WO1999028698A9

WO1999028698A9 - Standard image capture microscope for forensic identification of firearm ammunition

Info

Publication number: WO1999028698A9
Application number: PCT/US1998/025569
Authority: WO
Inventors: Daniel Bachenheimer; Gerald E Bishop Jr; Brett C Jones
Original assignee: Mnemonic Systems Inc; Daniel Bachenheimer; Gerald E Bishop Jr; Brett C Jones
Priority date: 1997-12-03
Filing date: 1998-12-03
Publication date: 1999-10-07
Also published as: AU3285099A; WO1999028698A3; WO1999028698A2

Abstract

An image capture microscope includes a stand (103) having a specimen positioning stage and a digital video camera (108) fixed with respect to the stand. A microscope (150), fixed with respect to the stand, is in an optical path from the position stage to the video camera. A light fixture (140), fixed with respect to the stand, includes an oblique light which illuminates the stage from locations on one side of the optical path. A high precision universal specimen holder is disposed on the stage to provide tilt, rotation and centering that enhances the correlation among digital images required for forensic analysis.

Description

STANDARD IMAGE CAPTURE

MICROSCOPE FOR FORENSIC

IDENTIFICATION OF FIREARM

AMMUNITION

This application claims the benefits under 35 U.S.C. § 120 of the filing date of provisional applications 60/067,356 filed on 3 December 1997 and 60/094,919 filed on 13 July 1998, both by Bachenheimer, et al., which applications are hereby incorporated in their entirety by reference.

BACKGROUND

Field of the Invention

This application is related to digital imaging apparatus and techniques and, more particularly, to a digital imaging apparatus and technique which capture microscope images for use in the forensic identification of firearm projectiles and casings.

Description of Related Art

Firearm ammunition typically includes a casing, such as a cartridge or a shotgun shell, and one or more projectiles, such as a bullet or shotgun pellets. When ammunition is loaded into a firearm and fired, mechanical components of the firearm that contact the ammunition during the firing and ejection process leave marks on the casing. As a projectile is accelerated down the barrel of a firearm, marks are also left on the projectile. The markings on spent ammunition, i.e., casings and projectiles that have been fired in a firearm, are distinctive and indicative of the firearm used at the time of the shooting. In forensic applications, spent ammunition found at a crime scene can be compared to spent ammunition testfired from a firearm or gathered at a crime scene. If markings are sufficiently similar, a firearm can be connected to the crime scene, or two crimes can be linked. Therefore, the recordation and comparison of markings on spent ammunition has important forensic applications.

Characteristic markings made on an ammunition casing when ammunition is fired from a firearm (spent casing) hold information used by forensic analysts to connect a spent casing to the firearm in which the ammunition was fired. Recent advances have led to the development of digital systems that can capture those markings as images and can compare those images to other images associated with particular firearms and crime scenes stored in a database. Many markings on spent ammunition are not easily observable by the unassisted human eye, so imaging systems have been developed to enlarge and record the markings on spent ammunition. Spent ammunition placed on the sampling stage of such an imaging system is called a specimen. A specimen may be a spent casing or a spent projectile. In a conventional imaging system, a specimen attached to a stage is illuminated, and the resulting image is enlarged by a microscope and recorded as a digital image by a video camera having a charge-coupled device array (CCD). A computer program or a separate processor can compute a similarity measure for any pair of digital images. Various types of known correlation procedures can be used for this. The higher the similarity measure, the more the two images resemble each other.

