Imaging Sciences in Forensics and Criminology
Richard W. Vorder Bruegge · 2002
Abstract Imaging and imaging technologies play an important role in forensics and criminology. Photographs and other visual recordings represent an efficient means for documenting the condition of a subject at an instant in time. The subjects of such images may include accident and crime scenes, items of evidence in a laboratory, victims, or suspects. Such visual records are easily preserved for later use by investigators, eyewitnesses, forensic scientists, court officials, and juries. The thorough and complete photographic recording of a scene, person, or item of evidence also enables investigators and forensic scientists who were not present when the images were recorded to develop meaningful information long after the person, scene, or item was photographed and may have lost all traces of a prior condition. The recording of this prior condition can be critical in many investigations due to the transient nature of the subjects or scenes. Photographs may also help eyewitnesses remember relevant facts they might otherwise discount or forget. In other instances, imaging technologies may provide the only means for revealing or recording evidence. Surveillance imagery depicting the robbery of a bank may be used to document the actions of the robbers, which might not otherwise have been witnessed. In the laboratory, forensic imaging techniques may be used to produce a visible record of writings that are not apparent to the naked eye through the selective use of lighting, specialized photographic papers, and filters. Image processing may be used to extract critical details or reduce extraneous noise from an image, thus helping clarify the picture. Finally, images may also be used as the subject of forensic analysis to derive information above and beyond that immediately apparent to the untrained eye. Such analyses may include comparing photographs of a latent impression with fingerprints of a known suspect or determining the height of a robber depicted in a surveillance image. The range of imaging technologies used in law enforcement and forensic applications encompasses a broad field from traditional silver‐based film to analog video, and now includes digital still and digital video imaging. Of particular importance to law enforcement today are technologies such as scanners and digitizers (or “frame grabbers”) that convert traditional film and analog video imagery to a digital format. Once in a digital format, such images may be analyzed using digital processing techniques. The range of situations in forensics and criminology in which imaging technologies play a role is wide. For simplicity, these situations may be divided into several general categories: field‐based photography and video, laboratory‐based photography, forensic image processing, and laboratory image analysis. These categories are rarely independent of one another, however, because images acquired in the field or in a laboratory frequently become the subject of forensic image processing or image analysis.