240 results about "Latent fingerprint" patented technology

The invention relates to a method and apparatus for imaging and documenting fingerprints. A fluorescent dye brought in intimate proximity with the lipid residues of a latent fingerprint is caused to fluoresce on exposure to light energy. The resulting fluorescing image may be recorded photographically.

A portable device for the live scanning of fingerprint, facial and crime scene images and the wireless transmission of said images to a central host system for identity verification. The portable device has the ability to allow the user to operate the device with a single hand. It can scan and record live fingerprint slap or roll images (via optical, solid state, or video sensors). It also includes a baffle that assists with the mechanical alignment of the fingerprints on the fingerprint sensor receiving surface and prevents bright light sources from interfering with fingerprint scans. The portable device also can scan, display, and record latent fingerprint images. It also has other data receiving and transmission functions, such as displaying and recording facial and incident scene images in conditions ranging from well lit to total darkness, recording and playing back incident scene audio information for incident description and contacting voice recordings for identification. The portable apparatus can also scan, record, and interpret magnetic stripe, smart card, or bar code information from standard and non-standard cards. It also obtains, displays, and records geographical position for incident description, mapping, and directional instruction to the user. It further provides an emergency transmission for assistance and provides a short-range wireless link to a mobile unit or a direct wireless link to the central site. It also provides for entry by the user of text data for demographics or operator use through either keyboard or voice activation.

Embodiments relate to methods and systems for gathering, archiving, transmitting, and processing forensic and latent fingerprints. An integrated forensic fingerprint scanning system is provided that includes a number of features for use with forensic-quality fingerprinting. One set of features of embodiments of the portable forensic fingerprint scanning system provides real-time feedback for accurate fingerprinting and training, including visual and/or audio feedback. Another set of features provides cadence-based functionality for improving fingerprinting results. Another set of features provides cryptographic-based approaches to secure highly sensitive collected fingerprint information against loss, theft, or surreptitious modification or tampering. Yet another set of features provides latent fingerprint collections and processing. Still another set of features provides various databasing functions, including centralized storage, data sharing, secure networking, etc. And another set of features provides compatibility with a large variety of jurisdiction-specific inputs and/or outputs, including linguistic interactivity, alerts, print cards, etc.

The invention discloses a preparation method of silica particles, a method for displaying latent fingerprints by using the silica particles prepared by using the method, and the silica particles prepared by using the method. The preparation method comprises the following step of: sufficiently reacting the silica particles with a silane coupling agent with a mass ratio of (1:2)-(10:1) or (50:1)-(1,000:1). Because modified silica particles provided by the invention have good oleophylic property, the modified silica particles have better binding force with residual substances in fingerprints and can be used as a dust brushing reagent for fingerprint detection and/or analysis. The invention also provides biparental silica particles which can be dispersed in water to obtain a stable suspension, and the suspension can be applied to the latent fingerprints or the surfaces in a liquid medium so as to determine whether the fingerprints exist or not.

The invention belongs to the technical field of trace amount detection, in particular relates to a method that surfaces functionalized nanogold particles are used for potential fingerprint appearance. The invention provides the method that the different surface functionalized nanogold particles (probe) are used for the potential fingerprint appearance. The particles are the hydrophobixated nanogold particles decorated by alkyl hydrosulfide, the hydrophobixated nanogold particles protected by surface active agent cetane trimethyl ammonium bromide (CTAB), the water-soluble nanogold particles protected by the CTAB and the water-soluble nanogold particles protected by L-cysteine respectively. The probe and the ingredients in the residual sweat in the potential fingerprint generate the absorption and static functions or the condensation reaction, then an argentation is utilized to lead potential fingerprint samples to colorate in the argentation liquid, the nanogold particle signals for the ingredient identification in the fingerprint are magnified and the reduced argentum particles deposite at the grain position of the fingerprint samples to further present black, thereby forming the clear fingerprint image that can be observed by naked eyes. The method is simple, fast and high in sensitivity and has no harmful side effects.

