IMAGE THROUGH A CAMERA

Image through a Camera

Image through a Camera

Introduction

No matter what social role an image plays, the creation of an image through a camera lens always involves some degree of subjective choice through selection, framing, and personalization... All camera-generated images, be they photographic, cinematic, or electronic (video or computer-generated), bear the cultural legacy of still photography, which historically has been regarded as a more objective practice than, say, painting or drawing. This combination of the subjective and the objective is a central tension in camera-generated images.'

To radically reconfigure the basic material components (lens, camera, lighting, film) and the basic techniques (the separation of production and post-production, special effects, the use of human actors and non-human props) of the cinematic apparatus as it has existed for decades. The film camera is increasingly supplemented by the virtual camera of computer graphics which is used to simulate sets and even actors (as in "Terminator 2" and "Jurassic Park"). Traditional film editing and optical printing are being replaced by digital editing and image processing which blur the lines between production and post-production, between shooting and editing. We describe a digital image forensics technique to distinguish images captured by a digital camera from computer generated images. Our approach is based on the fact that image acquisition in a digital camera is fundamentally different from the generative algorithms deployed by computer generated imagery. This difference is captured in terms of the properties of the residual image (pattern noise in case of digital camera images) extracted by a wavelet based denoising filter. In it is established that each digital camera has a unique pattern noise associated with itself. In addition, our results indicate that the two type of residuals obtained from different digital camera images and computer generated images exhibit some common characteristics that is not present in the other type of images. This can be attributed to fundamental differences in the image generation processes that yield the two types of images. Our results are based on images generated by the Maya and 3D Studio Max software, and various digital camera images. Index Terms: Computer graphics, image analysis, image classification, image processing.

Explanation

Advances in digital imaging technologies raised new issues and challenges concerning the integrity and authenticity of digital images. Digital images can now be easily created, edited and manipulated without leaving any obvious traces of such operations. These capabilities undermine the credibility of digital images in all aspects. Digital image forensics is an emerging research field aiming at determining the origin and potential authenticity of a digital image. One of the fundamental problems digital image forensics techniques attempt to solve is the identification of the source of a digital image. That is, to determine by what means a digital image has been created, e.g., digital camera, scanner, generative algorithms, etc. Possible solutions to the problem of image source identification may include one of the below approaches:

1. Verifying and evaluating the image statistics that are inherent to real-life sceneries and ...