Method and device for adjusting visual field of outside rear-view mirror

Abstract

The invention provides an outside rear-view mirror visual field adjusting method and device. The method comprises the steps that 1, a reference area of ORB feature detection is determined; 2, ORB feature detection is carried out according to the reference area, and a first feature point set is obtained; 3, turning information of a target vehicle is obtained, ORB feature detection is carried out in the reference area, and a second feature point set is obtained; step 4, matching the first feature point set and the second feature point set, and determining a first number and a first direction of pixel movement; and 5, adjusting the display visual field of the outer rearview mirror according to the first number and the first direction. According to the invention, follow-up view adjustment of the semitrailer truck is realized, and the driving safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic rearview mirrors, and in particular to a method and a device for adjusting the field of view of an 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 and device for adjusting the field of view of an exterior rearview mirror, aiming to solve the defects in the prior art, realize the follow-up field of view adjustment of a semi-trailer truck, and improve driving safety.

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

[0005] One aspect of the present invention provides a method for adjusting the field of view of an exterior rearview mirror, comprising:

[0006] Step 1, determine the reference area for ORB feature detection;

[0007] Step 2: Perform ORB feature detection according to the reference area to obtain a first feature point set;

[0008] Step 3: Obtain turning information of the target vehicle, and perform ORB feature detection in the reference area to obtain a second feature point set;

[0009] Step 4: Match the first feature point set and the second feature point set to determine a first amount and a first direction of pixel movement;

[0010] Step 5: Adjust the field of view displayed by the exterior rearview mirror according to the first number and the first direction.

[0011] Specifically, the step 1 includes:

[0012] Step 101, obtaining a target vehicle rear image, wherein the target vehicle rear image includes a marker for locating the vehicle rear position;

[0013] Step 102: Receive a region selection instruction, and use the marker and at least a portion of the rear image region as a reference region for ORB feature detection according to the region selection instruction.

[0014] Specifically, the step 2 includes:

[0015] Step 201: taking the smallest circumscribed square of the reference area as the current feature extraction area;

[0016] Step 202, performing ORB feature extraction in the current feature extraction area, and determining whether the number of extracted features exceeds a preset number, if yes, outputting the features as a first feature point set, otherwise proceeding to the next step;

[0017] Step 203, determine whether the side length of the current feature extraction area has reached the maximum value, if so, determine that the feature extraction has failed, otherwise increase the side length of the circumscribed square of the reference area by a preset step size as the new current feature extraction area, and return to step 202.

[0018] Specifically, the step 4 includes: determining the pixel movement amount and direction by using a local BA algorithm.

[0019] Specifically, step 5 includes: translating the image displayed by the exterior rearview mirror as a whole in the same direction as the first direction by the first amount.

[0020] Another aspect of the present invention provides a device for adjusting the field of view of an exterior rearview mirror, comprising:

[0021] A feature detection module, and a reference area determination module, a vehicle control module, and a feature matching module connected thereto, and also includes a movement determination module connected to the feature matching module, and an image adjustment module connected to the movement determination module;

[0022] The reference area determination module is used to determine the reference area for ORB feature detection;

[0023] The feature detection module is used to perform ORB feature detection to obtain a first feature point set and a second feature point set;

[0024] The vehicle control module is used to control the target vehicle to turn;

[0025] The feature matching module is used to match the first feature point set and the second feature point set;

[0026] The movement determination module is used to determine a first amount and a first direction of pixel movement;

[0027] The image adjustment module is used to adjust the visual field displayed by the exterior rearview mirror according to the pixel movement amount and direction.

[0028] Specifically, the reference area determination module includes an image unit and a human-computer interaction unit and a determination unit connected thereto;

[0029] The image unit is used to acquire and display the target vehicle rear image;

[0030] The human-computer interaction unit is used to receive an area selection instruction;

[0031] The determination unit is used to use the marker and at least a portion of the rear image area as a reference area for ORB feature detection according to the area selection instruction.

