Analytical Technologies Singapore

Imaging

Fingerprint Detection using DUV Fluorescence imaging

Fingerprint detection and ridge morphology analysis traditionally requires the use of additives and taggants such as Ninhydrin or DFO to enhance the contrast between a fingerprint and the background substrate and enable imaging of defining ridge details. Once captured and scanned digitally, these can be processed and further enhanced to match to existing databases.

However use of these additives or taggants require the addition of a contaminant to a forensic scene. In additional, the processing eliminates, or seriously degrades, the use of post chemical analyses that could provide insight into any illicit chemicals that may be present associated with the fingerprint.

Therefore a major challenge in the fingerprint analysis community is to address the use of a non-contact, non-invasive, non-destructive method. This challenge does not assume the latent fingerprint is well preserved. In a real-world scenario, the fingerprint will degrade by exposure to heat, sunlight, oxidation, or other environmental attributed effects. While the chemistry may change and adversely effect current methods, deep UV fluorescence imaging is not tied to a specific chemical compound and is significantly more tolerant to these environmental influences.

Since the fundamental nature of fingerprints, either fresh or latent, is an organic residue on a surface, deep UV autofluorescence imaging translates well to fingerprint detection and morphological analysis. As with environmental samples, deep UV autofluorescence alone provides a wealth of information. In addition, with the deep UV laser excitation, deep UV Raman can be used for additional chemical-specific characterization of the fingerprint; providing an orthogonal dimension of profiling and analysis of what an individual may have come in contact with.

Deep UV autofluorescence is most sensitive to aromatic structures such as aromatic amino acids (tryptophan, tyrosine, phenylalanine) found in the majority of proteins and as free amino acids in eukaryotic and prokaryotic cells. In addition it is highly sensitive to single and polyaromatic hydrocarbons (benzene, naphthalene, anthracene, etc) and various thermally altered forms of carbon (coals, diesel soot, etc).

Detection of this range of materials is what makes deep UV fluorescence tolerant to environmental effects. A fresh fingerprint may have a significant amount aromatic amino acids, however, if heated, these can thermally degrade to bituminous carbon; an organic that is still detectable by the deep UV autofluorescence methods. In addition to detecting these materials, the use of the deep UV also provides a signature that enables differentiation between these materials.

Fingerprint Detection using DUV Fluorescence imaging Read More »

How to Capture an Event when the Whole Experiment Destroys itself?

Ariane group has kindly permitted Specialised Imaging to share a sequence taken of a shockwave travelling through an energetic material. The sequence was captured by the Specialised Imaging KIRANA ultra high-speed camera running at 5 million frames/second.

Capturing shock waves travelling though solids is an application often captured by the KIRANA camera. Another example can be seen via the link below, where shock transmission through concrete is visualized using Digital Image Correlation analysis of the images:

Kirana05 – Digital Image Correlation: Split Hopkinson Pressure Bar impact on concrete 2M FPS (youtube.com)

However, there are two significant differences between the two applications. One is the hazardous nature of energetic materials, and the other is that energetic material shocks are generated by a primary (donor) charge that detonates adjacent to the acceptor material. This presents two issues, firstly the whole test set up is destroyed. Secondly, the self-illuminating nature of the donor can saturate and obscure the acceptor with light.

So how can the over brightness (saturation) generated by one area of the set up be mitigated to clearly capture the area of interest which is not self-illuminating and significantly darker? There is rarely enough camera sensor dynamic range to allow one exposure time setting to reduce the saturation affect, while also allowing a bright enough image of the darker area of interest.

One step to achieving a usable exposure time is to add supplementary lighting to raise the brightness of the darker region to a level closer to the self-illuminating region. For this application the light generated by the donor charge is significant and too hazardous for expensive lasers, LED’s or flash lamps, so for these tests a sacrificial argon “flash-bomb” was used to deliver the supplementary illumination required. It was placed very close to the event and generated significant light for tens of microseconds. Whilst this illuminates the area of interest sufficiently to allow a short enough shutter to freeze motion blur – it does not “balance” the lighting enough to stop the over saturation of light from the donor charge.

For the sequence below the answer was very simple and made possible by the microsecond timescale of shock transmission: A piece of cardboard was placed between the donor charge and camera field of view to obscure the flash and hold back the products of the detonating donor charge for long enough to see the shock transition. Since everything in the test area is destroyed, using cheap and easily available materials is paramount – and sometimes the solution can also be very simple.

KIRANA Detonic shock 5Mfps Ariane (youtube.com)

How to Capture an Event when the Whole Experiment Destroys itself? Read More »

LaVision published a paper about the novel Object-aware Lagrangian Particle Tracking (OA-LPT) scheme in the Measurement Science and Technology journal

The measurement of flows around objects such as cars, airfoils and maritime structures often poses major challenges for optical flow diagnostics methods such as Tomo-PIV or Lagrangian Particle Tracking (LPT)/Shake-the-Box (STB) within the measurement fields. Also, many flow reconstruction algorithms simply do not have the capabilities of incorporating such object information.


For this reason, measurements are often limited to observations directly behind the object (characterization of wake flows) or to the stitching of averaged flow fields in sub-sampled regions in order to avoid having negative impacts on the measurement data.


