CN109977857A - It is a kind of to improve the filming control method for referring to hand vein recognition picture quality - Google Patents
It is a kind of to improve the filming control method for referring to hand vein recognition picture quality Download PDFInfo
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- CN109977857A CN109977857A CN201910228254.1A CN201910228254A CN109977857A CN 109977857 A CN109977857 A CN 109977857A CN 201910228254 A CN201910228254 A CN 201910228254A CN 109977857 A CN109977857 A CN 109977857A
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- 210000003462 vein Anatomy 0.000 title claims abstract description 84
- 238000000034 method Methods 0.000 title claims abstract description 24
- 238000012805 post-processing Methods 0.000 claims abstract description 8
- 230000035945 sensitivity Effects 0.000 claims description 9
- 230000000694 effects Effects 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 230000001737 promoting effect Effects 0.000 abstract description 3
- 238000007796 conventional method Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/74—Circuitry for compensating brightness variation in the scene by influencing the scene brightness using illuminating means
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/80—Camera processing pipelines; Components thereof
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/14—Vascular patterns
Abstract
The invention discloses the filming control methods that a kind of raising refers to hand vein recognition picture quality, and using Infrared irradiation finger, the other side is obtained by cameras with fixed focus refers to vein picture for the first time, and the contrast value C1 for referring to vein picture for the first time is calculated using picture element brightness value；Increase certain infrared luminous intensity, the secondary acquisition of cameras with fixed focus is referred to vein picture, calculated the contrast value C2 for referring to vein picture again using picture element brightness value；Contrast value C2 and contrast value C1 compare, and C2 > C1 then increases infrared luminous intensity again, otherwise reduce infrared luminous intensity；By 3 times or more adjustings, the highest finger vein picture of contrast value is obtained；The decision content for setting contrast value, judges whether image quality meets the requirements.The present invention is not under the premise of changing hardware and shooting environmental, only change exposal control method, reaches the contrast for promoting vein picture, obtain the effect of more vein detailed information, and then the successful probability of vein image post-processing is increased, improve the precision of identification.
Description
Technical field
The present invention relates to image recognitions, in particular to a kind of to improve the filming control method for referring to hand vein recognition picture quality.
Background technique
In recent years due to leakage of personal information caused by loss in the trend rapidly magnified, the biology of more high safety grade
Identification technology using in the ascendant.
As the country refers to the rise of vein identification technology, various finger hand vein recognition module and terminal are used widely.So
And refer in vein identification technology, the superiority and inferiority of captured finger vein image quality, directly influence the height of accuracy of identification.
Due to referring to the particularity (light source is black light, and reference object is scatterer) of the image of hand vein recognition, by passing
The image that the screening-mode of system obtains, contrast is relatively low, causes lower picture quality, and then influence accuracy of identification.
In traditional filming control method, the conventional method that camera terminal obtains finger venous image is as follows:
1) the Infrared irradiation finger of fixed light intensity；
2) there is the place for referring to vein to absorb and be irradiated the infrared light of coming, the place of aphalangia vein penetrates infrared light, formed red
Outer smooth vein image；
3) infrared light filter filters off visible light；
4) common focusing video camera foundation exposure formula " EV (target light exposure value)=BV+SV=AV+TV " adjusts therein
TV and SV carries out EV target light exposure；
5) the vein image of object brightness is obtained；
6) enter post processing of image program.
APEX SYSTEM camera shooting exposure formula: Ev=Bv+Sv=Tv+Av, in which:
Sv=log2 (ISO × N), ISO=CMOS SENSOR sensitivity (Sensitivity Value),
Bv=log2 (B/ (NK)), B=are write body brightness value (Brightness Value),
Av=log2 (F^2), F=lens aperture value (Aperture Value),
Tv=log2 (1/T), T=shutter speed (Time Value),
N is the coefficient of setting, and K is the coefficient of setting.
Vein detection equipment for the needs for reducing cost and miniaturization, it is general using it is common focus, iris setting, 1M
Pixel camera below (such as the OV9740 camera of included ISP), the CMOS SENSOR stock size of this kind of camera is all very
It is small, between 1/6~1/9 inch.
Vein picture obtains, and often when thicker finger (such as reference object be) carries out under low light environment.At this moment it utilizes
This kind of camera, which is taken pictures, to be had the following problems:
1) when sensitivity value is set as higher (low light environment), while signal amplifies, noise is also amplified, signal-to-noise ratio
(S/N) it is deteriorated；
2) when the time for exposure is set as longer, finger effect of jitter increases, while noise also increases, signal-to-noise ratio (S/N)
It is deteriorated therewith；
This bad image quality increases the difficulty of vein image post-processing vein and background separation, as vein pattern mentions
It takes, increases the chance of processing failure.
Summary of the invention
Object of the present invention is to: a kind of improve is provided and refers to the filming control method of hand vein recognition picture quality, it is hard not changing
Under the premise of part and shooting environmental, only change exposal control method, reaches the contrast for promoting vein picture, obtain more veins
The effect of detailed information, and then the successful probability of vein image post-processing is increased, improve the precision of identification.
