CN1753490A - Weather interference resistant image acquiring system - Google Patents

Abstract

This invention relates to an anti-weather interference image collection system, in which, an AD converter converts the picked up image signals to digital image signals to be input to a computer via a communication interface, a time weight module gets time weight by time parameters and a parameter input module transmits the parameter information to a computer to transfer the modulated transferred function signals of the image to a signal filter module to filer the original image to get a recovered image of the weather. The work flow is: 1, initialization, 2,image collection, 3, image pre-process, 4, time weight computation, 5, computation of index of refraction structure constant, 6, computing the atmosphere modulated transferred function, 7, image filter, 8, storing the image 9, displaying the image.

Description

Weather interference resistant image acquiring system

Technical field

The invention belongs to the weather image process field, particularly a kind of to being subjected to the method that weather interference attenuation image restores.

Background technology

The world today, human vision can not satisfy the needs in other field in industrial circle and human lives far away.The appearance of computer vision system has remedied the deficiency of human vision, has all obtained using widely in a plurality of fields computer visions such as industry manufacturing, control of traffic and road, monitoring in real time, and it plays an increasingly important role in Human's production and life.Acquisition technology has also obtained widely development as one of computer vision important part in every field, especially in the field that need monitor and need information stores in real time to observed object (for example: control of traffic and road) more important.Common image capturing system is in the process that outdoor image is gathered, and it is very serious that the quality of image is subjected to the interference of weather condition.The picture quality that collects when fine is fine, can reach the standard of design in advance; But under atrocious weather conditions such as mist, haze, the quality serious degradation of image, even the objective fuzzy in the image are difficult to identification.This situation has had a strong impact on the stability of image capturing system, is subjected to simultaneously that weather disturbs and the image of degenerating also can have influence on the operate as normal of other system.Need a kind of image capturing system that can resist weather to disturb of design, this system can equally with other image capturing system take and IMAQ outdoor target when the weather condition is good; When the weather inclement condition, when influencing picture quality, this system can eliminate the influence of weather to picture quality to a certain extent, to be subjected to the decay image restoration of weather effect for comparing distinct image, make that under the atrocious weather condition this image capturing system still can keep stability and reliability preferably.

Summary of the invention

The present invention is primarily aimed at the problem that exists in the outdoor image acquisition system, provide a kind of simple in structure, image definition is high, recovery effect good, easy to use, Weather interference resistant image acquiring system that cost is low, be interfered and can the image of decay be restored during the image attenuation that causes photographing in weather condition, guarantee the quality of images acquired.

Native system comprises video camera, analog to digital converter, image acquisition device, data-interface, computer, time weights module, the parameter input module, filtration module, video memory and image display, video camera is given analog to digital converter with the analog picture signal that photographs, analog to digital converter is converted to data image signal with analog image and imports computer through communication interface, time weights module obtains the time weights by time-parameters and flows to computer, the parameter input module is given computer with the parameter information conveyance, computer is given filtration module with the atmosphere modulation transfer function signal conveys of image, filtration module carries out Filtering Processing to original image, obtain the weather restored image, give video memory and image display to the picture signal after restoring and store and show.

The workflow of Weather interference resistant image acquiring system, its job step is:

(1) initialization is carried out initialization to system;

(2) images acquired uses video camera that image is gathered;

(3) image preliminary treatment is handled the level and smooth and sharpening of image, and the removal of images noise also makes image edge clear;

(4) computing time weights, by the input time-parameters weights computing time;

(5) calculate refractive index structure parameter, utilize time weights and meteorological Parameters Calculation refractive index structure parameter;

(6) calculate atmosphere modulation transfer function MTF, by two component turbulent flow modulation transfer function MTF of the atmosphere modulation transfer function that calculates _eWith aerosol modulation transfer function MTF _a, draw atmosphere modulation transfer function MTF then;

(7) image filtering uses atmosphere modulation transfer function MTF that original image is carried out filtering;

(8) memory image, the image after storage is restored;

(9) display image shows the image after restoring.

That the present invention has is simple in structure, image definition is high, recovery effect good, easy to use, low cost and other advantages, is applicable to the environment that various outdoor image are gathered.

Description of drawings

Fig. 1 Weather interference resistant image acquiring system structured flowchart;

Fig. 2 Weather interference resistant image acquiring system workflow diagram;

Among the figure: 1 video camera, 2 analog to digital converters, 3 image acquisition devices, 4 data-interfaces, 5 computers, 6 time weights modules, 7 parameter input modules, 8 filtration modules, 9 video memories, 10 image displays.

