WO2023002474A1

WO2023002474A1 - System and method for high camerabots

Info

Publication number: WO2023002474A1
Application number: PCT/IL2022/050759
Authority: WO
Inventors: Tamir ANAVI; Miky Tamir; Michael Birnboim
Original assignee: Track160 Ltd
Priority date: 2021-07-19
Filing date: 2022-07-13
Publication date: 2023-01-26

Abstract

A system for deploying adjustable cameras capturing a substantially rectangular sports field is disclosed. The cameras may be mounted on drones, which in turn are tethered to a ground station. The sports field has a short side, a long side, and a centerline perpendicular to the long side. The system also includes a calibration server. Projections of the cameras on ground reside outside the sports field onto or proximate to a line continuing the centerline. Respective field of views (FOVs) of the cameras cover together the sports field in a substantial entirety. The cameras/drones height is more than a predetermined minimal height. A width of the sports field occupies vertical angle of views (AOVs) of the at least two adjustable cameras, where the AOVs are in the range of 3OP-450. The calibration server is connected to the cameras and/or drones for calculating initial camera parameters and for correcting camera parameters in accordance with ingested video frames from the cameras. The ground station may provide the cameras and/or drones electric power, and structural support. A fence may surround the sports field, and a fence segment separates the ground station from the camera projections.

Description

APPLICATION FOR A PATENT

Title

SYSTEM AND METHOD FOR HIGH CAMERABOTS

CROSS REFERENCE

The application claims the priority rights of US provisional patent application No. 63/223,073 entitled “System and method for high camerabots” filed by Michael Tamir, Tamir Anavi and Micha Bimboim, inventors of the present disclosure.

BACKGROUND OF THE INVENTION

Field of the invention

The invention is in the field of sports video capturing and sports analysis.

Related art

Sports events played in sports venues are photographed by moving and stationary, still and video cameras for journalistic reviews, for real time broadcasting and for analysis by coaches, analysts and scouts. Sports analysis, composed of extracting fitness and performance data of the players as well as a tactical analysis of the whole team, became mandatory for teams of almost all quality tiers. Recognition of the players and the sports objects (like a ball) is done using either wearable tags, optically by video cameras and computer vision techniques or a combination of both methods.

US 11,348,255 and US 11,373,354 both to Tamir et al, describe an exemplary system for object tracking in sports fields and their analysis. Video cameras used for either manual or automatic production for the media or for player data extraction and team tactical analysis are typically mounted on elevated platforms because of the following reasons:

• An elevated view provides the viewers a better understanding of the sports event.

• At low viewing points there are many occlusions of the players and the ball.

• At low viewing points, the vertical resolution of the camera is not fully used. Elite and pro events are typically held in venues with grandstands (stadiums) where cameras mounting in high locations is possible. In contrast, in many semi-pro, amateurs and youth venues like schools, colleges and sports academies where a portable video system is used, there are no grandstands at all or no grandstands with sufficient height. Capturing the event video in these cases with good quality, either for media production or for player/team data extraction becomes impossible.

The challenge is even more severe due to occlusions and resolution loss, when players need to be automatically identified using their jersey numbers or other cues. Vendors of automatic media production systems like Pixellot [www.pixellot.tv] or performance data extraction using optical tracking like Trackl60 [www.trackl60.com] and Chyron Hego [chyron.com] typically use multiple industrial or security cameras sets, each covering a portion of the playing field with small overlap between them so that together they cover the whole playing field. A panoramic view of the event is then produced using video stitching [www.pixellot.tv]. Pixellot and Trackl60 are using a single venue installation point for their cameras sets, each composed of two-four cameras, while Chyron Hego is using six such sets located around the playing field.

Current solutions of the height challenge are mounting the cameras on a fixed pole or on a hydraulic or pneumatic mast. In many cases a portable solution is used like a mast. Unfortunately, the mast solution has deficiencies like:

1. A mast is expensive to buy or rent, and needs heavy logistics before and after the event.

2. For automatic video production or analytics purposes, remote calibration of the pan, tilt and zoom (PTZ) camera parameters is required and thus an additional pan and tilt unit should be assigned to each camera.

3. In many cases, the width of the playing field is limited to just few meters beyond the field lines due to a neighboring court, a fence, etc. In such a case there is frequently no sufficient horizontal resolution at the far end of the court due to the need to cover the whole pitch even at the near (to the mast) length line of the playing field.

