Visual field adjusting method for electronic outside rear-view mirror

Abstract

The invention provides a method for adjusting the visual field of an electronic outside rear-view mirror. The method comprises the following steps: step 1, acquiring a set marker line; step 2, determining a target tracking area according to the marker line; 3, LK optical flow tracking is carried out on the tracking area, and a motion vector of the tail of the carriage is obtained; 4, determining the number of target moving pixels of the visual field of the electronic outside rear-view mirror according to the motion vector; and step 5, adjusting the display field of view of the electronic outside rear-view mirror according to the target moving pixel number. Follow-up adjustment of the visual field of the electronic outside rear-view mirror is achieved, and product competitiveness is improved.

Description

Technical Field

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

[0002] Since the blind spot of the trailer of a semi-trailer truck is large and prone to traffic accidents, how to reduce the blind spot of the trailer has always been a hot topic of research. The current mainstream solution is to calculate the steering angle of the front wheel of the tractor through the steering wheel rotation angle and the steering ratio, and collect the angle change relationship between the front wheel angle of the tractor and the body at different speeds, and then use the algorithm to cut and display the field of view of the rear of the trailer on the steering side, so that the field of view display range changes with the change of the steering wheel angle and the speed. However, in reality, the angle of the front wheel of the tractor changes in different speeds and the angle of the front wheel of the tractor varies, and it is difficult to obtain all situations. When the data obtained is not enough, the field of view display is very abrupt, and even suddenly jumps, and the follow-up field of view cannot be smoothly realized. Moreover, since the tractor and trailer of the semi-trailer truck can be freely combined, the pre-collected angle change relationship between the front wheel angle of the tractor and the body at different speeds cannot be used when the tractor or trailer is replaced, resulting in poor versatility of this solution. Summary of the invention

[0003] The present invention provides a method for adjusting the visual field of an electronic exterior rearview mirror, aiming to solve the defects in the prior art, realize the follow-up adjustment of the visual field of the electronic exterior rearview mirror, and improve the competitiveness of the product.

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

[0005] The present invention provides a method for adjusting the visual field of an electronic exterior rearview mirror, comprising:

[0006] Step 1: Get the set marker line;

[0007] Step 2: determining the target tracking area according to the marking line;

[0008] Step 3: Perform LK optical flow tracking on the tracking area to obtain the motion vector of the rear of the car;

[0009] Step 4, determining the target moving pixel number of the electronic exterior rearview mirror field of view according to the motion vector;

[0010] Step 5: adjusting the display field of view of the electronic exterior rearview mirror according to the target moving pixel number.

[0011] Specifically, the target tracking area is a rectangular area with the marking line as the axis of symmetry and including the rear part of the vehicle.

[0012] Specifically, the step 2 includes:

[0013] Step 201, creating an initial target tracking area with a height equal to the image height and a width equal to the initial width using the marker line, and setting the maximum width of the target tracking area to;

[0014] Step 202, performing image recognition in the initial target tracking area to determine whether a preset feature is recognized, if yes, taking the initial target tracking area as the final target tracking area, otherwise proceeding to the next step;

[0015] Step 203: Increase the width of the initial target tracking area with a preset step size, and determine whether the increased width does not exceed the maximum width. If yes, return to step 202; otherwise, prompt a message that the target tracking area fails to be established.

[0016] Specifically, the preset algorithm is the Hough transform algorithm.

[0017] Specifically, the preset feature is the rear part of the vehicle.

[0018] Specifically, step 4 includes:

[0019] Step 401, obtaining the frame rate of the electronic exterior rearview mirror camera;

[0020] Step 402: Determine the number of horizontal pixel changes between two adjacent frames according to the motion vector and the frame rate.

[0021] Specifically, the step 5 includes: adjusting the display field of view in the horizontal direction by the number of pixels changed in the horizontal direction.

[0022] Specifically, the number of pixel changes in the horizontal direction n=Δx / k, wherein Δx is the horizontal component of the motion vector, and k is the frame rate of the electronic exterior rearview mirror camera.

[0023] The beneficial effects of the present invention are as follows: the present invention sets a mark line, determines a target tracking area according to the mark line, then obtains a motion vector of the rear end of the vehicle in the tracking area, and then determines the target number of moving pixels of the electronic outside rearview mirror's field of view according to the motion vector, and finally adjusts the display field of view of the electronic outside rearview mirror according to the target number of moving pixels, thereby realizing follow-up adjustment of the electronic outside rearview mirror's field of view and improving product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic flow chart of the method for adjusting the visual field of an electronic exterior rearview mirror of the present invention;

[0025] Figure 2 It is a schematic diagram of a marking line of the present invention;

[0026] Figure 3 is a schematic diagram of the target tracking area of ​​the present invention;

[0027] Figure 4 It is a schematic diagram of light flow of the present invention. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] like Figure 1 As shown, this embodiment provides a method for adjusting the field of view of an electronic exterior rearview mirror, comprising:

[0031] Step 1: Get the set marker line.

[0032] In this embodiment, the marking line is the center line of the area that needs to be tracked by the dynamic field of view when the vehicle turns.