Embodiment

Further specify the organization plan of the present invention and the course of work in conjunction with example.

As shown in Figure 1, Weather interference resistant image acquiring system comprises video camera 1, analog to digital converter 2, image acquisition device 3, data-interface 4, computer 5, time weights module 6, parameter input module 7, filtration module 8, video memory 9 and image display 10.Video camera 1 is given analog to digital converter 2 with the picture signal of taking, analog to digital converter 2 is converted to digital picture with analog image, after gathering, image acquisition device 3 imports computers 5 by data-interface 4, parameter input module 7 is with time-parameters, meteorological parameter and other parameter input computer simultaneously, time weights module 6 is utilized time-parameters weights computing time, can obtain refractive index structure parameter input computer by time weights and meteorological parameter.Computer 5 calculates turbulent flow modulation transfer function MTF respectively by the parameter information of input _eWith aerosol modulation transfer function MTF _aComponent by these two atmosphere modulation transfer functions calculates atmosphere modulation transfer function MTF and flows to filtration module 8 then, filtration module 8 uses atmosphere modulation transfer function MTF that the original image of taking is carried out Filtering Processing and obtains the weather restored image, at last the image after restoring is flowed to video memory 9 storages and image display 10 demonstrations.

As shown in Figure 2, system works flow process of the present invention is:

(1) initialization is carried out initialization to the various piece of whole system, comprises the setting of camera parameters, the initialization of parameter input module and the initialization of image display;

(2) images acquired, the image that video camera is taken is at first handled through analog to digital converter, and the analog image that video camera is taken changes digital image sequence into, by the image acquisition device images acquired, by data-interface image is imported computer then;

(3) image preliminary treatment, the level and smooth and sharpening to original image makes picture noise be eliminated, it is clear that edge of image also becomes;

(4) computing time weights, time-parameters comprises: t at sunrise ₁, sunset time t ₂And shooting time t.With the symbol of TH as relative time, then relative time TH uses sunset time t ₂T between deducting at sunrise ₁, the result is obtained standard relative time TH divided by 12 ₁, deduct at sunrise with shooting time t then between t ₁, again with the result divided by standard relative time TH ₁, then obtaining relative time TH, mathematic(al) representation is TH ₁=(t ₂-t ₁)/12, TH=(t-t ₁)/TH ₁, can find and shooting time time corresponding weights W by relative time TH and relative time weight table;

(5) calculate refractive index structure parameter, calculate the time weights after, calculate refractive index structure parameter C by time weights, temperature, relative humidity, wind speed and solar radiation flux _n ²

${\mathrm{<figure-callout\; id="2"\; label="C\; n"\; filenames="A20051004757400081.png"\; state="\{\{state\}\}">C</figure-callout>}}_n^{}=5.9\&times;{10}^{-15}W+1.6\&times;{10}^{-15}T-3.7\&times;{10}^{-15}\mathrm{RH}+6.7\&times;{10}^{-17}R{H}^2-3.9\&times;{10}^{-19}\mathrm{<figure-callout\; id="3"\; label="R\; H"\; filenames="A20051004757400081.png"\; state="\{\{state\}\}">R</figure-callout>}{H}^{}{}^3$

-3.7×10 ^-15WS+1.3×10 ^-15WS ²-8.2×10 ^-17WS ³+2.8×10 ^-14SF-1.8×10 ^-14TCSA+1.4×10 ^-14TCSA ²-3.9×10 ^-13

Wherein W is the time weights, and T is an air themperature, and RH is a relative humidity, and WS is a wind speed, and SF is the solar radiation flux, and TCSA is a middle coefficient:

TCSA＝9.69×10 ^-4RH-2.75×10 ^-5RH ²+4.86×10 ^-7RH ³-4.48×10 ^-9RH ⁴+1.66×10 ^-11RH ⁵-6.26×10 ^-3lnRH-1.34×10 ^-5SF ⁴+7.30×10 ^-3

