CN110490187A

CN110490187A - Car license recognition equipment and method

Info

Publication number: CN110490187A
Application number: CN201910472683.3A
Authority: CN
Inventors: 聂鑫鑫; 范蒙
Original assignee: Hangzhou Hikvision Digital Technology Co Ltd
Current assignee: Hangzhou Hikvision Digital Technology Co Ltd
Priority date: 2019-05-31
Filing date: 2019-05-31
Publication date: 2019-11-22
Anticipated expiration: 2039-05-31
Also published as: CN110490187B

Abstract

It includes: filtering assembly, single image sensor, light aid, image processing unit that the application, which provides a kind of car license recognition equipment and method, the car license recognition equipment,；Imaging sensor by multiple exposure for being generated and exporting the first picture signal and the second picture signal, wherein the first picture signal is the picture signal generated according to the first default exposure, and the second picture signal is the picture signal generated according to the second default exposure；The light aid is for carrying out near-infrared light filling, wherein there are near-infrared light fillings at least within the Partial exposure period of the first default exposure, and near-infrared light filling is not present in the exposure period of the second default exposure；Filtering assembly is used to pass through visible light wave range and part near infrared light；Image processing unit, for identifying that Car license recognition effect is preferable to the license plate to be identified according to the first image signal and second picture signal.

Description

Car license recognition equipment and method

Technical field

This application involves technical field of image processing more particularly to a kind of car license recognition equipments and method.

Background technique

In traffic administration, by capturing the video image of vehicle, identifies license plate, have become presently the most common A kind of traffic administration means.The higher candid photograph image of quality in order to obtain, it will usually carry out light filling when capturing.

In the related technology, license plate image is obtained from infrared light filling image, is partitioned into license plate background area adjustment image face Car license recognition, output identification license plate are carried out after color, but will cause image color cast after carrying out infrared light filling in above scheme, Influence Car license recognition effect.

Summary of the invention

The application provides a kind of car license recognition equipment and method, to improve Car license recognition effect.

In a first aspect, the application provides a kind of car license recognition equipment, comprising:

Filtering assembly, imaging sensor, light aid, image processing unit, described image sensor are located at the optical filtering group The light emission side of part；

Described image sensor, for the first picture signal and the second picture signal to be generated and exported by multiple exposure, Wherein, the first image signal is the picture signal generated according to the first default exposure, and second picture signal is basis The picture signal that second default exposure generates, the described first default exposure and the described second default exposure are in the multiple exposure Wherein double exposure；The first image signal and second picture signal include the information of license plate to be identified；

The light aid includes the first light compensating apparatus, and first light compensating apparatus is used to carry out near-infrared benefit with strobe mode Light, wherein near-infrared light filling at least is carried out within the Partial exposure period of the described first default exposure, it is default described second Without near-infrared light filling in the exposure period of exposure；

The filtering assembly is used to pass through visible light wave range and part near infrared light；

Image processing unit is used for according to the first image signal and second picture signal to the vehicle to be identified Board is identified.

Second aspect, the application provide a kind of licence plate recognition method, are applied to car license recognition equipment, and the Car license recognition is set Standby includes imaging sensor, light aid and filtering assembly, and described image sensor is located at the light emission side of the filtering assembly, described Method includes:

Near-infrared light filling is carried out by the first light compensating apparatus that light aid includes, wherein at least in the first default exposure Near-infrared light filling is carried out in the Partial exposure period, without near-infrared light filling in the exposure period of the second default exposure, Described first default exposure and the described second default exposure are the wherein double exposure in the multiple exposure of imaging sensor；

Pass through the light of visible light wave range and part near infrared light by the filtering assembly；

Multiple exposure is carried out by described image sensor, to generate and export the first picture signal and the second image letter Number, the first image signal is the picture signal generated according to the described first default exposure, and second picture signal is root The picture signal generated according to the described second default exposure；The first image signal and second picture signal include to be identified The information of license plate；

Described image processing unit is according to the first image signal and second picture signal to the vehicle to be identified Board is identified.

Car license recognition equipment and method provided by the embodiments of the present application, comprising: filtering assembly, is mended single image sensor Light device, image processing unit；Imaging sensor by multiple exposure for being generated and exporting the first picture signal and the second image Signal, wherein the first picture signal is the picture signal generated according to the first default exposure, and the second picture signal is according to second The picture signal that default exposure generates；The light aid is for carrying out near-infrared light filling, wherein at least in the first default exposure There are near-infrared light fillings in the Partial exposure period, and near-infrared light filling is not present in the exposure period of the second default exposure； Filtering assembly is used to pass through visible light wave range and part near infrared light；Image processing unit, for being believed according to the first image Number and second picture signal license plate to be identified is identified, can over any time period in default exposed by first Light and the second default exposure while collecting the first picture signal comprising near infrared light information and the comprising visible optical information Two picture signals, the subsequent effect identified according to first picture signal and the second picture signal are preferable.

Detailed description of the invention

The drawings herein are incorporated into the specification and forms part of this specification, and shows the implementation for meeting the disclosure Example, and together with specification for explaining the principles of this disclosure.

Fig. 1 is a kind of structural schematic diagram of car license recognition equipment provided by the embodiments of the present application；

Fig. 2 is the wavelength and relative intensity that a kind of first light compensating apparatus provided by the embodiments of the present application carries out near-infrared light filling Between relation schematic diagram；

Fig. 3 is the pass between the wavelength and percent of pass of a kind of light that first optical filter passes through provided by the embodiments of the present application It is schematic diagram；

Fig. 4 is the structural schematic diagram of another car license recognition equipment provided by the embodiments of the present application；

Fig. 5 is a kind of schematic diagram of RGB sensor provided by the embodiments of the present application；

Fig. 6 is a kind of schematic diagram of RGBW sensor provided by the embodiments of the present application；

Fig. 7 is a kind of schematic diagram of RCCB sensor provided by the embodiments of the present application；

Fig. 8 is a kind of schematic diagram of RYYB sensor provided by the embodiments of the present application；

Fig. 9 is a kind of induction curve schematic diagram of imaging sensor provided by the embodiments of the present application；

Figure 10 is a kind of schematic diagram of roller shutter Exposure mode provided by the embodiments of the present application；

Figure 11 is the schematic diagram of the first the first default exposure and the second default exposure provided by the embodiments of the present application；

Figure 12 is the schematic diagram of second first provided by the embodiments of the present application default exposures and the second default exposure；

Figure 13 is the schematic diagram of the third the first default exposure and the second default exposure provided by the embodiments of the present application；

Figure 14 is the schematic diagram of the first roller shutter Exposure mode and near-infrared light filling provided by the embodiments of the present application；

Figure 15 is the schematic diagram of second of roller shutter Exposure mode and near-infrared light filling provided by the embodiments of the present application；

Figure 16 is the schematic diagram of the third roller shutter Exposure mode and near-infrared light filling provided by the embodiments of the present application；

Figure 17 is a kind of structural schematic diagram of image processing unit provided by the embodiments of the present application；

Figure 18 is a kind of structural schematic diagram of image pre-processing unit provided by the embodiments of the present application；

Figure 19 is the structural schematic diagram of another image pre-processing unit provided by the embodiments of the present application；

Figure 20 is a kind of image co-registration handling principle schematic diagram provided by the embodiments of the present application；

Figure 21 is a kind of schematic illustration of image identification unit provided by the embodiments of the present application；

Figure 22 is the schematic illustration of another image identification unit provided by the embodiments of the present application；

Figure 23 is a kind of flow diagram of licence plate recognition method provided by the embodiments of the present application.

Specific embodiment

Example embodiments are described in detail here, and the example is illustrated in the accompanying drawings.Following description is related to When attached drawing, unless otherwise indicated, the same numbers in different drawings indicate the same or similar elements.Following exemplary embodiment Described in embodiment do not represent all implementations consistent with this disclosure.On the contrary, they be only with it is such as appended The example of the consistent device and method of some aspects be described in detail in claims, the disclosure.

Term " includes " in the description and claims of this application and the attached drawing and " having " and they appoint What is deformed, it is intended that is covered and non-exclusive is included.Such as contain the process, method, system, production of a series of steps or units Product or equipment are not limited to listed step or unit, but optionally further comprising the step of not listing or unit, or Optionally further comprising the other step or units intrinsic for these process, methods, product or equipment.

Fig. 1 is a kind of structural schematic diagram of car license recognition equipment provided by the embodiments of the present application, and referring to Fig. 1, which knows Other equipment includes imaging sensor 01, light aid 02, filtering assembly 03 and image processing unit, and imaging sensor 01 is located at filter The light emission side of optical assembly 03.Imaging sensor 01 by multiple exposure for being generated and exporting the first picture signal and the second image Signal.Wherein, the first picture signal is the picture signal generated according to the first default exposure, and the second picture signal is according to second The picture signal that default exposure generates, the first default exposure and the second default exposure are wherein exposing twice in the multiple exposure Light.Light aid 02 includes the first light compensating apparatus 021, and the first light compensating apparatus 021 is for carrying out near-infrared light filling, wherein at least exists Carry out near-infrared light filling in the Partial exposure period of first default exposure, in the exposure period of the second default exposure not into Row near-infrared light filling.

Image processing unit, the first picture signal and the second picture signal for being exported according to imaging sensor are to described License plate to be identified is identified；Wherein, the first picture signal and the second picture signal include the information of license plate to be identified.

Referring to fig. 4, filtering assembly 03 includes the first optical filter 031, and the first optical filter 031 makes light and the portion of visible light wave range Point near infrared light passes through, wherein passes through the near-infrared of the first optical filter 031 when the first light filling fills 021 carry out near infrared light light filling The intensity of light is higher than when the first light compensating apparatus 021 does not carry out near-infrared light filling through the strong of the near infrared light of the first optical filter 031 Degree.It can be part near infrared light wave band by the near infrared light wave band of first optical filter (031).

In the embodiment of the present application, referring to Fig. 1, car license recognition equipment can also include camera lens 04, at this point, filtering assembly 03 Can be between camera lens 04 and imaging sensor 01, and imaging sensor 01 is located at the light emission side of filtering assembly 03.Alternatively, mirror First 04 between filtering assembly 03 and imaging sensor 01, and imaging sensor 01 is located at the light emission side of camera lens 04.As one Kind example, the first optical filter 031 can be light filter film, in this way, when filtering assembly 03 is located at camera lens 04 and imaging sensor 01 Between when, the first optical filter 031 can be attached to the surface of the light emission side of camera lens 04, alternatively, being located at filtering assembly 03 when camera lens 04 When between imaging sensor 01, the first optical filter 031 can be attached to the surface of the incident side of camera lens 04.

