KR102541061B1 - Method, system and non-transitory computer-readable recording medium for compensating brightness of ball images - Google Patents

Abstract

The present invention relates to a method, system and non-transitory computer readable recording medium for correcting the brightness of a blank image.
According to one aspect of the present invention, as a method for correcting the brightness of a ball image, calculating a brightness distribution of a region corresponding to the ball in each of a plurality of images of a ball to be measured, and correcting a captured brightness distribution of an area corresponding to the ball of at least one image among the plurality of images with reference to a reference brightness distribution.

Description

METHOD, SYSTEM AND NON-TRANSITORY COMPUTER-READABLE RECORDING MEDIUM FOR COMPENSATING BRIGHTNESS OF BALL IMAGES}

The present invention relates to a method, system and non-transitory computer readable recording medium for correcting the brightness of a blank image.

A virtual golf system that allows golfers to virtually enjoy golf at a low cost even in a city center has been widely spread. In such a virtual golf system, when a golfer hits a golf ball, a plurality of images of the golf ball are acquired, physical quantities related to the golf ball are measured based on the trajectory, interval, size, etc., and simulation is performed to obtain a simulation result of the shot. The basic concept may be to display on the screen. In this virtual golf system, it is important to obtain a captured image of a golf ball in as good a condition as possible.

In this regard, Korean Patent Laid-open Publication No. 10-2009-0112538 (Title of Invention: Apparatus for acquiring golf images using lighting control, and golf practice system based on image processing using the same) discloses golf while adjusting the position or color of lighting. A technique for obtaining more various images of a golf ball by photographing a practice scene has been disclosed (the specification of the Korean Patent Laid-open Publication should be regarded as incorporated herein in its entirety). However, various conventional technologies including this technology are techniques necessary for obtaining golf ball images in good condition necessary for accurately measuring the physical quantity of a golf ball or golf ball using a mark sequence obtained from a plurality of golf ball images. It is true that they are not interested in the technology of measuring the physical quantity of

Therefore, the inventor(s) of the present invention relates to a new technique for accurately measuring the physical quantity of a golf ball by analyzing a mark sequence appearing in a golf ball image obtained from a high-speed camera capable of capturing images of many frames in a short time. it is a suggestion

An object of the present invention is to measure the rotational speed and rotational direction of a golf ball by analyzing a mark sequence appearing in a plurality of golf ball images.

Another object of the present invention is to make the brightness distribution of a plurality of golf ball images uniform by correcting the brightness (specifically, the brightness distribution) of the plurality of golf ball images.

Representative configurations of the present invention for achieving the above object are as follows.

According to one aspect of the present invention, as a method for correcting the brightness of a ball image, calculating a brightness distribution of a region corresponding to the ball in each of a plurality of images of a ball to be measured, and correcting a captured brightness distribution of an area corresponding to the ball of at least one image among the plurality of images with reference to a reference brightness distribution.

According to another aspect of the present invention, a system for correcting the brightness of an image of a ball, comprising: an image acquisition unit acquiring a plurality of images obtained by photographing a ball, which is a target of physical quantity measurement; and each of the plurality of images corresponds to the ball. A system including an image correction unit that calculates a photographed brightness distribution of an area to be photographed and corrects a photographed brightness distribution of an area corresponding to the ball of at least one image among the plurality of images with reference to a reference brightness distribution. Provided.

In addition to this, other methods, systems and non-transitory computer readable recording media for implementing the present invention are further provided.

According to the present invention, since the distribution of brightness can be uniformed not only within each golf ball image but also across a plurality of golf ball images, an effect of being able to more accurately detect a mark sequence appearing in a plurality of golf ball images is achieved.

