CN115251907A - Fingerprint showing method based on nanosecond laser irradiation - Google Patents
Fingerprint showing method based on nanosecond laser irradiation Download PDFInfo
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- CN115251907A CN115251907A CN202210498477.1A CN202210498477A CN115251907A CN 115251907 A CN115251907 A CN 115251907A CN 202210498477 A CN202210498477 A CN 202210498477A CN 115251907 A CN115251907 A CN 115251907A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000010521 absorption reaction Methods 0.000 claims abstract description 6
- 230000002093 peripheral effect Effects 0.000 claims abstract description 6
- 210000004243 sweat Anatomy 0.000 claims description 9
- 239000004519 grease Substances 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 4
- 238000004590 computer program Methods 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000004033 plastic Substances 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- 239000002023 wood Substances 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims 1
- 239000003973 paint Substances 0.000 claims 1
- 238000011835 investigation Methods 0.000 abstract description 2
- 230000007613 environmental effect Effects 0.000 abstract 1
- 230000007774 longterm Effects 0.000 abstract 1
- 231100000956 nontoxicity Toxicity 0.000 abstract 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 5
- 229910052725 zinc Inorganic materials 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000011840 criminal investigation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000006247 magnetic powder Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 231100000167 toxic agent Toxicity 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
- 238000007794 visualization technique Methods 0.000 description 1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/117—Identification of persons
- A61B5/1171—Identification of persons based on the shapes or appearances of their bodies or parts thereof
- A61B5/1172—Identification of persons based on the shapes or appearances of their bodies or parts thereof using fingerprinting
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- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The invention relates to a fingerprint showing method based on nanosecond laser irradiation, and belongs to the technical field of fingerprint identification. The method utilizes the inconsistent absorption of the latent fingerprint lines and the peripheral area thereof to the laser energy, and leads the latent fingerprint on the surface of the material to be clearly shown by nanosecond laser irradiation in the atmospheric environment. Compared with the existing fingerprint showing technology, the fingerprint showing method has the advantages of simple operation, no toxicity, environmental protection, economy, high efficiency, wide application range, easy long-term storage and the like, and is expected to be applied to the fields of case investigation and the like.
Description
Technical Field
The invention relates to the technical field of fingerprint identification, in particular to a fingerprint showing method based on nanosecond laser irradiation, which has a potential application prospect in the criminal investigation field.
Background
The fingerprint refers to the texture formed by convex and concave skins on the finger pulp at the tail end of a human finger, and has the characteristics of 'different human bodies, no change for life, and trace on touch objects'. Thanks to these characteristics, fingerprints have become an important means of biometric identification, known as the "king of evidence" in the judicial community. However, fingerprints at the scene of a case are usually latent fingerprints that are difficult to distinguish with the naked eye, making subsequent identification and authentication processes difficult. Therefore, scientifically and correctly showing the latent fingerprints on the surfaces of the objects has important practical significance for detecting the cases.
The powder developing method is a method widely used for developing latent fingerprints on the surfaces of objects. In chinese patent (2021112050209), mary et al prepared a magnetic powder for latent fingerprint visualization, and obtained a fingerprint image with a clearer outline. Although the traditional powder visualization method is mature in technology, the method also has the defects of complex process flow, low sensitivity, short retention time, environmental pollution, narrow application range and the like. Therefore, it is necessary to develop a new latent fingerprint appearance method to overcome the above disadvantages.
Based on the difference of sweat or grease in the fingerprint and the absorption of the laser energy by substances around the sweat or grease, a new method for showing the fingerprint based on nanosecond laser irradiation is provided, and the method is simple in operation flow, non-toxic, environment-friendly, economical, efficient and wide in application range. More importantly, the fingerprint displayed by the method has better wear resistance and is easy to store for a long time. Therefore, the method has excellent practical application value in the field of case investigation.
Disclosure of Invention
The invention aims to provide a fingerprint showing method based on nanosecond laser irradiation, which solves the problems of complex process flow, short storage time and the like of the existing potential fingerprint showing technology. The method can rapidly and efficiently clearly show the latent fingerprints on the surface of the sample by controlling the laser irradiation parameters by utilizing the difference of sweat or grease in the latent fingerprints and peripheral substances thereof in absorbing the laser energy, and has potential application prospect in the field of case detection.
The above purpose of the invention is realized by the following technical scheme:
a fingerprint showing method based on nanosecond laser irradiation is characterized in that: nanosecond laser irradiation is carried out on a sample with latent fingerprints on the surface in an atmospheric environment, and laser energy absorption is inconsistent by utilizing latent fingerprint lines and peripheral areas thereof, so that the latent fingerprints on the surface of the sample are clearly shown, and the method specifically comprises the following steps:
(1) Lightly pressing the surface of the sample by using a finger to obtain the sample with the surface having the latent fingerprint;
(2) The method comprises the following steps of placing a sample with latent fingerprints on the surface on a sample table, leading nanosecond laser through a light path and focusing the nanosecond laser on the surface of the sample through a focusing lens, setting laser irradiation parameters by a computer program to carry out nanosecond laser line irradiation, and clearly showing the latent fingerprints on the surface of the sample based on the difference between sweat or grease in the latent fingerprints and the absorption of peripheral substances of the sweat or grease on laser energy, wherein the laser irradiation parameters are as follows: the laser wavelength is 1064nm, the pulse width is 250ns, the repetition frequency is 50kHz, the average laser power is 38.7W, the scanning speed is 700mm/s, the spacing between adjacent laser scanning lines is 150 mu m, and the laser energy distribution is Gaussian distribution.
