KR101762117B1 - Top view creating method for camera installed on vehicle and AVM system - Google Patents

Abstract

An apparatus and method for tolerance compensation of an AVM system are disclosed. The tolerance correcting device according to an embodiment of the present invention includes an image input unit for converting a video signal of a circular pattern disposed in the periphery of the vehicle taken by the camera into camera image data; And extracting an ellipse corresponding to the circular pattern from the camera image data, calculating a homography between the camera image and the top view image using a correlation between the ellipse and the circular pattern, And estimating the position of the camera on the world coordinates, wherein the circular pattern can be arbitrarily installed around the correction area where the vehicle is to be placed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and method for correcting tolerances of an AVM system,

The present invention relates to an apparatus and method for correcting tolerances of AVM systems.

Generally, the driver's vision (view) on the inside of the vehicle is mainly directed to the front, and the left and right and rear views of the driver are largely obscured by the vehicle body.

In order to solve such a problem, a clock assist means such as a side mirror for supplementing a limited range of the driver's clock is generally used. Recently, techniques including camera means for photographing an external image of a vehicle and providing the image to a driver This trend is being applied to vehicles.

Among them, there is an AVM (Around View Monitoring) system (hereinafter referred to as AVM) system in which a plurality of cameras are installed around the vehicle and 360-degree forward images around the vehicle are displayed. The AVM system combines not only each individual view captured through a plurality of cameras that photograph the surroundings of the vehicle but also images of the surroundings of the vehicle to provide a top view image in which the driver looks at the vehicle in the sky, Mark obstacles around the vehicle and eliminate blind spots.

The concept of the AVM system is schematically shown in Fig.

Referring to FIG. 1, cameras 110a, 110b, 110c, and 110d (hereinafter, collectively referred to as 110) are installed on front and rear sides, right and left sides of the vehicle 100, respectively. Each of the cameras 110 photographs the images A, B, C, and D on the front and rear sides and the left and right sides of the vehicle 100 and displays the captured image on an image 1 (b)) and outputs the reconstructed image to various display devices mounted on the vehicle 100.

Here, in the process of creating the top view as shown in FIG. 1 (b), when the peripheral images photographed using a plurality of cameras are combined, the mounting error of the cameras causes a defect such as mismatch The error caused in the process of mounting the camera on the vehicle is referred to as a tolerance.

An image correction method for removing a defect in software during a top view generation process has been studied, and US Patent Application Publication No. US2009 / 0010630 also discloses an image correction method for a camera system.

In the process of generating a top view of a vehicle peripheral image using a camera installed in a conventional vehicle, a polygonal pattern of a rectangular shape, a triangular shape, and a checkerboard shape has been used for tolerance correction. We have generated a top view by looking for features such as vertices and X marks for the polygonal patterns appearing in the image and correcting the tolerances using world coordinates and image coordinates for the features.

At this time, the world coordinates should be arbitrarily given to the polygon pattern. In order to assign the world coordinates, there is a restriction that the relative information that the polygon pattern is located in the world coordinates, such as the distance between the vertexes and the positional relationship of the vertexes, has to be known. This constraint is inconvenient for the polygon pattern to be installed in accordance with the specified standard in order to generate the top view, and it takes a lot of trouble to input or understand the pattern information.

United States Patent Application Publication No. US2009 / 0010630 (published on January 8, 2009) - Camera system and method of correcting camera fitting errors

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a display device capable of generating a top view when a pattern of a pattern satisfies a condition for displaying an image without inputting the world coordinates of the pattern using a circular pattern instead of a polygonal pattern, The present invention is to provide an apparatus and method for correcting tolerance of an AVM system that can accurately estimate an external parameter of a camera by using homography calculated for creation.

According to the present invention, it is possible to correct the tolerance even when the pattern is located at an arbitrary position, shorten the time required to install the pattern, enable image synthesis of a plurality of cameras without knowing the relative and absolute positions of the camera and the pattern, The present invention provides an apparatus and method for correcting tolerance of an AVM system that can be used for automatic tolerance correction by automatically finding a tolerance.

Other objects of the present invention will become more apparent through the following preferred embodiments.

According to an aspect of the present invention, there is provided an apparatus for correcting a tolerance of a camera installed in a vehicle, the apparatus comprising: an image input unit for converting a video signal of a circular pattern disposed in the periphery of the vehicle taken by the camera into camera image data; And extracting an ellipse corresponding to the circular pattern from the camera image data, calculating a homography between the camera image and the top view image using a correlation between the ellipse and the circular pattern, And estimating a position of the camera on the world coordinate, wherein the circular pattern is arbitrarily set around a correction area on which the vehicle is to be placed.