It should be noted is that light aid 02 can be located in car license recognition equipment, figure Car license recognition can also be located at The outside of equipment.It that is to say, light aid 02 can be a part of car license recognition equipment, or set independently of Car license recognition A standby device.When light aid 02 is located at the outside of car license recognition equipment, light aid 02 can with car license recognition equipment into Row communication connection, thereby may be ensured that the exposure time series of the imaging sensor 01 in car license recognition equipment and light aid 02 includes There are certain relationships for the near-infrared light filling timing of first light compensating apparatus 021, such as at least in the Partial exposure of the first default exposure Near-infrared light filling is carried out in period, without near-infrared light filling in the exposure period of the second default exposure.

It can guarantee the exposure time series of the imaging sensor 01 in car license recognition equipment and light aid 02 includes first mends There are certain relationships for the near-infrared light filling timing of electro-optical device 021, such as at least in the Partial exposure period of the first default exposure Interior progress near-infrared light filling, without near-infrared light filling in the exposure period of the second default exposure.

In addition, the first light compensating apparatus 021 is that can issue device, such as near-infrared light compensating lamp of near infrared light etc., first Light compensating apparatus 021 can carry out near-infrared light filling with strobe mode, can also carry out near-infrared with the other modes of similar stroboscopic Light filling, the embodiment of the present application do not limit this.In some instances, it is carried out when the first light compensating apparatus 021 with strobe mode close When infrared light filling, the first light compensating apparatus 021 can be controlled manually with strobe mode and carry out near-infrared light filling, it can also Near-infrared light filling, the application are carried out to control the first light compensating apparatus 021 by software program or particular device with strobe mode Embodiment does not limit this.Wherein, the period that the first light compensating apparatus 021 carries out near-infrared light filling can be with the first default exposure The exposure period of light is overlapped, and can also be greater than the exposure period of the first default exposure or the exposure less than the first default exposure The light period, as long as the entire exposure period in the first default exposure or progress near-infrared benefit in the Partial exposure period Light, and without near-infrared light filling in the exposure period of the second default exposure.

It should be noted that being exposed without near-infrared light filling for the overall situation in the exposure period of the second default exposure For mode, the exposure period of the second default exposure, which can be, to be started the time of exposure and terminates the time between the time of exposure Section, for roller shutter Exposure mode, it is effective that the exposure period of the second default exposure can be the second picture signal the first row Image starts the period of the time of exposure and last line effective image terminated between the time of exposure, but is not limited to This.For example, the exposure period of the second default exposure is also possible to the target image corresponding time for exposure in the second picture signal Section, target image are with several rows effective image corresponding to target object or target area in the second picture signal, this is several Period between the beginning time of exposure and the end time of exposure of row effective image is considered as the exposure of the second default exposure Period.

It needs to illustrate on the other hand, since the first light compensating apparatus 021 is when carrying out near-infrared light filling to outer scene, to enter The near infrared light for being mapped to body surface may be reflected by the object, hence into the first optical filter 031.And due to usual In the case of, environment light may include visible light and near infrared light, and when the near infrared light in environment light is incident on body surface It can be reflected by the object, hence into the first optical filter 031.Therefore, pass through the first optical filter when carrying out near-infrared light filling 031 near infrared light may include being reflected into the first optical filter through object when the first light compensating apparatus 021 carries out near-infrared light filling 031 near infrared light by the near infrared light of the first optical filter 031 may include the first light filling when without near-infrared light filling The near infrared light of the first optical filter 031 is reflected into when device 021 does not carry out near-infrared light filling through object.It that is to say, carrying out Include that the first light compensating apparatus 021 issues by the near infrared light of the first optical filter 031 when near-infrared light filling and is reflected through object Near infrared light near infrared light and environment light afterwards after object reflects passes through first when without near-infrared light filling The near infrared light of optical filter 031 includes the near infrared light in environment light after object reflects.

With in car license recognition equipment, filtering assembly 03 can be between camera lens 04 and imaging sensor 01, and image passes Sensor 01 is located at for the structure feature of the light emission side of filtering assembly 03, and car license recognition equipment acquires the first picture signal and second The process of picture signal are as follows: when imaging sensor 01 carries out the first default exposure, the first light compensating apparatus 021 carries out near-infrared benefit Light is reflected when the environment light in photographed scene and the first light compensating apparatus carry out near-infrared light filling at this time by object in scene close red After outer light is via camera lens 04, the first optical filter 031, first image letter is generated by the first default exposure by imaging sensor 01 Number；When imaging sensor 01 carries out the second default exposure, the first light compensating apparatus 021 is shot at this time without near-infrared light filling After environment light in scene is via camera lens 04, the first optical filter 031, generated by imaging sensor 01 by the second default exposure Second picture signal can have M first default exposure and the N number of second default exposure within a frame period of Image Acquisition, Between first default exposure and the second default exposure can there are many combined sequences, in a frame period of Image Acquisition, M It can be arranged according to actual needs with the value and M of N and the size relation of N, for example, the value of M and N can be equal, it can also not It is identical.

In addition, since the intensity of the near infrared light in environment light is lower than the near infrared light that the first light compensating apparatus 021 issues Intensity, therefore, the first light compensating apparatus 021 carry out high by the intensity of the near infrared light of the first optical filter 031 when near-infrared light filling Pass through the intensity of the near infrared light of the first optical filter 031 when the first light compensating apparatus 021 does not carry out near-infrared light filling.

Wherein, the wavelength band that the first light compensating apparatus 021 carries out near-infrared light filling can refer to wavelength band for second, the Two reference wavelength bands can be 700 nanometers~800 nanometers or 900 nanometers~1000 nanometers, in this way, can mitigate common 850 nanometers of nearly red light caused by interfere.In addition, the wavelength band for being incident on the near infrared light of the first optical filter 031 can be with Wavelength band is referred to for first, the first reference wavelength band is 650 nanometers~1100 nanometers.

Since when carrying out near-infrared light filling, the near infrared light by the first optical filter 031 may include the first light filling dress The warp in the near infrared light and environment light of the first optical filter 031 is reflected into through object when setting 021 carry out near infrared light light filling Near infrared light after object reflection.So stronger into the intensity of the near infrared light of filtering assembly 03 at this time.But without When near-infrared light filling, the near infrared light by the first optical filter 031 includes being reflected into filtering assembly 03 through object in environment light Near infrared light.Due to carrying out the near infrared light of light filling without the first light compensating apparatus 021, so passing through the first optical filter at this time The intensity of 031 near infrared light is weaker.Therefore, the first picture signal for generating and exporting according to the first default exposure includes close The intensity of infrared light is higher than the strong of the near infrared light that the second picture signal for generating and exporting according to the second default exposure includes Degree.

First light compensating apparatus 021 carries out the central wavelength of near-infrared light filling and/or wavelength band can be there are many selection, this Apply in embodiment, it, can be to the first light filling in order to make the first light compensating apparatus 021 and the first optical filter 031 have better cooperation The central wavelength that device 021 carries out near-infrared light filling is designed, and is selected the characteristic of the first optical filter 031, from And to carry out the central wavelength of near-infrared light filling in the first light compensating apparatus 021 as setting characteristic wavelength or fall in setting feature When wave-length coverage, constraint item can achieve by the central wavelength and/or waveband width of the near infrared light of the first optical filter 031 Part.The central wavelength that the constraint condition is primarily used to the near infrared light that constraint passes through the first optical filter 031 is as accurate as possible, with And it is as narrow as possible by the waveband width of the near infrared light of the first optical filter 031, to avoid the occurrence of because near infrared light wave band is wide It spends wide and introduces wavelength interference.

Wherein, the central wavelength that the first light compensating apparatus 021 carries out near-infrared light filling can issue for the first light compensating apparatus 021 Near infrared light spectrum in average value in the maximum wave-length coverage of energy, it is understood that sent out for the first light compensating apparatus 021 Energy is more than the wavelength of the middle position in the wave-length coverage of certain threshold value in the spectrum of near infrared light out.

Wherein, setting characteristic wavelength or setting characteristic wavelength range can preset.As an example, it first mends The central wavelength that electro-optical device 021 carries out near-infrared light filling can be any wavelength in 750 ± 10 nanometers of wave-length coverage；Or Person, the first light compensating apparatus 021 carry out any wave in the wave-length coverage that the central wavelength of near-infrared light filling is 780 ± 10 nanometers It is long；Alternatively, the first light compensating apparatus 021 carries out appointing in the wave-length coverage that the central wavelength of near-infrared light filling is 940 ± 10 nanometers One wavelength.It that is to say, setting characteristic wavelength may range from 750 ± 10 nanometers of wave-length coverage or 780 ± 10 nanometers of wave Long range or 940 ± 10 nanometers of wave-length coverage.Illustratively, the first light compensating apparatus 021 carries out the center of near-infrared light filling Wavelength is 940 nanometers, and the first light compensating apparatus 021 carries out relationship such as Fig. 2 institute between the wavelength and relative intensity of near-infrared light filling Show.Figure it is seen that the wavelength band that the first light compensating apparatus 021 carries out near-infrared light filling is 900 nanometers~1000 nanometers, Wherein, in 940 nanometers, the relative intensity highest of near infrared light.

Since when carrying out near-infrared light filling, the near infrared light by the first optical filter 031 is largely the first light filling dress The near infrared light of the first optical filter 031 is reflected into when setting 021 carry out near-infrared light filling through object, therefore, in some embodiments In, above-mentioned constraint condition may include: the central wavelength and the first light compensating apparatus by the near infrared light of the first optical filter 031 Difference between the central wavelength of 021 progress near-infrared light filling is located within the scope of wavelength fluctuation, as an example, wavelength fluctuation It may range from 0~20 nanometer.

It wherein, can be the close red of the first optical filter 031 by the central wavelength of the near-infrared light filling of the first optical filter 031 Wavelength within the scope of near infrared band in outer smooth percent of pass curve at crest location, it is understood that be the first optical filter 031 Near infrared light percent of pass curve in percent of pass be more than certain threshold value near infrared band within the scope of middle position wavelength.

