CN104243840A - Method and device for obtaining target image under hard light - Google Patents

Abstract

The invention discloses a method and device for obtaining a target image under hard light. An LED is modulated through a periodic sinusoidal modulation signal to illuminate a target, a computer sends a pulse signal TTL to control an LED array, images are synchronously collected through an SDK of a color CCD camera, RGB components of each image are respectively operated through the image reversal phase correlated operation technology, and therefore the target image under the hard light environment is extracted. An ordinary LED lamp and the color camera are adopted, the equipment cost is reduced, the color information of the target image can be effectively obtained, and the method and device can be applied to the fields of video monitoring and industrial inspecting.

Description

A kind of method and device obtaining target image under high light

Technical field

The invention belongs to electronic information technical field, be specifically related to a kind of image processing method and device.

Background technology

Under normal circumstances, when strong bias light and interested target one are in the visual field of imaging system together, target image will be buried in strong bias light or complex background, imaging system is made to lose imaging capability to target, target image is difficult to obtain, and the image that general method obtains not to be effect bad be exactly the image obtained is gray level image, the original information of target image cannot be obtained under strong bias light.

In the middle of industry monitoring, intense light source is unavoidably had to disturb testing environment.Such as in the measuring system of rail wear, due to the impact of strong sunlight and unknown light source, the image collected there will be the situation of strong bias light interference.Carry out crack detection to just shaping steel billet in addition, the object detected like this is that Timeliness coverage produces the quality of steel billet, thus production system is debugged as early as possible.And this just requires to detect the crackle of steel billet be also under the condition of high temperature or molten steel and other molten metal surfaces, and require the surround lighting remained with in certain special cases, because high temperature and flame are very strong, still lack effective image checking means at present.

In video monitoring system, one is to monitor in real time, reacts in time; Two is will obtain more information as far as possible.At present, video monitoring system has a wide range of applications in security fields.In city emergency traffic administration, various violation phenomenon is monitored, and relate to the identification of car plate under night or daytime high light here, the imaging system obtaining car plate can receive the irradiation of car light, license board information can to cover by the high light of car light and the ccd image sensor of imaging system can reach capacity, thus effectively cannot obtain the information of car plate; Enter 21 century, no matter terrorist attack and destruction are in scope, scale, frequency, or in technology, means, harmfulness etc., reach serious degree, and have the trend continuing to expand, along with the continuous progress of society and the development of economic construction, the pernicious accident that various social contradications cause also increases increasingly, and there is popularity, chronicity, complexity, prior sign is few, be difficult to prediction and paroxysmal feature.Video monitoring is as safety-protection system important component part, and directly perceived with it, convenient, the information content is enriched and is widely used in anti-terrorism field.Usual supervisory control system requires automatically, continuously to work, and the robustness of system is with regard to particular importance, and therefore the impact of system on factors such as such as noise, illumination, weather can not be too responsive.Such as in an outdoor environment, due to cloud in sky movement, rise the impact of the factors such as sunset day, very complicated to making light change; In indoor environment by the switch of the switch of door and window, electric light, light block and reflect, light that the factor such as the saturation effect that caused by light all can cause changes, and requires system in actual applications as far as possible not by the impact of these factors.The picture of the video monitoring system of the current overwhelming majority is all gray image, and video pictures is very undesirable when there being high light, in addition except seeing the appearance of monitored object, can not obtain more information, as color, and the filtering etc. of bias light.

Application so widely needs a kind of effective ways obtaining target image under strong bias light, thus sees target image clearly from invisible environment.

The people such as University of Electronic Science and Technology remaining, Su Ke proposed laser lock imaging technical scheme in 2010.The system of the program as shown in Figure 1.This laser lock imaging device, comprises one-period modulation signal generator, a semiconductor laser, divergence lens, an optically filtering sheet, CCD focal plane array, a video processing circuits and a display screen; The periodic modulation signal that periodic modulation signal generator produces is used for the laser that semiconductor laser modulation produces, and make semiconductor laser produce periodic modulation laser, periodic modulation laser irradiates field of regard after divergence lens diverges; The target scattering laser of field of regard and bias light are at the uniform velocity gathered by CCD focal plane array after carrying out the filtering of optically filtering sheet, obtain the sensed image of a series of field of regard; The sensed image of the field of regard that the periodic modulation signal produce periodic modulation signal generator and CCD focal plane array collect is stored in the memory in video processing circuits, the phase demodulation process of the sensed image of field of regard is completed: namely within the modulation period of one or an integer periodic modulation signal by video processing circuits, each the width sensed image of the field of regard collected by CCD focal plane array is multiplied with the periodic modulation signal gathering this sensed image corresponding moment, and then is superimposed as the target image that a width finally eliminates bias light; Target image shows finally by display.