Wherein the camera includes a first camera, a second camera, a third camera, and a fourth camera installed on the front, right, left, and rear sides of the vehicle, The first circular pattern being arranged to meet a positional condition such that the first circular pattern is placed at an arbitrary position within a predetermined area.

Wherein the tolerance correcting unit comprises: extracting an ellipse from the camera image data; Extracting an outline of the ellipse; Correcting distortion caused by an internal variable of the camera; Calculating an elliptic equation based on outline coordinates of the distortion-corrected ellipse; And calculating a homography between the world coordinates and the camera image data using the elliptic equation.

The tolerance correcting unit includes a matrix P for converting the world coordinates into image coordinates of the camera image data, R representing a rotation transformation between the internal coordinates of the camera and the world coordinates and the camera coordinates, We can estimate the position of the camera in the world coordinates using the homography H and the K known in advance.

The circular pattern may further include a second circular pattern arranged to be horizontal with the left and right wheels of the vehicle.

Further comprising an image synthesizing unit converting the camera image data using the position of the camera estimated by the tolerance correcting unit to generate the top view image of the entire periphery of the vehicle and synthesizing the top view image into AVM image data, The pixel pitch of the top view image can be calculated using the diameter information of the circular pattern.

According to another aspect of the present invention, there is provided a method of correcting a tolerance of a camera installed in a vehicle and a recording medium on which a program for performing the correcting method is recorded.

A tolerance correcting method according to an exemplary embodiment of the present invention includes converting a video signal of a circular pattern disposed in the periphery of the vehicle captured by a camera provided in the vehicle by an image input unit into camera image data; Extracting an ellipse corresponding to the circular pattern from the camera image data; Calculating a homography between the camera image data and the top view image using the correlation between the ellipse and the circular pattern; And estimating a position of the camera on world coordinates by calculating an extrinsic parameter of the camera, wherein the circular pattern may be arbitrarily installed around a correction area where the vehicle is to be placed.

Wherein the camera includes a first camera, a second camera, a third camera, and a fourth camera installed on the front, right, left, and rear sides of the vehicle, The first circular pattern being arranged to meet a positional condition such that the first circular pattern is placed at an arbitrary position within a predetermined area.

The homography calculation step may include: extracting an outline of the ellipse; Correcting distortion caused by an internal variable of the camera; Calculating an elliptic equation based on outline coordinates of the distortion-corrected ellipse; And calculating a homography between the world coordinates and the camera image data using the elliptic equation.

The camera position estimating step may include a matrix P for converting the world coordinates into image coordinates of the camera image data, R representing a rotation transformation between the internal variable K of the camera and the world coordinates and the camera coordinates, The position of the camera can be estimated from the world coordinates using the homography H and the K previously known.

The circular pattern may further include a second circular pattern arranged to be horizontal with the left and right wheels of the vehicle.

Further comprising the step of converting the camera image data using the estimated position of the camera to generate the top view image of the entire periphery of the vehicle and synthesizing the top view image with the AVM image data, The pixel pitch of the top view image can be calculated using the diameter information of the pattern.

Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the invention.

According to the present invention, it is possible to generate a top view if the condition of displaying a pattern image satisfies a condition that a world coordinate of a pattern is not input using a circular pattern instead of a polygonal pattern, It is possible to accurately estimate the external parameters of the vehicle.

Also, even if the pattern is located at an arbitrary position, the tolerance can be corrected and the time required for pattern installation can be shortened. Even if the relative position and the absolute position of the camera and the pattern are unknown, There is an effect that can be used for automatic tolerance correction by automatically finding.

1 is a diagram schematically illustrating the concept of an AVM system,
2 is a block diagram schematically showing a configuration of an AVM system according to an embodiment of the present invention;
3 is a schematic view for explaining an example of a circular pattern arrangement for performing tolerance correction according to an embodiment of the present invention,
FIG. 4 is a flowchart illustrating a tolerance correction process in the AVM system according to an embodiment of the present invention. FIG.
5 is a flowchart illustrating a homography calculation process in detail in the tolerance correction process,
Fig. 6 is a diagram showing an image obtained by photographing a circular pattern,
FIG. 7 is a view showing a state in which an ellipse is found in a video,
FIG. 8 is a view showing an outline of an ellipse,
Fig. 9 is a diagram showing the elliptical outline coordinates before and after the distortion correction,
FIG. 10 shows a top view image reconstructed using the calculated homography,
11 is a top view image showing an estimated position of the camera;

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that the components of the embodiments described with reference to the drawings are not limited to the embodiments and may be embodied in other embodiments without departing from the spirit of the invention. It is to be understood that although the description is omitted, multiple embodiments may be implemented again in one integrated embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

2 is a block diagram schematically showing a configuration of an AVM system according to an embodiment of the present invention.