The measure of similarity between two captured images is sensitive to lighting conditions, focus, orientation and centering of the specimen vis-a-vis the image capture optics of the system. The orientation of the specimen refers to the tilt and rotation of the specimen. The centering of the specimen refers to the location of a center point on the specimen in relation to a reference position in the digital camera used to produce the image. To facilitate establishing measures of similarity between images, a conventional system attempts to standardize the position and orientation of the specimen using a standard protocol to produce a characteristic image. J

In a conventional image capture microscope, a specimen is attached to a presentation mechanism, called a stage, using a sticky wax spud. The stage can be moved vertically for focus, and can be moved horizontally for centering the specimen The stage is moved manually without substantial constraint by the user. A single lamp is oriented obliquely and may be adjusted manually by the user to produce different illumination angles and intensities at the specimen. Reflected light from a specimen passes through one objective lens of a plurality of objective lenses arranged on a turret, and is then detected by the video camera such as a CCD camera. The objective lens is selected manually by the user by rotating the turret to provide a desired degree of magnification established by the standard protocol. The CCD camera is connected to a computer system that displays the digital images from the CCD camera, and stores selected digital images from the CCD camera into memory. The computer system can display previously stored digital images for comparison. The conventional image capture microscope has not eliminated all the sources of variability that adversely affect the measure of similarity between two images of a specimen. First, when a casing is mounted on the stage, if the breech face of the casing is not sufficiently level, i.e., is tilted too much, then only part of the face will be in focus when the image is captured. Different out-of-focus sections of such breech faces of two captured images can adversely affect the measure of similarity between the two images.

Second, the light intensity is selected subjectively by the user by manual positioning of the lamp. Different subjective light intensity choices by the user or users capturing two images can adversely affect measures of similarity between the two images.

Third, the specimen is centered manually by the user. Manual centering may not be precise enough to easily locate a casing specimen on the central pixel of the captured digital image. Any off center displacement may introduce comparison errors. SUMMARY OF THE INVENTION

The present invention overcomes the limitations of the prior art.

In addition, the present invention selectively permits precise small tilt angles for a casing specimen. Small tilt angles may be desirable to enhance certain details in the marks. Manual tilting using the sticky wax spud may not be precise enough to have two specimens tilted the same amount during image capture.

The problems of the prior art are overcome in accordance with the invention by providing an image capture microscope which includes a stand with a specimen positioning stage, a digital video camera, and a microscope fixed to the stand. A light fixture, fixed with respect to the microscope, includes an oblique light which illuminates the stage. A specimen holder is disposed on the stage.

In another aspect of the invention, an image capture microscope incudes a zoom microscope fixed in the optical path. A light fixture surrounds the optical path. This light fixture includes an oblique light having an arcuate emitter subtending a certain angle around the circumference of a circle centered on the optical path which illuminates the stage, and a ring light having a circular emitter centered on the optical path which illuminates the stage. In another aspect of the invention, a universal specimen holder includes a spindle for holding a specimen to be examined. The spindle is connected to a hollow cylinder having a horizontal axis so the spindle may rotate about a diameter of a cross section of the cylinder. A barrel surrounds the outside of the cylinder, and the cylinder rotates inside the barrel. The barrel is fixed to a riser block which supports the barrel and cylinder. A tilt control knob is fixed to the cylinder. The spindle tilts as the tilt control knob is turned around the horizontal axis of the cylinder and the cylinder turns inside the barrel. A shaft is mounted within the hollow cylinder and is connected to the spindle at one end to cause the spindle to rotate, and is connected to a rotate control knob on the other end. In another aspect of the invention, a method of operating an image capture microscope includes setting the intensity of a ring light to a ring minimum level, e.g., by turning the ring light off, and adjusting the intensity of an oblique light to produce a characteristic image from the video camera. The characteristic image is captured by the computer system, then the intensity of the oblique light is set to an oblique minimum level, e.g., by turning the oblique light off, and the intensity of the ring light is adjusted to produce a centering image from the video camera. The centering image is acquired by the computer system.

In another aspect of the invention, a casing mount includes a preformed elongated insert having a fitting width matched to an open end of a firearm casing whereby sides of the insert fit snugly against the open end of a firearm casing.

In another aspect of the invention, a casing mount includes a preformed disk having a groove.

The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of example embodiments of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with respect to the drawings in which:

Figure 1 is a diagram of an image capture microscope according to one embodiment of the present invention.

Figure 2A is a side view of a high precision universal specimen holder according to an embodiment of the present invention. Figure 2B is a cross-section of the upper portion of the high precision universal specimen holder of Figure 2 A.

