CN1083360C - Automatic optical control system for windshield wiper - Google Patents

Abstract

The present invention relates to an optical type automatic control system for a wiper of an automobile, particularly to a control system for a wiper of an automobile, which automatically starts the wiper and injects clean water in real time according to the rainfall amount of different degree and the cleanness degree of a windshield in order to provide a favorable visual field for driving. An imaging device is mainly arranged in a proper position on the automobile near the windshield in order to obtain the images before the automobile, and the images are processed by an operational formula previously designed; a wiper or a water injection system is provided in order to maintain the transparence and the cleanness degree of the windshield.

Description

A kind of automatic optical control system for windshield wiper

The present invention relates to a kind of windshield wiper autonomous cruise speed system.Especially refer to a kind of according in various degree rainfall or the clean-up performance of Windshield, open rain brush and ejection clean water in good time automatically, so that the automatic optical control system for windshield wiper of good driving vision to be provided.

Windshield wiper is that the standard on the car is equipped with, and rain brush provides and rains or Windshield is scrubbed usefulness when filth is arranged, automobile is with regard to raining, should be because of the size adjustment rain brush speed intermittence of rainfall, the driver need adjust the speed of rain brush often when rainfall becomes irregular the variation, especially when rainfall very little (drizzle) or shower, its alternative rain brush speed is still not as people's will (general rain brush speed density approximately has only three to four sections), especially when adjacent car or front truck cross sewage that the surface gathered water place splash moment fast and beat at windshield, a slice is fuzzy already at the moment the visual field under the situation that has little time to react toward contact, question response is come desire when transferring fast rain brush speed to remove sewage, how many distances has not car known to leave forward? though be in short several seconds, steerman is but driven as covering eyes, and its danger can have been suspected and obtained.

Main purpose of the present invention, be to provide a kind of automatic optical control system for windshield wiper, make the rain brush can be according to the get a clear view difference of degree and rainfall size of Windshield, and self-opening and adjust rain brush, and can provide water spray to strengthen cleaning performance, so that the driving environment of a kind of human nature and automation to be provided in good time.

Above-mentioned purpose of the present invention is realized by following technical proposals:

A kind of automatic optical control system for windshield wiper mainly is image pick-up device, a signal processing unit and a control unit that is installed on nearly Windshield place by, cooperates windshield wiper system and water-injection system to form, and it is characterized in that:

Utilize image pick-up device to obtain gray value X _Ij, calculate average gray $X=\frac{1}{\mathrm{NM}}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{X}_{\mathrm{ij}}$

Use operational formula again $D=E{\[X-E\left(X\right)\]}^2=\frac{1}{NM}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{(X_{\mathrm{ij}}-X)}^2$

Obtain gray scale variation numerical value D; In the formula:

X _IjBe gray value in the pixel (pixel) of coordinate ij

Ij is the coordinates of pixels on the sensor

Gray scale is made a variation numerical value D and default critical value B relatively, result is relatively driven relevant cooperating equipment action for studying and judging.

Except that above-mentioned essential features, in specific implementation process, also can replenish following technology contents:

The gray scale variation numerical value D that calculates via this operational formula starts Wiper system during greater than critical value B.

Gray scale variation numerical value D is greater than critical value B and X _Kl＜Y _KlRain brush and water-injection system start simultaneously during-a.

The image that this image pick-up device is obtained can be divided into some blocks, in the hope of being averaged gray value X _Kl

The invention has the advantages that: can judge the cleanliness level of Windshield automatically, can start water spray or Wiper system in good time, scrub the dirt on the Windshield, to avoid the continuous switch rain brush of driver according to the get a clear view difference of degree and rainfall size of Windshield.

Below be described in detail as follows with regard to composition device of the present invention and specific embodiment conjunction with figs. thereof now:

Description of drawings:

Fig. 1 is a system block diagram of the present invention.

Fig. 2 is a specific embodiments of the invention scheme drawing one.

Fig. 3 is a specific embodiments of the invention scheme drawing two.

Fig. 4 is a start diagram of circuit one of the present invention.

Fig. 5 is a start flowchart 2 of the present invention.