The AVM system 200 according to an embodiment of the present invention displays a peripheral image generated by correcting an image photographed through a camera installed in a vehicle and displays the generated peripheral image on a screen to allow a driver to check the surrounding situation of the vehicle to be. In this embodiment, by using a circular pattern to correct the tolerance generated when the camera is mounted on the vehicle, the tolerance can be corrected even if the pattern is located at an arbitrary position, and even if the relative position and the absolute position of the camera and the pattern are unknown And is capable of synthesizing images of a plurality of cameras.

2, the AVM system 200 includes an image input unit 210, a storage unit 220, a tolerance correcting unit 230, an image synthesizing unit 240, and a display unit 250 do. Although not shown, a controller for controlling the operation of one or more components included in the AVM system 200 may further be included.

The video input unit 210 is a circuit for inputting each camera video signal picked up and input from a camera 110 provided at each of a plurality of positions (for example, positions designated to photograph the front, rear, left, and right sides of the vehicle 100) And stores the generated camera image data in the storage unit 220. Here, the camera 110 can be realized as a wide-angle camera having a large angle of view in order to capture an environment around the vehicle with a small quantity.

For example, the storage unit 220 stores an operation program of the AVM system 200, camera image data generated by the image input unit 210, AVM image data synthesized by the image synthesizer 240, ) Can be stored. The storage unit 220 may be separated into a permanent storage memory for permanently storing data and a temporary storage memory for temporarily storing and operating data necessary for operation.

The tolerance correcting unit 230 analyzes the camera image data stored in the storage unit 220 to find a circular pattern (having an elliptical shape in the image), and obtains pattern information (circular pattern in the image ) Is processed to calculate homography. Also, extrinsic parameters of the camera 110 can be calculated in the process of calculating the homography, and the position of the camera 110 on the world coordinates can be estimated.

The image synthesizing unit 240 converts the camera image data using the camera position and pattern information estimated by the tolerance correcting unit 230 to obtain a top view of the surrounding environment of the vehicle as if looking down from above the vehicle And combines them into AVM image data. That is, after converting the camera image data for the image of the surroundings of the vehicle 100 into the top view image, the position and orientation of the top view image are adjusted and synthesized based on the camera position estimated by the tolerance correcting unit 230, The AVM image data corresponding to the top view can be generated.

The AVM image data generated by the image synthesizing unit 240 may be output through the display unit 250.

3 is a schematic view for explaining an example of a circular pattern arrangement for performing tolerance correction according to an embodiment of the present invention.

As shown in FIG. 3, the first circular patterns 311, 313, 315, and 317 may be arbitrarily installed around the correction area where the vehicle is to be placed.

The first circular patterns 311, 313, 315, and 317 used for the tolerance correction are circular in shape and always show the same shape irrespective of the angle about the center of rotation as shown in FIG. That is, it is not necessary to install the polygonal pattern at a predetermined angle in a predetermined position during the pattern installation process, and it is possible to shorten the time required to install the pattern.

Also, the first circular patterns 311, 313, 315, and 317 have advantages in that tolerance correction can be performed even when the first circular patterns 311, 313, 315, and 317 are positioned at predetermined positions, I have.

The positional condition of the first circular patterns 311, 313, 315, and 317 should be such that at least two patterns can be photographed using the camera 110 installed in the vehicle so that the two patterns are displayed on one image. That is, at least two patterns must be displayed for each camera image data because the same first circular pattern must be viewed in at least camera image data obtained from different views.

For example, as shown in the figure, two first circular patterns 311 and 313 are included in an image photographed by the first camera 110a installed in the front, and a second camera 110b The image photographed by the third camera 110c includes two first circular patterns 313 and 317 and the image photographed by the third camera 110c installed on the left side includes two first circular patterns 311 and 315, The image photographed by the fourth camera 110d installed on the rear side includes two first circular patterns 315 and 317. [

Therefore, in the present embodiment, the positional conditions of the first circular patterns 311, 313, 315, and 317 are placed in a region where the angle of view of two adjacent cameras overlap each other, will be.

