CN108805127A - Licence plate recognition method, system and car license recognition equipment - Google Patents
Licence plate recognition method, system and car license recognition equipment Download PDFInfo
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- CN108805127A CN108805127A CN201710304745.0A CN201710304745A CN108805127A CN 108805127 A CN108805127 A CN 108805127A CN 201710304745 A CN201710304745 A CN 201710304745A CN 108805127 A CN108805127 A CN 108805127A
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- 238000000034 method Methods 0.000 title claims abstract description 21
- 238000005286 illumination Methods 0.000 abstract description 14
- 230000000694 effects Effects 0.000 abstract description 10
- 238000005516 engineering process Methods 0.000 description 5
- 230000011218 segmentation Effects 0.000 description 3
- 239000000284 extract Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/26—Segmentation of patterns in the image field; Cutting or merging of image elements to establish the pattern region, e.g. clustering-based techniques; Detection of occlusion
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/28—Quantising the image, e.g. histogram thresholding for discrimination between background and foreground patterns
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V20/00—Scenes; Scene-specific elements
- G06V20/60—Type of objects
- G06V20/62—Text, e.g. of license plates, overlay texts or captions on TV images
- G06V20/625—License plates
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
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- Theoretical Computer Science (AREA)
- Traffic Control Systems (AREA)
Abstract
The invention discloses a kind of licence plate recognition method, system and car license recognition equipments, including：Obtain license plate image；Binaryzation is carried out with OTSU threshold values to the license plate image, obtains the outer boundary figure of the binaryzation；Judge whether the outer boundary figure meets predetermined relationship, if it is not, then by the outer boundary figure again binaryzation.The licence plate recognition method of the present invention can carry out binaryzation by the license plate image to getting using OTSU threshold values, it obtains outer boundary image and determines whether that car plate matches, the problem for causing Car license recognition mistake because of uneven illumination is not only effectively avoided, but also recognition effect is good, calculating speed is fast.
Description
Technical field
The present invention relates to field of license plate recognition, more particularly to a kind of licence plate recognition method, system and Car license recognition are set
It is standby.
Background technology
Vehicle License Plate Recognition System be the vehicle being able to detect that on monitored road surface and the license plate information that automatically extracts vehicle into
The corresponding treatment technology of row, this technology are managed in vehicle on highway in system, E-payment system, managing system of car parking
It is obtained for and is widely applied.Algorithm in Vehicle License Plate Recognition System is mainly License Plate Segmentation and Recognition of License Plate Characters, wherein vehicle
Board segmentation is used for positioning licence plate.However, in the license plate image that shooting obtains, shooting environmental leads to be radiated at the illumination of licence plate not
Uniformly, it is complete image to cause license plate image not, and causes the problem of Car license recognition mistake.
In the related technology, in Recognition Algorithm of License Plate generally asking for uneven illumination is solved using local binarization algorithm
Topic, but this algorithm speed is slow and effect is poor.
Invention content
The present invention is directed to solve at least to a certain extent it is above-mentioned in the related technology the technical issues of one of.
For this purpose, an object of the present invention is to provide a kind of licence plate recognition methods.The licence plate recognition method is effectively kept away
The problem for having exempted to cause Car license recognition mistake because of uneven illumination, and recognition effect is good, calculating speed is fast.
It is another object of the present invention to propose a kind of Vehicle License Plate Recognition System.
Another object of the present invention is to propose a kind of car license recognition equipment.
To achieve the goals above, an aspect of of the present present invention discloses a kind of licence plate recognition method, including：Obtain car plate figure
Picture；Binaryzation is carried out with OTSU threshold values to the license plate image, obtains the outer boundary figure of the binaryzation；Judge the outside
Whether boundary's figure meets predetermined relationship, if it is not, then by the outer boundary figure again binaryzation.