[0032] Specifically, the feature detection module includes a feature judgment unit, and a feature extraction unit, a feature output unit, and an extraction region update unit connected thereto, and also includes an extraction region determination unit connected to the feature extraction unit and the extraction region update unit;

[0033] The extraction region determination unit is used to use the smallest circumscribed square of the reference region as the current feature extraction region;

[0034] The feature extraction unit is used to perform ORB feature extraction in the current feature extraction area;

[0035] The feature judgment unit is used to judge whether the number of extracted features exceeds a preset number;

[0036] The feature output unit is used to output the detected features to the corresponding feature point set;

[0037] The extraction region updating unit is used to increase the side length of the circumscribed square of the reference region with a preset step size.

[0038] Specifically, the feature matching module is a local BA algorithm module.

[0039] The beneficial effects of the present invention are as follows: the present invention places a high-resolution marker at the rear of a trailer, selects the marker on a display screen, then extracts ORB feature points near the marker in the image, determines the number of pixels moved between adjacent frames by matching the ORB characteristics between frames, and finally translates the displayed image accordingly according to the number of pixels moved, thereby achieving follow-up field of view adjustment of the semi-trailer truck and improving driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic flow chart of a method for adjusting the field of view of an exterior rearview mirror of the present invention;

[0041] Figure 2 is a schematic structural diagram of the exterior rearview mirror field of view adjustment device of the present invention;

[0042] Figure 3 is a structural schematic diagram of a reference area determination module of the present invention;

[0043] Figure 4 It is a structural schematic diagram of the feature detection module of the present invention. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] Example 1

[0047] like Figure 1 As shown, this embodiment provides a method for adjusting the field of view of an exterior rearview mirror, comprising:

[0048] Step 1: Determine the reference area for ORB feature detection.

[0049] In this embodiment, step 1 includes:

[0050] Step 101: Acquire a target vehicle rear image, wherein the target vehicle rear image includes a marker for locating the vehicle rear position.

[0051] In the specific implementation, the semi-trailer truck is first parked in a parking lot, and then a marker with a large contrast in color with the car body is placed on the ground at the rear of the trailer. The marker should be visible in the display image of the exterior rearview mirror.

[0052] Step 102: Receive a region selection instruction, and use the marker and at least a portion of the rear image region as a reference region for ORB feature detection according to the region selection instruction.

[0053] In a specific implementation, the processor of the exterior rearview mirror receives a signal from an operator (e.g., a driver) via a human-computer interaction device (e.g., an adjustment knob, a touch screen, etc.) which circles the marker and a portion of the rear end of the vehicle in a preset shape (e.g., a circle) on the exterior rearview mirror display device. The image within the circled circular area is the reference area.

[0054] Step 2: Perform ORB feature detection based on the reference area to obtain a first feature point set.

[0055] ORB (Oriented FAST and Rotated BRIEF) is a fast and efficient image feature detection algorithm, which combines FAST corner detection and BRIEF descriptor and improves them to provide scale invariance, rotation invariance and certain noise resistance. Therefore, it is widely used in image processing.

[0056] In this embodiment, step 2 includes:

[0057] Step 201: Taking the minimum circumscribed square of the reference area as the current feature extraction area.

[0058] Due to regulatory requirements, the color of a trailer compartment is generally of high resolution, and reflective strips and other eye-catching signs are generally required to be affixed to the rear of the vehicle, so the color here often has a certain texture change with the surrounding environment. It is easy to extract a sufficient number of effective ORB features near the markers. Therefore, using the minimum circumscribed square of the reference area as the current initial feature extraction area can greatly reduce the amount of image calculations.

[0059] Step 202: perform ORB feature extraction in the current feature extraction area, and determine whether the number of extracted features exceeds a preset number. If yes, output the features as a first feature point set, otherwise proceed to the next step.

[0060] Step 203, determine whether the side length of the current feature extraction area has reached the maximum value, if so, determine that the feature extraction has failed, otherwise increase the side length of the circumscribed square of the reference area by a preset step size as the new current feature extraction area, and return to step 202.