According to the present invention, the effect of being able to accurately measure the rotational speed and rotational direction of a golf ball using a time-series set of marks (ie, a mark sequence) appearing across a plurality of golf ball images is achieved

1 is a diagram schematically showing the overall configuration of a virtual golf system according to an embodiment of the present invention.
2 is a diagram showing in detail the internal configuration of the photographing device 100 according to an embodiment of the present invention.
3 is a diagram showing in detail the internal configuration of the simulator 200 according to an embodiment of the present invention.
4 is a diagram illustrating an illustrative example of a golf ball image actually photographed according to an embodiment of the present invention.
5 is a diagram visually illustrating a correction model that can be applied to a golf ball image according to an embodiment of the present invention.
6 is a diagram showing a golf ball image whose brightness is corrected according to an embodiment of the present invention by way of example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention which follows refers to the accompanying drawings which illustrate, by way of illustration, specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable any person skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented from one embodiment to another without departing from the spirit and scope of the present invention. It should also be understood that the location or arrangement of individual components within each embodiment may be changed without departing from the spirit and scope of the present invention. Therefore, the detailed description to be described later is not performed in a limiting sense, and the scope of the present invention should be taken as encompassing the scope claimed by the claims and all scopes equivalent thereto. Like reference numbers in the drawings indicate the same or similar elements throughout the various aspects.

Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those skilled in the art to easily practice the present invention.

[Preferred Embodiments of the Present Invention]

Composition of the whole system

1 is a diagram schematically showing the overall configuration of a virtual golf system according to an embodiment of the present invention.

As shown in FIG. 1 , the virtual golf system may include a hitting unit 10 , a lighting device 20 , a photographing device 100 , a simulator 200 and a display device 300 .

First, the hitting unit 10 according to an embodiment of the present invention may be a part where a golfer places a golf ball while standing on his feet when using the virtual golf system. The hitting unit 10 may include a known swing plate whose inclination angle can be adjusted. For reference, those skilled in the art, when the present invention is applied to other types of virtual sports systems, the configuration of the striking unit 10, if necessary, together with the configuration of other components interlocking with it, according to the characteristics of the corresponding sport. You can change it appropriately to fit.

Next, the lighting device 20 according to an embodiment of the present invention may be a device capable of artificially radiating light when a golfer enjoys virtual golf indoors or outdoors. The lighting device 20 may be turned on or off, or its brightness may be adjusted as needed. Preferably, the lighting device 20 may be an infrared light to prevent natural deterioration of the golf ball image due to light flickering.

Next, the photographing device 100 according to an embodiment of the present invention includes at least one camera (eg, a high-speed camera) (not shown) to include an image of a golf ball (eg, a moving image). A function of acquiring two or more images of a golf ball) may be performed. As shown in FIG. 1 , the photographing device 100 may be disposed at a position looking down at a golf ball in motion, but may also be disposed at other positions.

According to one embodiment of the present invention, the image of the golf ball has a predetermined mark displayed on the surface of the golf ball so that it is better to specify the shape or location of the mark. can do. For example, if a mark displayed in a region corresponding to a ball in an image of a golf ball is clearer, the simulator 200 as described below may use a mark sequence, which is a time-sequential set of marks appearing over a plurality of golf ball images. ) can be captured more accurately to calculate the rotational speed and direction of rotation of the golf ball more accurately. In addition, for example, when the image of the golf ball is clearer, the simulator 200 more accurately captures the central point or the maximum brightness point of the plurality of golf ball images to more accurately calculate the brightness distribution of the region corresponding to the golf ball. can do.

A detailed configuration of the photographing device 100 as described above will be further described below with reference to FIG. 2 .

Next, the simulator 200 according to an embodiment of the present invention obtains a plurality of images of a ball, which is a target of physical quantity measurement, from the photographing device 100, and acquires an area corresponding to the ball in each of the plurality of images. The brightness distribution of the plurality of golf ball images is uniform by calculating the photographed brightness distribution of and correcting the photographed brightness distribution of the region corresponding to the ball of at least one image among the plurality of images with reference to the reference brightness distribution It can perform functions that make it happen. In addition, the simulator 200 according to an embodiment of the present invention analyzes a time-sequential set of marks (ie, a mark sequence) appearing over a plurality of corrected golf ball images as above, thereby rotating the golf ball. It may further perform functions of measuring speed and direction of rotation. In addition, the simulator 200 according to an embodiment of the present invention may implement the motion of the golf ball in virtual reality based on the information about the rotational speed and rotational direction of the golf ball measured as described above.