[0033] In specific implementation, the trailer truck is first parked in a safe parking lot, and the user sets a marking line on the vehicle image displayed by the electronic rearview mirror system by adjusting a human-machine interaction device such as a knob or a button.

[0034] In this embodiment, the marking line is the line segment where the rear of the carriage is located, such as Figure 2 as shown in .

[0035] Step 2: Determine the target tracking area according to the marking line.

[0036] In order to reduce the amount of calculation, in the entire image captured by the camera, only the area near the marking line needs to be considered. In addition, due to regulatory restrictions, the color of the trailer compartment is generally of high resolution, and the rear of the vehicle generally needs to be pasted with eye-catching signs such as reflective strips, so the color here often has a certain texture grayscale change with the surrounding environment, so it is easy to extract a sufficient number of effective features near the marking line.

[0037] In this embodiment, the target tracking area is a rectangular area with the marking line as the axis of symmetry and including the rear part of the vehicle, such as Figure 3 shown.

[0038] In this embodiment, step 2 includes:

[0039] Step 201: Create an initial target tracking area with the height of the image and the width of the initial width w0 using the marker line, and set the maximum width of the target tracking area to w max .

[0040] Step 202: perform image recognition in the initial target tracking area to determine whether a preset feature is recognized. If so, use the initial target tracking area as the final target tracking area, otherwise proceed to the next step.

[0041] Step 203: Increase the width of the initial target tracking area with a preset step size, and determine whether the increased width does not exceed the maximum width. If yes, return to step 202; otherwise, prompt a message that the target tracking area fails to be established.

[0042] In this embodiment, the preset algorithm is the Hough transform algorithm, and the preset feature is the rear part of the vehicle.

[0043] Step 3: Perform LK optical flow tracking on the tracking area to obtain the motion vector of the rear of the car.

[0044] Optical flow is the instantaneous speed of the pixel movement of a moving object in space on the observation imaging plane. The optical flow method uses the change of pixels in the time domain in the image sequence and the correlation between adjacent frames to determine the corresponding relationship between the previous frame and the current frame, thereby calculating the motion information of the object between adjacent frames.

[0045] In the target tracking area, the images between two adjacent frames are tracked using the LK optical flow method to obtain the motion vector (Δx, Δy) of the rear of the carriage, as shown in Figure 4 shown.

[0046] Step 4: Determine the target moving pixel number of the electronic exterior rearview mirror field of view according to the motion vector.

[0047] In this embodiment, step 4 includes:

[0048] Step 401: Obtain the frame rate k of the electronic exterior rearview mirror camera.

[0049] Step 402: Determine the number n of horizontal pixel changes between two adjacent frames according to the motion vector (Δx, Δy) and the frame rate k.

[0050] In this embodiment, n=Δx / k.

[0051] Step 5: adjusting the display field of view of the electronic exterior rearview mirror according to the target moving pixel number.

[0052] In this embodiment, the step 5 includes: adjusting the display field of view in the horizontal direction by the number n of horizontal pixel changes.

[0053] 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 adjusting the visual field of an electronic exterior rearview mirror, characterized in that: include: Step 1: Get the set marker line; Step 2: determining the target tracking area according to the marking line; Step 3: Perform LK optical flow tracking on the tracking area to obtain the motion vector of the rear of the car; Step 4, determining the target moving pixel number of the electronic exterior rearview mirror field of view according to the motion vector; Step 5: adjusting the display field of view of the electronic exterior rearview mirror according to the target moving pixel number.

2. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 1, characterized in that: The target tracking area is a rectangular area with the marking line as the axis of symmetry and including the rear part of the vehicle.

3. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 2, characterized in that: The step 2 comprises: Step 201, creating an initial target tracking area with a height equal to the image height and a width equal to the initial width using the marker line, and setting the maximum width of the target tracking area to; Step 202, performing image recognition in the initial target tracking area to determine whether a preset feature is recognized, if yes, taking the initial target tracking area as the final target tracking area, otherwise proceeding to the next step; Step 203: Increase the width of the initial target tracking area with a preset step size, and determine whether the increased width does not exceed the maximum width. If yes, return to step 202; otherwise, prompt a message that the target tracking area fails to be established.

4. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 3, characterized in that: The preset algorithm is the Hough transform algorithm.

5. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 3, characterized in that: The preset feature is the rear part of the vehicle.

6. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 1, characterized in that: The step 4 comprises: Step 401, obtaining the frame rate of the electronic exterior rearview mirror camera; Step 402: Determine the number of horizontal pixel changes between two adjacent frames according to the motion vector and the frame rate.

7. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 6, characterized in that: The step 5 includes: adjusting the display field of view in the horizontal direction by the number of pixels changed in the horizontal direction.

8. The method for adjusting the visual field of an electronic exterior rearview mirror according to claim 7, characterized in that: The number of pixel changes in the horizontal direction n=Δx / k, where Δx is the horizontal component of the motion vector, and k is the frame rate of the electronic exterior rearview mirror camera.

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