A low cost/logistics portable video system at a desired height is needed to overcome the above challenges and to enable automatic media production and player/team performance data analysis for the low end sports market. BRIEF SUMMARY OF THE INVENTION

According to an aspect of the invention, a system for deploying cameras capturing a substantially rectangular sports field is disclosed. The sports field has a short side, a long side, and a centerline perpendicular to the long side. The system includes at least two adjacent adjustable cameras, and a calibration server. Projections of the cameras on ground reside outside the sports field onto or proximate to a line continuing the centerline. Respective field of views (FOVs) of the cameras cover together the sports field in a substantial entirety. Height of each of the cameras above the ground is at least a predetermined minimal height. The calibration server is connected to the cameras for calculating initial camera parameters and for correcting camera parameters in accordance with ingested video frames from the cameras.

In some embodiments, a ground station provides the cameras electric power, structural support, and/or communication to and from the calibration server. Preferably, the ground station resides in between the camera projections and the long side of the sports field. Most preferably, the ground station is closer to the long side of the sports field than to any of the camera projections. Most preferably, a fence surrounds the sports field, and a fence segment separates the ground station from the camera projections.

In some embodiments, the system includes two or three adjustable cameras.

In some embodiments, the adjustable cameras are mounted on an adjustable base like a tripod, a pan unit on a tripod, a pan and tilt unit on a tripod, or an extender. Preferably, an adjustable base is mounted on a pole, a mast, a crane, a pedestal, a hydraulic ladder, or a pneumatic ladder.

In some embodiments, the predetermined minimal height is determined in accordance with a distance between the camera projections and a center of the sports field. Preferably, the distance between the camera projections and a center of the sports field is in the range of 50-60 meters and the predetermined minimal height is in the range of 12-17 meters. Alternatively, the distance between the camera projections and a center of the sports field is in the range of 38-40 meters and the predetermined minimal height is in the range of 10-14 meters.

In some embodiments, the ground projection of each adjustable camera is within 5 meters distance from a continuation of the centerline. Preferably, it is within 2 meters distance from a continuation of the centerline.

In some embodiments, two cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 80°-90°. Alternatively, three cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 52°-60°.

In some embodiments, two cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 9CP-10CP. Alternatively, three cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 58°-70°.

In some embodiments, a width of the sports field occupies vertical angle of views (AOVs) of the at least two adjustable cameras, where the AOVs are in the range of 30 45°.

In some embodiments, the adjustable cameras are mounted on drones. Preferably, the drones are tethered to a ground station.

According to an aspect of the invention, a method for deploying at least two adjacent adjustable cameras for capturing a substantially rectangular sports field is disclosed. The sports field has short side, a long side, and a centerline perpendicular to the long side. The method includes calculating camera parameters for the at least two adjacent adjustable cameras, and positioning the cameras in accordance with the calculated camera parameters. Projections of the cameras on ground reside outside the sports field onto or proximate to a line continuing the centerline. Respective field of views (FOVs) of the cameras cover together the sports field in a substantial entirety. Height of each of the cameras above the ground is at least a predetermined minimal height.

In some embodiments, the method further includes ingesting video frames from the cameras, detecting field lines or landmarks of the sports field in the video frames, calculating present parameters of the cameras in accordance with the detected field lines or landmarks, calculating parameter corrections for the cameras, and adjusting the camera parameters in accordance with the calculated parameter corrections. Preferably, the method further includes translating the camera parameter corrections to parameters of the cameras or parameters of their adjustable bases, and submitting the parameters of the cameras or the parameters of their adjustable base to an associated destination.

In some embodiments, the camera parameters include parameters like field of view, pan angle, tilt angle, a zoom parameter, and spatial coordinates of the camera.

In some embodiments, at least two camera-equipped drones capture the substantially rectangular sports field. The method includes calculating spatial locations for the drones and positioning the drones in the calculated locations. Preferably, the method further includes ingesting video frames from the cameras, detecting field lines or landmarks of the sports field in the video frames, calculating present parameters of the cameras and of the respective drones in accordance with the detected field lines or landmarks, calculating parameter corrections for cameras and/or for the drones, and adjusting the parameters in accordance with the calculated parameter corrections. Most preferably, the method further includes translating the parameter corrections to parameters of the drones, submitting the drone parameters to the associated drones.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by reference to the following detailed description when read with the accompanied drawings in which:

Fig. 1 A is a schematic top view of a stadium having a sports field with players, captured by two adjacent video cameras sharing the coverage of the whole sports field from an elevated place at a sufficient distance from the field.

