Summary of the invention
The technical problem to be solved in the present invention provides the video camera night vision illumination system that a kind of optics utilization factor height, angle of divergence range of adjustment are big, with due attention to both short and long-range targets.
For addressing the above problem, a kind of video camera night vision illumination of the present invention system comprises control module and the power module that links to each other with control module, photoresistance, optical coupled switch and stepper motor; Wherein, power module links to each other with infrared light supply, and the infrared light supply front end is provided with the angle camera lens, and stepper motor links to each other with the angle camera lens, it is characterized in that: described video camera night vision illumination system also comprises laser range sensor, and this laser range sensor links to each other with control module.
Described angle camera lens comprises first lens, second lens and the high permeability window mirror that is successively set on the infrared light supply front end, and stepper motor is mobile between infrared light supply and high permeability window mirror by transmission mechanism control first lens and second lens.
Described gear train comprises the leading screw that is fixed on the stepper motor clutch end, and is enclosed within the nut on the leading screw, and first lens and second lens are installed on the nut.
First lens in the described angle camera lens, second lens and high permeability window mirror, focal distance f 1~f3, radius of curvature R 1~R6, refractive index n 1~n3 meet the following conditions respectively:
5<f1<27 1.40<n1<1.65 6<R1<35 -9.7<R2<-36
10<f2<49 1.45<n2<1.92 5.5<R3<42 -7.0<R4<-35
750<f3<∞ 1.45<n3<1.92 524.8<R5<∞ -524.8<R6<∞
The unit of its mid-focal length and radius-of-curvature is mm;
Described first lens, second lens under the drive of stepper motor, its axially on away from or near infrared light supply, wherein the scope of the first lens distance infrared light supply is: 2.5~42mm.
The angle of divergence (FWHM) scope of described video camera night vision illumination system is: 0.89 °~50.15 °.
Described first lens, second lens and high permeability window mirror surface are coated with the infrared light anti-reflection film.
The control method of described video camera night vision illumination system may further comprise the steps:
1) video camera night vision illumination system initialization;
2) control system monitors whether the distance B of illuminated object and video camera night vision illumination system is 0; If monitoring result is for being then to enter 6) step; If monitoring result enters 3 for not) step;
3) whether the distance B of illuminated object and video camera night vision illumination system is greater than D
0If monitoring result is for being to enter 4) step; If monitoring result then enters 5 for not) step;
4) whether start laser ranging interlock angle pattern; If for being then to enter 5) step; If for not, enter 6) step.
5) start laser ranging interlock angle pattern;
6) start video camera and become the angle pattern that doubly links;
Night vision illumination system among the present invention, the spread angle range of bright dipping is big, takes into account far and near illumination simultaneously, satisfies the demand of camera field of view; The effective rate of utilization height of light, light path design is simpler, and is respond well to remote illumination power; With low cost, be easy to the assembling of processing and later stage; The present invention adopts laser ranging interlock angle, and is safe and reliable, can effectively avoid the potential safety hazard of this laser product.
Embodiment
In order to make those skilled in the art person understand technical solution of the present invention better, the present invention is described in further detail below in conjunction with drawings and embodiments.
As shown in Figure 1, video camera night vision illumination of the present invention system comprises control module and the power module that links to each other with control module, photoresistance, optical coupled switch, stepper motor and laser range sensor; Power module links to each other with infrared light supply, and the infrared light supply front end is provided with the angle camera lens, and stepper motor links to each other with the angle camera lens.
Wherein power module is adjustable constant-flow source current module, for whole night vision illumination system provides power supply; External environment condition illumination intensity is monitored in photoresistance, and monitoring information is passed to control module, and then control module judges whether to start the night vision illumination system; Optical coupled switch is used for the control step motor when starting the night vision illumination system, and the angle camera lens is carried out position initialization; Stepper motor drive the angle camera lens away from or near infrared light supply, thereby reach the purpose of adjusting rising angle; Laser range sensor is positioned at the front end of night vision illumination system, is used for the distance between monitoring irradiated object and the night vision illumination system.
As shown in Figure 2, described angle camera lens comprises first lens 2, second lens 3 and the high permeability window mirror 4 that is successively set on infrared light supply 1 front end, and described first lens 2, second lens 3 and high permeability 4 window mirror surfaces are coated with the infrared light anti-reflection film.
