A method for defoging an electronic exterior rearview mirror

Abstract

The present invention provides an electronic exterior rearview mirror defogging method, the method comprising: step 1, storing a reference picture; step 2, acquiring a current image, the shooting angle of the current image being the same as that of the reference picture; step 3, judging whether the electronic exterior rearview mirror is fogged by comparing the current image and the reference image, and if so, proceeding to step 4, otherwise proceeding to step 5; step 4, heating the lens of the electronic exterior rearview mirror, and returning to step 2; step 5, controlling the electronic exterior rearview mirror to unfold to a normal use angle. The present invention realizes the intelligentization of fogging judgment and heating defogging of the electronic exterior rearview mirror camera, and improves the product competitiveness.

Description

Technical Field

[0001] The invention relates to the technical field of electronic rearview mirrors, and in particular to a defogging method for an electronic exterior rearview mirror. Background Art

[0002] At present, cars have become a common means of transportation in people's lives. The electronic exterior rearview mirror uses an external camera and a built-in display screen to collect images of the vehicle's surrounding environment and transmit them to the in-car display screen for the driver to view in real time. This system can solve many problems that traditional mirrors have, such as large blind spots and unclear vision in rainy days. It has a tendency to gradually replace traditional optical exterior rearview mirrors. However, in a humid, rainy, and temperature-difference environment, the lens of the electronic exterior rearview mirror is prone to fogging, and the field of vision is difficult to deteriorate. The driver cannot accurately know the road conditions behind, which brings safety hazards. Summary of the invention

[0003] The present invention provides an electronic exterior rearview mirror defogger method, aiming to solve the defects in the prior art, realize the intelligentization of the electronic exterior rearview mirror camera fogging judgment and heating defogger, and improve the product competitiveness.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for defoging an electronic exterior rearview mirror, comprising:

[0006] Step 1: Store the reference image;

[0007] Step 2: Acquire a current image, wherein the shooting angle of the current image is the same as that of the reference image;

[0008] Step 3, judging whether the electronic exterior rearview mirror is fogged by comparing the current image and the reference image, if yes, proceeding to step 4, otherwise proceeding to step 5;

[0009] Step 4, heating the lens of the electronic exterior rearview mirror, and returning to step 2;

[0010] Step 5: Control the electronic exterior rearview mirror to unfold to a normal use angle.

[0011] Specifically, judging whether the electronic exterior rearview mirror is fogged by comparing the current image and the reference image in step 3 includes:

[0012] Step 301, obtaining sub-images of preset pixels in a plurality of preset areas from the current image and the reference image respectively;

[0013] Step 302: Calculate the first judgment parameter and the second judgment parameter of the reference image and the third judgment parameter and the fourth judgment parameter of the current image according to a preset formula;

[0014] Step 303: Determine whether the electronic exterior rearview mirror is fogged according to the first judgment parameter, the second judgment parameter, the third judgment parameter, and the fourth judgment parameter.

[0015] Specifically, the preset formula is:

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] Among them, C α (1) represents the first judgment parameter, C α (2) represents the second judgment parameter, C β (1) represents the third judgment parameter, C β (2) represents the fourth judgment parameter, H sk (i, j) represents the grayscale value of the current pixel in each preset area in the current image or the reference image, H sk (i+1,j) represents the grayscale value of the next pixel in each preset area in the current image or the reference image; R(i,j), G(i,j), B(i,j) represent the RGB value of the current pixel, R(i+1,j), G(i+1,j), B(i+1,j) represent the RGB value of the next pixel, m, n represent the image resolution, k 1 , k 2 is a constant.

[0022] Specifically, the k 1 = 0.3, k 2 =0.175.

[0023] Specifically, step 303 includes:

[0024] If C β (1)≥C α (1)- C 0 (1), and C β (2) ≥C α (2)- C 0 (2), it is determined that the electronic exterior rearview mirror is not fogged, otherwise it is determined that the electronic exterior rearview mirror is fogged, wherein C 0 (1) C 0 (2) is a constant.

