METHOD FOR SCANNING SURFACE OF BULLETS AND SHELLS OF RIFLE GUNS, DEVICE FOR SCANNING CYLINDRICAL BODIES Russian patent published in 1999 - IPC

FIELD: optoelectronic instruments, in particular, for criminal investigations of bullets and shells and storing databases of images of bullets and shells. SUBSTANCE: method involves use of TV camera with CCD matrix for projection of light spot towards object, serial reading of separate rectangular fragments of surface, digital sampling of resulted images and their storing in memory in order to achieve complete scanning image. This is achieved by positioning object under investigation in initial position and rotating object by constant precisely kept angle before making each scanning shot, focusing camera by means of automatic focusing system, calculation of current object diameter using defocusing angle in order to determine width of fragment which provides synthesis of scanning image without losses and overlaps. Then method involves detection of deviation angle of fragment surface with respect to normal to optical axis of TV camera, rotation of CCD matrix of TV camera by this angle about axis which is parallel to object rotation axis and belongs to matrix plane, and scanning and storing fragment by turning on right and left illumination devices in turn. Required width of surface fragment to be stored is provided by alternation of number of reading columns of CCD matrix elements. Angle of deviation of fragment surface with respect to normal to optical axis of camera is measured by rotation of light spot on object using computer analysis of its image on CCD matrix. Corresponding device has illumination devices, camera holder, mechanisms of linear scanning, object rotation and focusing movement, automatic focusing system, TV camera with CCD matrix, analog-to-digital converter and computer. Focusing movement drive is equipped with detector of initial position of object. CCD matrix is mounted for rotation about axis which is located in its plane and is parallel to axis of object under investigation and is equipped with drive for rotation. EFFECT: increased resolution and minimal distortion of digital scans of bullets, including deformed ones. 8 cl, 7 dwg