In order to avoid introducing wavelength interference by the way that the waveband width of the near infrared light of the first optical filter 031 is wide, one In a little embodiments, above-mentioned constraint condition may include: that first band width can be less than second band width.Wherein, first wave Duan Kuandu refers to that the waveband width of the near infrared light by the first optical filter 031, second band width refer to by the first optical filter The waveband width of 031 near infrared light stopped.It should be understood that waveband width refers to wave-length coverage locating for the wavelength of light Width.It is received for example, passing through wave-length coverage locating for the wavelength of the near infrared light of the first optical filter 031 for 700 nanometers~800 Rice, then first band width, which is 800 nanometers, subtracts 700 nanometers, i.e., 100 nanometers.In other words, pass through the first optical filter 031 Near infrared light waveband width less than the near infrared light that the first optical filter 031 stops waveband width.

For example, with reference to Fig. 3, Fig. 3 be the first optical filter 031 can by light wavelength and percent of pass between relationship A kind of schematic diagram.The wave band for being incident on the near infrared light of the first optical filter 031 is 650 nanometers~1100 nanometers, the first optical filter 031 visible light that wavelength can be made to be located at 380 nanometers~650 nanometers passes through and wavelength is positioned at 900 nanometers~1100 nanometers Near infrared light passes through, and wavelength is stopped to be located at 650 nanometers~900 nanometers of near infrared light.It that is to say, first band width is 1000 Nanometer subtracts 900 nanometers, i.e., 100 nanometers.Second band width is 900 nanometers and subtracts 650 nanometers, in addition 1100 nanometers subtract 1000 nanometers, i.e., 350 nanometers.100 nanometers less than 350 nanometers, that is, pass through the waveband width of the near infrared light of the first optical filter 031 Less than the waveband width for the near infrared light that the first optical filter 031 stops.Relation above curve is only a kind of example, for different Optical filter, can be different by the wavelength band of the nearly red spectral band of optical filter, by the near-infrared of filter blocks The wavelength band of light can also be different.

In order to avoid passing through the wide waveband of the near infrared light of the first optical filter 031 within the period of non-near-infrared light filling It spends wide and introduces wavelength interference, in some embodiments, above-mentioned constraint condition may include: by the first optical filter 031 The half-band width of near infrared light is less than or equal to 50 nanometers.Wherein, half-band width refers to the wave of near infrared light of the percent of pass greater than 50% Duan Kuandu.

In order to avoid introducing wavelength interference by the way that the waveband width of the near infrared light of the first optical filter 031 is wide, one In a little embodiments, above-mentioned constraint condition may include: that third waveband width can be less than with reference to waveband width.Wherein, third wave Duan Kuandu refers to that percent of pass as an example can with reference to waveband width greater than the waveband width of the near infrared light of setting ratio Think any waveband width in 50 nanometers~100 nanometers of wavelength band.Setting ratio can be times in 30%~50% One ratio, certain setting ratio can also be set as other ratios according to use demand, and the embodiment of the present application does not limit this. In other words, the waveband width that percent of pass is greater than the near infrared light of setting ratio, which can be less than, refers to waveband width.

For example, with reference to Fig. 3, the wave band for being incident on the near infrared light of the first optical filter 031 is 650 nanometers~1100 nanometers, Setting ratio is 30%, is 100 nanometers with reference to waveband width.From figure 3, it can be seen that close red at 650 nanometers~1100 nanometers In the wave band of outer light, the waveband width of near infrared light of the percent of pass greater than 30% is significantly less than 100 nanometers.

It is mended since the first light compensating apparatus 021 at least provides near-infrared within the Partial exposure period of the first default exposure Light does not provide near-infrared light filling in the entire exposure period that second presets exposure, and the first default exposure and second is preset Exposure is the wherein double exposure in the multiple exposure of imaging sensor 01, be that is to say, the first light compensating apparatus 021 is in image sensing Near-infrared light filling is provided in the exposure period of the Partial exposure of device 01, in the exposure that the another part of imaging sensor 01 exposes Near-infrared light filling is not provided in the light period.So light filling number of first light compensating apparatus 021 in unit time length can be with Lower than exposure frequency of the imaging sensor 01 in the unit time length, wherein the interval time section per adjacent light filling twice It is interior, it is spaced one or many exposures.

Illustratively, since human eye is easy to carry out the first light compensating apparatus 021 into the color and traffic lights of near infrared light light filling In the color of red light obscure, so, referring to fig. 4, light aid 02 can also include the second light compensating apparatus 022, the second light filling dress 022 is set for carrying out visible light light filling.In this way, if the second light compensating apparatus 022 is at least in the Partial exposure of the first default exposure Time provides visible light light filling, that is to say, at least there are near-infrared light fillings within the Partial exposure period of the first default exposure With visible light light filling, the blend color of both light can be different from the color of the red light in traffic lights, so as to avoid human eye The color that light aid 02 is carried out to the red light in the color and traffic lights of near-infrared light filling is obscured.In addition, if the second light filling fills It sets 022 and provides visible light light filling in the exposure period of the second default exposure, due to the exposure period of the second default exposure The intensity of interior visible light be not it is especially high, therefore, when carrying out visible light light filling in the exposure period of the second default exposure, also The brightness of the visible light in the second picture signal can be improved, and then guarantee the quality of Image Acquisition.

In some embodiments, the second light compensating apparatus 022 can be used for carrying out visible light light filling in a manner of being always on；Alternatively, Second light compensating apparatus 022 can be used for carrying out visible light light filling with strobe mode, wherein at least in the part of the first default exposure Visible light light filling is carried out in exposure period, without visible light light filling in the entire exposure period of the second default exposure； Alternatively, the second light compensating apparatus 022 can be used for carrying out visible light light filling with strobe mode, wherein at least in the first default exposure Entire exposure period in without visible light light filling, there are visible lights within the Partial exposure period of the second default exposure Light filling.It, not only can be to avoid human eye by the first light compensating apparatus when the second light compensating apparatus 022, which is always on mode, carries out visible light light filling The color of red light in the color and traffic lights of 021 progress near-infrared light filling is obscured, and can also improve in the second picture signal The brightness of visible light, and then guarantee the quality of Image Acquisition.When the second light compensating apparatus 022 carries out visible light light filling with strobe mode When, the color that the first light compensating apparatus 021 can be carried out to the red light in the color and traffic lights of near-infrared light filling to avoid human eye is mixed Confuse, alternatively, the brightness of the visible light in the second picture signal can be improved, and then guarantees the quality of Image Acquisition, but also can To reduce the light filling number of the second light compensating apparatus 022, to extend the service life of the second light compensating apparatus 022.

It should be noted that switching part 033 be used to the second optical filter 032 being switched to imaging sensor 01 enter light Side, it is understood that replace the first optical filter 031 in the position of the incident side of imaging sensor 01 for the second optical filter 032.In Second optical filter 032 is switched to after the incident side of imaging sensor 01, and the first light compensating apparatus 021 may be at closed state It may be at open state.

In some embodiments, above-mentioned multiple exposure refers to the multiple exposure in a frame period, that is to say, image sensing Device 01 carries out multiple exposure within a frame period, to generate and export at least first picture signal of frame and an at least frame Two picture signals.For example, including 25 frame periods in 1 second, imaging sensor 01 carries out multiple exposure within each frame period, from And at least first picture signal of frame and at least second picture signal of frame are generated, the first image that will be generated in a frame period Signal and the second picture signal are known as one group of picture signal, in this way, will generate 25 groups of picture signals in 25 frame periods.Its In, the first default exposure and the second default exposure can be double exposure adjacent in multiple exposure in a frame period, can also To be that non-conterminous double exposure in multiple exposure, the embodiment of the present application do not limit this in a frame period.

First picture signal is that the first default exposure is generated and exported, and the second picture signal is that the second default exposure generates And export, it, can be to the first picture signal and second after generating and exporting the first picture signal and the second picture signal Picture signal is handled.In some cases, the purposes of the first picture signal and the second picture signal may be different, so In some embodiments, the first default exposure can be different from least one exposure parameter of the second default exposure.Show as one kind Example, at least one exposure parameter can include but is not limited to the time for exposure, analog gain, digital gain, in aperture size It is one or more.Wherein, exposure gain includes analog gain and/or digital gain.

In some embodiments.It is understood that compared with the second default exposure, when carrying out near-infrared light filling, figure The intensity of the near infrared light sensed as sensor 01 is stronger, and the first picture signal for correspondingly generating and exporting includes close red The brightness of outer light also can be higher.But the near infrared light of higher brightness is unfavorable for the acquisition of outer scene information.And some In embodiment, exposure gain is bigger, and the brightness for the picture signal that imaging sensor 01 exports is higher, and exposure gain is smaller, image The brightness for the picture signal that sensor 01 exports is lower, therefore, in order to guarantee the bright of near infrared light that the first picture signal includes Degree is in suitable range, in the case where the first default exposure is different at least one exposure parameter of the second default exposure, As an example, the exposure gain of the first default exposure can be less than the exposure gain of the second default exposure.In this way, first When light compensating apparatus 021 carries out near-infrared light filling, imaging sensor 01 generates and the first picture signal for exporting includes near-infrared The brightness of light, will not be excessively high because of the first light compensating apparatus 021 progress near-infrared light filling.

In further embodiments, the time for exposure is longer, and the brightness that the picture signal that imaging sensor 01 obtains includes is got over Height, and motion smear of the object of the movement in outer scene in picture signal is longer；Time for exposure is shorter, image sensing The brightness that the picture signal that device 01 obtains includes is lower, and movement of the object of the movement in outer scene in picture signal It trails shorter.Therefore, in order to guarantee the brightness of near infrared light that the first picture signal includes in suitable range, and external field Motion smear of the object of movement in scape in the first picture signal is shorter.Exposure is preset in the first default exposure and second In the case that at least one exposure parameter is different, as an example, the time for exposure of the first default exposure can be less than second The time for exposure of default exposure.In this way, imaging sensor 01 generates simultaneously when the first light compensating apparatus 021 carries out near-infrared light filling The brightness for the near infrared light that first picture signal of output includes, will not be due to the first light compensating apparatus 021 carries out near-infrared light filling It is excessively high.And the motion smear that the shorter time for exposure occurs the object of the movement in outer scene in the first picture signal It is shorter, to be conducive to the identification to Moving Objects.Illustratively, the time for exposure of the first default exposure is 40 milliseconds, second The time for exposure of default exposure is 60 milliseconds etc..

It is worth noting that, in some embodiments, when the exposure gain of the first default exposure is less than the second default exposure Exposure gain when, the time for exposure of the first default exposure not only can be less than the time for exposure of the second default exposure, can be with Equal to the time for exposure of the second default exposure.Similarly, when exposure of the time for exposure of the first default exposure less than the second default exposure When between the light time, the exposure gain of the first default exposure can also be equal to second less than the exposure gain of the second default exposure The exposure gain of default exposure.