Figure 2C is a cross-section of the lower portion of the high precision universal specimen holder of Figure 2A. Figure 2D is a top view of the portion of the universal specimen holder depicted in Figure 2C.

Figure 2E is a side view of a gib screw used as a slide lock in Figures 2C and 2D. Figure 3A is a casing insert adapter for the universal specimen holder according to one embodiment of the present invention.

Figure 3B is an exemplary top view of the insert from Figure 3A.

Figure 3C is a disk adapter for the universal specimen holder according to another embodiment of the present invention. Figure 3D is a top view of the disk from Figure 3C.

Figure 4A is a side view of a ring/oblique light fixture according to one embodiment of the present invention.

Figure 4B is a bottom view of the ring/oblique light fixture of Figure 4A.

Figure 5 is a flow chart for using an image capture microscope with the light fixture of Figure 4 according to a method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is a diagram of an image capture microscope according to one embodiment of the present invention. An image capture microscope arranges various components needed to capture images of spent ammunition specimens for forensic analysis. The backbone of the image capture microscope is a stand 103 including a standard base plate 102, a column stand 104 and a positioning stage 106. A specimen 190 is placed on the positioning stage 106. Fixed directly or indirectly to the column stand 104, so as to be poised above the specimen 190, is a CCD video camera 108, a microscope 150 and a light fixture 140. A dashed line represents the optical path 109 from specimen 190 to CCD video camera 108. The optical path 109 passes through a microscope 150 such as a zoom microscope. The purpose of the light fixture 140 is to consistently and repeatedly illuminate the specimen 190 on the stage 106 at least obliquely - that is. from one side of the optical path 109. The image produced by the video camera 108 is fed through a communications link 119 such as a video cable to a computer system 110 where the image is processed and stored.

In the embodiment depicted in Figure 1, the light fixture is fed light through fiber optic cables 132a, 132b from two fiber optic light sources 130a, 130b, respectively. In this embodiment, the fiber optic light sources 130a, 130b are connected to the computer system 110 through a communication link 120. In this embodiment, the specimen 190 is attached to the positioning stage 106 using a high precision universal specimen holder 160. The high precision universal specimen holder 160 holds the specimen 190 securely using an adapter 170. This embodiment of the present invention eliminates many of the causes of variability that lead to reduced measures of similarity among images produced by a conventional image capture microscope. Several aspects of the present invention are described separately in the paragraphs to follow. Figure 2A depicts a high precision universal specimen holder according to one embodiment of the present invention that eliminates the imprecision in tilt, centering and rotation to which the conventional image capture microscope is subject. Imprecision in tilt, rotation and centering leads to reduced correlations among images in a forensic analysis. The high precision universal specimen holder 160 allows a specimen to be tilted and rotated precisely to facilitate centering of the specimen.

The specimen is attached to a spindle 206 with a long axis. The spindle is attached to a cylinder or turret 203 so that the spindle 206 can rotate about its long axis. The spindle 206 goes diametrically through the center of the cylinder 203. When the cylinder 203 is turned about its horizontal axis, the spindle 206 is tilted with respect to the optical path. In the view of Figure 2A, this tilt is represented by rotation into or out of the page. The portion of the cylinder 203 visible in Figure 2 A is the spindle portion of the cylinder 203, so named because of the spindle 206 that connects there. The cylinder 203 can rotate about its horizontal axis because it is rotatably mounted within a barrel 202, also called a case body. As the cylinder 203 rotates inside the barrel 202, the cylinder 203 is in sliding contact with the barrel 202. The portion of the cylinder 203 in sliding contact with the barrel 202 and hidden from the view of Figure 2A is called the barrel portion of the cylinder 203. The barrel 202 is held in position by a riser block 201 fixed to the lower outside of the barrel 202. A tilt control knob 204 is attached to the cylinder 203 at a section of the cylinder 203 that extends outside the barrel 202. When the tilt control knob 204 is turned, the cylinder 203 inside the barrel 202 turns about its horizontal axis and tilts the spindle 206. Though no gearing is depicted between the tilt control knob 204 and the cylinder 203, it is anticipated that such gearing can be employed to permit precision tilting.

