A method for obtaining a signature from a fired bullet is obtained by mounting the bullet to turn substantially about a longitudinal axis of the bullet, illuminating a surface of the bullet, obtaining and storing a frame image at a given position of the surface portion using microscope optics, the frame image having a transverse extent substantially transverse to the longitudinal axis, advancing the frame image position by an amount less than a transverse extent of the frame image, repeating the last two steps a plurality of times to obtain a plurality of overlapping frame images, combining the frame images to form a continuous composite image having a transverse extent much greater than the transverse extent of the frame images, and computing a signature of the composite image along a line extending in the transverse extent of the composite image. The points of the signature are determined from image data along a direction of striations in the composite image which is at an angle with respect to the transverse line and the longitudinal axis.
This application is a continuation-in-part of U.S. patent application Ser. No. 705,122, filed May 24, 1991, issued on Feb. 14, 1995 as U.S. Pat. No. 5,390,108.
The invention provides an apparatus and method for imaging markings on cartridge cases. It provides for the taking of two images of the cartridge case with light for illumination projected at the cartridge case from two different predetermined angles. In a first version, two different light sources are set at the two different predetermined angles. In a second version, one light source is moved between two different positions to project light at the two different predetermined angles. In a third version, the device holding the cartridge case is rotated between two different positions so light projects at the cartridge case from the two different predetermined angles. In a fourth version, the holding device rotates the cartridge case between two different positions so that light projects at the cartridge case at the two different predetermined angles. In another aspect, the invention provides diffuse light for the taking of the images. In yet another aspect, the invention provides a cartridge case holding device which can rotate the cartridge case about a longitudinal axis.
5857202 - Comparing projectile shells - Owned by Ministerie de L'Interieur - Direction de la Police Judicaire Sous-Direction de la Police Technique et Scientifique Service Central des Laboratoires (Ecully Cedex,FR)
Digital data, each piece of data corresponding to a different criterion associated with an impression on a projectile, is stored in a database. A number of images of a target projectile are processed to extract the data, where each datum corresponds to one of a different criterion. The different criteria include such features as shape, position, texture, and striation, center and shape of the percussion zone, caliber of the projectile, impressions of the stop, ejector, loading indicator, and feed mechanism et alia. The data from the target projectile is then compared to the data from the reference projectile for a possible match.
In a microscope, a position signal is generated in the form of coordinates in a pixel coordinate system by registering microscope images with partly overlapping contents. The position signal can be used to indicate the position of a partial object which has been identified in one of the microscope images. It can also be used to control the displacement of the microscope stage of the microscope, in which case it is possible to use a simple inaccurate drive mechanism for the microscope stage, without necessitating installation of position sensors.
A method for obtaining a signature from a fired bullet by mounting the bullet to turn substantially about a longitudinal axis of the bullet, illuminating a surface of the bullet, obtaining and storing a frame image at a given position of the surface portion using microscope optics, the frame image having a transverse extent substantially transverse to the longitudinal axis, advancing the frame image position by an amount less than a transverse extent of the frame image, repeating the last two steps a plurality of times to obtain a plurality of overlapping frame images, combining the frame images to form a continuous composite image having a transverse extent much greater than the transverse extent of the frame images, and computing a signature of the composite image along a line extending in the transverse extent of the composite image. The points of the signature are determined from image data along a direction of striations in the composite image which is at an angle with respect to the transverse line and the longitudinal axis.
A method and system for creating a digital, virtual slide having optimum image quality characteristics. Multiple regions of a physical slide are identified as well as at least two focus z-positions z1, and z2. Each region of the physical slide is scanned (imaged) at the first z position, so as to produce a first set of digital images of each defined region. Each region of the physical slide is also scanned (imaged) at the second z position, so as to produce a second set of digital images of each defined region. Each image of each set is evaluated against a focus quality metric and, for each region, either the first or second image, corresponding to that region, is selected that exhibits a focus quality metric corresponding to a desired focus quality. These images are then merged into a digital virtual slide. Additional focus z-positions may be included, and the multiple z-positions may be scanned seriatim, sequentially, and/or in overlapping fashion.