In further embodiments, the purposes of the first picture signal and the second picture signal can be identical, such as the first figure When being all used for intellectual analysis as signal and the second picture signal, in order to make the face for carrying out intellectual analysis or target during exercise There can be same clarity, the first default exposure can be identical at least one exposure parameter of the second default exposure.As A kind of example, the first default time for exposure exposed can be equal to the time for exposure of the second default exposure, if the first default exposure The time for exposure of light is different with the time for exposure of the second default exposure, it may appear that the time for exposure, longer picture signal all the way existed Motion smear causes the clarity of two-way picture signal different.Similarly, as another example, the exposure of the first default exposure Gain can be equal to the exposure gain of the second default exposure.

It is worth noting that, in some embodiments, being equal to the second default exposure when the time for exposure of the first default exposure Time for exposure when, the exposure gain of the first default exposure can also be equal to less than the exposure gain of the second default exposure The exposure gain of second default exposure.Similarly, when the exposure that the exposure gain of the first default exposure is equal to the second default exposure increases When beneficial, the time for exposure of the first default exposure it is default can also to be equal to second less than the time for exposure of the second default exposure The time for exposure of exposure.

Wherein, imaging sensor 01 may include multiple photosensitive channels, and each photosensitive channel can be used for incuding at least one The light of kind visible light wave range, and the light of induction near infrared band.It that is to say, each photosensitive channel can incude at least one can The light of light-exposed wave band, and the light of near infrared band can be incuded, in this manner it is ensured that in the first picture signal and the second picture signal With complete resolution ratio, not missing pixel values.Illustratively, multiple photosensitive channel can be used for incuding at least two differences Visible light wave range light.

In some embodiments, multiple photosensitive channel may include the photosensitive channel R, the photosensitive channel G, the photosensitive channel B, Y At least two in photosensitive channel, the photosensitive channel W and the photosensitive channel C.Wherein, the photosensitive channel R is for incuding red spectral band and close The light of infrared band, the photosensitive channel G are used to incude the light of green light band and near infrared band, and the photosensitive channel B is for incuding blue light The light of wave band and near infrared band, the photosensitive channel Y are used to incude the light of yellow band and near infrared band.Due in some implementations In example, the photosensitive channel for incuding full wave light can be indicated with W, in further embodiments, can be indicated with C For incuding the photosensitive channel of full wave light, so when multiple photosensitive channel includes for incuding the photosensitive of full wave light When channel, this photosensitive channel can be the photosensitive channel W, be also possible to the photosensitive channel C.It that is to say, it in practical applications, can be with The photosensitive channel for incuding full wave light is selected according to use demand.Illustratively, imaging sensor 01 can be RGB Sensor, RGBW sensor or RCCB sensor or RYYB sensor.Wherein, the photosensitive channel R in RGB sensor, G are photosensitive The distribution mode in channel and the photosensitive channel B may refer to Fig. 5, and the photosensitive channel R, the photosensitive channel G in RGBW sensor, B are photosensitive The distribution mode in channel and the photosensitive channel W may refer to Fig. 6, and the photosensitive channel R, the photosensitive channel C and B in RCCB sensor are photosensitive Channel distribution mode may refer to Fig. 7, the photosensitive channel R, the photosensitive channel Y and the photosensitive channel distribution mode of B in RYYB sensor It may refer to Fig. 8.

In further embodiments, some photosensitive channels can also only incude the light of near infrared band, visible without incuding The light of optical band, in this manner it is ensured that having complete resolution ratio, not missing pixel values in the first picture signal.As one kind Example, multiple photosensitive channel may include the photosensitive channel R, the photosensitive channel G, the photosensitive channel B, at least two in the photosensitive channel IR Kind.Wherein, the photosensitive channel R is used to incude the light of red spectral band and near infrared band, the photosensitive channel G for incude green light band and The light of near infrared band, the photosensitive channel B are used to incude the light of blue wave band and near infrared band, and the photosensitive channel IR is close for incuding The light of infrared band.

Illustratively, imaging sensor 01 can be RGBIR sensor, wherein each IR in RGBIR sensor is photosensitive logical Road can incude the light of near infrared band, the light without incuding visible light wave range.

Wherein, when imaging sensor 01 is RGB sensor, compared to other imaging sensors, such as RGBIR sensor RGB information Deng the acquisition of, RGB sensor is more complete, some photosensitive channel of RGBIR sensor does not acquire visible light, So the color detail of the image of RGB sensor acquisition is more acurrate.

It is worth noting that, multiple photosensitive channels that imaging sensor 01 includes can correspond to a plurality of induction curve.Example Property, referring to Fig. 9, R-curve representative image sensor 01 in Fig. 9 represents figure to the induction curve of the light of red spectral band, G curve As sensor 01 is to the induction curve of the light of green light band, induction of the B curve representative image sensor 01 to the light of blue wave band Curve, W (or C) curve representative image sensor 01 incude the induction curve of full wave light, NIR (Near infrared, Near infrared light) curve representative image sensor 01 incude near infrared band light induction curve.

As an example, imaging sensor 01 can also use roller shutter Exposure mode using global Exposure mode. Wherein, global Exposure mode refers to that the exposure start time of every a line effective image is all the same, and the exposure of every a line effective image Light finish time is all the same.In other words, global Exposure mode is all row effective images while being exposed and at the same time tying A kind of Exposure mode of beam exposure.Roller shutter Exposure mode refers to that the time for exposure for effective image of not going together not exclusively is overlapped, namely It is that the exposure start time of a line effective image is all later than the exposure start time of lastrow effective image, and a line effectively figure The end exposure moment of picture is all later than the end exposure moment of lastrow effective image.In addition, every a line in roller shutter Exposure mode Effective image terminate exposure after can carry out data output, therefore, since the data of the first row effective image output time to Time between the end of data output time of last line effective image can be expressed as readout time.

It illustratively, is a kind of schematic diagram of roller shutter Exposure mode referring to Figure 10, Figure 10.From fig. 10 it can be seen that the 1st row Effective image starts to expose at the T1 moment, terminates to expose at the T3 moment, and the 2nd row effective image starts to expose at the T2 moment, in T4 Moment terminates to expose, and the T2 moment has elapsed a period compared to the T1 moment backward, and the T4 moment is compared to the T3 moment to pusher A period is moved.In addition, the 1st row effective image terminated to expose and start output data at the T3 moment, terminate at the T5 moment The output of data, line n effective image terminated to expose and start output data at the T6 moment, terminated the defeated of data at the T7 moment Out, then the time between T3~T7 moment is readout time.

In some embodiments, when imaging sensor 01 carries out multiple exposure using global Exposure mode, for any The exposure period of near-infrared light filling, the period of near-infrared light filling and the closest second default exposure, which is not present, to be handed over Collection, the period of near-infrared light filling is the subset of the exposure period of the first default exposure, alternatively, the period of near-infrared light filling The exposure period for presetting exposure there are intersection or first with the exposure period of the first default exposure is near-infrared light filling Subset.In this way, can be realized at least within the Partial exposure period of the first default exposure, there are near-infrared light fillings, pre- second If near-infrared light filling is not present in the entire exposure period of exposure, to will not be impacted to the second default exposure.

For example, with reference to Figure 11, for any near-infrared light filling, the period of near-infrared light filling and closest second Intersection is not present in the exposure period of default exposure, and the period of near-infrared light filling is the exposure period of the first default exposure Subset.Referring to Figure 12, for any near-infrared light filling, the period of near-infrared light filling and the closest second default exposure Exposure period be not present intersection, there are intersections for the exposure period of the period of near-infrared light filling and the first default exposure. Referring to Figure 13, for any near-infrared light filling, the exposure of the period of near-infrared light filling and the closest second default exposure Intersection is not present in the light period, and the exposure period of the first default exposure is the subset of near-infrared light filling.Figure 11 to Figure 13 is only The sequence of a kind of example, the first default exposure and the second default exposure can be not limited to these examples.

In further embodiments, when imaging sensor 01 carries out multiple exposure using roller shutter Exposure mode, for appointing It anticipates a near-infrared light filling, there is no hand over for the exposure period of the period of near-infrared light filling and the closest second default exposure Collection.Also, when the exposure for being no earlier than last line effective image in the first default exposure at the beginning of near-infrared light filling starts It carves, the finish time of near-infrared light filling is not later than the end exposure moment of the first row effective image in the first default exposure.Alternatively, The last line of the default exposure of closest second before being no earlier than the first default exposure at the beginning of near-infrared light filling has It imitates the end exposure moment of image and is not later than the end exposure moment of the first row effective image in the first default exposure, near-infrared The finish time of light filling is no earlier than the exposure start time of last line effective image in the first default exposure and is not later than first The exposure start time of the first row effective image of the default exposure of closest second after default exposure.Alternatively, near-infrared The last line effective image of the default exposure of closest second before the first default exposure is no earlier than at the beginning of light filling The end exposure moment and be not later than exposure start time of the first row effective image in the first default exposure, near-infrared light filling Finish time is no earlier than the end exposure moment of last line effective image in the first default exposure and is not later than the first default exposure The exposure start time of the first row effective image of the default exposure of closest second after light.

For example, with reference to Figure 14, for any near-infrared light filling, the period of near-infrared light filling and closest second Intersection is not present in the exposure period of default exposure, also, is no earlier than in the first default exposure at the beginning of near-infrared light filling The exposure start time of last line effective image, the finish time of near-infrared light filling are not later than the first row in the first default exposure The end exposure moment of effective image.Referring to Figure 15, for any near-infrared light filling, the period of near-infrared light filling with most Intersection is not present in the exposure period of the default exposure of neighbouring second, also, is no earlier than first at the beginning of near-infrared light filling The end exposure moment of the last line effective image of the default exposure of closest second before default exposure and it is not later than the The end exposure moment of the first row effective image in one default exposure, the finish time of near-infrared light filling are no earlier than the first default exposure Exposure start time of last line effective image and closest second being not later than after the first default exposure is default in light The exposure start time of the first row effective image of exposure.Referring to Figure 16, for any near-infrared light filling, near-infrared light filling Period and the exposure period of closest second default exposure intersection is not present, also, at the beginning of near-infrared light filling When carving the end exposure of the last line effective image of the default exposure of closest second before being no earlier than the first default exposure The exposure start time of the first row effective image in the first default exposure is carved and is not later than, the finish time of near-infrared light filling is late It the end exposure moment of last line effective image and is not later than most adjacent after the first default exposure in the first default exposure The exposure start time of the first row effective image of the default exposure of close second.Figure 14 is into Figure 16, for the first default exposure With the second default exposure, inclined dashed line indicates exposure start time, and inclination solid line indicates the end exposure moment, default for first It exposes, indicated for the first default period for exposing corresponding near-infrared light filling between vertical dotted line, Figure 14 to Figure 16 is only a kind of The sequence of example, the first default exposure and the second default exposure can be not limited to these examples.