Shown in Figure 1, be system block diagram of the present invention, mainly be by an image pick-up device 1, a signal processing unit 2 and a control unit 3, cooperate windshield wiper system 4 and water-injection system 5 to form, wherein:

-image pick-up device 1 is the combination of general pick-up lens 11 of general reference and CIS 12;

-signal processor 2 is for relevant signal conditioning and calculating etc.;

-control unit 3 is to be subjected to the control of signal processor 2 and to drive and adjust Wiper system 4 and water-injection system 5;

Nationality is by the combination of said units, see also Fig. 1,2, image pick-up device 1 is located at the appropriate location of nearly Windshield F on the car, and be provided with a control unit 3 in Wiper system 4, this image pick-up device 1 then makes its focal length BT adjust on windshield F, because Windshield F is the transparent body, CIS 12 (CCD or CMOS... etc.) in camera lens 11 back, the exhausted major part of the image of being caught is the scenery image from the glass F opposite of keeping out the wind brokenly), and these scenery images C is because of the relation of distance, its imaging DT can't focus on and the fuzzy projection of formation on sensor 12, the distribution of its image intensity is very level and smooth, says the gray value of being responded between its two adjacent pixels (gray va1ue) [or claiming that picture is color] from space field, here we only discuss black and white gray value, i.e. { V|V=|X _Ij-X _Ij-1, i=1,2...N, j=1,2...M} are very little;

[X: gray value, ij: be respectively coordinate, V: two adjacent gray value differences], the moment (Moments) of its space field gray value of perhaps also can saying so

μ _k=E[X-E (X)] ^k[E: expectation value, k is a parameter, is to be integer] also can be very little for focusing on image, (following we cited be K=2, be the second order moment, also be called variance (Variance); And, also can say that the composition of its spatial frequency domain concentrates on low frequency part if with spatial frequency domain, and high frequency is partly seldom.

Hence one can see that (seeing also Fig. 3,4), often there is raindrop F1 to drop on the Windshield F, when the light of its opposite side image C sees through raindrop F1, be subjected to the refraction of different angles and be incident upon (because of raindrop is transparent arcuation) on the sensor 12, some image composition contain focusing effect and on the sensor 12 variance of gray value (Variance) just can increase relatively and the composition of the close more focusing of raindrop is many more, its variance (Variance) is just big more.We are as follows with its flow process and substitution operational formula:

[flow process]

1, wins pixel value and (promptly get X _IjGray value)

2, calculate average gray X

3, calculate gray scale variation numerical value D $D=E{\[X-E\left(X\right)\]}^2=\frac{1}{\mathrm{NM}}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{(X_{\mathrm{ij}}-X)}^2$

D is a gray scale variation numerical value (Variance)

X _IjBe gray value in the pixel (pixel) of coordinate ij

Ij is the coordinates of pixels on the sensor

4, judge that whether gray scale variation numerical value D is greater than critical value B

Now we just can gray scale the parameter judged as Windshield F pollution level and diaphaneity of variation numerical value D, an and critical value decided at the higher level but not officially announced (Threshold) B in addition, or allow the driver comply with oneself hobby and adjust critical value B, as gray scale variation numerical value D (Variance) during greater than critical value B, represent that promptly raindrop density is too high, angle from the driver, just represent that Windshield is too fuzzy, control unit 3 just drives the action that Wiper system 4 is carried out brush rain, and the brush rain speed of the size reflection rain brush of gray scale variation numerical value D, and the speed responsing that gray scale variation numerical value D value increases is the variation of the brush rain speed of rain brush, the speed that is big more its rain brush brush rain of its value speedup of gray scale variation numerical value D is fast more, otherwise also with, and gray scale variation numerical value D just makes rain brush stop action when being less than or equal to critical value B.

