The ordinary microscope can only look at one sample at a time, and the two samples should be "back and forth, according to the memory ratio". The human eye is very insensitive to nuances in memory, especially in scenarios where trace ratio requires "homologous identification".
The practice of comparing microscopes is: two completely symmetrical optical paths, each looking at a sample, and finally synthesizing into the same eyepiece. You see a picture of Sample A on the left, Sample B on the right, with a dividing line in the middle; or switch to overlapping mode, where two images are stacked together.
This comparison is two images presented at the same time, not memories.
① Criminal investigation material evidence comparison: bullet rifle marks, shell case pinholes, tool pry indentations, and shoe sole patterns. Judging whether two items of evidence come from the same gun and the same tool is a key link in the evidence chain of the court.
② Material and failure analysis: comparison of two fractures (judging whether the same failure mode is used), comparison of microstructures on both sides of the weld, comparison of the interface between the coating and the substrate, and process differences between the imitation and the original.
③ Quality inspection and imitation product identification: compare the details of printed products, packaging, textiles, and jewelry to determine whether they are the same batch or counterfeit.
| Comparison microscope | Stereomicroscope | |
|---|---|---|
| Optical Path | Two independent paths, one sample for each pair | Both paths, but both facing the same sample |
| Imaging | Left and Right Divide or Overlap Synthesis | Stereoscopic vision, single object |
| Purpose | Two samples compared to each other | Stereoscopic observation and operation of a sample |
| Typical Scenarios | Ballistic alignment, fracture control | Assembly, Rework, Dissection |
| Multiplier | Usually 10X–100X | Usually 5X–50X |
In a word: stereoscopic is "seeing three-dimensional", compared to "comparing".
① Optical path switching mode: There are usually two types: left and right demarcation (a line in the middle of the picture, A on the left and B on the right) and superposition (two images are superimposed together, distinguished by different colors or brightness). Trajectory matching is a multi-purpose demarcation mode, and trace detail matching is a commonly used overlapping mode.
② Magnification and objective: 10x-100X covers most scenes. It takes 40X-100X to see the fine marks on the rifle, and 10x-20X is enough to see the overall shape.
③ Stage: Two samples should be able to fine-tune the position and angle independently. XY bi-directional fine-tuning + rotation is a basic requirement, and the warhead comparison also needs to be able to rotate the sample to see the rifle.
④ Illumination: It is important that the two sides are independently adjustable - the reflectivity of the two samples is often different, and the light source cannot be linked.
⑤ Camera interface: trinoculars can be connected to the camera, and the comparison results will be photographed and archived, which is a necessary item for reporting and evidence.
The most easy to ignore when actually purchasing is the independence of lighting and the fine-tuning accuracy of the stage - these two direct decisions can not be trusted.
COMP100A Comparison Microscope (Left and Right Boundary Mode)
Six models cover everything from basic visual comparisons to electric digital comparisons:
· Comp6C comparative microscope - continuous magnification 8.4X–108X (expandable 3.36 X-216X), 0.7X-4.5X continuously adjustable, suitable for overall comparison of traces
· COMP100A Comparison Microscope - Fixed-gear zoom 8X-96X, 0.8X/1 .2X/2X/3X/4.8X Five-gear, accurate magnification, good repeatability, suitable for reporting
· Comparison microscope COMP100D - same as 100a optical specification, digital configuration version
· Comp8A digital comparison microscope - standard 5X–120X (optional auxiliary objective up to 240X), suitable for fine traces
· Comp8D criminal investigation electric comparison microscope - electric stage, programmable to move, suitable for mass comparison
· COMP900DR digital comparison microscope - large field of view eyepiece WF10X/φ22mm, 0.75 X-5X continuous zoom, suitable for large objects
· Visual comparison only, limited budget → COMP6C or COMP100A
· To report and retain evidence, you → must have trinoculars + camera, and choose COMP100D or COMP8A
· Bulk comparison of ballistics and tool traces to COMP8D → motorized table can save a lot of repetitive operations
For the complete model comparison, see the Comparison Microscope column.
Tell us the material, the feature you need to see and the magnification range. We will recommend a configuration and quote it.