An optical fingerprinting method extracts high quality latent fingerprints from a surface without any invasive chemical or physical contact with the examined object, and requires no cooperation of the subject. Rather than employing extraneous material, the optical properties of the latent fingerprint are used to generate one or more images with sufficient contrast to distinguish the latent fingerprint or some other deformation in the surface. The system includes a light source oriented to apply light at an angle of incidence to the surface at the position to be examined for the latent fingerprint or deformation, a camera oriented to receive light specularly and diffusely reflected from the surface and/or by the fingerprint or deformation on the surface, and a processor that performs the computation for digital contrast enhancement and/or reprojection of the recovered fingerprint image to a frontal view if necessary. The technique uses optical polarization properties to enhance the images by placing a linearly polarized filter(s) in front of the observing camera. At least two pictures of the same scene with the same lighting and view angle arrangement are taken whereby each of the pictures differ only in that the orientations of the polarization filter are different. At least two light polarization parameters for each pixel are computed from the two or more images taken with different polarizer orientations. An image with each pixel value representing the value of one of the polarization parameters or a function of the polarization parameters is generated and displayed, with some digital contrast enhancement and/or reprojection applied. The hidden latent fingerprint pattern is revealed in at least one such image with the interfering background pattern significantly suppressed.

A latent fingerprint developing compound is formed by mixing cyanoacrylate, a solvent, and a fluorogenic reagent to provide a homogenous blend. The mixture is then solidified with the mixture having the characteristic of being capable of sublimating at a given temperature and in its sublimated state reacting with one or more of the constituent components of the residue of a latent fingerprint to form a discernable fluorescent image of the print. A latent fingerprint may be developed by exposing a substrate containing the latent print to the sublimated fumes of the compound.

The invention belongs to the technical field of detection, and particularly relates to a method for manifesting latent fingerprints. The invention provides the method for manifesting the latent fingerprints. A magnetic brush is used to attract magnetic powder; the powder forms a 'magnetic powder ear' under the action of magnetic force; and the latent fingerprints on the surfaces of A4 paper, sheet glass, plastic bottles, pop-top cans, sheet copper, aluminum foils, tables or experiment tables can be manifested by using the tip of the powder ear to slightly brush various object surfaces printed with the latent fingerprints. The method is based on magnetic ferroferric oxide nano-powder and utilizes an phase reversal microemulsion polymerization method to prepare fluorescent magnetic silica gel spheres; and the method jointly coats magnetic granular ferroferric oxide and dye molecules in silicon dioxide microspheres by utilizing the hydrolysis of TEOS under alkaline conditions to perform one-step synthesis of magnetic silica monodisperse gel spheres and dye-doped magnetic fluorescent silica gel spheres to obtain magnetic fluorescent multi-functional powder, can be applied to more conditions and ranges, and has simple operation and no toxic or side effect.

The invention relates to the technical field of trace amount detection, and discloses a method of adopting a fluorescence quenching system to potential fingerprint display. The method is characterized in that potential fingerprint is displayed by utilizing 'turn-on' effect of the fluorescence quenching system to transmit fluorescence once again and includes: firstly, preparing the fluorescence quenching system, wherein the quenching state can be destroyed by fingerprint components; then spraying and painting the fluorescence on various objects with fingerprints, wherein the fingerprint components of chloride ion, amino acid or glucose and the like destroy the quenching state of the fluorescence quenching system to enable the fluorescence to appear to display the fingerprints; taking photos directly through a filter under special light or under natural light. The method is simple and rapid; when fingerprint details are not clear enough, common components like DFO (1.8-diazo-flurene-9-one), IND (indanedione), ninhydrin, silver nitrate and the like are used for continuously displaying the fingerprints, and the method can be further used for 'marking' or 'tracing' the fingerprints.

The invention discloses preparation of solid fluorescent carbon dots and application thereof in an aspect of latent fingerprint detection, belongs to the technical fields of material synthesis and fingerprint detection. The solid fluorescent carbon dots are synthesized by adopting glutathione as a nitrogen/sulfur source and adopting citric acid as a carbon source by virtue of a microwave method. Raw materials are safe and easy to obtain, a preparation method is simple and rapid, and particles are safe and nontoxic. The surfaces of the solid fluorescent carbon dots (SFCDs) provided by the invention contain an amino, a sulfydryl and a carboxyl functional group, a particle size is 2 to 7 nm, and the solid fluorescence property is excellent. The SFCDs are used as a fingerprint developing agent and can develop the aged fingerprint, and the developing time can reach 30 days in an experimental range; and the solid fluorescent carbon dots can be applied to a liquid spray method and powder method, the two methods are complementary to each other, and the universality of the developing agent is improved.