Further, the latent fingerprint in the step (1) is a sweat latent fingerprint or an oil latent fingerprint.
Further, the sample in the step (1) is metal, wood, ceramic or plastic.
Compared with the traditional fingerprint showing technology, the invention has the beneficial effects that:
1. the fingerprint can be clearly preserved on the surface of the sample for a long time;
2. the environment is friendly, and no toxic substance is generated in the implementation process;
3. the process flow is simple and quick, the cost is low, the application range is wide, the displayed fingerprints can be seen by naked eyes, and the method has great practical application value.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention and do not constitute a limitation of the invention.
FIG. 1 is a digital photograph of an original latent fingerprint according to example 1 of the present invention;
FIG. 2 is a digital photograph of an original latent fingerprint exposed by laser irradiation according to example 1 of the present invention;
fig. 3 is a digital photograph of a fingerprint after wiping after laser irradiation development according to example 1 of the present invention.
Detailed Description
The technical scheme of the invention is further explained by combining the drawings and the embodiment.
The implementation process and the beneficial effects of the nanosecond laser irradiation-based fingerprint showing method are illustrated by taking a high-purity zinc sheet as an example.
Example 1:
1. preparing a latent fingerprint sample: the tester lightly presses the surface of the high-purity zinc sheet with fingers to obtain latent fingerprints, and the latent fingerprints are photographed and recorded.
2. And (3) laser irradiation display: the method comprises the steps of placing a high-purity zinc sheet with latent fingerprints on the surface on a sample table, leading nanosecond laser through a light path, focusing the nanosecond laser on the surface of the high-purity zinc sheet through a focusing lens, setting laser irradiation parameters by a computer program to perform nanosecond laser multi-line irradiation (the laser wavelength is 1064nm, the pulse width is 250ns, the repetition frequency is 50kHz, the laser average power is 38.7W, the scanning speed is 700mm/s, the distance between adjacent laser scanning lines is 150 mu m, and the laser energy distribution is Gaussian distribution), and observing clear fingerprints by naked eyes under natural light. The developed fingerprint is placed on a horizontal object and then photographed and recorded by a digital camera.
Referring to fig. 1 and fig. 2, digital photographs of latent fingerprints on the surface of a high-purity zinc sheet before and after nanosecond laser irradiation in this embodiment are shown. The fingerprint outline after being displayed by laser irradiation is clear and visible, and the requirement of criminal investigation personnel on fingerprint display can be met. According to the characteristics, the fingerprint is judged to be of a thread type.
Figure 3 shows a digital photograph of a fingerprint after wiping after laser irradiation has been revealed. It was found that clear fingerprint streaks were observed after wiping.
The test result shows that the method provided by the invention can quickly and efficiently clearly show the latent fingerprints on the surface of the sample, and can still show clear fingerprint lines after simple wiping.
The above description is only a preferred example of the present invention and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made to the present invention shall fall within the protection scope of the present invention.
Claims (3)
1. A fingerprint showing method based on nanosecond laser irradiation is characterized in that: nanosecond laser irradiation is carried out on a sample with latent fingerprints on the surface in an atmospheric environment, and laser energy absorption is inconsistent by utilizing latent fingerprint lines and peripheral areas thereof, so that the latent fingerprints on the surface of the sample are clearly shown, and the method specifically comprises the following steps:
(1) Lightly pressing the surface of the sample by using a finger to obtain the sample with the surface having the latent fingerprint;
(2) The method comprises the following steps of placing a sample with latent fingerprints on the surface on a sample table, leading nanosecond laser through a light path and focusing the nanosecond laser on the surface of the sample through a focusing lens, setting laser irradiation parameters by a computer program to perform nanosecond laser multi-line irradiation, and clearly showing the latent fingerprints on the surface of the sample based on the difference between sweat or grease in the latent fingerprints and the absorption of peripheral substances of the sweat or grease on laser energy, wherein the laser irradiation parameters are as follows: the laser wavelength is 1064nm, the pulse width is 250ns, the repetition frequency is 50kHz, the laser average power is 38.7W, the scanning speed is 700mm/s, the spacing between adjacent laser scanning lines is 150 mu m, and the laser energy distribution is Gaussian distribution.
2. The method for showing fingerprints based on nanosecond laser irradiation, according to claim 1, wherein: the latent fingerprint in the step (1) is a sweat latent fingerprint or an oil latent fingerprint.