[0025] Furthermore, after step 2 and before step 3, the method further includes:

[0026] Step 21, obtain the current real-time temperature, humidity data, and lens temperature of the electronic exterior rearview mirror, and determine whether the fogging condition is met. If so, proceed to the next step, otherwise proceed to step 5.

[0027] Specifically, the step 21 includes:

[0028] Step 211: Calculate the dew point temperature T according to the current real-time temperature and humidity data. d ;

[0029] Step 212: Obtain the temperature margin T for starting defogger s ;

[0030] Step 213: Obtain the lens temperature T j , judge T j >T d +T s If yes, it is judged that the fogging condition is not met; otherwise, it is judged that the fogging condition is met.

[0031] Specifically, the dew point temperature is calculated according to the following formula:

[0032] Among them, T d represents the dew point temperature, t represents the current real-time temperature, φ represents the current real-time humidity, lg represents logarithmic operation, λ 1 , 2 is a constant.

[0033] Specifically, step 4 includes:

[0034] The duty cycle of the control PWM signal for heating the lens of the electronic exterior rearview mirror is determined according to the following rule:

[0035] If T d +T s -T j ≥△T 1 (e.g. 10), the heating control PWM is used with the maximum duty cycle D max Output;

[0036] If T d +T s -T j <△T 2 (e.g. 0), the heating control PWM signal is turned off;

[0037] If △T 2 <T d +T s -T j<△T 1 , then the duty cycle of heating control PWM is D=D max *(T d +T s -T j ) / (△T 1 -△T 2 ).

[0038] Specifically, the λ 1 =235,λ 2 =7.45.

[0039] The beneficial effects of the present invention are as follows: the present invention stores a reference picture, obtains a current image, and compares the current image with the reference image to determine whether the electronic outside rearview mirror is fogged; if fogged, the lens of the electronic outside rearview mirror is heated; otherwise, the electronic outside rearview mirror is controlled to be unfolded to a normal use angle, thereby realizing the intelligence of the electronic outside rearview mirror camera judgment and heating and defogger, and improving product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic flow chart of the electronic exterior rearview mirror defog method of the present invention;

[0041] Figure 2 It is a schematic diagram of the preset area of ​​the present invention. DETAILED DESCRIPTION

[0042] The following specifically describes the embodiments of the present invention in conjunction with the accompanying drawings, which are only for reference and illustration and do not constitute a limitation on the scope of patent protection of the present invention.

[0043] In the process described in the specification, claims or drawings of the present invention, the serial numbers of each step (such as step 10, 20, etc.) are included. The serial numbers are only used to distinguish the steps, and the serial numbers themselves do not represent any execution order. It should be noted that the descriptions such as "first" and "second" in this article are only used to distinguish the description objects, etc., and do not represent the order of precedence, nor do they mean that "first", "second", etc. are different types.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment provides a method for defogging an electronic exterior rearview mirror, comprising:

[0046] Step 1: Store the reference image.

[0047] The reference image is a clear image of a preset area taken by the electronic exterior rearview mirror at a preset angle under non-fogging conditions. The preset angle is the angle when folded or other unfolded angle that can obtain an image of the preset area (such as the vehicle body).

[0048] This step can be completed before the electronic exterior rearview mirror is produced, or it can be set by the user during the use of the vehicle.

[0049] It is easy to understand that the saved information of the reference image includes image information and the deployment angle (ie, shooting angle) of the electronic exterior rearview mirror.

[0050] Step 2: Acquire a current image, wherein the shooting angle of the current image is the same as that of the reference image.

[0051] In this embodiment, step 2 includes: after controlling the electronic exterior rearview mirror to open to the preset angle, taking a frame of image and saving it to generate the current image.

[0052] Step 3: Determine whether the electronic exterior rearview mirror is fogged by comparing the current image and the reference image. If so, proceed to step 4; otherwise, proceed to step 5.

[0053] In this embodiment, judging whether the electronic exterior rearview mirror is fogged by comparing the current image and the reference image in step 3 includes:

[0054] Step 301: Obtain a number (eg, 5) of sub-images of preset pixels in preset areas from the current image and the reference image respectively.

