CN115251907B - Fingerprint display method based on nanosecond laser irradiation - Google Patents
Fingerprint display method based on nanosecond laser irradiation Download PDFInfo
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- CN115251907B CN115251907B CN202210498477.1A CN202210498477A CN115251907B CN 115251907 B CN115251907 B CN 115251907B CN 202210498477 A CN202210498477 A CN 202210498477A CN 115251907 B CN115251907 B CN 115251907B
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- 238000000034 method Methods 0.000 title claims abstract description 29
- 238000010521 absorption reaction Methods 0.000 claims abstract description 7
- 230000002093 peripheral effect Effects 0.000 claims abstract description 7
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 6
- 210000004243 sweat Anatomy 0.000 claims description 6
- 229910052725 zinc Inorganic materials 0.000 claims description 6
- 239000011701 zinc Substances 0.000 claims description 6
- 239000004519 grease Substances 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- 238000004590 computer program Methods 0.000 claims description 3
- 238000011835 investigation Methods 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 231100000956 nontoxicity Toxicity 0.000 abstract description 2
- 230000007774 longterm Effects 0.000 abstract 1
- 230000009286 beneficial effect Effects 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
- 210000001015 abdomen Anatomy 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000011840 criminal investigation Methods 0.000 description 1
- 230000007547 defect Effects 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
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- 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
Landscapes
- 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 display method based on nanosecond laser irradiation, and belongs to the technical field of fingerprint identification. According to the method, the latent fingerprints on the surface of the material are clearly displayed by utilizing inconsistent absorption of laser energy by the latent fingerprint lines and the peripheral area of the latent fingerprint lines and performing nanosecond laser irradiation in an atmospheric environment. Compared with the existing fingerprint display technology, the fingerprint display method has the advantages of simplicity in operation, no toxicity, environmental protection, economy, high efficiency, wide application range, easiness in 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 display method based on nanosecond laser irradiation, which has potential application prospect in the field of case investigation.
Background
The fingerprint refers to the texture of the human finger, which is composed of the convex and concave skins on the finger abdomen, and has the characteristics of 'different people, unchanged life and trace on touching objects'. Thanks to these characteristics, fingerprints have become an important means of biometric identification, known as the "king of evidence" of the judicial community. However, the fingerprints at the scene of the incident are often latent fingerprints that are difficult to distinguish by the naked eye, making the subsequent identification and authentication process difficult. Therefore, scientific and correct visualization of latent fingerprints on the object surface is of great practical significance for detecting cases.
The powder developing method is a method widely used for developing latent fingerprints on the surface of objects. In chinese patent (2021112050209), marie et al prepared a magnetic powder for latent fingerprint development to obtain a fingerprint image with a clearer profile. Although the traditional powder developing method has mature technology, the defects of complex process flow, low sensitivity, short retention time, environmental pollution, narrow application range and the like exist. Therefore, there is a need to develop a new method for developing latent fingerprints to remedy the above-mentioned shortcomings.
Based on the difference of absorption of sweat or grease in the fingerprint and peripheral substances thereof to laser energy, a novel fingerprint display method based on nanosecond laser irradiation is provided, and the method has the advantages of simple operation flow, no toxicity, environmental protection, economy, high efficiency and wide application range. More importantly, the fingerprint developed 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 case investigation field.
Disclosure of Invention
The invention aims to provide a fingerprint display method based on nanosecond laser irradiation, which solves the problems of complex process flow, short preservation time and the like in the existing potential fingerprint display technology. The invention utilizes the difference of sweat or grease in the latent fingerprints and the absorption of peripheral substances thereof to laser energy, can quickly and efficiently clearly show the latent fingerprints on the surface of the sample by controlling laser irradiation parameters, and has potential application prospect in the field of case investigation.