Its feature: Active Imaging, phase discriminating technology combines with optics and has certain versatility, requires low to the complexity of environment, the advantages such as anti-various light disturbance ability is strong.This technology obtains application in measurement of rail wear based system and steel billet profile real-time measuring system.But also have weak point: one be this technology obtain target image be gray level image, the colour element information obtaining target under strong light environment cannot be met; Two is that this technology uses laser monochromatic source, and infrared phase video camera or B/W camera gather image, and cost is relatively high.Limit the scope of application of lock imaging technology.

Summary of the invention

In order to solve the problem, the present invention proposes a kind of under high light, obtain target image method and device.

Concrete technical scheme of the present invention is as follows:

Under high light, obtain a method for target image, comprise the following steps:

S1: adopt periodic sinusoidal modulation signal to modulate LED light source, gained modulation LED light source irradiates field of regard;

S2: adopt optically filtering sheet to carry out filtering process to the target scattering LED light of field of regard and bias light;

S3: the target scattering LED light after filtering process and bias light, adopt CCD focal plane array synchronous acquisition, obtain the sensed image of a series of field of regard, described step 2 specifically comprises the following steps:

S31: half period before sinusoidal modulation signal modulation, adopts high level pulse signal TTL, and field of regard is irradiated in control LED luminescence, and the synchronous CCD of employing focal plane array gathers A two field picture;

S32: sinusoidal modulation signal modulation later half cycle, adopts low level pulse signal TTL, controls LED light source and closes, and the synchronous CCD of employing focal plane array gathers the A two field picture identical with the front half period;

S33: the pixel RGB that the half period before sinusoidal modulation signal modulation obtains the same position of image is added up respectively, then deducts the RGB accumulated value of the later half cycle same position pixel of sinusoidal modulation signal modulation, obtain target image;

Further, the synchronous acquisition of described CCD focal plane array, is realized by the SDK of colourful CCD video camera.

The present invention provides a kind of device obtaining target image under high light simultaneously, comprises a computer, a CCD focal plane array, a LED array; Computer provides periodic modulation signal and sinusoidal signal for modulating LED light, provides TTL pulse signal to control LED luminous simultaneously, irradiates field of regard; The target scattering LED light of field of regard and bias light are gathered by CCD focal plane array after carrying out the filtering of optically filtering sheet, obtain the sensed image of a series of field of regard; The image obtaining field of regard is stored in computer, and complete the anti-phase calculation process of the sensed image of field of regard: namely within the modulation period of one or several periodic modulation signal, each width sensed image of the field of regard of CCD focal plane array collection be multiplied with the periodic modulation signal in corresponding moment, then superposition produces the target image of last removal bias light; Target image shows finally by computer display.

Beneficial effect of the present invention: the present invention proposes a kind of method and the device that obtain target image under high light, adopt and by periodic sinusoidal modulation signal modulation LED, target is irradiated, computer sends pulse signal TTL and controls LED array, and carry out synchronous acquisition image by the SDK of colourful CCD video camera, the anti-phase related operation technology of image is utilized to carry out calculation process to RGB tri-components of image respectively, thus the target image under extraction strong light environment, the present invention adopts common LED lamp and color camera, reduce equipment cost, and effectively can obtain the colour information of target image, can be applicable to the field such as video monitoring and industrial detection.

Accompanying drawing explanation

Fig. 1 is laser lock imaging technical schematic diagram in prior art.

Fig. 2 is image procossing schematic diagram provided by the invention.

Embodiment

Below in conjunction with specific embodiment, content of the present invention is described further.

Concrete scheme of the present invention as shown in Figure 2, specifically comprises the following steps:

S1: adopt periodic sinusoidal modulation signal to modulate LED light source, gained modulation LED light source irradiates field of regard;

S2: adopt optically filtering sheet to carry out filtering process to the target scattering LED light of field of regard and bias light;

S3: the target scattering LED light after filtering process and bias light, adopt the SDK of colorful CCD camera to control camera synchronization collection, obtain the sensed image of a series of field of regard, described step 2 specifically comprises the following steps:

S31: half period before sinusoidal modulation signal modulation, adopts high level pulse signal TTL, and field of regard is irradiated in control LED luminescence, and Synchronization Control colorful CCD camera gathers A two field picture, the value of described A value for presetting;

S32: sinusoidal modulation signal modulation later half cycle, adopts low level pulse signal TTL, control LED light source and close, and Synchronization Control colorful CCD camera gathers the A two field picture identical with the front half period;

S33: the pixel RGB that the half period before sinusoidal modulation signal modulation obtains the same position of image is added up respectively, then deducts the RGB accumulated value of the later half cycle same position pixel of sinusoidal modulation signal modulation, obtain target image.