The invention relates to application of polyamide-amine (PAMAM) dendrimer coated ZnX (X=S, Se, Te) semiconductor quantum dots in fingerprint development, belonging to the technical field of material preparation. The method comprises the following steps: synthesizing a PAMAM dendrimer coated ZnX semiconductor quantum dot solution; and carrying out fluorescence labeling on latent fingerprints by using the PAMAM dendrimer coated ZnX semiconductor quantum dot solution. The method provided by the invention avoids the problem of toxicity of heavy metal ion Cd<2+> in the existing developing reagent, and the PAMAM dendrimer coated ZnX semiconductor quantum dots are harmless to the environment and users; the addition of the metal ion M<2+> can further enhance the fluorescence-emission strength of the ZnX semiconductor quantum dots; and by using the interaction between the PAMAM dendrimer and the fingerprint residue, the invention reserves the high development efficiency in the physical development method, and overcomes the defect of insufficient detailed development of fingerprint lines in the physical development method, thereby enhancing the precision and accuracy of the latent fingerprint development.

The invention discloses a latent fingerprint displaying method, and belongs to the technical field of fingerprint identification. The invention provides the latent fingerprint displaying method which is high in detection sensitivity, less in damage to the fingerprint and simple to operate. The latent fingerprint displaying method comprises the following steps of dipping a fingerprint hair brush into an up-conversion luminescence nano-particle powder, covering the fingerprint with the powder, after finding a fingerprint streakline, removing the powder on the hairbrush, and brushing along the orientation of the streakline until the streakline is clear. Infrared light directly radiates the area where the fingerprint is displayed, the surface of the fingerprint generates bright visible light, and then a fingerprint image can be shot by a digital camera. The other latent fingerprint displaying method comprises the following steps of sequentially adding absolute ethyl alcohol and water into the up-conversion luminescence nano-particle powder, stirring well, and ultrasonically dispersing to obtain a mixture; mixing the mixture with a surfactant aqueous solution and stirring well, thus obtaining the small-particle suspension liquid of the up-conversion luminescence nano-particles.

The present invention relates to a print detection composition comprising nanoparticles having an aerogel metal oxide core covered by a layer of zerovalent noble metal, and optionally, a fluorescent organic dye, wherein the fluorescent organic dye is within an interacting distance of the plasmon resonance field of the layer of zerovalent noble metal. The invention is also directed to surface-enhanced spectroscopic methods for imaging a latent print, particularly a latent fingerprint, by use of the print detection composition.

The invention belongs to the technical field of detection, in particular to a method for showing fingerprints on various object surfaces and keeping DNA information. The method adopts metaliding, takes functionalized gold nanoparticles and silver nanoparticles as probes, and is combined with argentation to realize that the latent fingerprints and blood fingerprints on different object surfaces can be shown in one method. The gold and silver nanoparticles are adsorbed due to the action with the ingredients of the latent and blood fingerprints, silver ions in silver staining solution can be catalyzed to be reduced on the surfaces of the fingerprints, and the generated silver covers the surfaces of the gold nanoparticles, thus enhancing the detection signals. After the blood fingerprints are shown in the method, the DNA sequence can be further detected. In the invention, the reducing agent in the silver staining solution is further expanded, when vitamin C is taken as the reducing agent, the cost is lower, the reaction condition is wild, the operation is simpler, and further environmental protection can be realized. The method has high sensitivity and wide application range, and can show old fingerprints.

The invention belongs to the technical field of criminal science, and particularly relates to an aldehyde group modification method of surface functionalization nanometer upconversion materials, wherein the aldehyde group modification method is used for display of latent fingerprints. Aldehyde group reacts with amino acid residue in the latent fingerprints, is deposited on the fingerprints through chemical coupling, and can emit visible colored fluorescence under radiating of 980 nanometer infrared light, and therefore the latent fingerprints on the surface of an object can be cleared displayed. The surface functionalization nanometer upconversion materials have the advantages that the using method is simple and easy to carry out, functionalization particles can be stored for a long time, background interference is little, and the like.

The present invention provides a fingerprint revealing spray. Based on the total weight of components (A), (B) and (C), the spray includes: (A) 1 to 10 parts by weight of an amino acid reactant; (B) 5 to 30 parts by weight of a dispersant; and (C) 50 to 150 parts by weight of a propellant. According to the present invention, due to containing the dispersant and the dispersant, the spray has a good fingerprint revealing effect with convenience, and reduces the use of toxic chemicals which pollute the environment, to achieve purposes of low cost and non-contamination to a specimen; and thus purpose of applying the spray in the latent fingerprint detection technical field can be achieved.