Partial stops, or detents, can be disposed on the tilt control knob 204 or cylinder so that the knob will stop automatically or easily at predetermined tilt angles. These detents are preferably placed at 0°, ±4° and ±90° from top dead center. The ideal angle of tilt, that angle where optimal detail enhancements occur for breech face examination, is believed to be top dead center (0°).

The centering of the spindle 206 can be accomplished by means of a slider base 220, and a rotating base 230. A mounting base 240 can be attached to a specimen positioning stage (106 in Figure 1). The rotating base 230 is rotatably connected to a top side of the mounting base 240. A slider base 220 is slidably connected to the rotating base 230, i.e., the slider base 220 moves linearly with respect to the rotating base plate 230. For example, the slider base plate 220 can move radially through the center, or the axis of rotation, on the rotating base plate 230. In the view of Figure 2 A, the slider base plate 220 is disposed above the rotating base 230, i.e., on the top surface, and can move linearly out of the page, and then return into the page.

One embodiment is shown in more detail in Figures 2C and 2D. In this embodiment, the mounting base 240 includes a rectangular base plate 242 with bolt or screw holes 245, and a circular base 244 with bolt or screw holes 249 that align with the holes 245 on the base plate 242. The base plate 242 and circular base 244 are fixed to each other with bolts or screws (not shown) that pass thi-ough the aligned holes, 245 and 249, respectively. The circular base 244 includes horizontally inward extending lips and provides a circular seat into which the rotating base 230 fits.

In this embodiment, the rotating base 230 includes a circular housing 234 with a plurality of through holes 235, and with a horizontal linear groove 233 on its top surface into which portions of the slider base 220 can fit. The housing 234 is held on the circular base 244 by means of a capture plate 236 which fits under the lips of the circular base 244 and which is attached to the housing 234 with bolts or screws that extend through the through holes 235 of the housing and aligned through holes.237 in the capture plate 236. The housing 234 and capture plate 236 can thus rotate in the horizontal plane inside the circular base 244. A shim 238, made, for example, of brass, may be disposed below the housing 234 and above the circular base 244 to facilitate rotation. The rotating base 230 also includes a horizontal through hole 239 perpendicular to the linear groove 233 into which a gib screw can be placed to act as a slide lock 222. A screw can also be inserted through one of the vertical through holes 235 to engage a clamp 248, made, for example, of brass, to act as a rotation lock 232. When this screw is tightened, the clamp 248 presses up on the bottom side of the lips of the circular base 244, to prevent motion of the housing 234 relative to the circular base 244. In this embodiment, the slider base 220 consists of a slide plate 224 with angled sides and the gib screw acting as a slide lock 222. In the embodiment shown, a slide gib 231 is disposed between the housing 234 and a side of the slide plate 224 opposite the slide lock 222. This gib 231 helps to hold the slide plate 234 in the groove during assembly. As shown in Figure 2D, the slide plate 224 can move in the horizontal plane in the direction of the arrows, linearly to the left or right through the center of the housing 234 of the rotating base 230. as the housing 234 rotates in the horizontal plane in the direction of the curved arrows. A slide stop 223 disposed in the linear groove 233 fits into a stop groove 225 on the underside of the slide plate 224. The stop groove is closed at either end, as shown by the dashed line in Figure 2D, so that neither end of the slide plate 224 can extend past the slide stop 223. Thus the slide plate 224 can not exit the linear groove 233 after the slide gib 231 is in place.

The riser block 201 is then fixed to the slide plate 222 of the slider base

220 so that the barrel 202, cylinder 203 and spindle 206 can all be moved in concert with the slider base 220 and the rotating base 230. A specimen (190 in

Figure 1) mounted on the spindle 206 is thereby centered by a combination of movement of the slider base 220 and the rotating base 230.