The technical scheme is that
It is a kind of to improve the filming control method for referring to hand vein recognition picture quality, comprising steps of
S1, using Infrared irradiation finger, the other side obtains finger vein picture for the first time by cameras with fixed focus, and is transmitted to meter
Calculation machine；
S2, computer calculate the contrast value C1 for referring to vein picture for the first time using picture element brightness value；
S3, increase certain infrared luminous intensity；
The secondary acquisition of S4, cameras with fixed focus refers to vein picture, and is transmitted to computer；
S5, computer calculate the contrast value C2 for referring to vein picture using picture element brightness value again；
S6, contrast value C2 and contrast value C1 compare, and C2 > C1 then increases infrared luminous intensity again, otherwise reduce infrared light
Intensity；
S7,3 times or more the adjustings by step S4-S6 obtain the highest finger vein picture of contrast value；
S8, the decision content for setting contrast value, judge whether image quality meets the requirements.
Preferably, the computer calculates the method for referring to vein picture contrast value using picture element brightness value are as follows:
1) it cuts and refers to vein center picture picture element；
2) contrast is calculated using statistics mean square deviation formula:
Wherein C is contrast value, and Xi is each picture element brightness value, XMFor total picture element average brightness value, N is total picture element number.
Preferably, the Infrared irradiation finger has the place for referring to vein to absorb and is irradiated the infrared light of coming, aphalangia vein
Place penetrate infrared light.
Preferably, the infrared light filter that the place of the aphalangia vein penetrates, which filters off, removes visible light.
Preferably, the cameras with fixed focus obtains refer in vein picture every time, fixed shutter speed value Tv, sensitivity value
Sv, f-number Av exposure.
Preferably, the finger vein picture that decision content requirement is met to image quality, into post processing of image program.
The invention has the advantages that
Raising of the invention refers to the filming control method of hand vein recognition picture quality, is not changing hardware and shooting environmental
Under the premise of, only change exposal control method, reaches the contrast for promoting vein picture, obtain the effect of more vein detailed information
Fruit, and then the successful probability of vein image post-processing is increased, improve the precision of identification.
Detailed description of the invention
The invention will be further described with reference to the accompanying drawings and embodiments:
Fig. 1 is the schematic diagram of device for the filming control method that raising of the invention refers to hand vein recognition picture quality；
Fig. 2 is light intensity and picture contrast corresponding relationship curve；
Fig. 3 is the finger vein picture of the thin finger obtained in conventional method；
Fig. 4 is the finger vein picture of the thick finger obtained in conventional method；
Fig. 5 is the finger vein picture of the thin finger obtained in the present invention；
Fig. 6 is the finger vein picture of the thick finger obtained in the present invention.
Specific embodiment
The cameras with fixed focus obtains every time to be referred in vein picture,
As shown in Figure 1, raising of the invention refers to the filming control method of hand vein recognition picture quality, comprising steps of
S1, using Infrared irradiation finger, set infrared light intensity for the first time；
S2, the place for referring to vein absorbs irradiated next infrared light, the place of aphalangia vein penetrates infrared light, formed red
Outer smooth vein image
S3, infrared light filter filter off visible light；
S4, the fixed shutter speed value Tv of cameras with fixed focus of the other side, sensitivity value Sv, f-number Av exposure.
S5, cameras with fixed focus obtain refers to vein picture for the first time, and is transmitted to computer；
S6, computer calculate the contrast value C1 for referring to vein picture for the first time using picture element brightness value；
S7, increase certain infrared luminous intensity；
S8, cameras with fixed focus are exposed according to the fixed shutter speed value Tv of condition, sensitivity value Sv, the f-number Av of step S4
Light；
The secondary acquisition of S9, cameras with fixed focus refers to vein picture, and is transmitted to computer；
S10, computer calculate the contrast value C2 for referring to vein picture using picture element brightness value again；
S11, contrast value C2 and contrast value C1 compare, and C2 > C1 then increases infrared luminous intensity again, otherwise reduce infrared
Luminous intensity, light intensity and picture contrast corresponding relationship are as shown in Figure 2；
S12,3 times or more the adjustings by step S4-S6 obtain the highest finger vein picture of contrast value；
S13, the decision content for setting contrast value, judge whether image quality meets the requirements；
S14, the finger vein picture for meeting decision content requirement to image quality, into post processing of image program.
The computer calculates the method for referring to vein picture contrast value using picture element brightness value are as follows:
1) it cuts and refers to vein center picture picture element；
2) contrast is calculated using statistics mean square deviation formula:
Wherein C is contrast value, and Xi is each picture element brightness value, XMFor total picture element average brightness value, N is total picture element number.
In specific implementation, by comparing the contrast for the image that new and old two kinds of filming control methods obtain.
Fig. 3 is fixed light intensity, the automatic AE of camera, the finger vein picture of the thin finger of acquisition；
Fig. 5 is that sensitivity/shutter/aperture is fixed in the present invention, adjusts brightness, and edge exposure side calculates picture contrast, obtains
The finger vein picture of thin finger and Fig. 3 compare when the contrast maximum obtained, are on close level.