To solve this practical problem, LaVision introduces the novel Object-aware Lagrangian Particle Tracking (OA-LPT) method to seamlessly integrate the knowledge about the presence of view-obstructing objects in the measurement domain during the 3D particle reconstruction.
It minimizes the occurrence of reconstruction artifacts and provides a measurement approach for instantaneous 360° LPT/STB measurements around the objects of interest.

LaVision published a paper about the novel Object-aware Lagrangian Particle Tracking (OA-LPT) scheme in the Measurement Science and Technology journal Read More »

LaVision launches the next generation of PIV cameras – the Imager CX3p Camera Series!

All the advantages of the Imager CX3 camera series, which was successfully introduced last year, were the basis for this further development.

The small and compact cameras of the Imager CX3 camera series, which are equipped with the innovative back-illuminated technology that enables incredible sensitivity and very low noise, have already been a resounding sales success. The small pixels enable very small fields of view for a given lens, and the hardware binning guarantees exceptional frame rates and therefore increased flexibility when using these cameras.

LaVision is now launching the unique Imager CX3p camera series, which is equipped with an integrated Scheimpflug mount for adjusting the angle between camera and lens (Scheimpflug angle) for C-mount and F-mount lenses.This ensures quick and easy alignment of the viewing direction, Scheimpflug angle and sensor orientation.

The integrated Scheimpflug mount offers three independent setting options for tilt, rotation and sensor orientation. All settings are supported by an intuitive DaVis software tool resulting in very quick and easy Scheimpflug adjustment.

Here you can watch our video, showing the easy handling of this camera with all its Scheimpflug settings as well as the adjustment of the Scheimpflug mount supported by our user-friendly DaVis software tool.

LaVision launches the next generation of PIV cameras – the Imager CX3p Camera Series! Read More »

Supersonic Electrical Discharge in Water

Researchers at Loughborough University have been using a SIMX framing camera at frame rates up to 100 million frames / second to capture the initial stages of supersonic electrical discharges driven by nanosecond rise time, high-voltage ( 100 kV) impulses applied across a pair of electrodes mounted in water.

This research in high voltage breakdown in water, has progressed our understanding of how high-power ultrasound waves generated in a liquid by a high-voltage pulsed source can be used for industrial applications such as rock fracturing or in the medical or food industry domains to kill bacteria in a sterilisation process. The SIM camera was contained within a Faraday cage and viewed the electrodes mounted in a water tank. Pressure variation with different voltage rise times and interelectrode gaps were measured using a set of hydrophones placed 0.5m from the source.

This sequence shows results for an electrode gap of 3 mm and voltage rise time of 30 ns which corresponded to a streamer propagation speed of 63 Km/s and a peak pressure of 0.25 MPa.

Consistent peak pressures between 0.1 MPa and 1.1 MPa were found for inter-electrode gaps between 1 mm and 12 mm. The research concluded that the inter-electrode gap had a significantly greater effect on peak pressure than rise time for the same input energy.

The SIM camera’s nanosecond timing accuracy provided the flexible delays and exposure times required to capture and freeze the motion of these extremely fast events. To accommodate the different illumination conditions required to see both the source electrodes and the event, the camera control software “image merge” feature was used to overlay a static sequence, which used longer exposure times, with the dynamic sequence which used much shorter exposure times.

These merged images provide context and the relative positions of the event and electrode for all the tests.

Congratulations to Jessica Stobbs for receiving the EAPPC (Euro-Asian Pulsed Power Conference, Seoul, S. Korea, 2022) outstanding Young Researcher Award with this research.

Supersonic Electrical Discharge in Water Read More »

Advancing forensic interpretation of ballistic wounds

Ultra high-speed photography has been used by scientists at the Massachusetts Institute of Technology to study high-velocity micro-particle impact on gelatine and synthetic hydrogel. Potential advancements are, guiding the design of drug delivery methods using accelerated microparticles and the assessment of explosive–related injuries for better forensic interpretation in cases where fragments originating from explosions can cause severe tissue damage injuries. Micro debris, which typically travels at supersonic velocities, can cause serious injury by penetrating deep into tissue where it is hard to detect using standard medical imaging methods.

Multi–frame sequence showing a high-velocity impact on 10 wt% gelatine at 1290 m/s.

The research investigates the high-velocity impact response of gelatine and synthetic hydrogel samples using a laser-induced microparticle impact test platform for launching and imaging supersonic micro-particles travelling up to 1,500m/s. The micro-particles, typically less than 10um in diameter are captured prior and during impact penetration into translucent gels using a Specialised Imaging SIMX16 ultra high-speed multi-frame camera, capable of recording up to 16 images with nanosecond interframe time and short exposure times (down to 3ns) to stop motion blur. Illumination was provided by the Cavilux 640nm wavelength laser.

The impact response was quantified using the images by measuring pre-impact velocity, particle penetration depth and charted against time. These results were compared against a Poncelet predictive model for different gelatine samples. Further tests and measurements were conducted using an engineered protein hydrogel to investigate whether the Poncelet model could be applied to other soft materials which might be expensive to manufacture or otherwise in short supply.

The results indicate the Poncelet model provided a reasonable prediction of micro particle penetration and could offer an initial estimation of deformation of soft materials at high strain rates in more complex models.

See the Research Article here >> https://www.specialised-imaging.com/application/fi…

Advancing forensic interpretation of ballistic wounds Read More »