Fig. IB is a side view of the scene of Fig. 1A, showing the vertical angle of view (AOV) of a camera.

Fig. 2A is a top view illustrating a sports field with a fence close to the field line and cameras located in between.

Fig. 2B is a side view of the scene of Fig. 2 A, showing a vertical AOV of a camera mounted between the long side of the field and the fence.

Fig. 3A is a top view of the sports field of Fig. 2 with two drones capturing the field while residing outside the fence to be far enough from the long field side.

Fig. 3B is a side view of the scene of Fig. 3A showing a vertical Angle of View (AOV) of a camera.

Fig. 4 is a top view of the sports field of Fig. 2 with three drones capturing the entire field.

Fig. 5A schematically shows a horizontal angle of view of a right camera which together with a left camera (not shown) covers the entire field.

Fig. 5B schematically shows horizontal angle of view of a right camera and a central camera which cover the whole field with a left camera (not shown).

Fig. 6 is a block diagram of a system for deploying drones and their cameras which capture a sports field by an automatic calibration process. Fig. 7 is a flowchart of a method for deploying tethered drones for capturing a sports field by an automatic calibration process.

Fig. 8 schematically shows an adjustable camera on a controlled base capturing the sports field while its projection on the ground is outside a fence.

Fig. 9 is a block diagram of a system for deploying adjustable cameras which capture a sports field by an automatic calibration process.

Fig. 10 is a flowchart of a method for deploying the adjustable cameras by an automatic calibration process.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in terms of specific example embodiments. It is to be understood that the invention is not limited to the example embodiments disclosed. It should also be understood that not every feature of the methods and systems handling the described system is necessary to implement the invention. Various elements and features of the invented system are described to fully enable the invention. It should also be understood that throughout this disclosure, where a method is shown or described, the steps of the method may be performed in any order or simultaneously, unless it is clear from the context that one step depends on another being performed first.

Before explaining several embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The systems, methods, and examples provided herein are illustrative only and not intended to be limiting .

In the description and claims of the present application, each of the verbs "comprise", "include" and "have", and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.

The sports captured may be soccer (association football), football, basketball, etc. Soccer field is shown in the drawings and related to in the text by a way of example only, without limiting the described invention. A soccer field is rectangular, but the invention is not limited to strictly rectangular sports field and may be applied as well to sports fields which are substantially rectangular like ice hockey field. Namely, the field may have rounded comers. Also, the field may be blocked by a first rectangle of up to 15% more area than the field itself, and the field may block a second rectangle of up to 15% less area than the field itself.

In the prior art, a soccer stadium 10 illustrated schematically in a top view of Fig. 1A, includes a rectangular sports field 15 with players 20, field lines 25, 30 and 35, and goals 40. Cameras 45-1 and 45-2 are mounted on an elevated platform 50, as illustrated schematically in Fig. IB by a constructive element 50, which may be a high grandstand, a roof element, or other element at a stadium built to be populated by thousands of fans. The entire sports field is captured by the two adjacent video cameras with respective horizontal angles of view (AOVs) 55-1 and 55-2. Together, the field of views associated with theses two AOVs cover of the entire sports field. Moreover, as shown in Fig. IB, the elevated place at a sufficient distance from the field ensures that the field width occupies a large vertical angle of view 60, essential for achieving a sufficient vertical resolution.

It is noted that covering the entire sports field or covering the sport field in a substantial entirety, is equivalent to achieving at least 98% or 99% coverage of the field area.

At the low end of sports arenas, as illustrated in a top view of Fig. 2A, a fence 75 of a sports field 70 limits available locations for the cameras. When one locates the cameras between the fence and the long side of the field, the field width occupies a small vertical AOV 80, as illustrated in Fig. 2B, which in turn leads to poor vertical resolution, and to mutual occlusion of players 20 by one another, in case they share a common direction of sight from a camera.

The following two sections provide two embodiments of the present disclosure which overcome the above problem. A camera-equipped drone embodiment (Figs. 3A, 3B, 4, 5A, 5B, 6,7)

A top view and a side view of a preferred system for capturing the sports field 70 are schematically presented in Fig. 3 A and Fig. 3B, respectively. Two camera-equipped drones 80-1 and 80-2 hover outside the fence such as to be far enough from a field line 25 of the long side of the sports field 70, as well as high enough above the ground. Consequently, the field width occupies a large vertical AOV 85 of each of respective cameras 82-1 and 82-2 carried by the drones and sufficient vertical resolutions of the field are achieved. The achieved vertical AOVs are in the range of 30P-45⁰.