In addition, the first circular patterns 311, 313, 315, and 317 may have the same size. Also, if the diameter information is known, it is possible to calculate an accurate pixel pitch (mm / pixel) when the top view is generated in the image synthesizer 240. However, the diameter information is not limited. That is, it is also possible to use a first circular pattern of different diameter depending on the case.

In the case where only the first circular patterns 311, 313, 315, and 317 are present in this embodiment, the circle is basically not directional, and a phenomenon in which the top view is rotated when the AVM image data is generated by the image synthesizing unit 240 Visible phenomenon) may occur.

In order to compensate for this, the second circular patterns 321, 323, 325, and 327 are positioned so as to be horizontal with the left and right wheels of the vehicle 100, It is also possible to prevent the top view from turning around by matching the front and rear regions after matching the horizontal positions of the top view images.

Hereinafter, the process of correcting the tolerance and generating the top view using the circular pattern will be described with reference to the related drawings.

FIG. 4 is a flowchart illustrating a tolerance correction and a top view generation process in the AVM system according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating a homography calculation process in detail in the tolerance correction process, FIG. 8 is a diagram showing an ellipse outline extracted, FIG. 9 is a diagram showing elliptic outline coordinates before and after distortion correction, and FIG. Fig. 11 is a top view image showing the estimated position of the camera. Fig. 11 is a top view image reconstructed using the calculated homography.

When the placement of the first circular patterns 311, 313, 315, and 317 and / or the second circular patterns 312, 323, 325, and 327 is completed as shown in FIG. 3, The surrounding environment of the vehicle including the circular pattern is photographed (step S410), and the image input unit 210 receives the camera image data in which the circular pattern is photographed. Here, the camera image data may be stored in the storage unit 220 or directly to the image input unit 210. An example of the camera image data is shown in Fig.

The tolerance correction unit 230 calculates the homography using the camera image data received directly from the image input unit 210 or stored in the storage unit 220 (step S420).

The calculation process of the homography is shown in detail in Fig.

The tolerance correcting unit 230 extracts an ellipse from the camera image data (step S510). This is because, when a circular pattern is photographed, it appears as an elliptical shape except for the case where it is photographed vertically above. Referring to FIG. 7, ellipses found in image data are shown in white.

As the method of extracting the ellipse from the camera image data, an image segmentation technique, a hough transform technique and the like can be used. The image segmentation technique separates a specific region in an image. The Hough Transform technique extracts features in an image and uses a voting technique to extract a straight line or a circle component from the image. Since the technique of extracting an ellipse from an image is obvious to those skilled in the art, a detailed description thereof will be omitted.

Next, the outline of the ellipse is extracted (step S520). Referring to FIG. 8, an outline of an ellipse extracted from an image is shown.

The elliptical outline can be extracted using a method of detecting an edge of an image generally such as Canny, soble, prewitt, and the like. Since the process of extracting the ellipse outline is also obvious to those skilled in the art, a detailed description thereof will be omitted.

Next, since the image of the camera installed in the vehicle is distorted due to the intrinsic parameter of the camera, distortion correction is performed (step S530) and the outer coordinates of the extracted ellipse are converted into the coordinates of the image without distortion. The internal variable of the camera may be lens distortion due to the shape of the lens, which can be expressed by Taylor series. Another internal variable may be the focal length, which is the distance between the CCD panel and the center of the lens, and the image center, which is the center point of the actual image when the image is formed on the CCD panel.

The distortion coefficients due to the camera internal variables may be calculated in advance for each camera, and the outline coordinates of the ellipses before and after the distortion correction by the camera internal variables are shown in Fig. Red is the outline coordinates of the ellipse before distortion correction, and blue is the outline coordinates of the ellipse after distortion preservation.

Compared with FIG. 8, the size and shape of the ellipse are different because the upper left corner is (0, 0) in the image of FIG. 8, whereas the lower left corner is (0, 0) in FIG. In addition, the range is 0 to 480 in FIG. 8 on the basis of the Y-axis, and 270 to 370 in FIG. 9.

Next, an elliptic equation is calculated based on the elliptical outline coordinates (step S540). SVD or RANSAC algorithms can be used to calculate ellipse equations, such as ellipsefit, which calculates the ellipse best suited to the outline using contour information of the corresponding region using edge information of the image . The method of calculating the elliptic equation is also obvious to those skilled in the art, so a detailed description thereof will be omitted.

The homography between the world coordinates and the image is calculated using the elliptic equation (step S550). The homography calculation process will be described in more detail as follows.