In order to maintain a given position, i.e., a given rotation angle and a given slide distance, locks are included in the embodiment described in Figure 2A, 2B and 2C. A rotate lock 232 is connected to the rotating base 230 and engages the circular base 244 when the rotating base 230 is at a desired rotated angle. After the rotate lock 232 is engaged, the rotating base plate 230 will no longer rotate with respect to the mounting plate 240. Similarly, a slide lock 222 is included in the slider base 220 to engage the rotating base plate 230 when the slider base plate 220 is at a desired slid distance. Figure 2E shows a detail of one embodiment of the gib screw used as a slide lock 222 in Figures 2C and 2D. It includes a threaded section 225, a central section 226, and a sloped contact section 227 which presses against the sloped sides of the slide plate 224. When the specimen (190 in Figure 1) is substantially centered, both the rotate lock 232 and the slide lock 222 are engaged and the centering is fixed.

Once a specimen (190 in Figure 1) has been tilted as described above, it can be centered as also described above. The specimen (190 in Figure 1) can then be rotated by rotating the spindle 206 without changing the centering. The spindle 206 is rotated by rotating the spindle rotate control knob 207. Figure 2B is a cross-section of an upper portion of the universal specimen holder 160 that illustrates how the spindle 206 can be rotated by the rotation of the rotate control knob 207. As shown in Figure 2B. a spindle gear collar 211 is disposed on the spindle 206, and a shaft gear collar 212 is disposed on a shaft 205. The shaft 205 is disposed along the horizontal axis of the cylinder 203 and rotabably connected thereto. Teeth of the spindle gear collar 211 engage teeth of the shaft gear collar 212 so that, as the shaft 205 rotates about the horizontal axis of the cylinder 203, the spindle 206 rotates about its own long axis. The end of the shaft 205 with the shaft gear collar 212 is called the collar end of the shaft. At the opposite end of the shaft, a spindle rotate control knob 207 is attached to the shaft 205. In this configuration, when the rotate control knob 207 is turned around the horizontal axis, the spindle 206 rotates about its long axis. Depending on the ratio of the shaft gear collar 212 to the spindle gear collar 211, the spindle 206 can rotate at a different angular speed than the rotate control knob 207.

In the embodiment of the spindle 206 depicted in Figure 2B, a spindle slot 207 is disposed longitudinally in the spindle 206. With no specimen or adapter mounted on the spindle 206, the spindle 206 has a diameter d_s, and the spindle slot 207 has a width w_s. In this configuration, the spindle 206 can be inserted into a hole with a diameter between d_s and (d_s-w_s), at least to a depth somewhat less than the longitudinal extent of the spindle slot 207. In such a hole the sides of the spindle 206 act to apply pressure against the sides of the hole and to ensure a snug fit and firm hold on the specimen or adapter.

Figure 3A shows an adapter that may be used with various caliber casings. In general, an adapter 170 has a spindle mount portion 302 and a casing mount portion. In this case, for the caliber adapter shown in Figure 3A, the casing mount consists of a caliber specific casing insert 304 over which a spent cartridge fits. The spindle mount 302 includes a hole 306 with diameter d designed to fit snugly over the spindle. The diameter d may be chosen from about d_s to about (d_s-w_s). The adapter 170 is secured to the spindle 206 through the hole 306 in the spindle mount 302. In the preferred embodiment, the casing mount and the spindle mount are integrally formed of urethane.

The casing insert 304 is tapered from a minimum insert width d_mm at an interior position C to a maximum insert width d_max at end A. The tapering permits observed variations in the inner diameter of the open end of casings of spent ammunition of a given caliber to be accommodated. Thus, a spent casing can be positioned over the casing sides of the insert 340 with the bottom (open end) of the casing fitting snugly against the insert at some point, e.g. B, between A and C. This serves to snugly fasten the spent casing to the adapter 170a. Different sizes of adapters are used for different calibers of casings. In the preferred embodiment, the different adapters are color-coded by caliber. The maximum insert width and the minimum insert width are specific to a caliber of the casing specimen to be imaged. The insert cross section can be circular, or ribbed as shown in Figure 3B.