Licence plate recognition method according to the present invention can carry out two by the license plate image to getting using OTSU threshold values
Value obtains outer boundary image and determines whether that car plate matches, not only effectively avoids and cause car plate because of uneven illumination
Identify the problem of mistake, and recognition effect is good, calculating speed is fast.
In addition, licence plate recognition method according to the above embodiment of the present invention can also have following additional technical characteristic：
Further, further include：If meeting predetermined relationship, the outer boundary figure is exported.
Further, the predetermined relationship refers to that the left and right length of the outer boundary figure is less than wide 2/3 of car plate.
Another aspect of the present invention discloses a kind of Vehicle License Plate Recognition System, including：Acquisition module, for obtaining car plate figure
Picture；Processing module obtains the outer boundary figure of the binaryzation for carrying out binaryzation with OTSU threshold values to the license plate image
Shape；Judgment module, for judging whether the outer boundary figure meets predetermined relationship, if it is not, then by the outer boundary figure
Again binaryzation.
Vehicle License Plate Recognition System according to the present invention can carry out two by the license plate image to getting using OTSU threshold values
Value obtains outer boundary image and determines whether that car plate matches, not only effectively avoids and cause car plate because of uneven illumination
Identify the problem of mistake, and recognition effect is good, calculating speed is fast.
In addition, Vehicle License Plate Recognition System according to the above embodiment of the present invention can also have following additional technical characteristic：
Further, the judgment module is additionally operable to：If meeting predetermined relationship, the outer boundary figure is exported.
Further, the predetermined relationship refers to that the left and right length of the outer boundary figure is less than wide 2/3 of car plate.
The third aspect of the present invention discloses a kind of car license recognition equipment, including according to described in any one above-mentioned embodiment
Vehicle License Plate Recognition System.The car license recognition equipment can be used by the license plate image in Recognition Algorithm of License Plate, got
OTSU threshold values carry out binaryzation, obtain outer boundary image and determine whether that car plate matches, effectively avoid because of uneven illumination
And cause the problem of its mistake, and recognition effect is good, calculating speed is fast.
The additional aspect and advantage of the present invention will be set forth in part in the description, and will partly become from the following description
Obviously, or practice through the invention is recognized.
Description of the drawings
The above-mentioned and/or additional aspect and advantage of the present invention will become in the description from combination following accompanying drawings to embodiment
Obviously and it is readily appreciated that, wherein：
Fig. 1 is the flow chart of licence plate recognition method according to an embodiment of the invention；And
Fig. 2 is the structure chart of Vehicle License Plate Recognition System in accordance with another embodiment of the present invention.
Specific implementation mode
The embodiment of the present invention is described below in detail, examples of the embodiments are shown in the accompanying drawings, wherein from beginning to end
Same or similar label indicates same or similar element or element with the same or similar functions.Below with reference to attached
The embodiment of figure description is exemplary, and is only used for explaining the present invention, and is not considered as limiting the invention.
Licence plate recognition method, system and car license recognition equipment according to the ... of the embodiment of the present invention are described below in conjunction with attached drawing.
Fig. 1 is the flow chart of licence plate recognition method according to an embodiment of the invention.
As shown in Figure 1, licence plate recognition method according to an embodiment of the invention, including：
S110：Obtain license plate image.
Specifically, license plate image information is shot using photographic device, and then obtains license plate image, when using photographic device
Other environment around vehicle license plate and vehicle license plate may be taken on same photo when being shot, i.e., it is acquired
License plate image may include vehicle license plate and ambient background.
S120：Binaryzation is carried out with OTSU threshold values to license plate image, obtains the outer boundary figure of binaryzation.
Wherein, outer boundary figure is rectangle, i.e., after license plate image being carried out binaryzation, extraction is the outer boundary square of car plate
Shape picture frame.
Specifically, after obtaining license plate image, in the segmentation module in Recognition Algorithm of License Plate, license plate image will be used
OTSU threshold values carry out binaryzation, with this come eliminate due to uneven illumination when shooting and the phenomenon that cause to identify car plate,
After carrying out binaryzation, the outer boundary figure of car plate is obtained.