The drones are tethered to a ground station 90 by a power cable 95. While the ground station resides well within the sports arena, between the fence and a field line 25, the drones are hovering outside the fence, such that their projections 100 on the ground are far enough from a center of the sports field for the cameras to have an optimal field of view. The ground station may be closer to the long side of the sports field than to any of the drone ground projections.

Three or more camera-equipped drones may be used to capture the entire sports field. Fig. 4 is a top view of the sports field with three drones 80-1, 80-2 and 80-3 carrying respective cameras 82-1, 82-2, (see Fig. 3A) and 82-3 which together capture the entire sports field.

In Fig. 4, a centerline 30, which divides the sports field 70 on its long side, is continued outside the field. The ground projections 100 (see Fig. 3B) of drones 80-1, 80-2 are proximate to the centerline while the ground projection of drone 80-3(not shown) may be even on the centerline. Anyhow, the ground projection of each drone is within 5 meters distance from centerline 30, preferably within 3 meters distance, most preferably within 2 meters distance from the centerline. In view of a soccer pitch (sports field) length of 105 meters, and for discussing horizontal angle of view(AOV), the drones are shown in Figs. 5A and 5B with ground projection on the centerline. Plus sign 105 indicates the location of a ground projection of drone 80-1 and camera 82-2 in Fig. 5A, as well as the locations of ground projections of drones 80-2 and 80-3, cameras 82-2 and 82-3 in Fig. 5B. The field center 110 is in the middle of the field both on the long side 25 and on the short side 120. A corner 125 of the field is also shown in Figs. 5A and 5B.

Fig. 5A stands for a case of two drone cameras 82-1 and 82-2 covering the entire field 70. Only the details associated with right camera 82-2 are shown in Fig. 5A as the left camera 82-1 is substantially symmetric to right camera 82-2. Horizontal angle of view 130-2 extends from a line 135 which connects plus sign 105 with comer 125 to a line 140 which originates in plus sign 105 and traverses field 70 slightly to the left of field center 110. The two cameras cover together the entire sports field, each camera with a horizontal angle of view 130-2 in the range 80°-90°. Alternatively, two cameras cover together the entire sports field, each camera with a horizontal angle of view 130- 2 in the range 9CP-10CP. These angle ranges may be dependent on the distances between field center 110 and plus sign 105.

Fig. 5B stands for a case of three drone cameras 82-1, 82-2 and 82-3 covering the entire field 70. Only the details associated with right camera 82-2 and central camera 82-3 are shown since left camera 82-1 is substantially symmetric to camera 82-2. A horizontal AOV 145-2 of the right camera, a horizontal AOV 145-3 of the central camera and a horizontal AOV of the left camera cover the entire sports field, each camera has a horizontal angle of view in the range 52°-60°. Alternatively, each camera has a horizontal angle of view in the range 58°-70°. The horizontal angle range may be dependent on the distance between field center 110 and plus sign 105.

The size and limits of a camera horizontal AOV is determined as desired by setting camera parameters like field of view, pan angle, tilt angle, a zoom parameter, and spatial coordinates of the camera or of the carrying drone.

The drones hover at a height which is higher than a predetermined minimal height H150, as shown in Fig. 3B. The predetermined minimal height is determined in accordance with the distance between camera projections 100 and center 110 of the sports field. Preferably, the distance between the camera projections and the center of the sports field is in the range of 50-60 meters and the predetermined minimal height is in the range of 12-17 meters. Alternatively, the distance between the camera projections and the center of the sports field is in the range of 38-40 meters and the predetermined minimal height is in the range of 10-14 meters.

Ground station 90 may communicate with a ground calibration server 160, as shown in the block diagram of Fig. 6, which presents a system 170 for deploying drones 80-1 and 80-2 and their respective cameras 82-1 and 82-2 for capturing a sports field 70 by an automatic calibration process.

In some embodiments, a single drone 80-1 may carry two cameras 82-1 and 82- 2. Also, two drones may carry two cameras each, such that four cameras cover the whole field. In some embodiments, calibration server 160 is a remote server, a cloud server for example, which may communicate with the drones using the internet and/or a G5 communication network.

