduated

Graduated from Washington University in St. Louis, with a major in Computer Science and Applied Mathematics


Heliometric Stereo: Shape from Sun Position

A. Abrams, C. Hawley, and R. Pless. Heliometric Stereo: Shape From Sun Position. In Proc. European Conference on Computer Vision, October 2012.
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In this work, we present a method to uncover shape from webcams "in the wild." We present a variant of photometric stereo which uses the sun as a distant light source, so that lighting direction can be computed from known GPS and timestamps. We propose an iterative, non-linear optimization process that optimizes the error in reproducing all images from an extended time-lapse with an image formation model that accounts for ambient lighting, shadows, changing light color, dense surface normal maps, radiometric calibration, and exposure. Unlike many approaches to uncalibrated outdoor image analysis, this procedure is automatic, and we report quantitative results by comparing extracted surface normals to Google Earth 3D models. We evaluate this procedure on data from a varied set of scenes and emphasize the advantages of including imagery from many months.