Still Searching…

From 2012 to 2023, the discursive blog format of Fotomuseum Winterthur subjected all aspects of photography and its role in visual culture to interdisciplinary scrutiny. The approximately 50 bloggers that contributed to Still Searching… discussed photographic media and forms within their complex technological, capitalist and ideological networks and negotiated some of the most pressing and relevant questions surrounding photography.

Blog series: Photo Forensics

Hany Farid | 15.10. – 15.12.2015
Photo Forensics

From October 15 until mid-December, Hany Farid will shed light on the ubiquity of image manipulation and the nature of trust in photography from the point of view of photo forensics. He will discuss digital forensic techniques used to detect various forms of tampering in visual material that he argues may have the potential to restore — at least partially — our faith in photography.

Photo Forensics: In the Shadows

Thursday, 29.10.2015
<p>When asked to judge the location of the sun relative to this scene, most people would respond quickly that it is on the right. When asked to localize the sun more precisely, most people would need to think before responding and they would still be inaccurate. (For evidence of this perceptual failure see <span class="frzfn fn"><span class="marker">1</span><span class="text">Hany Farid and Mary J. Bravo. Image Forensic Analyses that Elude the Human Visual System. <em>SPIE Symposium on Electronic Imaging</em>, San Jose, CA, 2010.</span></span>, but also test yourself: the answer is below.) The difficulty we have localizing light sources is surprising because the scene contains abundant information for making this judgment. The fact that we cannot easily perceive information that is clearly contained within the image provides an opening for forensic analysis because forgers may be unaware that they have introduced telltale clues that we can easily detect. In this post, we will see how to determine whether the cast shadows in an image are consistent with a single light source. If the shadows are inconsistent in a scene that is clearly illuminated by a single source (e.g., the sun), then we have strong evidence of image tampering.</p>

Photo Forensics: Can You Enhance That?

Tuesday, 15.12.2015
<p>When you view a sign from a highly oblique angle, the perspective distortion may cause the text and graphics to be unrecognizable. To make the sign interpretable, you could change your vantage point and view the sign head-on. But what if the sign appears at an oblique angle in a photograph? Is it possible to remove the perspective distortion and view the sign head-on? This question arises in forensic settings when the evidence contained within an image is obscured by perspective distortion. In this post, I describe how perspective distortion can be removed to reveal, for example, the identity of a barely visible license plate.</p>