In homogeneous coordinates, all circles are expressed as:

[Equation 1]

Where (x, y, w) is the homogeneous coordinate, (a, b, 1) is the center of the circle, and r is the radius of the circle.

Then, (1, i, 0) ^T and (1, - i, 0) ^T satisfy the above equation 1 irrespective of a, b, and r. Therefore, these two points are points where any two circles intersect on the complex plane, and this point is called a circular point.

Thus, circles appearing in elliptical form in the image always have an intersection at I and J , which are circular points.

이다. I and J are expressed in the following coordinates. I = (1, i, 0) ^T , J = (1, - i, 0) ^T. Here, i is

to be.

Homography H and H ^-1 exist between the world coordinates and the photographed image, and H and H ^-1 can be expressed as the product of S, A, and P as follows.

&Quot; (2) "

Where S is a similarity matrix, A is an affinity matrix, and P is a projectivity matrix.

,

로 표현된다. here,

,

Lt; / RTI >

와

는 아핀성 변환의 계수로, 다음과 같이 계산된다.

Wow

Is a coefficient of the affine transformation, and is calculated as follows.

,

,

) 은 소실선(vanishing line)이다.Here ㅣ = (

,

,

) Is a vanishing line.

&Quot; (3) "

는 회전각(rotational angle),

는 앙각(elevation angle)이다. here,

A rotational angle,

Is an elevation angle.

는 서큘러 포인트의 변환에 영향을 주지 않으므로 생략가능하다. 여기서, s는 스케일(scale), r₁~r₄는 회전, t_x, t_y는 이동량을 나타낸다.

Can be omitted because it does not affect the conversion of the circular point. Here, s is scale, r ₁ to r ₄ are rotation, and t _x and t _y are movement amounts.

Circular points I and J are points at which two arbitrary circles meet, and therefore, the points that are encountered in the image are represented by H I and H J , which are the points at which the circulating points I and J are converted.

&Quot; (4) "

H J is the complex conjugate of H I. All the ellipses appearing in the image have an intersection at the two points H I and H J on the image.

For convenience, using two ellipses, two ellipses can be expressed in the following manner.

&Quot; (5) "

The intersection of two ellipses of Equation (5) is obtained, and P ^-1 and A ^-1 can be obtained by substituting for the above-mentioned H I , and the homography H from the image to the top view image can be obtained.

In this case, if the diameter of the photographed circular pattern is known, the s (scale) of S ^-1 is also known.

Referring again to FIG. 4, when the homography H is calculated as described above, the position of the camera existing in the world coordinates can be estimated through the following process (step S430).

Between the world coordinate X and the image coordinate x, there exists a projection matrix P that maps the coordinates to each other. This can be expressed as follows.

&Quot; (6) "

Here, P denotes a matrix for converting the world coordinates into the image coordinates of the camera image data. As shown in Equation (7), R is a rotation transformation between the camera internal variable K and the world coordinates and the camera coordinates, C, which is the amount of movement between them. Here, the internal variable K may include a scale factor in the X-axis direction, a scale factor in the Y-axis direction, a skew, and a position of a principal point.

&Quot; (7) "

Here, since the homography H is a transformation matrix between the top view image (two-dimensional image) and the camera image data, it can be regarded as a special case in which r ₃ is excluded from P because there is no Z-axis transformation.

&Quot; (8) "

의 관계를 가진다. In this case, since r ₃ can be determined externally of r ₁ and r ₂ ,

.

를 유추할 수 있게 된다. Using this relationship, we can infer P by analogy to r ₃ . Since K and R are known in P, we use the previously obtained homography H and K, which are known in advance,

.

Next, the image synthesizer 240 converts the camera image data into the top view image using the previously estimated camera position information and the pattern information, synthesizes the front view images, the back view, the left view, and the right view image to generate AVM image data (Step S440).

In the synthesis process of the top view image, the top view images of the left and right regions are horizontally aligned by analyzing the pattern information on the ellipses extracted from the second circular patterns 321, 323, 325, and 327, You can tailor it.

Referring to FIG. 10, the reconstructed top view image is shown using the homography calculated in step S420. In FIG. 11, the camera position estimated in step S430 is indicated by a red *.

The method of generating a top view and estimating an external variable in the AVM system according to the present invention can be implemented as computer-readable codes on a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording media storing data that can be decoded by a computer system. For example, it may be a ROM (Read Only Memory), a RAM (Random Access Memory), a magnetic tape, a magnetic disk, a flash memory, an optical data storage device, or the like. In addition, the computer-readable recording medium may be distributed and executed in a computer system connected to a computer network, and may be stored and executed as a code readable in a distributed manner.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that various modifications and changes may be made.