Drone 80-1, for example, includes a camera 82-1 associated with a gimbal and a zoom module 180, a navigation module 190 and a communication module 200. The communication module receives instructions from the ground station and/or from the calibration center regarding the location of the drone and regarding camera parameters. The instructions are executed in the navigation module and in the gimbal and zoom module such that the drone hovers on the desired location and the camera parameters are set for a desired FOV.

Ground station 90 may include an electric power module 210, a cable management module 220 and a communication unit 230. The electric power module receives electric power supply from the line, for example, and provide it to the drones through cable 95. The cable management module releases the cable as desired, in accordance with instructions from calibration server 160 and in accordance with data from the drone. Cable management modules for associated tethered drones are known in the art.

Calibration server 160 may include a drone communication module 235, a video ingest module 240, a field line detector 245, a camera pose/zoom/location calculator 250 and a drone pose/location calculator 255. The drone communication module receives video from the drone, the video ingest module processes the video frames, and the field line detector detects field lines 25, 30 and 35, as well as landmarks like goals 40. Consequently, the camera pose/zoom/location calculator calculates the present location and pose of the camera as well as the camera parameters using the detected field lines and landmarks. The drone pose/location calculator calculates the location and pose of the drone. If the present parameters of the camera and drone should be changed, calculators 250 and 255 calculate new parameters, translate them to drone and camera instructions, and the drone communication module delivers the instructions to the drone and camera for execution.

A method 300 for deploying camera-equipped drones capturing a substantially rectangular sports field 70 is provided in the flow chart of Fig. 7. The method includes a step 305 of calculating spatial locations for camera-equipped drones 80-1 and 80-2, and a step 310 of positioning the drones in the calculated locations and aligning the camera parameters. Projections 100 of the drones on ground reside outside the sports field onto or proximate to a line continuing a centerline 30. Respective field of views (FOVs) of cameras 82-1 and 82-2 of respective drones 80-1 and 80-2 cover together the entire sports field. Height of each of the drones above the ground is at least a predetermined minimal height H150.

The method may further includes a step 315 of ingesting video frames from the cameras, a step 320 of detecting field lines 25, 30 and 35, as well as landmarks like goals 40 of the sports field in the video frames, a step 325 of calculating present parameters of the cameras and of the respective drones in accordance with the detected field lines or landmarks, a step 330 of calculating parameter corrections for the cameras or for the respective drones, and a step 345 of adjusting the parameters of the cameras and/or of the respective drones in accordance with the calculated parameter corrections.

Preferably, the method further includes a step 335 of translating the parameter corrections to parameters of the respective drones, and a step 340 of submitting the parameters of the respective drones to the drones.

During a match, the steps 315-345 of method 300 may be repeated several times as indicated by a cycling arrow which connects step 345 to step 315.

An adjustable camera embodiment (Figs. 5A, 5B, 8, 9,101

A system 400 for deploying adjacent adjustable cameras 405-1 and 405-2 for capturing a substantially rectangular sports field 70 in arena 410 is illustrated in Figs. 8 and 9. The sports field has a short side 120, a long side 25, and a centerline 30 perpendicular to the long side. The system further includes a calibration server 420 connected to the cameras for calculating initial camera parameters and for correcting camera parameters in accordance with ingested video frames from the cameras. Projections 425 of the cameras on ground reside outside the sports field onto or proximate to a line continuing the centerline 30. The camera projections are shown in Fig. 8 to be located beyond a fence 75 of the arena. Respective FOVs of the cameras cover together the entire sports field. Height of each of the cameras above the ground is at least a predetermined minimal height H430.

The adjustable cameras are far enough from a long side 25 of the sports field 70, as well as high enough above the ground. Consequently, the field width occupies a large vertical AOV 510 of each of respective cameras 405-1 and 405-2 and sufficient vertical resolutions of the field are achieved. The vertical AOVs are in the range of 30P-45⁰. Each adjustable camera may include a base controller 440, a video sensor 445, a gimbal and zoom module 450, and a communication unit 455. The base controller controls the location of the camera. The video sensor captures a scene, and the gimbal and zoom unit controls camera parameters like FOV, pan and tilt angles, and zoom.