The above object of the present invention is achieved by the following technical solutions:
A fingerprint display method based on nanosecond laser irradiation is characterized by comprising the following steps: nanosecond laser irradiation is carried out on a sample with the latent fingerprints on the surface in the atmospheric environment, the latent fingerprints on the surface of the sample are clearly displayed by utilizing inconsistent absorption of the latent fingerprints and the peripheral area of the latent fingerprints, and the specific steps comprise:
(1) Lightly pressing the surface of the sample with a finger to obtain a sample with a latent fingerprint on the surface;
(2) Placing a sample with a latent fingerprint on the surface on a sample table, focusing nanosecond laser on the surface of the sample through a focusing lens after being guided by a light path, setting laser irradiation parameters by a computer program to irradiate nanosecond laser rays, and enabling the latent fingerprint on the surface of the sample to clearly appear based on the difference of absorption of sweat or grease in the latent fingerprint and peripheral substances thereof to 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 power of the laser 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.
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 display technology, the invention has the beneficial effects that:
1. The developed fingerprint can be stored on the surface of the sample for a long time and clearly;
2. the environment is friendly, and toxic substances are not generated in the implementation process;
3. The process flow is simple and quick, the cost is low, the application range is wide, the developed fingerprints are visible to naked eyes, and the method has great practical application value.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate and explain the application and together with the description serve to explain the application.
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 according to example 1 of the present invention after laser irradiation;
Fig. 3 is a digital photograph of a fingerprint after wiping after the fingerprint is developed by laser irradiation according to example 1 of the present invention.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings and examples.
The implementation process and the beneficial effects of the fingerprint display method based on nanosecond laser irradiation provided by the invention are illustrated by taking a high-purity zinc sheet as an example.
Example 1:
1. preparing a latent fingerprint: the tester gently presses the surface of the high purity zinc sheet with a finger to obtain a latent fingerprint, and photographs are recorded.
2. And (3) laser irradiation and appearance: the high-purity zinc sheet with the latent fingerprints on the surface is placed on a sample stage, nanosecond laser is guided by a light path and focused on the surface of the high-purity zinc sheet by a focusing lens, laser irradiation parameters are set 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), so that clear fingerprints can be observed by naked eyes under natural light. The developed fingerprint is placed on a horizontal object, and then recorded by photographing with a digital camera.
Referring to fig. 1 and 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. It can be found that the fingerprint outline after 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 belong to the thread type.
Figure 3 shows a digital photograph of the fingerprint after wiping after laser irradiation has been developed. It was found that a clearly running fingerprint ridge was still 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 clear fingerprint lines can be still shown after simple wiping.
The above description is only a preferred example of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. A fingerprint display method based on nanosecond laser irradiation is characterized by comprising the following steps: the method comprises the steps of carrying out nanosecond laser irradiation on a sample with a latent fingerprint on the surface in an atmospheric environment, utilizing the inconformity of the absorption of laser energy by the latent fingerprint lines and the peripheral area thereof, so that the latent fingerprint on the surface of the sample can be clearly displayed, and the clear fingerprint lines can be still displayed after simple wiping, and the method comprises the following specific steps:
(1) Lightly pressing the surface of the high-purity zinc sheet sample with a finger to obtain a sample with a latent fingerprint on the surface;
(2) Placing a sample with a latent fingerprint on the surface on a sample table, focusing nanosecond laser on the surface of the sample through a focusing lens after being guided by a light path, setting laser irradiation parameters by a computer program to perform nanosecond laser multi-line irradiation, enabling the latent fingerprint on the surface of the sample to clearly show based on the difference of absorption of sweat or grease in the latent fingerprint and peripheral substances thereof to laser energy, and observing clear fingerprints with naked eyes under natural light, 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 power of the laser 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.
2. A fingerprint developing method based on nanosecond laser irradiation as claimed in claim 1, wherein: the latent fingerprints in the step (1) are sweat latent fingerprints or oil latent fingerprints.
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 CN115251907A (en) | 2022-11-01 |
| CN115251907B true CN115251907B (en) | 2024-04-26 |
Family
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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
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|---|---|---|---|---|
| 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 |
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| 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 |
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| Publication number | Publication date |
|---|---|
| CN115251907A (en) | 2022-11-01 |
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