The invention discloses small-particle yellow rare-earth fluorescent powder and a preparation method and a purpose of visualizing a latent fingerprint thereof. The general structure formula of the fluorescent powder is Y3-x-yCexGdyA15O12, wherein the x is not less than 0.1 and no larger than 0.4, y is no less than 0.1 and no larger than 0.4 and the particle size is between 1.5 to 3 Mum. The preparation method comprises the steps of weighing up raw materials according to the stoichiometric ratio of the structure formula, grinding and evenly mixing up the raw materials, sintering the raw materials with high-temperature solid-phase method to obtain powder and obtaining the small-particle yellow rare-earth fluorescent powder by adopting an ultrasonic dispersion technology after the powder goes through a mesh with 300 to 400 eyes. The small-particle yellow rare-earth fluorescent powder can be applied to visualizing the latent finger print after being amido-functionalized by gamma-Aminopropyl triethoxy silane and being mixed with reduced iron powder which goes through a mesh according to a certain ratio. The fluorescent powder provided by the invention has even and small particles, high fluorescent intensity, the excitation wave length between 460 to 480nm which is within the range of the light source commonly used in criminal investigation and the emission wave length between 520 to 570nm, is conducive to visualizing the latent finger print on the site and eliminating the disturbance of the object background and is important for establishing a high-efficient, non-toxic, lossless and convenient finger print visualizing method.

The invention discloses a method for manifesting latent fingerprints on the basis of an electrochemical luminescence marker. According to the method, an activated terpyridine ruthenium composite is used as the electrochemical luminescence marker; the activated terpyridine ruthenium composite can be subjected to covalent binding with an amino group in fingerprint amino acid through N-hydroxysuccinimide eater on a molecule, so that the terpyridine ruthenium composite is marked and fixed on the fingerprints; then the terpyridine ruthenium composite and a coreactant (namely dinormal-butyl ethanolamine) in a solution are subjected to electrochemical luminescence reaction under certain potential, so that lines of the fingerprints comprising the integral morphology (namely a primary structure) and detailed features (namely a secondary structure) are manifested; according to the adopted electrochemical luminescence technology, an excitation light source is not required to be added, back light is eliminated, a self-quenching phenomenon of a radiant agent is greatly avoided, and the method is obviously superior to the traditional fluorescence imaging method; and an image can be quickly acquired by an imaging technology, and the speed of acquiring the image by the imaging technology is far higher than the speed of acquiring the image by a scanning electrochemical microscopy; and the used electrochemical luminescence coreactant is dinormal-butyl ethanolamine, and has the characteristics of high luminous intensity and environment-friendliness.

Latent fingerprints on a porous substrate such as paper are developed for viewing and recordal by applying heat to cause the fingerprint to be clearly viewed under radiation to cause the fingerprint to fluorescence (e.g. a few seconds heating with air or client contact with a heated device at around 260° C.) and viewing under e.g. light of 200 nm to 550 nm with a filter in the yellow to orange wavelength region. Alternatively more extended heating can render the fingerprint assemble under ultraviolet light, and under yet more extended heating permits viewing under white light.

The invention provides rare earth long-persistence luminescent powder, a preparation method and a method of applying the powder as a latent fingerprint revealing reagent. The structural general formula of the rare earth long-persistence luminescent powder is M1-x-yAl2O4:Eux<2+>, Dyy<3+ > (x=0.005, and y=0.011), wherein M is any one of Sr, Ca or Ba; and the grain diameter of the long-persistence luminescent powder is 1-3 microns. The rare earth long-persistence luminescent powder is prepared by a sol-gel method. The method of applying the powder as the latent fingerprint revealing reagent comprises the following steps: the rare earth long-persistence luminescent powder is mixed with reduced iron powder; then the compound is used to reveal the latent fingerprint on an object; white light or UV-light excitation is used to collect fingerprint images or self-luminous images. The preparation method of the rare earth long-persistence luminescent powder is simple; the excitation wavelength coverage of the prepared rare earth long-persistence luminescent powder is wider and the emission wavelength coverage is narrower, so that the powder is convenient to reveal the latent fingerprint in the field. The powder has the characteristics of higher fluorescent intensity and long persistence (self-luminous); and after the fingerprint is revealed, the object background interference can be effectively eliminated. The powder is non-toxic, lossless and environment-friendly.