Wherein, multiple exposure may include odd-times exposure and even-times exposure, in this way, the first default exposure and second is in advance If exposure can include but is not limited to following several modes:

The first possible implementation, first, which presets exposure, presets exposure for the single exposure in odd-times exposure, second Light is the single exposure in even-times exposure.In this way, multiple exposure may include presetting to expose according to the first of odd even sequential arrangement Light and the second default exposure.For example, expose for the 1st time in multiple exposure, the 3rd exposure, the odd-times exposure such as the 5th exposure it is equal For the first default exposure, the even-times exposure such as the 2nd exposure, the 4th exposure, the 6th exposure is the second default exposure.

Second of possible implementation, first, which presets exposure, presets exposure for the single exposure in even-times exposure, second Light is the single exposure in odd-times exposure, in this way, multiple exposure may include presetting to expose according to the first of odd even sequential arrangement Light and the second default exposure.For example, expose for the 1st time in multiple exposure, the 3rd exposure, the odd-times exposure such as the 5th exposure it is equal For the second default exposure, the even-times exposure such as the 2nd exposure, the 4th exposure, the 6th exposure is the first default exposure.

The third possible implementation, the first default exposure are the single exposure in specified odd-times exposure, second Default exposure is the single exposure in other exposures in addition to specified odd-times exposure, be that is to say, the second default exposure can Think the odd-times exposure in multiple exposure, or the even-times exposure in multiple exposure.

4th kind of possible implementation, the first default exposure are the single exposure in specified even-times exposure, second Default exposure is the single exposure in other exposures in addition to specified even-times exposure, be that is to say, the second default exposure can Think the odd-times exposure in multiple exposure, or the even-times exposure in multiple exposure.

5th kind of possible implementation, the first default exposure are the single exposure in the first exposure sequence, and second is default Exposure is the single exposure in the second exposure sequence.

6th kind of possible implementation, the first default exposure are the single exposure in the second exposure sequence, and second is default Exposure is the single exposure in the first exposure sequence.

Wherein, above-mentioned multiple exposure includes multiple exposure sequences, and the first exposure sequence and the second exposure sequence are classified as multiple The same exposure sequence or two different exposure sequences in sequence are exposed, each exposure sequence includes n times exposure, the N Secondary expose includes that 1 time first default exposes presets exposure with N-1 times second, alternatively, n times exposure presets exposure including 1 time second Light and N-1 times second default exposure, N are the positive integer greater than 2.

For example, each exposure sequence includes 3 exposures, this 3 times exposures may include 1 time first default exposure and 2 times the Two default exposures, in this way, the 1st exposure of each exposure sequence can be for the first default exposure, the 2nd time and the 3rd time exposure Second default exposure.It that is to say, each exposure sequence can indicate are as follows: the first default exposure, the second default exposure, second are preset Exposure.Alternatively, this 3 times exposures may include 1 time second default exposure and 2 times first default exposures, in this way, each exposure sequence The 1st exposure can be the second default exposure, the 2nd time and the 3rd time exposure default exposes for first.It that is to say, each exposure Sequence can indicate are as follows: the second default exposure, the first default exposure, the first default exposure.

The above-mentioned possible implementation for providing only six kind of first default exposure and the second default exposure, practical application In, above-mentioned six kinds of possible implementations are not limited to, the embodiment of the present application does not limit this.

To sum up, when the visual intensity in environment light is weaker, such as night, 021 frequency of the first light compensating apparatus can be passed through Flash light filling generates imaging sensor 01 and exports the first picture signal comprising near-infrared luminance information, and comprising Second picture signal of visible light luminance information, and since the first picture signal and the second picture signal are passed by the same image Sensor 01 obtains, so the viewpoint of the first picture signal is identical as the viewpoint of the second picture signal, to be believed by the first image Number and the available complete outer scene of the second picture signal information.When visual intensity is stronger, for example, daytime, daytime The accounting of near infrared light is stronger, and the color rendition degree of the image of acquisition is bad, can be generated by imaging sensor 01 and defeated The third picture signal comprising visible light luminance information out, accordingly even when on daytime, can also collect color rendition degree and compare Good image, can efficiently, easily no matter daytime or night in other words no matter also can reach the power of visual intensity The realistic colour information for obtaining outer scene, improves the using flexible of image collecting device, and can also easily with Other image collecting devices are compatible with.

The application controls the near-infrared light filling timing of light compensating apparatus using the exposure time series of imaging sensor, so as to Carry out near-infrared light filling during one default exposure and generate the first picture signal, during the second default exposure not into Row near-infrared light filling simultaneously generates the second picture signal, such data acquisition modes, can it is simple in structure, reduce the same of cost When directly collect luminance information different the first picture signal and the second picture signal, namely just by an imaging sensor Available two different picture signals, so that the car license recognition equipment is easier, so that obtaining the first image letter Number and the second picture signal also more efficiently.Also, the first picture signal and the second picture signal are by the same image sensing Device is generated and is exported, so the corresponding viewpoint of the first picture signal viewpoint corresponding with the second picture signal is identical.Therefore, pass through First picture signal and the second picture signal can obtain the information of outer scene jointly, and there is no because of the first picture signal Corresponding viewpoint viewpoint corresponding with the second picture signal is not identical, and causes according to the first picture signal and the second picture signal The image of generation is misaligned.

In one embodiment of the application, referring to Figure 17, image processing unit, comprising:

Image pre-processing unit, image fusion unit and image identification unit；

Wherein, described image pretreatment unit, for the first image signal to be generated gray scale gray scale after pretreatment Second picture signal is generated color image by image after pretreatment；

Described image integrated unit obtains coloured silk for the color image and the gray level image to be carried out fusion treatment Color blending image；

Described image recognition unit, the color fusion image for being exported according to described image integrated unit is to described wait know Other license plate is identified, or, being identified according to the gray level image to the license plate to be identified.

Specifically, image can be passed through after getting the first picture signal and the second picture signal of sensor output Pretreatment unit first pre-processes the first picture signal and the second picture signal, respectively obtains pretreated gray level image And color image, fusion treatment is then carried out to color image and gray level image by image fusion unit, obtains color integration Image；The color fusion image or gray level image exported by image identification unit to image fusion unit identifies, obtains The license plate number of license plate to be identified.

Interior over any time period exposure can be preset by the first default exposure and second while being collected comprising near-infrared First picture signal of optical information and the second picture signal comprising visible optical information, it is subsequent according to first picture signal and The quality for the image that two picture signals are handled is higher, therefore the effect of Car license recognition is preferable.

Illustratively, in some embodiments, as shown in figure 18, image pre-processing unit can also include:

First pretreatment unit, the second pretreatment unit, and locate in advance with first pretreatment unit and second respectively Manage the joint noise reduction unit of unit connection；

Wherein, first pretreatment unit is obtained for carrying out the first pretreatment operation to the first image signal Pretreated gray level image；

Second pretreatment unit obtains colour for carrying out the second pretreatment operation to second picture signal Image；

The joint noise reduction unit is dropped for being filtered to the color image and the gray level image Color image and gray level image after making an uproar；Or,

As shown in figure 19, described image pretreatment unit, comprising:

Joint noise reduction unit, and the first pretreatment unit being connect respectively with the joint noise reduction unit and the second pre- place Manage unit；

Wherein, the joint noise reduction unit, for being filtered to the first image signal and second picture signal Wave processing, the first picture signal and the second picture signal after obtaining noise reduction；

First pretreatment unit is obtained for carrying out the first pretreatment operation to the first picture signal after noise reduction Pretreated gray level image；Second pretreatment unit is located in advance for carrying out second to the second picture signal after noise reduction Reason operation, obtains color image.

Wherein, the first pretreatment operation is for example including at least one of following operation: black level processing, bad point correction, brightness Calculating, gamma correction, noise reduction and Edge contrast；

Second pretreatment operation is for example including at least one of following operation: black level processing, bad point correction, white balance school Just, color interpolation, gamma correction, colour correction, RGB turn YUV operation, noise reduction and Edge contrast.

Joint noise reduction unit, for the correlation using information between the first picture signal and the second picture signal, to the One picture signal or the second picture signal carry out joint noise reduction process, such as joint bilateral filtering processing, obtain signal-to-noise ratio promotion Noise reduction after the first picture signal and the second picture signal.

It is right according to the correlation between the color image and the gray level image in some embodiments of the present application The color image and the gray level image carry out Federated filter processing respectively, color image and gray scale after obtaining the noise reduction Image；

Or, the joint noise reduction unit, is specifically used for:

According to the correlation between the first picture signal and the second picture signal, to the first image signal and the second figure As signal carries out Federated filter processing respectively, the first picture signal and the second picture signal after obtaining the noise reduction.

Illustratively, in one embodiment of the application, when imaging sensor is the sensor arranged in a manner of bayer, The picture signal of output will be mosaic image signal.First pretreatment unit can also carry out Marseille to the first picture signal Gram processing, thus the first picture signal after being repaired.

It should be noted that bilinear interpolation can be used when carrying out demosaicing processing to the first picture signal Or the methods of adaptive-interpolation method is handled, details are not described herein again.Further, image fusion unit includes: that color mentions Unit, brightness extraction unit are taken, the fusion treatment list connecting respectively with the Color Picking unit and the brightness extraction unit Member；

Wherein, the Color Picking unit, for extracting the chrominance signal of the color image；

The brightness extraction unit, for extracting the luminance signal of the color image；

The fusion treatment unit obtains filtered high-frequency signal for carrying out high-pass filtering to the gray level image；

Low-pass filtering is carried out to the luminance signal of the color image, obtains filtered low frequency signal；

Fusion treatment is carried out to the high-frequency signal, the low frequency signal and the chrominance signal, the colour is obtained and melts Close image.

