文检司法鉴定 Forensic document examination

Signature 3D mapping for forensic document examination

Signature 3D topography is becoming a new trend in forensic research. It is a powerful method for forensic document examination. The surface to measure for characterizing an entire specimen is often very large. Considering  the structure and the signature imprint depth on paper, a relatively good lateral resolution is needed. Therefore, stitching over many images to retrieve the full field of view is necessary.

In this application, a dedicated system and user interface have been developed for the Institute of Forensic Sciences in Shanghai, China. This customized system offers two simultaneous measurement mode: DHM and color intensity images. The benefit of it is to acquire real color information and height information at each pixel, providing a new perspective and dream tool for forensic document examination.

Description:

• Courtesy of: Institute of Forensic Sciences in Shanghai, China
• Material: Normal paper
• Typical signature imprint depth: 1-20 microns
• Automated Process
  • Loading and pre-positioning of the paper at a right corner of the signature area
  • Automated scan of the signature (typ. 50×200 individual measurements)
  • Automated stitching of both 3D topography and color image
• Instrument:
  • DHM® R-2200 with Motorized stage 300x300x38 mm
  • Dual camera (Monochrome and white light)
• Software
  • Customized user interface dedicated to the application.
• Time scale for full signature scanning (20 mm x 30 mm): <60 s
• Magnification: 10x