For casings that are too large or too irregularly shaped to be conveniently accommodated by a casing insert, a different casing mount is used. This is depicted in Figure 3C where the casing mount is a casing disk 310, preferably of urethane, having one or more grooves 312 cut in the surface opposite to the side connected to the spindle mount 302. The casing is fixed to this mount by attaching wax to the casing and pressing the wax against the disk 310. The grooves 312 help the wax adhere to the disk 310. Given the adapters described above and made of a hard plastic such as urethane, it is possible to precisely center a specimen using the high precision universal specimen holder (160 in Figure 1). In addition, given the mount designs described above, the adapters are reusable; the casing can be removed from the casing mount and the spindle mount 302 can be removed from the spindle 206 and used again with other specimens.

The high precision universal specimen holder 160 is still a manually operated device, therefore it is not possible to center a specimen to the level of one pixel accuracy in the resultant digital image. To avoid the degradation in measures of similarity which can be caused by multi-pixel differences in centering of images, software centering can be used to align the digital characteristic images. Unfortunately, the oblique light that serves to emphasize the markings on the closed face of the casings also can cause software centering algorithms to perform badly.

Therefore, according to another aspect of the present invention, the outer perimeter of the breech face of the spent casing is emphasized over the markings on the breech face by using a non-oblique light source. The present invention contemplates the use of a dual purpose ring light to provide illumination of the casing specimen. Thus, according to the embodiment of the present invention shown in Figure 1 and in Figure 4, a ring light is included in the light fixture 140. In this embodiment, one light fixture 140 surrounds the optical path 190 as shown in the side view in Figure 4A. The light fixture 140 illuminates specimens in an angular area defined by the angle β. Referring to Figure 4B, as viewed from below, the oblique light of the light fixture 140 consists of an arced emitter 404 which subtends an angle α around a circle centered on the optical path. The ring light of the light fixture 140 is a circular emitter 406 distributed around the entire circumference of a circle centered on the optical path. In one embodiment, the light emitters are diffuser hood segments 410 illuminated by light from a fiber optic light source (130 in Figure 1) connected to the diffuser hood segment by a fiber optic cable 132. In this embodiment, the oblique light emitter consists of a first diffuser hood segment in which α is 90°. The other emitters may consist of one or more diffuser hood segments forming a complete circle with the first segment. Alternatively, the ring light source may be one or more segments formed as a full circle concentric with the first segment.

The fiber optic light sources can be controlled manually or by a computer system connected to the fiber optic light sources 130a, 130b as shown in Figure 1. In this embodiment, the computer system is also connected to the video camera 108. The computer system may turn the fiber optic light sources 130a. 130b on and off or adjust their intensity. This may optionally be done in accordance with the imagery received from the video camera 108. This configuration of the light sources 130 and the computer system 110 can be used to enhance the efficacy of the software centering, as described in a subsequent paragraph.

To diminish the need for re-centering with software every time a magnification is changed, the turret of microscope objective lenses of the conventional image capture microscope is replaced by a zoom microscope 150. The variable focal length objective or zoom lens permits fixed light sources which reduces variability of angle and intensity. The zoom microscope may have click stops, or detents, that can be used for specified magnification levels. This can permit backward compatibility with the conventional image capture microscopes. For example, detents can be inserted at magnifications of 2X, 2.4 IX, 3.6X, and 5.4X as required by the protocol for capturing characteristic images.

In accordance with one method of the present invention, software centering is utilized as shown in Figure 5. The intensity of the ring light is set to a ring minimum level (e.g. turned off). Then the intensity of the oblique light is set to produce a characteristic or standard image from the video camera 520 having high contrast markings from the casing specimen. The high contrast image of the markings is then captured in digital form by the computer system 530. In the preferred embodiment, the obliquely lit characteristic image is captured at one intensity determined by image processing software. Thereafter, a ring light image is acquired 550 after turning the oblique light to an oblique minimum level (e.g. off) 540. This produces a centering image which has relatively low contrast specimen markings. The centering image is acquired by the computer system 560. Using known software centering algorithms, the computer system automatically determines a vector displacement from a pixel closest to a center of the specimen as determined using the ring light source to a pixel at the center of the image 570. This displacement is then applied to the camera output image 580 to relocate the off-center images to a standard location for image capture.

