Scene Illumination as an Indicator of Image Manipulation

Abstract

Abstract. The goal of blind image forensics is to distinguish original and manipulated images. We propose illumination color as a new indicator for the assessment of image authenticity. Many images exhibit a combination of multiple illuminants (flash photography, mixture of indoor and outdoor lighting, etc.). In the proposed method, the user selects illuminated areas for further investigation. The illuminant colors are locally estimated, effectively decomposing the scene in a map of differently illuminated regions. Inconsistencies in such a map suggest possible image tampering. Our method is physics-based, which implies that the outcome of the estimation can be further constrained if additional knowledge on the scene is available. Experiments show that these illumination maps provide a useful and very general forensics tool for the analysis of color images.

Detection of Forgery Part in Forgery Image Using Color Intensity

“…Methods for illumination color estimation are machine-learning based. C. Riess and E. Angelopoulos in [2] presented a different approach by employing a physics based color constancy algorithm that operates on partly reflective pixels. during this approach, the automated detection of extremely reflective half is unnoticed.…”

“…In geometrybased schemes center of attention is on detecting inconsistencies in light source spots between particular objects in the picture [5]- [11] . Color-based schemes search for inconsistencies in the interactions between object color and light color [2], [12], [13] .…”

Exposing Photo Manipulation from Shading and Shadows

“…In the forensics literature, shading and shadows have been individually exploited to detect photo tampering [Johnson and Farid 2005;2007;Zhang et al 2009;Kee and Farid 2010;Liu et al 2011;Riess and Angelopoulou 2010]. The combination of shading and shadow has been considered for estimating 2-D light direction [Johnson et al 2008], and for estimating the location of light sources [Stork and Johnson 2006a;2006b].…”

Exposing photo manipulation with inconsistent reflections

“…These include techniques for detecting cloning [Fridrich et al 2003;Popescu and Farid 2004;Pan and Lyu 2010], splicing [Ng and Chang 2004], resampling artifacts [Popescu and Farid 2005a;Kirchner and Gloe 2009], color filter array aberrations [Popescu and Farid 2005b;Kirchner 2010], disturbances of a camera's sensor noise pattern [Lukas et al 2006;Fridrich 2009], chromatic aberrations [Johnson and Farid 2006;Gloe et al 2010], and lighting inconsistencies [Johnson and Farid 2005;Johnson and Farid 2007b;Kee and Farid 2010;Riess and Angelopoulou 2010].…”