Meanwhile, the simulator 200 according to an embodiment of the present invention may communicate with the photographing device 100 and the display device 300 and may include a dedicated processor for virtual golf simulation. Such a dedicated processor may have a memory means and have numerical calculation capability and graphic processing capability.

The above configuration of the simulator 200 will be further described below with reference to FIG. 3 .

Finally, the display device 300 according to an embodiment of the present invention may perform a function of displaying results of physical quantity measurement and virtual reality implementation of the simulator 200 . The display device 300 may display a predetermined image through a predetermined display means, for example, a screen that absorbs the impact of a hit golf ball and does not directly emit light, and a projector that outputs an image to the screen. may consist of

Composition of the shooting device

Below, an internal configuration of the photographing device 100 according to an embodiment of the present invention and functions of each component will be described.

2 is a diagram showing in detail the internal configuration of the photographing device 100 according to an embodiment of the present invention.

As shown in FIG. 2 , the photographing device 100 may include a camera unit 110 , a communication unit 120 and a control unit 130 .

According to an embodiment of the present invention, the camera unit 110, the communication unit 120, and the control unit 130 may be program modules, at least some of which communicate with the simulator 200. These program modules may be included in the photographing device 100 in the form of an operating system, application program modules, or other program modules, and may be physically stored in various known storage devices. Also, these program modules may be stored in a remote storage device capable of communicating with the photographing device 100 . Meanwhile, these program modules include routines, subroutines, programs, objects, components, data structures, etc. that perform specific tasks or execute specific abstract data types according to the present invention, but are not limited thereto.

First, the camera unit 110 according to an embodiment of the present invention may include a camera capable of optically obtaining a plurality of images. For example, the camera unit 110 according to an embodiment of the present invention may include a high-speed camera or an ultra-high-speed camera capable of capturing images of several tens of frames per second. According to an embodiment of the present invention, the camera of the camera unit 110 may acquire a predetermined image by taking pictures with or without a moving golf ball.

Next, the communication unit 120 according to an embodiment of the present invention may perform a function of mediating data transmission and reception between the control unit 130 and the simulator 200 as needed. According to an embodiment of the present invention, there is no particular limitation on the communication method that the communication unit 120 can take, but a wired communication method such as wired LAN communication or cable communication, wireless LAN communication, infrared communication, RF communication, Bluetooth communication, etc. The same wireless communication scheme may be desirable.

Finally, the controller 130 according to an embodiment of the present invention may perform a function of controlling data flow between the camera unit 110 and the communication unit 120 . That is, the control unit 130 according to the present invention controls the data flow from/to the outside of the photographing apparatus 100 or the data flow between each component of the photographing apparatus 100, thereby controlling the camera unit 110 and the communication unit 120. ), each can be controlled to perform its own function.

Composition of the simulator

Below, the internal configuration of the simulator 200 according to an embodiment of the present invention and the functions of each component will be described.

3 is a diagram showing in detail the internal configuration of the simulator 200 according to an embodiment of the present invention.

As shown in FIG. 3, the simulator 200 according to an embodiment of the present invention includes an image processing unit 210, a physical quantity measurement unit 220, a simulation unit 230, a database 240, and a communication unit 250. And it may be configured to include a control unit 260. Also, according to an embodiment of the present invention, the image processing unit 210 may include an image acquisition unit (not shown) and an image correction unit (not shown). According to an embodiment of the present invention, at least a part of the image processing unit 210, the physical quantity measurement unit 220, the simulation unit 230, the database 240, the communication unit 250, and the control unit 260 is a photographing device. 100 or a program module that communicates with the display device 300. These program modules may be included in the simulator 200 in the form of an operating system, application program modules, or other program modules, and may be physically stored in various known storage devices. Also, these program modules may be stored in a remote storage device capable of communicating with the simulator 200 . Meanwhile, these program modules include routines, subroutines, programs, objects, components, data structures, etc. that perform specific tasks or execute specific abstract data types according to the present invention, but are not limited thereto.