[0055] In this embodiment, the five preset areas include: the upper left corner area (denoted as Z 1 ), the lower left corner area is recorded as Z 2 , the upper right corner area is recorded as Z 3 , the lower right corner area is recorded as Z 4 , the central area is denoted as Z 5 ,like Figure 2 It is easy to understand that the number of the preset areas can also be increased or increased according to actual conditions.

[0056] In this embodiment, the preset pixels are 100*100 pixels. It is easy to understand that the preset pixels can be adjusted according to actual effects, for example, 200*200 pixels.

[0057] In this embodiment, the reference image is recorded as image α, and the current image is recorded as image β.

[0058] Step 302: Calculate the first judgment parameter C of the reference image according to a preset formula α (1) Second judgment parameter C α (2) The third judgment parameter C of the current image β (1) Fourth judgment parameter C β (2).

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] Among them, H sk (i, j) represents the grayscale value of the current pixel in each preset area in the current image or the reference image, H sk (i+1,j) represents the grayscale value of the next pixel in each preset area in the current image or the reference image; R(i,j), G(i,j), B(i,j) represent the RGB value of the current pixel, R(i+1,j), G(i+1,j), B(i+1,j) represent the RGB value of the next pixel, m, n represent the image resolution of the preset area, k 1 , k 2 is a constant and can be set according to the actual effect. In this embodiment, k 1 = 0.3, k 2 =0.175.

[0065] Step 303: According to the first judgment parameter C α (1) Second judgment parameter C α (2) The third judgment parameter C β (1) Fourth judgment parameter C β (2) Determine whether the electronic exterior rearview mirror is fogged.

[0066] In this embodiment, step 303 includes:

[0067] If C β (1)≥C α (1)- C 0 (1), and C β (2) ≥C α (2)- C 0 (2), it is determined that the electronic exterior rearview mirror is not fogged, otherwise it is determined that the electronic exterior rearview mirror is fogged, wherein C 0 (1) C 0 (2) is a constant that can be obtained through calibration and evaluation results.

[0068] Step 4, heating the lens of the electronic exterior rearview mirror, and returning to step 2.

[0069] Step 5: Control the electronic exterior rearview mirror to unfold to a normal use angle.

[0070] Example 2

[0071] Different from Example 1, this embodiment further includes after step 2 and before step 3:

[0072] Step 21, obtain the current real-time temperature, humidity data, and lens temperature of the electronic exterior rearview mirror, and determine whether the fogging condition is met. If so, proceed to the next step, otherwise proceed to step 5.

[0073] In this embodiment, step 21 includes:

[0074] Step 211: Calculate the dew point temperature T according to the current real-time temperature and humidity data. d .

[0075] In this embodiment, the dew point temperature is calculated according to the following formula:

[0076] Among them, T d represents the dew point temperature, t represents the current real-time temperature, φ represents the current real-time humidity, lg represents logarithmic operation, λ 1 , 2 is a constant obtained by calibration. In this embodiment, λ 1 =235,λ 2 =7.45.

[0077] Step 212: Obtain the temperature margin T for starting defogger s .

[0078] Step 213: Obtain the lens temperature T j , judge T j >T d +T s If yes, it is judged that the fogging condition is not met; otherwise, it is judged that the fogging condition is met.

[0079] Example 3

[0080] This embodiment provides a specific implementation method of step 4 in embodiment 1 based on embodiment 2, including:

[0081] The duty cycle of the control PWM signal for heating the lens of the electronic exterior rearview mirror is determined according to the following rule:

[0082] If T d +T s -T j ≥△T 1 (e.g. 10), the heating control PWM is used with the maximum duty cycle D max Output;

[0083] If T d +T s -T j <△T 2 (e.g. 0), the heating control PWM signal is turned off;

[0084] If △T 2 <T d +T s -T j <△T 1 , then the duty cycle of heating control PWM is D=D max *(T d +T s -T j ) / (△T 1 -△T 2 ).