System 400 further includes a ground station 460, which includes an electric power module 465, and a communication unit 475, and is associated with a structural mechanism 470. The electric power module receives electric power from an external source, the line for example, and empowers the structural mechanism and the adjustable camera. The structural mechanism may be a pole, a mast, a crane, a pedestal, a hydraulic ladder, or a pneumatic ladder. An adjustable base 480 may be mounted on structural mechanism 470. The adjustable base may be a tripod, a pan unit on a tripod, a pan and tilt unit on a tripod, or an extender. Communication unit 475 communicates with calibration server 420 and/or with the adjustable cameras.

As illustrated schematically in Fig. 8, ground station 460 resides in between the camera projections 425 and the long side of the field. Preferably, ground station 460 is closer to long side 25 of the sports field than to any of camera projections 425. Fence 75 of the sports arena is located between the ground station and the camera projections.

Calibration server 420 may include a camera communication module 500, a video ingest module 240, a field line detector 245, and a camera pose/zoom/location calculator 250. The camera communication module receives video frames from the camera, the video ingest module processes the video frames, the field line detector detects field lines 25, 30 and 35, as well as landmarks like goals 40, the camera pose/zoom/location calculator calculates the present location and pose of the camera as well as the camera parameters, using the detected field lines and landmarks. If the present parameters of the camera should be changed, calculator 250 calculates new parameters, translate them to instructions of adjustable bases and cameras and the camera communication module delivers the instructions to the camera for execution.

In some embodiments, system 400 includes three adjustable cameras. The division of desired viewing field between the two or three cameras are the same as detailed above for cameras carried by drones, and as illustrated in Figs. 5A and 5B.

The adjustable cameras are located at a height which is higher than a predetermined minimal height H430, as shown in Fig. 8. The predetermined minimal height is determined in accordance with the distance between the camera projections 425 and center 110 of the sports field. Preferably, the distance between the camera projections and a center of the sports field is in the range of 50-60 meters and the predetermined minimal height is in the range of 12-17 meters. Alternatively, the distance between the camera projections and a center of the sports field is in the range of 38-40 meters and the predetermined minimal height is in the range of 10-14 meters. A flowchart of a method 600 for deploying adjacent adjustable cameras 405-1 and 405-2 for capturing a substantially rectangular sports field 70 is illustrated schematically in Fig. 10. The method includes a step 605 of calculating camera parameters for the adjacent adjustable cameras, and a step 610 of positioning the cameras in accordance with the calculated camera parameters. Projections 425 of the cameras on ground reside outside the sports field onto or proximate to a line continuing centerline 30. Respective field of views (FOVs) of the cameras cover together the entire sports field. Height of each of the cameras above the ground is at least a predetermined minimal height H430.

The method may further include a step 615 of ingesting video frames from the cameras, a step 620 of detecting field lines 25, 30 and 35 or landmarks like goals 40 in the video frames, a step 625 of calculating present parameters of the cameras in accordance with the detected field lines or landmarks, a step 630 of calculating parameter corrections for the cameras, and a step 645 of adjusting the camera parameters in accordance with the calculated parameter corrections. The method may further include a step 635 of translating the camera parameter corrections to parameters of adjustable bases and to camera parameters, and a step 640 of submitting the parameters of adjustable bases and the camera parameters to associated destinations.

During a match, the steps 615-645 of method 600 may be repeated several times as indicated by a cycling arrow which connects step 645 to step 615.

Claims

Claims:

1. A system for deploying cameras capturing a substantially rectangular sports field having a short side, a long side, and a centerline perpendicular to the long side, the system comprising: a. at least two adjacent adjustable cameras located such that:

A. projections of the cameras on ground residing outside the sports field onto or proximate to a line continuing the centerline;

B. respective field of views (FOVs) of the cameras covering together the sports field in a substantial entirety; and

C. height of each of the cameras above the ground being at least a predetermined minimal height; and b. a calibration server connected to said at least two adjacent adjustable cameras for calculating initial camera parameters and for correcting camera parameters in accordance with ingested video frames from the cameras.

2. The system of claim 1 further including a ground station providing at least one camera at least one of electric power, structural support, and communication to and from said calibration server.

3. The system of claim 2 wherein said ground station resides in between the camera projections and the long side of the sports field.

4. The system of claim 3 wherein said ground station is closer to said long side of the sports field than to any of the camera projections.

5. The system of claim 3 wherein a fence surrounds at least part of the sports field, and a fence segment separates said ground station from said camera projections.

6. The system of claim 1 wherein the system includes two or three adjustable cameras.

7. The system of claim 1 wherein at least one adjustable camera is mounted on at least one adjustable base which includes at least one base selected from a group of adjustable bases consisting of a tripod, a pan unit on a tripod, a pan and tilt unit on a tripod, and an extender.