Wherein, the fusion treatment unit, is specifically used for:

Fusion treatment is weighted to the high-frequency signal and the low frequency signal, obtains fusion luminance picture；

Fusion treatment is carried out to the chrominance signal of the fusion luminance picture and the color image, the colour is obtained and melts Close image.

Specifically, in Figure 17 image fusion unit function, be by the bright of the luminance signal of color image and gray level image Degree signal is weighted fusion, obtains fusion luminance picture, then synthesizes again with the chrominance signal of color image, obtain colour and melt Close image.

In Figure 20, low-pass filtering can be carried out to luminance signal before Weighted Fusion and obtain low frequency signal, to grayscale image High-frequency signal is obtained as carrying out High frequency filter, low frequency signal and high-frequency signal are weighted fusion and obtain fusion luminance picture.

Illustratively, it is assumed that the luminance signal of gray level image Y, color image are W, utilize high-pass filtering and low pass filtered Wave extracts the high-frequency signal of the luminance signal W of color image and the low-frequency information of gray level image Y, as described in following formula,

W_high=HPF (W)

Y_low=LPF (Y)

Wherein, HPF indicates that high-pass filter, LPF indicate low-pass filter, W_highIndicate the high-frequency signal of gray level image, Y_lowIndicate the low frequency signal of the luminance signal of color image.By the low frequency signal and gray level image of the luminance signal of color image High-frequency signal be added, obtain fusion luminance picture, i.e. FUS=W_high+VIS_low.It finally will fusion luminance picture and cromogram The chrominance signal of picture synthesizes, and obtains color fusion image.

Illustratively, as shown in figure 21, in the embodiment of the application, image identification unit, comprising:

License Plate unit, the Car license recognition unit being connect with the License Plate unit；

Wherein, the License Plate unit, the color fusion image for being exported according to described image integrated unit use Deep learning algorithm extracts the Color License Plate area image of the license plate to be identified；

The Car license recognition unit obtains described wait know for carrying out character recognition to the Color License Plate area image The license plate number of other license plate.

Specifically, when License Plate license plate area image can be extracted based on deep learning algorithm, first by color integration figure As input License Plate unit, color fusion image is generated into multiple candidate regions, calculates separately the feature of multiple candidate regions, One in multiple candidate regions is regard as license plate area image finally by classification, and license plate area image at this time is colored vehicle Board area image.

Character recognition is carried out to Color License Plate area image by Car license recognition unit, such as can be with advanced line character point It cuts and then carries out character recognition again, the license plate number identified.Vertical projection method for example can be used in Character segmentation, according to Have the characteristics that interval is equal between characters on license plate, upright projection is carried out to bianry image, is partitioned into character information；Character recognition is logical Frequently with template matching method, final character information is identified.

In another embodiment of the application, as shown in figure 22, described image recognition unit, comprising:

License Plate unit, the Car license recognition unit and image interception unit being connect respectively with the License Plate unit；

Wherein, the License Plate unit, the gray level image for being exported according to described image pretreatment unit, using depth Degree learning algorithm extracts the gray scale license plate area image of the license plate to be identified, and obtains license plate position in the license plate area image Set coordinate；

Described image interception unit, color fusion image and the vehicle for being exported according to described image integrated unit The license plate position coordinates of board positioning unit output, extract the Color License Plate area image of the license plate to be identified；

The Car license recognition unit, the gray scale license plate area image for being exported according to the License Plate unit carry out word Symbol identification, obtains the license plate number of the license plate to be identified.

Specifically, the first picture signal and the second picture signal can be with by image pre-processing unit and image fusion unit Output gray level image and color fusion image, (license plate is more clear in gray level image for License Plate and Car license recognition for gray level image It is clear, more conducively License Plate and identification), export license plate number；License Plate unit inputs obtained license plate position coordinates simultaneously To image interception unit, Color License Plate area image is taken from color fusion image, that is, removes license plate number, also exportable colored vehicle Board area image, color fusion image etc..

In the embodiment of the application, according to following formula (1) is referred to, noise reduction process is carried out to the color image, Color image after obtaining noise reduction；

(2) according to the following formula carry out noise reduction process to the gray level image, the gray level image after obtaining noise reduction；

Wherein, x, y indicate that the coordinate of any current pixel point, img_vis (x+i, y+j) indicate current picture in color image The pixel value of pixel in the corresponding neighborhood of vegetarian refreshments, img_vis'(x, y) it indicates in color image after current pixel point noise reduction Pixel value, img_nir (x+i, y+j) indicates the pixel of the pixel in gray level image in the corresponding neighborhood of current pixel point Value, img_nir'(x, y) indicate that pixel value in gray level image after current pixel point noise reduction, S indicate that current pixel point is corresponding Size of Neighborhood, weight (x+i, y+j)=weight_vis(x+i,y+j)+weight_nir(x+i, y+j), weight_vis(x+i,y+ It j) is the corresponding weight of current pixel point in color image, weight_nir(x+i, y+j) is current pixel point pair in gray level image The weight answered, weight_nir(x+i, y+j) and weight_vis(x+i, y+j) can pass throughMeter It calculates, f_xyIndicate the pixel value of current pixel point, f_ijIndicate that the pixel value of the neighborhood territory pixel point of current pixel point, i, j are neighborhood picture Vegetarian refreshments coordinate, δ₁, δ₂Indicate Gaussian Profile standard deviation.

In the embodiment of the application, following formula (3) can be referred to, the first image signal is carried out at noise reduction Reason, the first picture signal after obtaining noise reduction；

Following formula (4) can be referred to, noise reduction process be carried out to second picture signal, the second figure after obtaining noise reduction As signal；

Wherein, x, y indicate that the coordinate of any current pixel point, img1 (x+i, y+j) indicate current in the first picture signal The pixel value of pixel in the corresponding neighborhood of pixel, img1'(x, y) indicate current pixel point noise reduction in the first picture signal Pixel value afterwards, img2 (x+i, y+j) indicate the picture of the pixel in the second picture signal in the corresponding neighborhood of current pixel point Element value, img2'(x, y) indicate that pixel value in the second picture signal after current pixel point noise reduction, S indicate that current pixel point is corresponding Size of Neighborhood, weight (x+i, y+j)=weight_vis(x+i,y+j)+weight_nir(x+i, y+j), weight_vis(x+i, It y+j is) the corresponding weight of current pixel point in the first picture signal, weight_nir(x+i, y+j) be the second picture signal in when The corresponding weight of preceding pixel point, weight_nir(x+i, y+j) and weight_vis(x+i, y+j) can pass throughIt calculates, f_xyIndicate the pixel value of current pixel point, f_ijIndicate the neighborhood territory pixel point of current pixel point Pixel value, i, j be neighborhood territory pixel point coordinate, δ₁, δ₂Indicate Gaussian Profile standard deviation.

A kind of licence plate recognition method is also provided in the embodiment of the present application, is provided based on embodiment shown in above-mentioned Fig. 1-2 2 Car license recognition equipment is illustrated licence plate recognition method.Referring to fig. 23 this method comprises:

Step 240 carries out near-infrared light filling by the first light compensating apparatus that light aid includes, wherein at least pre- first If carrying out near-infrared light filling in the Partial exposure period of exposure, without close red in the exposure period of the second default exposure Outer light filling, the described first default exposure and the described second default exposure are wherein exposing twice in the multiple exposure of imaging sensor Light；

Step 241 during light filling, is made outside first light compensating apparatus carries out near-infrared by the filtering assembly The light and part near infrared light of visible light wave range pass through；

Step 242, after the filtering assembly is by the light and part near infrared light of visible light wave range, pass through the figure As sensor progress multiple exposure, to generate and export the first picture signal and the second picture signal, the first image signal It is the picture signal generated according to the described first default exposure, second picture signal is produced according to the described second default exposure Raw picture signal；The first image signal and second picture signal include the information of license plate to be identified；

Step 243, described image processing unit are according to the first image signal and second picture signal to described License plate to be identified is identified.

Illustratively, pass through the near infrared light of the filtering assembly when first light compensating apparatus carries out near-infrared light filling Intensity is higher than near infrared light intensity when first light compensating apparatus does not carry out near-infrared light filling by the filtering assembly.

Illustratively, further includes:

Visible light light filling is carried out by the second light compensating apparatus that light aid includes.

Illustratively, it is to set characteristic wavelength or fall that first light compensating apparatus, which carries out the central wavelength of near-infrared light filling, When setting characteristic wavelength range, reached by the central wavelength and/or waveband width of the near infrared light of first optical filter Constraint condition.

Illustratively, described image processing unit is according to the first image signal and second picture signal to described License plate to be identified is identified, comprising:

The first image signal is generated gray level image by image pre-processing unit after pretreatment, by second image Signal generates color image gray scale after pretreatment；

The color image and the gray level image are carried out fusion treatment by image fusion unit, obtain color integration figure Picture；

Image identification unit knows the license plate to be identified according to the color fusion image of described image fusion output Not, or, being identified according to the gray level image that described image pretreatment unit exports to the license plate to be identified.

Illustratively, the first image signal is generated gray level image by image pre-processing unit after pretreatment, by institute It states the second picture signal and generates color image gray scale after pretreatment, comprising:

First pretreatment unit carries out the first pretreatment operation to the first image signal, obtains pretreated gray scale Image；

Second pretreatment unit carries out the second pretreatment operation to second picture signal, obtains color image；

Joint noise reduction unit is filtered the color image and the gray level image, the colour after obtaining noise reduction Image and gray level image；Or,

Joint noise reduction unit is filtered the first image signal and second picture signal, obtains noise reduction The first picture signal and the second picture signal afterwards；

First pretreatment unit carries out the first pretreatment operation to the first picture signal after noise reduction, obtains pretreated Gray level image；

Second pretreatment unit carries out the second pretreatment operation to the second picture signal after noise reduction, obtains color image.

Illustratively, the color fusion image that described image recognition unit is exported according to described image fusion is to described wait know Other license plate is identified, comprising:

The color fusion image that License Plate unit is exported according to described image integrated unit is mentioned using deep learning algorithm Take the Color License Plate area image of the license plate to be identified；

Car license recognition unit carries out character recognition to the Color License Plate area image, obtains the vehicle of the license plate to be identified Trade mark code.