Fig. 4 is fixed light intensity, the automatic AE of camera, the finger vein picture of the thick finger of acquisition；
Fig. 6 is that sensitivity/shutter/aperture is fixed in the present invention, adjusts brightness, and edge exposure side calculates picture contrast, obtains
The finger vein picture of thickness finger and Fig. 4 compare when the contrast maximum obtained, hence it is evident that improve.
The above embodiments merely illustrate the technical concept and features of the present invention, and its object is to allow person skilled in the art
It cans understand the content of the present invention and implement it accordingly, it is not intended to limit the scope of the present invention.It is all to lead according to the present invention
The modification for wanting the Spirit Essence of technical solution to be done, should be covered by the protection scope of the present invention.
Claims (6)
1. a kind of improve the filming control method for referring to hand vein recognition picture quality, which is characterized in that comprising steps of
S1, using Infrared irradiation finger, the other side obtains finger vein picture for the first time by cameras with fixed focus, and is transmitted to calculating
Machine；
S2, computer calculate the contrast value C1 for referring to vein picture for the first time using picture element brightness value；
S3, increase certain infrared luminous intensity；
The secondary acquisition of S4, cameras with fixed focus refers to vein picture, and is transmitted to computer；
S5, computer calculate the contrast value C2 for referring to vein picture using picture element brightness value again；
S6, contrast value C2 and contrast value C1 compare, and C2 > C1 then increases infrared luminous intensity again, otherwise reduce infrared light intensity
Degree；
S7,3 times or more the adjustings by step S4-S6 obtain the highest finger vein picture of contrast value；
S8, the decision content for setting contrast value, judge whether image quality meets the requirements.
2. raising shown according to claim 1 refers to the filming control method of hand vein recognition picture quality, which is characterized in that described
Computer calculates the method for referring to vein picture contrast value using picture element brightness value are as follows:
1) it cuts and refers to vein center picture picture element；
2) contrast is calculated using statistics mean square deviation formula:
Wherein C is contrast value, and Xi is each picture element brightness value, XMFor total picture element average brightness value, N is total picture element number.
3. raising shown according to claim 1 refers to the filming control method of hand vein recognition picture quality, which is characterized in that described
Infrared irradiation finger has the place for referring to vein to absorb and is irradiated the infrared light of coming, and the place of aphalangia vein penetrates infrared light.
4. the raising according to shown in claim 3 refers to the filming control method of hand vein recognition picture quality, which is characterized in that described
The infrared light filter that the place of aphalangia vein penetrates, which filters off, removes visible light.
5. the raising according to shown in claim 4 refers to the filming control method of hand vein recognition picture quality, which is characterized in that described
Cameras with fixed focus obtains every time to be referred in vein picture, fixed shutter speed value Tv, sensitivity value Sv, f-number Av exposure.
6. the raising according to shown in claim 5 refers to the filming control method of hand vein recognition picture quality, which is characterized in that picture
Matter meets the finger vein picture of decision content requirement, into post processing of image program.
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| CN201910228254.1A CN109977857A (en) | 2019-03-25 | 2019-03-25 | It is a kind of to improve the filming control method for referring to hand vein recognition picture quality |
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| CN201910228254.1A CN109977857A (en) | 2019-03-25 | 2019-03-25 | It is a kind of to improve the filming control method for referring to hand vein recognition picture quality |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021077393A1 (en) * | 2019-10-25 | 2021-04-29 | 深圳市汇顶科技股份有限公司 | Below-screen fingerprint acquisition method and apparatus, electronic device, and storage medium |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103886282A (en) * | 2014-02-26 | 2014-06-25 | 中国船舶重工集团公司第七一〇研究所 | Finger vein image acquisition method |
| CN103984925A (en) * | 2014-05-08 | 2014-08-13 | 山东大学 | Light source and light intensity automatic control method of finger vein recognition device |
| CN104766073A (en) * | 2015-04-28 | 2015-07-08 | 天津理工大学 | Self-adaptive hand back vein image collecting system |
| CN106372611A (en) * | 2016-09-09 | 2017-02-01 | 康佳集团股份有限公司 | Identity identification method and system based on palm vein features, and image acquisition apparatus |
-
2019
- 2019-03-25 CN CN201910228254.1A patent/CN109977857A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103886282A (en) * | 2014-02-26 | 2014-06-25 | 中国船舶重工集团公司第七一〇研究所 | Finger vein image acquisition method |
| CN103984925A (en) * | 2014-05-08 | 2014-08-13 | 山东大学 | Light source and light intensity automatic control method of finger vein recognition device |
| CN104766073A (en) * | 2015-04-28 | 2015-07-08 | 天津理工大学 | Self-adaptive hand back vein image collecting system |
| CN106372611A (en) * | 2016-09-09 | 2017-02-01 | 康佳集团股份有限公司 | Identity identification method and system based on palm vein features, and image acquisition apparatus |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021077393A1 (en) * | 2019-10-25 | 2021-04-29 | 深圳市汇顶科技股份有限公司 | Below-screen fingerprint acquisition method and apparatus, electronic device, and storage medium |
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Application publication date: 20190705 |
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