Operation principle of the present invention is as follows:

Utilize LED light source from strong light environment, obtain the colour information of target image, mainly anti-phase algorithm process has been carried out respectively to target image RGB tri-components.

The embodiment of the present invention is described with the anti-phase computing of the R component of target image.

Field of regard is irradiated owing to adopting the LED light source of sinusoidal modulation signal modulation, the light intensity of colorful CCD camera target acquisition scattering is also sinusoidal variations, but the light intensity of surround lighting is indeclinable, be located at colorful CCD camera in a sinusoidal voltage modulation period and acquire N two field picture, m two field picture can be expressed as in the R component of the pixel at point (x, y) place

G _R(m)＝G _C(m)cosΦ ₁+G _L(m)cosΦ ₂ (1)

Wherein, G _cm () is the R component in strong light environment, wherein comprise the interference signal (dark current) of colorful CCD camera inside, G _lm light scattering that () sends for LED is to the R component of the target image in target; Φ ₁, Φ ₂respective phase constant respectively.

Modulation voltage due to LED is sinusoidal signal, so the R component G of target area image _lm () can be expressed as

G _L(m)＝G _L0[1+ξsin(ωmΔI+Φ)] (2)

Wherein, G _l0for not adding modulation voltage, LED is under rated voltage work, colorful CCD camera collects the image R component of field of regard, Δ I is the time interval that camera obtains two width images, Φ is known constant, is the phase information of modulation signal, and ξ is modulate intensity, ω is signal of telecommunication modulation angular frequency, and carrying out multiplying has G _m(m):

$\begin{array}{c}{G}_m\left(m\right)=\{G_C\left(m\right)+G_{L0}[1+\mathrm{\ξ}\sin (\mathrm{\ωm\ΔI}+\mathrm{\Φ})\left]\right\}\×\sin \left(\mathrm{\ωm\ΔI}\right)=\\ [G_C\left(m\right)+G_{L0}]\sin \left(\mathrm{\ωm\ΔI}\right)+\frac{1}{2}{G}_{L0}\mathrm{\ξ}\cos \mathrm{\Φ}+\frac{1}{2}\mathrm{\ξ}{G}_{L0}\cos (2\mathrm{\ωm\ΔI}+\mathrm{\Φ})\end{array}---\left(3\right)$

To G _cm the image collected in () monocycle carries out the integration of image R component, because picture signal is discrete, process transition of quadraturing is summation:

$G_R\left(m\right)=\underset{m=1}{\overset{N}{\mathrm{\Σ}}}{G}_C\left(m\right)=\frac{1}{2}{G}_{\mathrm{RL}0}\mathrm{N\ξ}\cos \mathrm{\Φ}---\left(4\right)$

Wherein, G _rm () is expressed as the R component distribution after the summation of m frame target image, N represents the number of image frames of acquisition.

Superpose because use sinusoidal modulation signal to carry out after locking is multiplied, in one-period, frequency signal obtains filtering, so [the G in (3) formula again _c(m)+G _l0] sin (ω m Δ I) and all can cancel out each other, only have reflection field of regard scattering LED light signal retained, thus by the gray scale filtering of field of regard bias light.In like manner can show that image G, B component is respectively:

$G_G\left(m\right)=\underset{m=1}{\overset{N}{\mathrm{\Σ}}}{G}_G\left(m\right)=\frac{1}{2}{G}_{\mathrm{GL}0}\mathrm{N\ξ}\cos \mathrm{\Φ}---\left(5\right)$

$G_B\left(m\right)=\underset{m=1}{\overset{N}{\mathrm{\Σ}}}{G}_B\left(m\right)=\frac{1}{2}{G}_{\mathrm{BL}0}\mathrm{N\ξ}\cos \mathrm{\Φ}---\left(6\right)$

From formula (4), formula (5), formula (6): after above algorithm process, the RGB component of strong light environment is almost by complete filtering, only have the image RGB component information of target area, and the only strong figure direct proportionality with the phase place of added modulation signal.

Therefore, the target image method showing to utilize LED light source to obtain under high light background can effectively obtain targeted color image information, and this system has strong surround lighting inhibitory action.