Illustratively, the gray level image that described image recognition unit is exported according to described image pretreatment unit, to described License plate to be identified is identified, comprising:

The gray level image that the License Plate unit is exported according to described image pretreatment unit, using deep learning algorithm The gray scale license plate area image of the license plate to be identified is extracted, and obtains license plate position coordinates in the license plate area image；

The color fusion image and the license plate that described image interception unit is exported according to described image integrated unit are determined The license plate position coordinates of bit location output, extract the Color License Plate area image of the license plate to be identified；

The Car license recognition unit carries out character knowledge according to the gray scale license plate area image that the License Plate unit exports Not, the license plate number of the license plate to be identified is obtained.

Illustratively, the color image and the gray level image are carried out fusion treatment by image fusion unit, obtain coloured silk Color blending image, comprising:

The Color Picking unit extracts the chrominance signal of the color image；

The brightness extraction unit extracts the luminance signal of the color image；

The fusion treatment unit carries out high-pass filtering to the gray level image, obtains filtered high-frequency signal；To institute The luminance signal for stating color image carries out low-pass filtering, obtains filtered low frequency signal；To the high-frequency signal, the low frequency Signal and the chrominance signal carry out fusion treatment, obtain the color fusion image.

Illustratively, the fusion treatment unit to the high-frequency signal, the low frequency signal and the chrominance signal into Row fusion treatment obtains the color fusion image:

Illustratively, the joint noise reduction unit is filtered the color image and the gray level image, obtains Color image and gray level image after to noise reduction, comprising:

According to the correlation between the color image and the gray level image, to the color image and the grayscale image As carrying out Federated filter processing, color image and gray level image after obtaining the noise reduction respectively.

Illustratively, the joint noise reduction unit is filtered the first image signal and second picture signal Processing, the first picture signal and the second picture signal after obtaining noise reduction, comprising:

According to the correlation between the first image signal and the second picture signal, to the first image signal and Two picture signals carry out Federated filter processing respectively, the first picture signal and the second picture signal after obtaining the noise reduction.

Illustratively, filtering assembly can also include the second optical filter and switching part, at this point, can also pass through switching part Second optical filter is switched to the incident side of imaging sensor by part.The second optical filter be switched to imaging sensor incident side it Afterwards, pass through the light of visible light wave range by the second optical filter, stop the light of near infrared light wave band, passing through in the second optical filter can The light of light-exposed wave band and after stopping the light of near infrared light wave band, is exposed by imaging sensor, to generate and export the Three picture signals.

Optionally, the wavelength band for being incident on the near infrared light of the first optical filter is first with reference to wavelength band, the first ginseng Examining wavelength band is 650 nanometers~1100 nanometers.

Optionally, the first light compensating apparatus carries out in the wave-length coverage that the central wavelength of near-infrared light filling is 750 ± 10 nanometers Any wavelength；Or

First light compensating apparatus carries out any wave in the wave-length coverage that the central wavelength of near-infrared light filling is 780 ± 10 nanometers It is long；Or

First light compensating apparatus carries out any wave in the wave-length coverage that the central wavelength of near-infrared light filling is 940 ± 10 nanometers It is long.

Optionally, constraint condition includes:

The center of near-infrared light filling is carried out by the central wavelength of the near infrared light of the first optical filter and the first light compensating apparatus Difference between wavelength is located within the scope of wavelength fluctuation, and wavelength fluctuation range is 0~20 nanometer.

Optionally, constraint condition includes:

It is less than or equal to 50 nanometers by the half-band width of the near infrared light of the first optical filter.

Optionally, constraint condition includes:

First band width is less than second band width；Wherein, first band width refers to through the close of the first optical filter The waveband width of infrared light, second band width refer to by the waveband width of the near infrared light of the first filter blocks.

Optionally, constraint condition are as follows:

Third waveband width, which is less than, refers to waveband width, and third waveband width refers to that percent of pass is greater than the close red of setting ratio Any waveband width in wavelength band that the waveband width of outer light is 50 nanometers~150 nanometers with reference to waveband width.

Optionally, any proportion in proportional region that setting ratio is 30%~50%.

Optionally, the first default exposure is different from least one exposure parameter of the second default exposure, at least one exposure Parameter is one of time for exposure, exposure gain, aperture size or a variety of, and exposure gain includes analog gain, and/or, number Word gain.

Optionally, exposure gain of the exposure gain of the first default exposure less than the second default exposure.

Optionally, the first default exposure is identical at least one exposure parameter of the described second default exposure, at least one Exposure parameter includes one of time for exposure, exposure gain, aperture size or a variety of, and exposure gain includes analog gain, and/ Or, digital gain.

Optionally, the time for exposure of the first default exposure is equal to the time for exposure of the second default exposure.

Optionally, imaging sensor includes multiple photosensitive channels, and each photosensitive channel is for incuding at least one visible light The light of wave band, and the light of induction near infrared band.

Optionally, multiple photosensitive channels are used to incude the light of at least two different visible light wave ranges.

Optionally, multiple photosensitive channels include the photosensitive channel R, the photosensitive channel G, the photosensitive channel B, the photosensitive channel Y, W photosensitive At least two in channel and the photosensitive channel C；

Wherein, the photosensitive channel R is used to incude the light of red spectral band and near infrared band, and the photosensitive channel G is for incuding green light The light of wave band and near infrared band, the photosensitive channel B are used to incude the light of blue wave band and near infrared band, and the photosensitive channel Y is used for Incude the light of yellow band and near infrared band, for incuding full wave light, the photosensitive channel C is complete for incuding in the photosensitive channel W The light of wave band.

Optionally, imaging sensor is RGB sensor, RGBW sensor or RCCB sensor or RYYB sensor.

Optionally, the second light compensating apparatus in a manner of being always on for carrying out visible light light filling；Or

Second light compensating apparatus is used to carry out visible light light filling with strobe mode, wherein at least in the described first default exposure The Partial exposure period in carry out visible light light filling, without visible light in the entire exposure period of the second default exposure Light filling；Or

Second light compensating apparatus is used to carry out visible light light filling with strobe mode, wherein at least in the whole of the first default exposure Without visible light light filling in a exposure period, visible light benefit is carried out within the Partial exposure period of the second default exposure Light.

Optionally, light filling number of first light compensating apparatus in unit time length is lower than imaging sensor in the unit time Exposure frequency in length, wherein in the interval time section per adjacent light filling twice, be spaced one or many exposures.

Optionally, imaging sensor carries out multiple exposure using global Exposure mode, for any near-infrared light filling, The exposure period of the period of near-infrared light filling and the closest second default exposure is not present intersection, near-infrared light filling when Between section be the first default exposure exposure period subset, alternatively, the period of near-infrared light filling and the first default exposure There are the subsets that the exposure period of intersection or the first default exposure is near-infrared light filling for exposure period.

Optionally, imaging sensor carries out multiple exposure using roller shutter Exposure mode, for any near-infrared light filling, Intersection is not present in the period of near-infrared light filling and the exposure period of the closest second default exposure；

When being no earlier than the exposure of last line effective image in the first default exposure at the beginning of near-infrared light filling and starting It carves, the finish time of near-infrared light filling is not later than the end exposure moment of the first row effective image in the first default exposure；

Alternatively,

Closest second before being no earlier than the first default exposure at the beginning of near-infrared light filling presets exposure most End exposure moment of a line effective image and when being not later than the end exposure of the first row effective image in the first default exposure afterwards It carves, the finish time of near-infrared light filling is no earlier than in the first default exposure exposure start time of last line effective image and not It is later than the exposure start time of the first row effective image of the default exposure of closest second after the first default exposure；Or

Closest second before being no earlier than the first default exposure at the beginning of near-infrared light filling presets exposure most End exposure moment of a line effective image and when being not later than the exposure of the first row effective image in the first default exposure and starting afterwards It carves, the finish time of near-infrared light filling is no earlier than in the first default exposure end exposure moment of last line effective image and not It is later than the exposure start time of the first row effective image of the default exposure of closest second after the first default exposure.

Optionally, multiple exposure includes odd-times exposure and even-times exposure；

First default exposure is the single exposure in odd-times exposure, and the second default exposure is primary in even-times exposure Exposure；Or

First default exposure is the single exposure in even-times exposure, and the second default exposure is primary in odd-times exposure Exposure；Or

First default exposure is the single exposure in specified odd-times exposure, and the second default exposure is except specified odd number The single exposure in other exposures except secondary exposure；Or

First default exposure is the single exposure in specified even-times exposure, and the second default exposure is except specified even number The single exposure in other exposures except secondary exposure；Alternatively,

First default exposure is the single exposure in the first exposure sequence, and the second default exposure is in the second exposure sequence Single exposure；Or

First default exposure is the single exposure in the second exposure sequence, and the second default exposure is in the first exposure sequence Single exposure；

Wherein, multiple exposure includes multiple exposure sequences, and the first exposure sequence and the second exposure sequence are classified as multiple exposure sequences An exposure sequence or two exposure sequences in column, each exposure sequence include n times exposure, and n times exposure includes 1 time first It presets to expose and preset for N-1 times second and expose, alternatively, n times, which are exposed, presets exposure with N-1 times second including 1 time second default exposes Light, N are the positive integer greater than 2.

It should be noted that the embodiment as shown in the present embodiment and above-mentioned Fig. 1-2 3 can use same invention structure Think, can be with reference to the explanation of related content in above-mentioned 3 illustrated embodiment of Fig. 1-2 accordingly, with respect to explaining for the present embodiment content, this Place repeats no more.

Those skilled in the art will readily occur to its of the disclosure after considering specification and practicing application disclosed herein Its embodiment.This application is intended to cover any variations, uses, or adaptations of the disclosure, these modifications, purposes or Person's adaptive change follows the general principles of this disclosure and including the undocumented common knowledge in the art of the disclosure Or conventional techniques.The description and examples are only to be considered as illustrative, and the true scope and spirit of the disclosure are by following Claims are pointed out.

It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and And various modifications and changes may be made without departing from the scope thereof.The scope of the present disclosure is only limited by appended claims System.

Claims

1. a kind of car license recognition equipment characterized by comprising

Filtering assembly, imaging sensor, light aid, image processing unit, described image sensor are located at the filtering assembly Light emission side；

Described image sensor, for being generated by multiple exposure and exporting the first picture signal and the second picture signal, wherein The first image signal is the picture signal generated according to the first default exposure, and second picture signal is pre- according to second If the picture signal that exposure generates, the described first default exposure and the described second default exposure be in the multiple exposure wherein Double exposure；The first image signal and second picture signal include the information of license plate to be identified；

The light aid includes the first light compensating apparatus, and first light compensating apparatus is for carrying out near-infrared light filling, wherein at least exists Near-infrared light filling is carried out in the Partial exposure period of described first default exposure, in the time for exposure of the described second default exposure Without near-infrared light filling in section；

Image processing unit, for according to the first image signal and second picture signal to the license plate to be identified into Row identification.

