Component Forensics [ Theory , methodologies , and applications ] [

isual sensor technologies have experienced tremendous growth in recent decades, and digital devices are becoming ubiquitous. Digital images taken by various imaging devices have been used in a growing number of applications, from military and reconnaissance to medical diagnosis and consumer photography. Consequently, a series of new forensic issues arise amidst such rapid advancement and widespread adoption of imaging technologies. For example, one can readily ask what kinds of hardware and software components as well as their parameters have been employed inside these devices? Given a digital image, which imaging sensor or which brand of sensor was used to acquire the image? How was the image acquired? Was it captured using a digital camera, cell phone camera, image scanner, or was it created artificially using an imageediting software? Has the image undergone any manipulation after capture? Is it authentic, or has it been tampered in any way? Does it contain any hidden information or steganographic data? Many of these forensic questions are related to tracing the origin of the digital image to its creation process. Evidence obtained from such analysis would provide useful forensic information to law enforcement, security, and intelligence agencies. Knowledge of image acquisition techniques can also help answer further forensic questions regarding the nature of additional processing that the image might have undergone after capture. There are various ways to address the questions at hand. In this article, we survey one of the major class of techniques based on component forensics that aims to answer these forensic questions. Component forensics aims at identifying the algorithms and parameters employed in the various components of the device that was used in capturing the data. Component forensic analysis works by finding the intrinsic fingerprint traces that are left behind in a digital image when it goes through various processing blocks in the information processing chain, and uses such traces for estimating component parameters. Component Forensics [Theory, methodologies, and applications] [ Ashwin Swaminathan, Min Wu, and K.J. Ray Liu]