The clutch end of stepper motor 5 fixedly has leading screw 6, and nut 7 is enclosed within on the leading screw 6; Installation shaft 8 is positioned at leading screw 6 tops and parallels with leading screw 6, first lens 2 and second lens 3 are positioned on the installation shaft, and fix with nut 7, can be under the drive of stepper motor 5 along installation shaft 8 axially, movement between infrared light supply 1 and high permeability window mirror 4.
Shown in Fig. 3,4,5, stepper motor 5 drives first lens 2, second lens 3 move axially, and changes the distance of itself and infrared light supply 1.When distance was more near, the light angle of divergence was more little; Otherwise then the light angle of divergence is more big.
First lens in the described angle camera lens, second lens and high permeability window mirror, focal distance f 1~f3, radius of curvature R 1~R6, refractive index n 1~n3 meet the following conditions respectively:
5<f1<27 1.40<n1<1.65 6<R1<35 -9.7<R2<-36
10<f2<49 1.45<n2<1.92 5.5<R3<42 -7.0<R4<-35
750<f3<∞ 1.45<n3<1.92 524.8<R5<∞ -524.8<R6<∞
The unit of its mid-focal length and radius-of-curvature is mm;
Described first lens, second lens are under the drive of stepper motor, its axially on away from or near infrared light supply, wherein the scope of the first lens distance infrared light supply is: 2.5~42mm, its light angle (FHWM) variation range is: 0.89 °~50.15 °.
For avoiding burning human eye or cause potential safety hazard such as fire, night vision illumination of the present invention system adopts two kinds of interlock schemes: laser ranging interlock angle pattern and video camera become the angle pattern that doubly links.
Wherein, D
0Safe distance when throwing light on peak power and minimum divergence angle for the night vision illumination system; Simultaneously, repeatedly measure according to reality, under the prerequisite of considering the illuminator individual difference, the light distribution that draws by statistics when the hot spot unit area is E
0The time, illuminating effect is more excellent and to the comparatively safe (E of human eye
0<0.9W/m
2).
Night vision illumination system and illuminated object distance are at D
0In, all adopt laser ranging interlock angle to focus.The control module of illuminator is according to the illumination distances value D that obtains in real time, and regulating the angle of divergence automatically, to make its light distribution theory average at the hot spot at D place be E
0
Night vision illumination system and illuminated object distance surpass D
0After, regardless of the light dispersion angle of night vision illumination system, the intensity of illumination on the final hot spot unit area all can not cause potential safety hazard.Therefore, the night vision illumination system can adopt video camera to become the angle pattern that doubly links, and becomes doubly interlock according to the video camera zoom lens and focuses.Certainly, the night vision illumination system also can adopt laser ranging interlock angle pattern to focus, till the angle of divergence is transferred to Upper threshold or Lower Threshold;
When the distance value D that obtains in real time is sky, then illuminator adopts video camera to become the angle pattern that doubly links, follow video camera fully and become and doubly to focus, this measure illuminator when making no laser range sensor or its work undesired also can be followed video camera and be become doubly that a realization links.
A kind of video camera night vision illumination system control method may further comprise the steps:
1) video camera night vision illumination system initialization; This step is by photoresistance induced environment intensity of illumination, and control module is judged as Night and starts infrared illumination system; Simultaneously by optical coupled switch control step motor initialization angle camera lens;
2) control system monitors whether the distance B of illuminated object and video camera night vision illumination system is 0; If monitoring result is for being then to enter 6) step; If monitoring result enters 3 for not) step; Behind system's power-up initializing, read the D value; If it all is 0 that continuous several times is read the D value, can think that then laser range sensor is unusual, become the angle pattern that doubly links so directly enter video camera; If D is not 0, judge that then distance measuring sensor is normal, enter the stage that D value linkage is read in circulation;
3) whether the distance B of illuminated object and video camera night vision illumination system is greater than D
0If monitoring result is for being to enter 4) step; If monitoring result then enters 5 for not) step;
4) whether start laser ranging interlock angle pattern; If for being then to enter 5) step; If for not, enter 6) step.
5) start laser ranging interlock angle pattern; Under the laser ranging interlock angle pattern in this step, by laser range sensor illuminated object is carried out the distance monitoring, again this range information is passed to control system, control system is according to the light angle of divergence of this distance adjustment illuminator, thereby the light intensity on guarantor unit's area is in than stationary value, guarantees good illuminating effect and ensures lighting safety;
6) start video camera and become the angle pattern that doubly links; Video camera in this step becomes under the angle pattern that doubly links, and stepper motor drives angle camera lens zoom, and the visual angle of its searchlighting angle and video camera zoom lens is complementary.