Meanwhile, although the simulator 200 has been described as above, this description is exemplary, and some or all of functions or components required for the simulator 200 may be realized or included in the photographing device 100 as needed. is obvious to those skilled in the art.

First, according to an embodiment of the present invention, the image processing unit 210 (specifically, the image acquisition unit) captures a plurality of images of a ball, which is a target of physical quantity measurement, from the photographing device 100 above. function to obtain.

4 is a diagram illustrating an illustrative example of a golf ball image actually photographed according to an embodiment of the present invention.

Referring to FIG. 4 , due to various environmental factors such as the location of lighting, the direction or intensity of light irradiation, the location, specifications or settings of a camera, and the location or color of a ball, the brightness distribution of a region corresponding to a ball in a plurality of images may appear differently in each image. For example, the overall brightness of the area corresponding to the ball may be dark (see FIG. 4(a)), and the brightness of the center of the area corresponding to the ball may be too bright compared to other parts (see FIG. 4(b)). ) reference).

First, according to an embodiment of the present invention, the image processing unit 210 (specifically, the image correction unit) captures brightness of an area corresponding to the ball in each of a plurality of images in which a ball, which is a target of physical quantity measurement, is photographed. It can perform the function of calculating the distribution.

Specifically, the image correction unit according to an embodiment of the present invention may specify an area corresponding to a ball in each image by calculating a center point, a maximum brightness point, a radius, and the like of the area corresponding to the ball in each of a plurality of images. can In addition, the image correction unit according to an embodiment of the present invention, based on a predetermined point (eg, a center point, a point of maximum brightness, etc.) in a region corresponding to a ball in each of a plurality of images, The brightness distribution of the area can be calculated.

More specifically, the image correction unit according to an embodiment of the present invention uses an estimation model or a statistical model such as a linear regression model or a non-parametric model to calculate data from each of a plurality of images. The brightness distribution of the area corresponding to can be calculated.

For example, based on a prior regression model, a relationship between a distance between a maximum brightness point and an arbitrary point in a region corresponding to a ball in each of a plurality of images and a brightness of the corresponding arbitrary point may be derived. For another example, based on a non-parametric model such as a blurring filter, a low pass filter, and a Gaussian filter, a random point within a region corresponding to a ball in each of a plurality of images Brightness can be calculated.

In addition, according to an embodiment of the present invention, the image processing unit 210 (specifically, the image correction unit), with reference to the reference brightness distribution, of a region corresponding to the ball of at least one image among a plurality of images A function of correcting a captured brightness distribution may be performed. Here, according to an embodiment of the present invention, the reference brightness distribution is a brightness distribution preset as suitable for detecting and recognizing a mark displayed on the surface of the ball, and may be stored in the database 240. can

Specifically, the image correction unit according to an embodiment of the present invention is configured to adjust the uniformity of the brightness distribution of the area corresponding to the ball of the image to be corrected to a predetermined level or higher. The captured brightness distribution can be corrected.

More specifically, the image correction unit according to an embodiment of the present invention compares the first captured brightness distribution of the area corresponding to the ball of the first image with the reference brightness distribution, thereby correcting the first captured brightness distribution. A correction model may be calculated, and the brightness distribution of the first image may be corrected with reference to the calculated correction model.

For example, a correction model according to an embodiment of the present invention may be expressed as Equations 1 and 2 below.

<Equation 1>

E(P) = c * B(P) + d

<Equation 2>

F(P) = B(P) + E(P) or F(P) = B(P) * E(P)

In Equations 1 and 2 above, B(P) refers to the brightness of point P, which is an arbitrary point, E(P) refers to a correction model for the brightness of point P, and c and d are correction models E (P) denotes a correction factor specifying, and F(P) denotes the brightness of point P corrected (i.e., equalized) by the correction model E(P).