[0061] In this embodiment, the side length of the feature extraction area is determined by the number of extracted ORB features. The lower limit of the number of extracted features is set to n. When the number of extracted features is less than n, the side length of the square of the extraction area continues to increase in increments of δ until the number of extracted features meets the quantity requirement.

[0062] Step 3: Obtain turning information of the target vehicle, and perform ORB feature detection in the reference area to obtain a second feature point set.

[0063] The method for obtaining the second feature point set is the same as that in step 2 above, and will not be repeated here.

[0064] Step 4: Match the first feature point set and the second feature point set to determine a first amount and a first direction of pixel movement.

[0065] In this embodiment, the amount and direction of pixel movement are determined by a local BA (Bundle Adjustment) algorithm.

[0066] Step 5: Adjust the field of view displayed by the exterior rearview mirror according to the first number and the first direction.

[0067] In this embodiment, step 5 includes: translating the image displayed by the exterior rearview mirror as a whole in the same direction as the first direction by the first amount.

[0068] The exterior rearview mirror field of view adjustment method of this embodiment can be executed by a processor built into the exterior rearview mirror itself, or by a processor outside the exterior rearview mirror, and the execution result is returned to the exterior rearview mirror, and the present invention is not limited to this.

[0069] Example 2

[0070] like Figure 2 As shown, this embodiment provides a device for adjusting the field of view of an exterior rearview mirror, comprising:

[0071] A feature detection module, and a reference area determination module, a vehicle control module, and a feature matching module connected thereto, and also includes a movement determination module connected to the feature matching module, and an image adjustment module connected to the movement determination module;

[0072] The reference area determination module is used to determine the reference area for ORB feature detection;

[0073] The feature detection module is used to perform ORB feature detection to obtain a first feature point set and a second feature point set;

[0074] The vehicle control module is used to control the target vehicle to turn;

[0075] The feature matching module is used to match the first feature point set and the second feature point set;

[0076] The movement determination module is used to determine a first amount and a first direction of pixel movement;

[0077] The image adjustment module is used to adjust the visual field displayed by the exterior rearview mirror according to the pixel movement amount and direction.

[0078] The working process of the exterior rearview mirror field of view adjustment device described in this embodiment is as shown in the exterior rearview mirror field of view adjustment method described in Example 1, and will not be repeated here.

[0079] like Figure 3 As shown, in another embodiment of the present invention, the reference area determination module includes an image unit and a human-computer interaction unit and a determination unit connected thereto;

[0080] The image unit is used to acquire and display the target vehicle rear image;

[0081] The human-computer interaction unit is used to receive an area selection instruction;

[0082] The determination unit is used to use the marker and at least a portion of the rear image area as a reference area for ORB feature detection according to the area selection instruction.

[0083] like Figure 4 As shown, in another embodiment of the present invention, the feature detection module includes a feature judgment unit, and a feature extraction unit, a feature output unit, and an extraction region update unit connected thereto, and also includes an extraction region determination unit connected to the feature extraction unit and the extraction region update unit;

[0084] The extraction region determination unit is used to use the smallest circumscribed square of the reference region as the current feature extraction region;

[0085] The feature extraction unit is used to perform ORB feature extraction in the current feature extraction area;

[0086] The feature judgment unit is used to judge whether the number of extracted features exceeds a preset number;

[0087] The feature output unit is used to output the detected features to the corresponding feature point set;

[0088] The extraction region updating unit is used to increase the side length of the circumscribed square of the reference region with a preset step size.

[0089] In another embodiment of the present invention, the feature matching module is a local BA algorithm module.

[0090] The outside rearview mirror field of view adjustment device of this embodiment can be integrated into the processor built into the outside rearview mirror itself, or integrated into a processor outside the outside rearview mirror, or part of it can be integrated into the processor built into the outside rearview mirror itself, and the other part can be integrated into a processor outside the outside rearview mirror. The present invention is not limited to this.

