The digital domain
The Los Angeles Sheriff's Department crime lab images a lot of threatening letters and forgeries. It has brought the electrostatic detection apparatus technique into the digital domain with CLAB-2000, a mobile video-to-digital workstation from Mideo Systems of Huntington Beach, Calif. These two instruments allow superior visualization of latent indented writing impressions.
The CLAB-2000 is useful in the examination of alterations, obliterations, credit card embossers and rubber stamps. The workstation has an articulated arm with two flexible high-intensity fiber optic light pipes. At the end of the arm is a charge-coupled device (CCD) video camera with a manually adjustable macro zoom lens. The camera's output is sent into a desktop computer's frame grabber board, digitized, saved as a TIFF and stored on the disk. In those cases where the image needs digital enhancement, it is exported to an image processing software program. What follows is a labor-intensive job of processing the image with image processing software that requires a skilled computer operator.
Streamlining the process
The crime lab has streamlined the process and increased the efficiency and accuracy of the document examiner's efforts with the DEI-750 three-CCD camera from Goleta, Calif.-based Optronics Engineering Inc. Besides spatial resolution of 750 lines, the camera provides real-time video-rate digital image processing and manual control over the exposure time. Controlled by the camera's keyboard, it allows a document examiner to perform in minutes the same level of processing that once took hours. In addition, the manual control over exposure time allows the examiner to focus optimal illumination in the area of interest.
The crime lab staff said that the DEI-750 has significantly increased the speed and ease with which its images are processed. It plans more testing and evaluation of the Mideo CLAB-2000 workstation with this camera configuration for ballistics, trace evidence and serology for viewing fluids, fibers, hair and other hard-to-work-with samples.