5 is a diagram visually illustrating a correction model that can be applied to a golf ball image according to an embodiment of the present invention. 5 (a) and (b) correspond to visualizations of correction models applicable to the images of FIG. 4 (a) and (b), respectively.

6 is a diagram showing a golf ball image whose brightness is corrected according to an embodiment of the present invention by way of example.

Referring to FIG. 6 , it can be seen that the distribution of brightness in a region corresponding to a ball in the golf ball images shown in (a) and (b) of FIG. 4 is uniform.

As described above, according to an embodiment of the present invention, by correcting (i.e., equalizing) the brightness distribution of a region corresponding to a ball not only within each golf ball image but also across a plurality of golf ball images, a plurality of images In detecting and recognizing marks that appear in common throughout, it is possible to increase the accuracy of detection and recognition by reducing the possibility of errors due to differences in brightness.

However, it should be noted that the method for correcting the brightness distribution of the golf ball image according to the present invention is not necessarily limited to the above-listed algorithms, and may be modified within a range capable of achieving the object of the present invention.

Meanwhile, the physical quantity measurement unit 220 according to an embodiment of the present invention, the plurality of golf ball images (more specifically, the plurality of golf ball images that are temporally adjacent) corrected as above (ie, the brightness distribution is uniformed) ), it is possible to perform the function of measuring the rotational speed and rotational direction of the golf ball by analyzing the mark sequence appearing in . Specifically, the physical quantity measuring unit 220 according to an embodiment of the present invention refers to the moving speed and moving direction of the mark observed from the above mark sequence on the golf ball surface, and determines the rotational speed and rotational direction of the golf ball. can be estimated. In addition, the physical quantity measurer 220 according to an embodiment of the present invention may further perform a function of calculating a motion trajectory of a golf ball, calculating a motion speed of a golf ball, or calculating a height of a golf ball. .

Next, the simulation unit 230 according to an embodiment of the present invention, based on various information about the physical quantity of the golf ball measured as above, the motion of the golf ball (eg, rotational speed, rotation) in virtual reality direction, movement speed, movement direction, launch angle, etc.) can be implemented. In addition, the simulation unit 230 according to an embodiment of the present invention reflects the motion of the golf ball on a graphic object or transmits a control signal including an image signal to the display device 300 so that the motion of the golf ball is displayed on the display device ( 300) can be realistically expressed.

Next, in the database 240 according to an embodiment of the present invention, information about a captured image of a golf ball, an image in which the brightness distribution of the golf ball is corrected, a mark sequence, a calculated physical quantity, or the like, or information necessary for simulation (eg For example, data necessary for implementing virtual reality, etc.) may be stored. Although the database 240 is shown in FIG. 3 as being included in the simulator 200, the database 240 may be configured separately from the simulator 200 according to the needs of those skilled in the art to implement the present invention. . On the other hand, the database 240 in the present invention is a concept including a computer-readable recording medium, and may be a database in a broad sense including not only a database in a narrow sense but also data records based on a file system, and a simple log Even a set can be a database 240 in the present invention if data can be extracted by searching it.

Next, the communication unit 250 according to an embodiment of the present invention may perform a function of enabling data transmission/reception from/to the simulator 200 . According to an embodiment of the present invention, there is no particular limitation on the communication method that the communication unit 250 can take, but a wired communication method such as wired LAN communication or cable communication, wireless LAN communication, infrared communication, RF communication, Bluetooth communication, etc. The same wireless communication scheme may be desirable.

Finally, the control unit 260 according to an embodiment of the present invention controls the flow of data between the image processing unit 210, the physical quantity measuring unit 220, the simulation unit 230, the database 240 and the communication unit 250. It can perform control functions. That is, the control unit 260 according to the present invention controls the flow of data from/to the outside of the simulator 200 or the flow of data between each component of the simulator 200, thereby controlling the image processing unit 210 and the physical quantity measurement unit 220. ), the simulation unit 230, the database 240, and the communication unit 250 can be controlled to perform unique functions.