2. equipment according to claim 1, which is characterized in that first light compensating apparatus pass through when near-infrared light filling The intensity of the near infrared light of the filtering assembly is higher than when first light compensating apparatus does not carry out near-infrared light filling through the filter The near infrared light intensity of optical assembly.

3. equipment according to claim 1 or 2, which is characterized in that the light aid further includes the second light compensating apparatus, described Second light compensating apparatus is for carrying out visible light light filling.

4. equipment according to claim 3, which is characterized in that second light compensating apparatus is used to carry out in a manner of being always on can Light-exposed light filling；

Or

Second light compensating apparatus is used to carry out visible light light filling with strobe mode, wherein at least in the described first default exposure The Partial exposure period in carry out visible light light filling, without can in the entire exposure period of the described second default exposure Light-exposed light filling；

Or

Second light compensating apparatus is used to carry out visible light light filling with strobe mode, wherein at least in the described first default exposure Entire exposure period in without visible light light filling, carrying out within the Partial exposure period of the described second default exposure can Light-exposed light filling.

5. equipment according to claim 1 or 2, which is characterized in that

Described first default exposure is different from least one exposure parameter of the described second default exposure, at least one described exposure Parameter is one of time for exposure, exposure gain, aperture size or a variety of, and the exposure gain includes analog gain, and/ Or, digital gain.

6. equipment according to claim 1 or 2, which is characterized in that

Described first default exposure is identical at least one exposure parameter of the described second default exposure, at least one described exposure Parameter includes one of time for exposure, exposure gain, aperture size or a variety of, and the exposure gain includes analog gain, and/ Or, digital gain.

7. equipment according to claim 1 or 2, which is characterized in that

Described image sensor includes multiple photosensitive channels, and each photosensitive channel is for incuding at least one visible light wave range Light, and the light of induction near infrared band.

8. equipment according to claim 1 or 2, which is characterized in that

Described image sensor carries out multiple exposure using global Exposure mode, for any near-infrared light filling, near-infrared Intersection, the time of near-infrared light filling is not present in the period of light filling and the exposure period of the closest described second default exposure Section is the subset of the exposure period of the described first default exposure, alternatively, the period of near-infrared light filling is default with described first There are the subsets that the exposure period of intersection or the first default exposure is near-infrared light filling for the exposure period of exposure.

9. equipment according to claim 1 or 2, which is characterized in that

Described image sensor carries out multiple exposure using roller shutter Exposure mode, for any near-infrared light filling, near-infrared Intersection is not present in the period of light filling and the exposure period of the closest described second default exposure；

When being no earlier than the exposure of last line effective image in the described first default exposure at the beginning of near-infrared light filling and starting It carves, the finish time of near-infrared light filling is not later than the end exposure moment of the first row effective image in the described first default exposure；

Alternatively,

Closest second before being no earlier than the described first default exposure at the beginning of near-infrared light filling presets exposure most The end exposure moment of a line effective image and it is not later than the exposure knot of the first row effective image in the described first default exposure afterwards Beam moment, the exposure that the finish time of near-infrared light filling is no earlier than last line effective image in the described first default exposure start The exposure of the first row effective image of moment and the default exposure of closest second being not later than after the described first default exposure Start time；Or

Closest second before being no earlier than the described first default exposure at the beginning of near-infrared light filling presets exposure most It the end exposure moment of a line effective image and is not later than the exposure of the first row effective image in the described first default exposure afterwards and opens Begin the moment, the finish time of near-infrared light filling is no earlier than the end exposure of last line effective image in the described first default exposure The exposure of the first row effective image of moment and the default exposure of closest second being not later than after the described first default exposure Start time.

10. equipment according to claim 1 or 2, which is characterized in that

First light compensating apparatus carries out the central wavelength of near-infrared light filling as setting characteristic wavelength or falls in setting characteristic wave When long range, constraint condition is reached by the central wavelength and/or waveband width of the near infrared light of the filtering assembly.

11. equipment according to claim 10, which is characterized in that the constraint condition include it is following any one:

It is carried out in near-infrared light filling by the central wavelength of the near infrared light of the filtering assembly and first light compensating apparatus Difference between cardiac wave is long is located within the scope of wavelength fluctuation, and the wavelength fluctuation range is 0~20 nanometer；

Or

It is less than or equal to 50 nanometers by the half-band width of the near infrared light of the filtering assembly；

Or

First band width is less than second band width；Wherein, the first band width refers to through the filtering assembly The waveband width of near infrared light, the second band width refer to the wide waveband of the near infrared light stopped by the filtering assembly Degree；

Or

Third waveband width, which is less than, refers to waveband width, and the third waveband width refers to that percent of pass is greater than the close red of setting ratio The waveband width of outer light, described with reference to waveband width is any waveband width in 50 nanometers~150 nanometers of wavelength band, institute State any proportion in the proportional region that setting ratio is 30%~50%.

12. equipment according to claim 1 or 2, which is characterized in that described image processing unit, comprising:

Image pre-processing unit, image fusion unit and image identification unit；

Wherein, described image pretreatment unit, for the first image signal to be generated gray level image after pretreatment, by institute It states the second picture signal and generates color image after pretreatment；

Described image integrated unit obtains colour and melts for the color image and the gray level image to be carried out fusion treatment Close image；

Described image recognition unit, for according to described image fusion output color fusion image to the license plate to be identified into Row identification, or, being identified according to the gray level image that described image pretreatment unit exports to the license plate to be identified.

13. equipment according to claim 12, which is characterized in that described image pretreatment unit, comprising:

First pretreatment unit, the second pretreatment unit, and joint noise reduction unit；

Wherein, first pretreatment unit obtains pre- place for carrying out the first pretreatment operation to the first image signal Gray level image after reason；

Second pretreatment unit obtains color image for carrying out the second pretreatment operation to second picture signal；

The joint noise reduction unit, for being filtered to the color image and the gray level image, after obtaining noise reduction Color image and gray level image；Or,

Described image pretreatment unit, comprising:

Joint noise reduction unit, the first pretreatment unit and the second pretreatment unit；

Wherein, the joint noise reduction unit, for being filtered place to the first image signal and second picture signal Reason, the first picture signal and the second picture signal after obtaining noise reduction；

First pretreatment unit obtains pre- place for carrying out the first pretreatment operation to the first picture signal after noise reduction Gray level image after reason；

Second pretreatment unit obtains colour for carrying out the second pretreatment operation to the second picture signal after noise reduction Image.

14. equipment according to claim 12, which is characterized in that described image recognition unit, comprising:

License Plate unit, Car license recognition unit；

Wherein, the License Plate unit, the color fusion image for being exported according to described image integrated unit, using depth Learning algorithm extracts the Color License Plate area image of the license plate to be identified；

The Car license recognition unit obtains the vehicle to be identified for carrying out character recognition to the Color License Plate area image The license plate number of board.

15. equipment according to claim 12, which is characterized in that described image recognition unit, comprising:

License Plate unit, Car license recognition unit, image interception unit；

Wherein, the License Plate unit, the gray level image for being exported according to described image pretreatment unit, using depth It practises algorithm and extracts the gray scale license plate area image of the license plate to be identified, and obtain license plate position in the license plate area image and sit Mark；

Described image interception unit, the color fusion image and the license plate for being exported according to described image integrated unit are fixed The license plate position coordinates of bit location output, extract the Color License Plate area image of the license plate to be identified；

The Car license recognition unit, the gray scale license plate area image for being exported according to the License Plate unit carry out character knowledge Not, the license plate number of the license plate to be identified is obtained.

16. equipment according to claim 12, which is characterized in that image fusion unit includes: Color Picking unit, brightness Extraction unit, the fusion treatment unit being connect respectively with the Color Picking unit and the brightness extraction unit；

Fusion treatment is carried out to the high-frequency signal, the low frequency signal and the chrominance signal, obtains the color integration figure Picture.

17. equipment according to claim 16, which is characterized in that the fusion treatment unit is specifically used for:

Fusion treatment is carried out to the chrominance signal of the fusion luminance picture and the color image, obtains the color integration figure Picture.

18. equipment according to claim 13, which is characterized in that the joint noise reduction unit is specifically used for:

According to the correlation between the color image and the gray level image, to the color image and the gray level image point Not carry out Federated filter processing, color image and gray level image after obtaining the noise reduction.

19. equipment according to claim 13, which is characterized in that the joint noise reduction unit is specifically used for:

According to the correlation between the first image signal and the second picture signal, to the first image signal and the second figure As signal carries out Federated filter processing respectively, the first picture signal and the second picture signal after obtaining the noise reduction.

20. a kind of licence plate recognition method, which is characterized in that be applied to car license recognition equipment, the car license recognition equipment includes figure As sensor, light aid and filtering assembly, described image sensor are located at the light emission side of the filtering assembly, which is characterized in that The described method includes:

Near-infrared light filling is carried out by the first light compensating apparatus that light aid includes, wherein at least in the part of the first default exposure Near-infrared light filling is carried out in exposure period, it is described without near-infrared light filling in the exposure period of the second default exposure First default exposure and the described second default exposure are the wherein double exposure in the multiple exposure of imaging sensor；

Multiple exposure is carried out by described image sensor, to generate and export the first picture signal and the second picture signal, institute Stating the first picture signal is the picture signal generated according to the described first default exposure, and second picture signal is according to The picture signal that second default exposure generates；The first image signal and second picture signal include license plate to be identified Information；

Described image processing unit according to the first image signal and second picture signal to the license plate to be identified into Row identification.

21. according to the method for claim 20, which is characterized in that

By the intensity of the near infrared light of the filtering assembly higher than described when the first light compensating apparatus progress near-infrared light filling Pass through the near infrared light intensity of the filtering assembly when first light compensating apparatus does not carry out near-infrared light filling.

22. the method according to claim 20 or 21, which is characterized in that further include:

23. the method according to claim 20 or 21, which is characterized in that

24. the method according to claim 20 or 21, which is characterized in that described image processing unit is according to first figure As signal and second picture signal identify the license plate to be identified, comprising:

The first image signal is generated into gray level image after pretreatment, second picture signal is generated after pretreatment Color image；

The color image and the gray level image are subjected to fusion treatment, obtain color fusion image；

The license plate to be identified is identified according to the color fusion image, or, according to the gray level image, to it is described to Identification license plate is identified.