S130：Judge whether the outer boundary figure meets predetermined relationship, if it is not, then again by the outer boundary figure
Binaryzation.
Wherein, predetermined relationship refers to that the left and right length of outer boundary figure is less than wide 2/3 of vehicle license plate.Outer boundary figure
It can be rectangle.
Specifically, judge that carrying out the outer boundary image that binaryzation extracts using OTSU threshold values from license plate image is less than vehicle
Wide 2/3 of board, if cannot, binaryzation is re-started, avoids causing to identify mistake because of uneven illumination.
In some embodiments, licence plate recognition method further includes：If meeting predetermined relationship, the outside of vehicle license plate is exported
Boundary's figure, to realize the positioning of vehicle license plate in the case of uneven illumination.
Licence plate recognition method according to the present invention can carry out two by the license plate image to getting using OTSU threshold values
Value obtains outer boundary image and determines whether that car plate matches, not only effectively avoids and cause car plate because of uneven illumination
Identify the problem of mistake, and recognition effect is good, calculating speed is fast.
Fig. 2 is the structure chart of Vehicle License Plate Recognition System according to an embodiment of the invention.
As shown in Fig. 2, Vehicle License Plate Recognition System 200 according to an embodiment of the invention, including：Acquisition module 210, processing
Module 220 and judgment module 230.
Wherein, for acquisition module 210 for obtaining license plate image, car plate figure includes vehicle license plate and ambient background.Processing
Module 220 obtains the outer boundary figure of binaryzation for carrying out binaryzation with OTSU threshold values to license plate image.Judgment module 230
For judging whether outer boundary figure meets predetermined relationship, if it is not, then by outer boundary figure again binaryzation.
Vehicle License Plate Recognition System according to the present invention can carry out two by the license plate image to getting using OTSU threshold values
Value obtains outer boundary image and determines whether that car plate matches, not only effectively avoids and cause car plate because of uneven illumination
Identify the problem of mistake, and recognition effect is good, calculating speed is fast.
In some embodiments, judgment module 230 is additionally operable to：If meeting predetermined relationship, the outer boundary figure is exported,
Vehicle license plate is detached with ambient background in the case of uneven illumination with realizing.Further, predetermined relationship refers to outer boundary
The left and right length of figure is less than wide 2/3 of car plate.Wherein, outer boundary figure is rectangle.
It should be noted that the specific implementation and the embodiment of the present invention of the Vehicle License Plate Recognition System of the embodiment of the present invention
The specific implementation of licence plate recognition method is similar, specifically refers to the description of licence plate recognition method part, in order to reduce redundancy,
It is not repeated herein.
Further, embodiment of the invention discloses that a kind of car license recognition equipment, the car license recognition equipment are provided with
State the Vehicle License Plate Recognition System described in any one embodiment.The car license recognition equipment can be by Recognition Algorithm of License Plate, obtaining
The license plate image got carries out binaryzation using OTSU threshold values, obtains outer boundary image and determines whether that car plate matches, effectively
Avoid the problem for causing its mistake because of uneven illumination, and recognition effect is good, calculating speed is fast.
In addition, other compositions of car license recognition equipment according to the ... of the embodiment of the present invention and effect are for the common of this field
All it is known for technical staff, in order to reduce redundancy, does not repeat.
In addition, term " first ", " second " are used for description purposes only, it is not understood to indicate or imply relative importance
Or implicitly indicate the quantity of indicated technical characteristic.Define " first " as a result, the feature of " second " can be expressed or
Implicitly include at least one this feature.In the description of the present invention, the meaning of " plurality " is at least two, such as two, three
It is a etc., unless otherwise specifically defined.
In the present invention unless specifically defined or limited otherwise, term " installation ", " connected ", " connection ", " fixation " etc.