(6) calculate atmosphere modulation transfer function MTF, when given width of cloth image that degenerate or that be subjected to noise pollution, utilizing degradation phenomena to rebuild or recover original image is the basic process that image restoration is handled, Weather interference resistant image acquiring system is exactly the method for utilizing based on physical model, remove weather condition to the influence that image brings, the image of degeneration is restored.The quality of propagation in atmosphere process influence imaging is that light path is long more, influences remarkable more.It mainly is reason: (1) atmospheric turbulance by two aspects; (2) scattering of particle and absorption, corresponding this two aspects reason atmosphere modulation transfer function is divided into two components, i.e. turbulent flow modulation transfer function MTF _eWith aerosol modulation transfer function MTF _a, turbulent flow modulation transfer function MTF _eRelevant with factors such as time, temperature, relative humidity, illumination, wind speed, solar illuminations, the shooting condition of native system is suitable for the situation of short exposure time, obtains turbulent flow modulation transfer function MTF _eFor:

${\mathrm{MTF}}_e=\exp \{-57.3v^{5/3}{\mathrm{<figure-callout\; id="2"\; label="C\; n"\; filenames="A20051004757400081.png"\; state="\{\{state\}\}">C</figure-callout>}}_n^{}{\mathrm{\&lambda;}}^{-1/3}R{[1-\mathrm{\&mu;}\left(\frac{\mathrm{\&lambda;v}}{D}\right)}^{1/3}]\}$

Wherein: v is the angle spatial frequency, C _n ²Be refractive index structure parameter, R is a light path, and λ is a radiation wavelength, and D is a diaphragm diameter, and μ is a coefficient, near field μ=1, far field μ=0.5.

The aerosol influence of actual imaging can be by the aerosol modulation transfer function MTF that measures _aRepresent aerosol modulation transfer function MTF _aFor:

${\mathrm{MTF}}_a=\left\{\begin{array}{c}\exp [-A_{a}R-S_{a}R{(v/v_c)}^2],v\&le;v_c,\\ \exp [-(A_a+S_a)R],v>v_c,\end{array}\right.$

Wherein: S _a, A _aBe atmospheric scattering and absorption coefficient, v _cBe the angle spatial-cut-off frequency, be the ratio of particle diameter and radiation wavelength.When angle spatial frequency v is higher, can think MTF _aBe constant, A _a+ S _aBe attenuation coefficient Q _e, Q _e≈ S _a=3.912/R _mR wherein _mBe visibility distance.Because the diameter and the number of wavelengths magnitude of haze are closer, so to general atmosphere condition v _cQuite little, i.e. v＞v _cLike this by formula MTF=MTF _e* MTF _aCan obtain atmosphere modulation transfer function MTF;

(7) image filtering as noise of original image, is handled by Wiener filtering the MTF that tries to achieve to image, eliminate the influence of MTF to image, the image after obtaining repairing;

(8) memory image is stored the image after restoring;

(9) display image is by the image after the display demonstration recovery.

Weather interference resistant image acquiring system is primarily aimed at the shooting of outdoor image, treatment of picture is improved, introduced the atmosphere modulation transfer function, the image that is subjected to the weather interference attenuation is restored, strengthen the robustness of outdoor camera system, improved the operating efficiency of image capturing system.

Claims (2)

1, Weather interference resistant image acquiring system, it is characterized in that, comprise video camera, analog to digital converter, image acquisition device, data-interface, computer, time weights module, the parameter input module, filtration module, video memory and image display, video camera is given analog to digital converter with the analog picture signal that photographs, analog to digital converter is converted to data image signal with analog image and imports computer through communication interface, time weights module obtains the time weights by time-parameters and flows to computer, the parameter input module is given computer with the parameter information conveyance, computer is given filtration module with the atmosphere modulation transfer function signal conveys of image, filtration module carries out Filtering Processing to original image, obtain the weather restored image, give video memory and image display to the picture signal after restoring and store and show.

2, the workflow of Weather interference resistant image acquiring system is characterized in that, job step is:

(1) initialization is carried out initialization to system;

(2) images acquired uses video camera that image is gathered;

(3) image preliminary treatment is handled the level and smooth and sharpening of image, and the removal of images noise also makes image edge clear;

(4) computing time weights, by the input time-parameters weights computing time;

(5) calculate refractive index structure parameter, utilize time weights and meteorological Parameters Calculation refractive index structure parameter;

(6) calculate atmosphere modulation transfer function MTF, two component turbulent flow modulation transfer function MTFe and aerosol modulation transfer function MTFa by the atmosphere modulation transfer function that calculates draw atmosphere modulation transfer function MTF then;

(7) image filtering uses atmosphere modulation transfer function MTF that original image is carried out filtering;

(8) memory image, the image after storage is restored;

(9) display image shows the image after restoring.

Images