There has been disclosed an image capture microscope which overcomes the problems of the prior art. Although the present invention has been described above by way of detailed embodiments thereof, it is clearly understood that variations and modifications may be made by one of ordinary skill in the art and still lie within the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

What is Claimed Is:

1. An image capture microscope comprising: a stand having a specimen positioning stage; a digital video camera fixed with respect to the stand; a microscope in an optical path from the specimen positioning stage to the video camera; a light fixture fixed to the microscope, the light fixture comprising at least an oblique light which illuminates the stage from locations on one side of to the optical path; and a specimen holder disposed on the stage for controlling at least one of rotation and tilt of a specimen with respect to the optical path.

2. The image capture microscope of claim 1, the specimen holder comprising a spindle that can be tilted relative to the optical path and rotated.

3. The image capture microscope of claim 2, the specimen holder further comprising an adapter comprising a spindle mount portion for removably connecting to the spindle, and a casing mount portion.

4. The image capture microscope of claim 3, wherein the adapter is integrally formed of urethane.

5. The image capture microscope of claim 3, the casing mount comprising a preformed casing insert having a first width closely matched to an open end of a firearm casing.

6. The image capture microscope of claim 5, wherein the casing insert is tapered from a maximum insert width greater than the first width at one end to a minimum insert width less than the first width at an interior position.

7. The image capture microscope of claim 6, wherein the maximum insert width is specific to a caliber of the specimen.

8. The image capture microscope of claim 6, wherein the minimum insert width is specific to a caliber of the specimen.

9. The image capture microscope of claim 3, in which the casing mount comprises a preformed casing disk having a groove.

10. The image capture microscope of claim 3, in which the spindle mount comprises a spindle hole having a spindle hole diameter.

11. The image capture microscope of claim 10, in which the spindle comprises a spindle slot having a spindle slot width.

12. The image capture microscope of claim 11, wherein the spindle has a spindle diameter, the hole diameter is less than the spindle diameter, and the hole diameter is greater than a difference between the spindle diameter and the slot width, whereby the spindle provides spring-like contact against inner walls of the spindle hole to firmly hold the adapter.

13. A universal specimen holder comprising: a spindle; a hollow cylinder having a horizontal axis, wherein the spindle is rotatably connected diametrically through the cylinder at a spindle portion of the cylinder; a barrel in sliding contact with the outside of the cylinder along a barrel portion of the cylinder; a riser block fixed to the lower outside of the barrel for supporting the barrel; and a tilt control knob fixed to a knob portion of the cylinder, whereby the spindle tilts as the cylinder is turned inside the barrel as the tilt control knob is turned around the horizontal axis.

14. The universal specimen holder of claim 13 further comprising: a shaft disposed along the horizontal axis of the cylinder and rotatably connected to the cylinder; a shaft gear collar at a collar end of the shaft; a spindle gear collar connected to the spindle such that teeth of the spindle gear collar engage teeth of the shaft gear collar; and a spindle rotate control knob attached at an end of the shaft opposite to the collar end, whereby the spindle rotates as the rotate control knob is turned around the horizontal axis.

15. The universal specimen holder of claim 13, further comprising: a horizontal mounting plate for attaching to a specimen positioning stage of a device; a rotating base plate rotatably connected to a top side of the horizontal mounting plate; and a slider base plate slidably connected to a top side of the rotating base plate, and fixed to a lower side of the riser block.

16. The universal specimen holder of claim 15, further comprising: a rotate lock to hold the rotating base plate at a given rotated angle with respect to the mounting plate; and a slide lock to hold the slider base plate at a given slid distance with respect to the rotating plate.