8. The system of claim 7 wherein said at least one adjustable base is mounted on at least one of a pole, a mast, a crane, a pedestal, a hydraulic ladder, and a pneumatic ladder.

9. The system of claim 1 wherein said predetermined minimal height is determined in accordance with a distance between said camera projections and a center of the sports field.

10. The system of claim 9 wherein said distance between said camera projections and a center of the sports field is in the range of 50-60 meters and said predetermined minimal height is in the range of 12-17 meters.

11. The system of claim 9 wherein said distance between said camera projections and a center of the sports field is in the range of 38-40 meters and said predetermined minimal height is in the range of 10-14 meters.

12. The system of claim 1 wherein the ground projection of each adjustable camera is within 5 meters distance from a continuation of said centerline.

13. The system of claim 12 wherein the ground projection of each adjustable camera is within 2 meters distance from a continuation of said centerline.

14. The system of claim 1 wherein two cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 80°- 90°.

15. The system of claim 1 wherein three cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 52°- 60°.

16. The system of claim 1 wherein two cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 90°- lOOP.

17. The system of claim 1 wherein three cameras cover together the sports field in a substantial entirety, each camera with a horizontal angle of view in the range 58°- 70°.

18. The system of claim 1 wherein a width of the sports field occupies vertical angle of views (AOVs) of said at least two adjustable cameras, said AOVs being in the range of 3CP-45⁰.

19. The system of claim 1 wherein said at least two adjustable cameras are mounted on respective drones.

20. The system of claim 19 wherein at least one drone is tethered to a ground station.

21. The system of claim 20 wherein said ground station resides in between ground projections of the drones and the long side of the sports field.

22. The system of claim 20 wherein said ground station is closer to said long side of the sports field than to any drone ground projection.

23. The system of claim 20 wherein a fence of the sports field is located between said ground station and said drone ground projections.

24. A method for deploying at least two adjacent adjustable cameras for capturing a substantially rectangular sports field having a short side, a long side, and a centerline perpendicular to the long side, the method comprising: a. calculating camera parameters for the at least two adjacent adjustable cameras such that:

A. projections of the cameras on ground residing outside the sports field onto or proximate to a line continuing the centerline; B. respective field of views (FOVs) of the cameras covering together the sports field in a substantial entirety; and

C. height of each of the cameras above the ground being at least a predetermined minimal height; and b. positioning said cameras in accordance with the calculated camera parameters.

25. The method of claim 24 further comprising; c. ingesting at least one video frame from at least one camera; d. detecting at least one field line or landmark of the sports field in said at least one video frame; e. calculating at least one present parameter of said at least one camera in accordance with the detected at least one field line or landmark; f. calculating at least one parameter correction for said at least one camera; g. adjusting the at least one camera parameter in accordance with the calculated at least one parameter correction.

26. The method of claim 25 further comprising: h. translating the at least one camera parameter correction to at least one parameter of at least one camera or its adjustable base; and i. submitting said at least one parameter of the at least one camera or its adjustable base to an associated destination.

27. The method of claim 24 wherein said camera parameters include at least one parameter selected from a group of camera parameters consisting of field of view, pan angle, tilt angle, a zoom parameter, and spatial coordinates of the camera.

28. The method of claim 24 wherein at least two camera-equipped drones capture the substantially rectangular sports field, the method comprising: a. calculating spatial locations for the at least two camera-equipped drones such that:

A. projections of the drones on ground residing outside the sports field onto or proximate to a line continuing the centerline; and B. respective field of views (FOVs) of the cameras of the respective drones covering together the sports field in a substantial entirety; and

C. height of each of the drones above the ground being at least a predetermined minimal height; and b. positioning said drones in the calculated locations.

29. The method of claim 28 further comprising; c. ingesting at least one video frame from at least one camera; d. detecting at least one field line or landmark of the sports field in said at least one video frame; e. calculating at least one present parameters of said at least one camera and of the respective drone in accordance with the detected at least one field line or landmark; f. calculating at least one parameter correction for said at least one camera or for said respective drone; and g. adjusting the at least one parameter of the at least one camera or of said respective drone in accordance with the calculated at least one parameter correction.

30. The method of claim 29 further comprising: h. translating the at least one parameter correction to at least one parameter of said respective drone; and i. submitting said at least one parameter of said respective drone to the drone.