100: vehicle 110a, 110b, 110c, 110d:
200: AVM system 210: video input unit
220: storage unit 230: tolerance correcting unit
240: image synthesizer 250:
311, 313, 315, 317: first circular pattern
321, 323, 325, 327: a second circular pattern

Claims (13)

An apparatus for correcting a tolerance of a camera installed in a vehicle,
An image input unit for converting an image signal of a circular pattern disposed in the periphery of the vehicle taken by the camera into camera image data; And
Calculating a homography between the camera image and the top view image by using a correlation between the ellipse and the circular pattern, calculating an external variable of the camera, extracting an ellipse corresponding to the circular pattern from the camera image data, And a tolerance correcting unit for estimating the position of the camera on the world coordinates,
The circular pattern is arbitrarily installed around a correction area where the vehicle is to be placed,
Further comprising an image synthesizing unit converting the camera image data using the position of the camera estimated by the tolerance correcting unit to generate the top view image of the entire periphery of the vehicle and synthesizing the top view image into AVM image data,
Wherein the image synthesizer calculates a pixel pitch for the top view image using the diameter information of the circular pattern.
The method according to claim 1,
The camera includes a first camera, a second camera, a third camera, and a fourth camera installed at the front, right, left, and rear of the vehicle,
Wherein the circular pattern includes a first circular pattern arranged to satisfy a positional condition such that an angle of view of cameras adjacent to each other in the camera is placed at an arbitrary position within an overlapping area.
The method according to claim 1,
Wherein the tolerance correcting unit comprises:
Extracting an ellipse from the camera image data;
Extracting an outline of the ellipse;
Correcting distortion caused by an internal variable of the camera;
Calculating an elliptic equation based on outline coordinates of the distortion-corrected ellipse;
And calculating a homography between the world coordinate and the camera image data using the elliptic equation.
The method of claim 3,
The tolerance correcting unit includes a matrix P for converting the world coordinates into image coordinates of the camera image data, R representing a rotation transformation between the internal coordinates of the camera and the world coordinates and the camera coordinates, And estimating the position of the camera in the world coordinates using the homography H and the previously known K. [
3. The method of claim 2,
Wherein the circular pattern further comprises a second circular pattern arranged to be horizontal with the left and right wheels of the vehicle.
delete A method of correcting a tolerance of a camera installed in a vehicle,
Converting a video signal of a circular pattern disposed in the periphery of the vehicle captured by a camera provided in the vehicle by the video input unit into camera video data;
Extracting an ellipse corresponding to the circular pattern from the camera image data;
Calculating a homography between the camera image data and the top view image using the correlation between the ellipse and the circular pattern; And
Calculating extrinsic parameters of the camera to estimate the position of the camera on world coordinates,
The circular pattern is arbitrarily installed around a correction area where the vehicle is to be placed,
And converting the camera image data using the estimated position of the camera to generate the top view image of the entire periphery of the vehicle and synthesizing the top view image with the AVM image data,
Wherein the AVM image data synthesizing step calculates a pixel pitch for the top view image using the diameter information of the circular pattern.
8. The method of claim 7,
The camera includes a first camera, a second camera, a third camera, and a fourth camera installed at the front, right, left, and rear of the vehicle,
Wherein the circular pattern includes a first circular pattern arranged to satisfy a positional condition such that the angle of view of the cameras adjacent to each other in the camera is placed at an arbitrary position within an overlapping region.
8. The method of claim 7,
The homography-
Extracting an outline of the ellipse;
Correcting distortion caused by an internal variable of the camera;
Calculating an elliptic equation based on outline coordinates of the distortion-corrected ellipse; And
And calculating a homography between the world coordinate and the camera image data using the elliptic equation.
10. The method of claim 9,
The camera position estimating step may include:
A matrix P for transforming the world coordinates into image coordinates of the camera image data, a matrix P for converting the internal variable K of the camera into R, a rotation transformation between the world coordinate and the camera coordinates, and a movement amount C between the camera coordinates And estimating a position of the camera in the world coordinates using the homography H and the previously known K using the correlation.
8. The method of claim 7,
Wherein the circular pattern further comprises a second circular pattern arranged to be horizontal with the left and right wheels of the vehicle.
delete 12. A recording medium in which a program for performing the method of any one of claims 7 to 11 is recorded so as to be read by a computer.

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