17. An image capture microscope comprising: a. a stand having a specimen positioning stage; b. a digital video camera fixed with respect to the stand; c. a zoom microscope fixed with respect to the stand, the microscope in an optical path from the specimen positioning stage to the video camera; and d. a light fixture fixed with respect to the stand around the optical path, the light fixture comprising

(dl) an oblique light having an arcuate emitter subtending a certain angle along a circle centered on the optical path, which illuminates the stage, and

(d2) a ring light having a circular emitter centered on the optical path, which illuminates the stage.

18. The image capture microscope of claim 17, further comprising: a fiber optic light source; and a fiber optic cable connecting the fiber optic light source to the arcuate emitter.

19. The image capture microscope of claim 18, wherein the arcuate emitter comprises a diffuser hood segment.

20. The image capture microscope of claim 18, further comprising a computer system in data communication with the video camera and the fiber optic light source, wherein the computer system adjusts intensity of the fiber optic light source.

21. The image capture microscope of claim 17, further comprising: a fiber optic light source; and a fiber optic cable connecting the fiber optic light source to the circular emitter.

22. The image capture microscope of claim 21, the circular emitter comprising a diffuser hood segment.

23. The image capture microscope of claim 21, further comprising a computer system in communication with the video camera and the fiber optic light source, wherein the computer system adjusts intensity of the fiber optic light source.

24. The image capture microscope of claim 17, the zoom microscope comprising a plurality of detents, each detent associated with a certain standard image magnification.

25. The image capture microscope of claim 21 , the circular emitter comprising a plurality of diffuser hood segments.

26. The image capture microscope of claim 25 further comprising: a second fiber optic light source; and a second fiber optic cable connecting the second fiber optic light source to one segment of the plurality of diffuser hood segments, wherein the one segment operates as the arcuate emitter of the oblique light.

27. A method of operating an image capture microscope having a light fixture fixed around an optical path from a specimen to a video camera, the light fixture including an oblique light and a ring light, the video camera connected to a computer system, the method comprising: setting intensity of the ring light to a ring minimum level; adjusting intensity of the oblique light to produce a standard image from the video camera, the standard image having high contrast specimen markings; capturing the standard image by the computer system; setting the intensity of the oblique light to an oblique minimum level, after said capturing; adjusting the intensity of the ring light to produce a centering image from the video camera, the centering image having low contrast specimen markings, after said capturing; and acquiring the centering image by the computer system.

28. The method of claim 27, further comprising: automatically determining a displacement from a pixel closest to a center of the specimen in the centering image to a pixel at a center of the centering image, after said acquiring the centering image; and automatically shifting the standard image by the displacement.

29. The method of claim 27, wherein the oblique light is connected to the computer system, and said adjusting intensity of the oblique light is performed automatically by the computer system to optimize contrast in the standard image.

30. The method of claim 29, wherein said setting the intensity of the oblique light is performed automatically by the computer system.

31. The method of claim 27, wherein the ring light is connected to the computer system, and said adjusting the intensity of the ring light is performed automatically by the computer system.

32. The method of claim 31, wherein said setting intensity of the ring light is performed automatically by the computer system.

33. A casing mount for forensic analysis of firearm casings, the mount comprising a preformed elongated insert having a first width matched to an open end of a firearm casing whereby sides of the insert fit snugly against the open end of the firearm casing.

34. The mount of claim 33 wherein the insert is formed of urethane.

35. The mount of claim 34 wherein the insert is tapered from a maximum insert width greater than the first width at one end to a minimum insert width less than the first width at an interior position.

36. The mount of claim 35 wherein the maximum insert width is specific to a caliber of the casing, and the minimum insert width is specific to the caliber of the casing.

37. The mount of claim 36 wherein an insert color is specific to the caliber of the casing.

38. A casing mount for forensic analysis of firearm casings, the mount comprising a preformed casing disk having a groove.

39. The mount of claim 38 wherein the disk is formed of urethane.