Above, the virtual sports system of the present invention has been mainly described assuming a virtual golf system, but it can be applied to all kinds of virtual sports systems (for example, a virtual baseball system or a virtual soccer system) requiring simulation of ball motion. It will be apparent to those skilled in the art that the technical principles and configurations of the present invention can be applied.

Embodiments according to the present invention described above may be implemented in the form of program instructions that can be executed through various computer components and recorded on a computer-readable recording medium. The computer readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the computer-readable recording medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floptical disks. medium), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. A hardware device may be modified with one or more software modules to perform processing according to the present invention and vice versa.

Although the present invention has been described above with specific details such as specific components and limited embodiments and drawings, these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Those with ordinary knowledge in the technical field to which the invention belongs may seek various modifications and changes from these descriptions.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments and should not be determined, and all scopes equivalent to or equivalently changed from the claims as well as the claims described below are within the scope of the spirit of the present invention. will be said to belong to

100: shooting device
110: camera unit
120: communication department
130: control unit
200: simulator
210: image processing unit
220: physical quantity measuring unit
230: simulation unit
240: database
250: communication department
260: control unit

Claims (13)

As a method for correcting the brightness of an empty image,
Calculating a photographed brightness distribution of an area corresponding to the ball in each of a plurality of images obtained by photographing the ball, which is a target of physical quantity measurement; and
correcting a captured brightness distribution of an area corresponding to the ball of at least one image among the plurality of images with reference to a reference brightness distribution;
including,
In the correcting step, a correction model for correcting a captured brightness distribution of an area corresponding to the ball of the at least one image is calculated for each point of the area corresponding to the ball of the at least one image. According to claim 1,
In the calculating step, the method of calculating the captured brightness distribution using at least one of a linear regression model and a non-parametric model. According to claim 1,
In the calculating step, the captured brightness distribution is calculated based on at least one of center coordinates and maximum brightness coordinates of a region corresponding to the ball in each of the plurality of images. According to claim 1,
In the correcting step, the method of performing the correction such that the uniformity of the captured brightness distribution of the region corresponding to the ball of the at least one image is equal to or greater than a predetermined level. According to claim 1,
The correction step is
Calculating a correction model for correcting the first captured brightness distribution by comparing a first captured brightness distribution of an area corresponding to the ball of a first image with the reference brightness distribution; and
Correcting the brightness distribution of the first photographed image with reference to the calculated correction model.
How to include. According to claim 5,
The method of claim 1 , wherein the calibration model is specified based on at least one calibration coefficient. A computer readable recording medium recording a computer program for executing the method according to claim 1. A system for correcting the brightness of an empty image, comprising:
An image acquisition unit for acquiring a plurality of images of a ball, which is a target of physical quantity measurement, and
Calculate the captured brightness distribution of the area corresponding to the ball in each of the plurality of images, and with reference to the reference brightness distribution, the captured brightness distribution of the area corresponding to the ball of at least one image among the plurality of images image correction unit that corrects
including,
wherein the image correction unit calculates a correction model for correcting a captured brightness distribution of an area corresponding to the ball of the at least one image for each point of the area corresponding to the ball of the at least one image. According to claim 8,
The system of claim 1 , wherein the image correction unit calculates the captured brightness distribution using at least one of a linear regression model and a non-parametric model. According to claim 8,
wherein the image compensator calculates the captured brightness distribution based on at least one of center coordinates and maximum brightness coordinates of a region corresponding to the ball in each of the plurality of images. According to claim 8,
The system of claim 1 , wherein the image correction unit performs the correction so that the uniformity of the captured brightness distribution of the area corresponding to the ball of the at least one image is equal to or greater than a predetermined level. According to claim 8,
The image correction unit calculates a correction model for correcting the first captured brightness distribution by comparing a first captured brightness distribution of an area corresponding to the ball of the first image with the reference brightness distribution, and the calculation A system for correcting the first photographed brightness distribution with reference to the correction model. According to claim 12,
The system of claim 1 , wherein the correction model is specified based on at least one correction coefficient.

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