3. A fingerprint developing method based on nanosecond laser irradiation according to claim 1, characterized in that: the sample in the step (1) is metal, wood, ceramic, plastic, paint, glass and the like.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210498477.1A CN115251907B (en) | 2022-05-09 | 2022-05-09 | Fingerprint display method based on nanosecond laser irradiation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210498477.1A CN115251907B (en) | 2022-05-09 | 2022-05-09 | Fingerprint display method based on nanosecond laser irradiation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115251907A true CN115251907A (en) | 2022-11-01 |
| CN115251907B CN115251907B (en) | 2024-04-26 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210498477.1A Active CN115251907B (en) | 2022-05-09 | 2022-05-09 | Fingerprint display method based on nanosecond laser irradiation |
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Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU5158385A (en) * | 1984-12-27 | 1986-07-03 | Kawasaki Steel Corporation | A method for detecting fingerprints using a laser and an apparatus therefor |
| JP2000090241A (en) * | 1998-09-11 | 2000-03-31 | Sukara Kk | Method and device for detecting fingerprint |
| US6306662B1 (en) * | 1999-02-04 | 2001-10-23 | Texas Tech University | Fingerprint development methods |
| JP2002028152A (en) * | 2000-07-14 | 2002-01-29 | Toyobo Co Ltd | Latent fingerprint detecting method, and kit therefor |
| CN201707530U (en) * | 2010-05-20 | 2011-01-12 | 上海市公安局物证鉴定中心 | Ultraviolet laser imaging device |
| CN202104921U (en) * | 2011-04-18 | 2012-01-11 | 裴浩 | Trace-showing laser torch |
| CN103784149A (en) * | 2014-03-05 | 2014-05-14 | 北京科技大学 | Method for developing latent fingerprints through multi-metal deposition technology |
| CN104382600A (en) * | 2014-11-24 | 2015-03-04 | 中国刑事警察学院 | Two-step latent fingerprint manifesting method based on nano-particles |
| CN204495717U (en) * | 2015-03-19 | 2015-07-22 | 上海市刑事科学技术研究院 | The detection of the fluorescence emission wavelengths of biological vestige and visualization means thereof |
| CN206208764U (en) * | 2016-09-23 | 2017-05-31 | 杭州浙锐科技有限公司 | Lossless quick fingerprint manifestation device |
| CN108494984A (en) * | 2018-03-13 | 2018-09-04 | 四川大学 | It is a kind of to realize fingerprint extraction method using femtosecond laser |
| CN112979161A (en) * | 2021-03-10 | 2021-06-18 | 昆明理工大学 | Preparation method and application of tungsten phosphate glass based on photochromic effect |
| CN113582931A (en) * | 2021-07-13 | 2021-11-02 | 上海师范大学 | Fluorescent dye probe for latent fingerprint detection and preparation method and application thereof |
-
2022
- 2022-05-09 CN CN202210498477.1A patent/CN115251907B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU5158385A (en) * | 1984-12-27 | 1986-07-03 | Kawasaki Steel Corporation | A method for detecting fingerprints using a laser and an apparatus therefor |
| JP2000090241A (en) * | 1998-09-11 | 2000-03-31 | Sukara Kk | Method and device for detecting fingerprint |
| US6306662B1 (en) * | 1999-02-04 | 2001-10-23 | Texas Tech University | Fingerprint development methods |
| JP2002028152A (en) * | 2000-07-14 | 2002-01-29 | Toyobo Co Ltd | Latent fingerprint detecting method, and kit therefor |
| CN201707530U (en) * | 2010-05-20 | 2011-01-12 | 上海市公安局物证鉴定中心 | Ultraviolet laser imaging device |
| CN202104921U (en) * | 2011-04-18 | 2012-01-11 | 裴浩 | Trace-showing laser torch |
| CN103784149A (en) * | 2014-03-05 | 2014-05-14 | 北京科技大学 | Method for developing latent fingerprints through multi-metal deposition technology |
| CN104382600A (en) * | 2014-11-24 | 2015-03-04 | 中国刑事警察学院 | Two-step latent fingerprint manifesting method based on nano-particles |
| CN204495717U (en) * | 2015-03-19 | 2015-07-22 | 上海市刑事科学技术研究院 | The detection of the fluorescence emission wavelengths of biological vestige and visualization means thereof |
| CN206208764U (en) * | 2016-09-23 | 2017-05-31 | 杭州浙锐科技有限公司 | Lossless quick fingerprint manifestation device |
| CN108494984A (en) * | 2018-03-13 | 2018-09-04 | 四川大学 | It is a kind of to realize fingerprint extraction method using femtosecond laser |
| CN112979161A (en) * | 2021-03-10 | 2021-06-18 | 昆明理工大学 | Preparation method and application of tungsten phosphate glass based on photochromic effect |
| CN113582931A (en) * | 2021-07-13 | 2021-11-02 | 上海师范大学 | Fluorescent dye probe for latent fingerprint detection and preparation method and application thereof |
Non-Patent Citations (1)
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| CN115251907B (en) | 2024-04-26 |
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