The present invention provides a kind of device obtaining target image under high light simultaneously, comprises a computer, a CCD focal plane array (colorful CCD camera), a LED array; It is luminous that computer provides TTL pulse signal to control LED, provides periodic modulation signal and sinusoidal signal for modulating LED light simultaneously, irradiates field of regard; The target scattering LED light of field of regard and bias light are gathered by CCD focal plane array after carrying out the filtering of optically filtering sheet, obtain the sensed image of a series of field of regard; The image obtaining field of regard is stored in computer, and complete the anti-phase calculation process of the sensed image of field of regard: namely within the modulation period of one or several periodic modulation signal, each width sensed image of the field of regard of ccd array collection be multiplied with the periodic modulation signal in corresponding moment, then superposition produces the target image of last removal bias light; Target image shows finally by computer display.

The present invention, when carrying out anti-phase calculation process to the sensed image of target, is by the sensed image in or several modulation period is processed into a width target image.Bias light eliminate number with modulation period number relevant, more overall background light is fewer for periodicity; In addition for moving target, need modulating frequency to increase, also will improve the sample frequency of CCD focal plane array simultaneously.And the process of target image is all come by computer, so will improve processing speed and can adopt the computer or translation and compiling environment that performance is high while guarantee image definition, control LED can adopt drive circuit and without relay in addition.

The present invention proposes a kind of under high light, obtain target image method and device, adopt and by periodic sinusoidal modulation signal modulation LED, target is irradiated, computer sends pulse signal TTL and controls LED array, and carry out synchronous acquisition image by the SDK of colourful CCD video camera, the anti-phase related operation technology of image is utilized to carry out calculation process to RGB tri-components of image respectively, thus the target image under extraction strong light environment, the present invention adopts common LED lamp and color camera, reduce equipment cost, and effectively can obtain the colour information of target image, can be applicable to the field such as video monitoring and industrial detection.

Those of ordinary skill in the art will appreciate that, embodiment described here is to help reader understanding's principle of the present invention, should be understood to that protection scope of the present invention is not limited to so special statement and embodiment.For a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within right of the present invention.

Claims (3)

1. under high light, obtain a method for target image, it is characterized in that, comprise the following steps:

S1: adopt periodic sinusoidal modulation signal to modulate LED light source, gained modulation LED light source irradiates field of regard;

S2: adopt optically filtering sheet to carry out filtering process to the target scattering LED light of field of regard and bias light;

S3: the target scattering LED light after filtering process and bias light, adopt CCD focal plane array synchronous acquisition, obtain the sensed image of a series of field of regard, described step 2 specifically comprises the following steps:

S31: half period before sinusoidal modulation signal modulation, adopts high level pulse signal TTL, and field of regard is irradiated in control LED luminescence, and the synchronous CCD of employing focal plane array gathers A two field picture;

S32: sinusoidal modulation signal modulation later half cycle, adopts low level pulse signal TTL, controls LED light source and closes, and the synchronous CCD of employing focal plane array gathers the A two field picture identical with the front half period;

S33: the pixel RGB that the half period before sinusoidal modulation signal modulation obtains the same position of image is added up respectively, then deducts the RGB accumulated value of the later half cycle same position pixel of sinusoidal modulation signal modulation, obtain target image.

S3: the pixel RGB that the sinusoidal modulation signal modulation front half period that S2 obtains in steps obtains the same position of image is added up respectively, then deducts the RGB accumulated value of the later half cycle same position pixel of sinusoidal modulation signal modulation, obtain target image.

2. a kind of method obtaining target image under high light according to claim 1, is characterized in that, the synchronous acquisition of described CCD focal plane array is realized by the SDK of colourful CCD video camera.

3. under high light, obtain a device for target image, it is characterized in that, comprise a computer, a CCD focal plane array, a LED array; Computer provides periodic modulation signal and sinusoidal signal for modulating LED light, provides TTL pulse signal to control LED luminous simultaneously, irradiates field of regard; The target scattering LED light of field of regard and bias light are gathered by CCD focal plane array after carrying out the filtering of optically filtering sheet, obtain the sensed image of a series of field of regard; The image obtaining field of regard is stored in computer, and complete the anti-phase calculation process of the sensed image of field of regard: namely within the modulation period of one or several periodic modulation signal, each width sensed image of the field of regard of CCD focal plane array collection be multiplied with the periodic modulation signal in corresponding moment, then superposition produces the target image of last removal bias light; Target image shows finally by computer display.