If we only consider that clean transparent raindrop consider to differentiate attached to its dirty situation of rainwater on glass again in above-mentioned example, then Wu Zhuo water droplet is depended merely on the action of rain brush brush rain, and can't be clean Windshield F removing, must be according to water-injection system 5 starts with joint efforts.So we suppose that image pick-up device 1 is to be loaded in the car, and the brightness in the car is to be lower than car outer (in fact also being like this), when raindrop F1 is clean when transparent, though because of the increase of raindrop F1 increases its gray scale variation numerical value D, but its average gray value X is a unmodified, because the luminous energy that always is incident upon on the sensor 12 is constant, if but dirty water droplet, can reduce owing to the luminous energy that its light-proofness is come in projection, though water droplet has reflecting effect, but the brightness in actual the getting on the bus is darker, so the reflected value recruitment is much smaller than the reduction of refraction value, if the scene that we obtain image pick-up device 1 is divided into some blocks, each block is asked its gray scale variance D and average gray X individually, when some block gray scale makes a variation numerical value D greater than critical value B, the a value and its average gray value X has also descended simultaneously, relatively other gray scale variation numerical value D does not have the block of obvious increase, when its average gray value X does not also have obvious decline, just decidable drops on the sewage that is on the Windshield, this moment, control unit 3 just started water-injection system 5 and Wiper system 4, and can scrub achievement by above-mentioned judgement action supervision, whether finish with decision and scrub action (also can avoid secretly judge by accident generation) because of the sky.

We are described as follows (consulting Fig. 5) with its formula now. ${\mathrm{<figure-callout\; id="1"\; label="X\; K"\; filenames="C9910900500101.png"\; state="\{\{state\}\}">X</figure-callout>}}_K=\frac{1}{\mathrm{NM}}\underset{i=k}{\overset{k+N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{k+M}{\mathrm{\&Sigma;}}}{X}_{\mathrm{ij}}$

K, l represents: the block coordinate $D_k$ $1_{}=\frac{1}{\mathrm{NM}}\underset{i=k}{\overset{k+N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{k+M}{\mathrm{\&Sigma;}}}(X_{\mathrm{iJ}}-X_{\mathrm{kl}})$

Calculate the value of gray scale variation numerical value D according to above-mentioned formula

1, as gray scale variation numerical value D during greater than critical value B

(1) works as X _Kl＜Y _Kl(the Y when condition of-a is set up _KlThe X of time before in the expression memory body _Kl, a represents critical value), the dirty degree of Windshield F need utilize Wiper system 4 to cooperate water-injection system 5 starts to reach, so control unit 3 drives Wiper system 4, water-injection system 5 starts;

(2) as all X _Kl＜Y _KlWhen the condition of-a all is false, i.e. all X _Kl〉=Y _Kl-a represents that the water droplet on the Windshield there is no dirty phenomenon, and 3 of control units need to drive Wiper system 4 starts at this moment.

2, when the condition of D＞B is false, i.e. D≤B, all Y _Kl＜X _Kl-a is good because of the visual field of Windshield this moment, and Wiper system, water-injection system must starts.

In sum, the present invention can utilize simple formula to judge the cleanliness level of its Windshield, and in good time startup water spray or Wiper system, to scrub the dirt on the Windshield, and can be because of the speed of the size automatic compensation rain brush of rainfall, to avoid the essential constantly switch rain brush of driver.

Claims (4)

1, a kind of automatic optical control system for windshield wiper mainly is image pick-up device, a signal processing unit and a control unit that is installed on nearly Windshield place by, cooperates windshield wiper system and water-injection system to form, and it is characterized in that:

Utilize image pick-up device to obtain gray value X _Ij, calculate average gray $X=\frac{1}{\mathrm{NM}}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{X}_{\mathrm{ij}}$

Use operational formula again $D=E{\&lsqb;X-E\left(X\right)\&rsqb;}^2=\frac{1}{\mathrm{NM}}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{(X_{\mathrm{ij}}-X)}^2$

Obtain gray scale variation numerical value D; In the formula:

X _IjBe gray value in the pixel (pixel) of coordinate ij

Ij is the coordinates of pixels on the sensor

Gray scale is made a variation numerical value D and default critical value B relatively, result is relatively driven relevant cooperating equipment action for studying and judging.

2, as the said a kind of automatic optical control system for windshield wiper of claim 1, it is characterized in that: the gray scale variation numerical value D that calculates via this operational formula starts Wiper system during greater than critical value B.

3, as the said a kind of automatic optical control system for windshield wiper of claim 1, it is characterized in that: gray scale variation numerical value D is greater than critical value B and X _Kl＜Y _KlRain brush and water-injection system start simultaneously during-a.

4, as the said a kind of automatic optical control system for windshield wiper of claim 1, it is characterized in that: the image that this image pick-up device is obtained can be divided into some blocks, in the hope of being averaged gray value X _Kl

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