[0085] The above disclosure is only a preferred embodiment of the present invention, which cannot be used to limit the scope of protection of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for defoging an electronic exterior rearview mirror, characterized in that: include: Step 1: Store the reference image; Step 2: Acquire a current image, wherein the shooting angle of the current image is the same as that of the reference image; Step 3, judging whether the electronic exterior rearview mirror is fogged by comparing the current image and the reference image, if yes, proceeding to step 4, otherwise proceeding to step 5; Step 4, heating the lens of the electronic exterior rearview mirror, and returning to step 2; Step 5, controlling the electronic exterior rearview mirror to unfold to a normal use angle; The step 3 of comparing the current image and the reference image to determine whether the electronic exterior rearview mirror is fogged includes: Step 301, obtaining sub-images of preset pixels in a plurality of preset areas from the current image and the reference image respectively; Step 302: Calculate the first judgment parameter and the second judgment parameter of the reference image and the third judgment parameter and the fourth judgment parameter of the current image according to a preset formula; Step 303, judging whether the electronic exterior rearview mirror is fogged according to the first judgment parameter, the second judgment parameter, the third judgment parameter, and the fourth judgment parameter; The preset formula is: Among them, C α (1) represents the first judgment parameter, C α (2) represents the second judgment parameter, C β (1) represents the third judgment parameter, C β (2) represents the fourth judgment parameter, H sk (i, j) represents the grayscale value of the current pixel in each preset area in the current image or the reference image, H sk (i+1,j) represents the gray value of the next pixel in each preset area in the current image or the reference image; R(i,j), G(i,j), B(i,j) represent the RGB value of the current pixel, R(i+1,j), G(i+1,j), B(i+1,j) represent the RGB value of the next pixel, m and n represent the image resolution, k1 and k2 are constants; Z1~Z5 represent the upper left corner area, lower left corner area, upper right corner area, lower right corner area, and center area of ​​the image respectively; The step 303 includes: If C β (1)≥C α (1)- C0(1), and C β (2) ≥C α (2)- C0(2), it is judged that the electronic exterior rearview mirror is not fogged, otherwise it is judged that the electronic exterior rearview mirror is fogged, wherein C0(1) and C0(2) are constants.

2. The electronic exterior rearview mirror defogging method according to claim 1, characterized in that: The k1=0.3, k2=0.

175.

3. The electronic exterior rearview mirror defogging method according to claim 1, characterized in that: After step 2 and before step 3, the method further includes: Step 21, obtain the current real-time temperature, humidity data, and lens temperature of the electronic exterior rearview mirror, and determine whether the fogging condition is met. If so, proceed to the next step, otherwise proceed to step 5.

4. The electronic exterior rearview mirror defogging method according to claim 3, characterized in that: The step 21 comprises: Step 211: Calculate the dew point temperature T according to the current real-time temperature and humidity data. d ; Step 212: Obtain the temperature margin T for starting defogger s ; Step 213: Obtain the lens temperature T j , judge T j >T d +T s Is it true? If yes, it is judged that the fogging condition is not met; otherwise, it is judged that the fogging condition is met; The dew point temperature is calculated according to the following formula: Among them, T d represents the dew point temperature, t represents the current real-time temperature, φ represents the current real-time humidity, lg represents logarithmic operation, and λ1 and λ2 are constants.

5. The electronic exterior rearview mirror defogging method according to claim 4, characterized in that: The step 4 comprises: The duty cycle of the control PWM signal for heating the lens of the electronic exterior rearview mirror is determined according to the following rule: If T d +T s -T j ≥△T1, the heating control PWM is used with the maximum duty cycle D max Output; If T d +T s -T j <△T2, then turn off the heating control PWM signal; If △T2<T d +T s -T j <△T1, then the duty cycle of heating control PWM is D=D max (T d +T s -T j ) / (△T1-△T2); Among them, △T1 and △T2 are preset thresholds.

6. The electronic exterior rearview mirror defogging method according to claim 5, characterized in that: The λ1=235, λ2=7.45.

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