Term shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integral；Can be that machinery connects
It connects, can also be electrical connection；It can be directly connected, can also can be indirectly connected through an intermediary in two elements
The interaction relationship of the connection in portion or two elements, unless otherwise restricted clearly.For those of ordinary skill in the art
For, the specific meanings of the above terms in the present invention can be understood according to specific conditions.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is included at least one embodiment or example of the invention.In the present specification, schematic expression of the above terms are not
It must be directed to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be in office
It can be combined in any suitable manner in one or more embodiments or example.In addition, without conflicting with each other, the skill of this field
Art personnel can tie the feature of different embodiments or examples described in this specification and different embodiments or examples
It closes and combines.
Although the embodiments of the present invention has been shown and described above, it is to be understood that above-described embodiment is example
Property, it is not considered as limiting the invention, those skilled in the art within the scope of the invention can be to above-mentioned
Embodiment is changed, changes, replacing and modification.
Claims (7)
1. a kind of licence plate recognition method, which is characterized in that including：
Obtain license plate image；
Binaryzation is carried out with OTSU threshold values to the license plate image, obtains the outer boundary figure of the binaryzation；
Judge whether the outer boundary figure meets predetermined relationship, if it is not, then by the outer boundary figure again binaryzation.
2. licence plate recognition method according to claim 1, which is characterized in that further include：
If meeting predetermined relationship, the outer boundary figure is exported.
3. licence plate recognition method according to claim 1 or 2, which is characterized in that the predetermined relationship refers to the outside
The left and right length of boundary's figure is less than wide 2/3 of car plate.
4. a kind of Vehicle License Plate Recognition System, which is characterized in that including：
Acquisition module, for obtaining license plate image；
Processing module obtains the outer boundary figure of the binaryzation for carrying out binaryzation with OTSU threshold values to the license plate image
Shape；
Judgment module, for judging whether the outer boundary figure meets predetermined relationship, if it is not, then by the outer boundary figure
Again binaryzation.
5. Vehicle License Plate Recognition System according to claim 4, which is characterized in that the judgment module is additionally operable to：If meeting pre-
Determine relationship, then exports the outer boundary figure.
6. Vehicle License Plate Recognition System according to claim 4 or 5, which is characterized in that the predetermined relationship refers to the outside
The left and right length of boundary's figure is less than wide 2/3 of car plate.
7. a kind of car license recognition equipment, which is characterized in that including：According to claim 4-6 any one of them Car license recognitions system
System.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710304745.0A CN108805127A (en) | 2017-05-03 | 2017-05-03 | Licence plate recognition method, system and car license recognition equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710304745.0A CN108805127A (en) | 2017-05-03 | 2017-05-03 | Licence plate recognition method, system and car license recognition equipment |
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| Publication Number | Publication Date |
|---|---|
| CN108805127A true CN108805127A (en) | 2018-11-13 |
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ID=64054466
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710304745.0A Pending CN108805127A (en) | 2017-05-03 | 2017-05-03 | Licence plate recognition method, system and car license recognition equipment |
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| Country | Link |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1920849A (en) * | 2005-08-26 | 2007-02-28 | 电子科技大学 | Vehicle license plate extraction method based on high-hat switch and wavelet switch |
| TW201528159A (en) * | 2014-01-03 | 2015-07-16 | Nat Univ Chin Yi Technology | License plate recognition system and method of smart phone with gyroscope sensor included |
-
2017
- 2017-05-03 CN CN201710304745.0A patent/CN108805127A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1920849A (en) * | 2005-08-26 | 2007-02-28 | 电子科技大学 | Vehicle license plate extraction method based on high-hat switch and wavelet switch |
| TW201528159A (en) * | 2014-01-03 | 2015-07-16 | Nat Univ Chin Yi Technology | License plate recognition system and method of smart phone with gyroscope sensor included |
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Application publication date: 20181113 |