[0091] 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 field of view of an exterior rearview mirror, characterized in that: include: Step 1, determine the reference area for ORB feature detection; Step 2: Perform ORB feature detection according to the reference area to obtain a first feature point set; Step 3: Obtain turning information of the target vehicle, and perform ORB feature detection in the reference area to obtain a second feature point set; Step 4: Match the first feature point set and the second feature point set to determine a first amount and a first direction of pixel movement; Step 5: Adjust the field of view displayed by the exterior rearview mirror according to the first number and the first direction.

2. The method for adjusting the field of view of an exterior rearview mirror according to claim 1, characterized in that: The step 1 comprises: Step 101, obtaining a target vehicle rear image, wherein the target vehicle rear image includes a marker for locating the vehicle rear position; Step 102: Receive a region selection instruction, and use the marker and at least a portion of the rear image region as a reference region for ORB feature detection according to the region selection instruction.

3. The method for adjusting the field of view of an exterior rearview mirror according to claim 2, characterized in that: The step 2 comprises: Step 201: taking the smallest circumscribed square of the reference area as the current feature extraction area; Step 202, performing ORB feature extraction in the current feature extraction area, and determining whether the number of extracted features exceeds a preset number, if yes, outputting the features as a first feature point set, otherwise proceeding to the next step; Step 203, determine whether the side length of the current feature extraction area has reached the maximum value, if so, determine that the feature extraction has failed, otherwise increase the side length of the circumscribed square of the reference area by a preset step size as the new current feature extraction area, and return to step 202.

4. The method for adjusting the field of view of an exterior rearview mirror according to claim 3, characterized in that: The step 4 includes: determining the pixel movement amount and direction by using a local BA algorithm.

5. The method for adjusting the field of view of an exterior rearview mirror according to claim 4, characterized in that: The step 5 comprises: translating the image displayed by the exterior rearview mirror as a whole in the same direction as the first direction by the first amount.

6. An exterior rearview mirror field of view adjustment device, characterized in that: include: A feature detection module, and a reference area determination module, a vehicle control module, and a feature matching module connected thereto, and also includes a movement determination module connected to the feature matching module, and an image adjustment module connected to the movement determination module; The reference area determination module is used to determine the reference area for ORB feature detection; The feature detection module is used to perform ORB feature detection to obtain a first feature point set and a second feature point set; The vehicle control module is used to control the target vehicle to turn; The feature matching module is used to match the first feature point set and the second feature point set; The movement determination module is used to determine a first amount and a first direction of pixel movement; The image adjustment module is used to adjust the visual field displayed by the exterior rearview mirror according to the pixel movement amount and direction.

7. The device for adjusting the field of view of an exterior rearview mirror according to claim 6, characterized in that: The reference area determination module includes an image unit and a human-computer interaction unit and a determination unit connected thereto; The image unit is used to acquire and display the target vehicle rear image; The human-computer interaction unit is used to receive an area selection instruction; The determination unit is used to use the marker and at least a portion of the rear image area as a reference area for ORB feature detection according to the area selection instruction.

8. The exterior rearview mirror field of view adjustment device according to claim 7, characterized in that: The feature detection module includes a feature judgment unit, and a feature extraction unit, a feature output unit, and an extraction region update unit connected thereto, and also includes an extraction region determination unit connected to the feature extraction unit and the extraction region update unit; The extraction region determination unit is used to use the smallest circumscribed square of the reference region as the current feature extraction region; The feature extraction unit is used to perform ORB feature extraction in the current feature extraction area; The feature judgment unit is used to judge whether the number of extracted features exceeds a preset number; The feature output unit is used to output the detected features to the corresponding feature point set; The extraction region updating unit is used to increase the side length of the circumscribed square of the reference region with a preset step size.

9. The exterior rearview mirror field of view adjustment device according to claim 8, characterized in that: The feature matching module is a local BA algorithm module.

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