Realization of Highly Realistic Broadcast that Includes the Eye

Movements of Basketball Players

Kanji Kitahama

1,a

, Takuya Sarugaku

2,b

and Mitsuho Yamada

2,c

Liberal Arts Education Center, Tokai University, Minato, Tokyo, Japan

School of Inf. and Telecom. Eng., Tokai University, Minato, Tokyo, Japan

Keywords: Sports, Basketball, Wireless Eye Movement Measurement, 4K Video.

Abstract: Sport spectatorship changes with the introduction of new technologies. There are many video editing methods

in sports broadcasting, but it is more important to base video presentation on the characteristics of a specific

sport. We examined the eye movements of basketball players and found. An essential relationship between

their skill level and their eye movements in making successful shots. Analysis of eye movements during free

throws revealed that a player was more likely to score if they focused on the support frame line on the

backboard not only before the shot but even after releasing the ball. Overlaying reveals the movements of

both players and their focus simultaneous analysis. Overlaying technology proved that spectators could watch

a player’s focus and body movement specifically at the same time. By recording with 4K video cameras,

spectators could easily understand the directions of the players. Furthermore, we proved that the analysis of

a player's eye movement in a play situation can be beneficial to the team. As a result of this study, the

differences in court awareness during a play according to the skill levels of different players became apparent.

1 INTRODUCTION

Unfortunately, the International Olympic Committee

and the Japanese government have decided to

postpone the 2020 Tokyo Olympic and Paralympic

Games until 2021 due to the global spread of the new

corona virus (COVID-19). However, this happen

might be an excellent opportunity to further develop

techniques that convey the attractiveness of sports for

the broadcast companies to spectators, including

those watching TV as well as Internet-distributed

(computers, smartphones, tablets, and so on) viewers.

A study of TV viewers concluded that most

people would watch the 2020 Tokyo Olympic games

on TV (92%), and that spectators will expect better

and more realistic image quality (Saito, 2019). TV

and Internet-distributed viewers seek more

information and a more powerful experience than

they would get in the stadium, such as through virtual

reality (VR). Another author emphasized "a more

realistic feeling" as a key phrase for the near future

(Noma, 2002). In other words, growing numbers of

https://www.u-tokai.ac.jp/staff/detail/MDgwMDcw/MjA2MTU4

https://www.u-tokai.ac.jp/english/academics/graduate/information_and_telecommunication_engineering.html

http://eyemove.g1.xrea.com/yamadalab_ENG.htm

spectators will watch sports on TV or the Internet as

technology improves. The enjoyment of sports on

T.V. or Internet-distributed content will be the new

norm and will be increased more and more in the

future.

Basketball is one of the sports where a group of

people form a team and face each other in offense and

defense, competing for points using individual and

group tactics around a "single contested object."

According a textbook on basketball, one of the

abilities players need is situational awareness (Japan

Basketball Association, 2014). To improve their

situational awareness, players need to broaden their

peripheral vision. Basketball, players must be aware

of valuable information and take appropriate action

amid the rapid changes in their surroundings (Japan

Basketball Association, 2014). Therefore, all players

are always anticipating something, watching

something, feeling something, thinking something,

judging the ever-changing situation, and choosing

when to try to score (Toyoda et al., 2016). In a

previous study about a player’s eye movements, the

234

Kitahama, K., Sarugaku, T. and Yamada, M.

Realization of Highly Realistic Broadcast that Includes the Eye Movements of Basketball Players.

DOI: 10.5220/0010167602340241

In Proceedings of the 8th International Conference on Sport Sciences Research and Technology Support (icSPORTS 2020), pages 234-241

ISBN: 978-989-758-481-7

passer (usually a point guard) looks to the left and

right, finds open player and, when passing, uses their

eye mislead defenders (Sasaki et al., 1995).

Ryu et al. (2013), experimented with the roles of

central and peripheral vision in expert decision

making. The authors watched basketball scenarios on

video (11 expert and less-skilled men's basketball

players in each group) and, determined whether it was

a correct decision for the ball carrier to pass, or to

drive to the basket. The expert players responded

faster than the less-skilled players. A similar study

concluded that regular basketball players' latency of

vergence divergence was shorter than that of non-

regular basketball players (Kokubu et al., 2019).

Those authors mentioned that players with more

experience, were able to quickly initiate a gaze

movement in the direction of depth.

A significant factor that determines the success or

failure of a shot is the "quiet eye ”(QE). QE is a

characteristic eye behavior exhibited by experts

during successful aiming movements, such as free-

throws and darts. Vickers stated that good free-throw

shooters spent more time looking at the ring before

the start of the shot than when they were successful.

Although the QE mean durations of the expert are

1000 ms (successful) and 800 ms (unsuccessful),

those of the near-expert are less than 400 ms

(successful) and more than 400ms (unsuccessful) in

the study of (1996). Based on that study, university

basketball team took QE training for two seasons. As

a result, that team improved its who free-throw

success rate from the first season to the second and

also showed better results than the teams that did not

do QE training (Harle et al., 2001).

Although there are many types of research into the

eye movements of basketball players, most of them

have been conducted in fast attack situations, such as

two-on-one, or three-on-two, to prove their

hypothesis. However, it is hard to have these "best

situations" in real games. Therefore, we decided to

conduct an experiment similar to the actual game and

selected free-throws, one-on-one and two-on-two, on

a limited quarter area of a basketball court. The

reason for the space limitation is that, during practice,

most players play on only one side of the half-court

(a quarter) when playing one-on-one or two-on-two.

The purpose of this study was not to statistically

analyze basketball skills to improve athletic

performance but rather to identify new ways to

represent those skills to new spectators.

2 EXPERIMENTAL METHOD

The experimental equipment included wireless eye-

movement measurement devices and 4K video

cameras. The wireless eye-movement measurement

uses an external control system comprised of a video

transmitter. A Bluetooth mouse was added to the

TalkEye Lite system (Takei Science Instruments Co.,

Ltd.) using the corneal reflection method. This

wireless device allows the subject to move freely. The

researcher can check the measurement status from a

remote location with a wireless monitor. If the

calibration shifts due to an experimenter's hard

movement, it can be readjusted remotely. Neither the

experimental data recorded in the wireless eye

movement measurement device nor the delay caused

by the wireless transmission affects the measurement

result. The device can be secured to the subject's head

with a hook and loop fastener to prevent the eye-

movement sensor from slipping during exercise

(Sarugaku et al., 2020).

Two experiments were conducted at different

places with different players. One of them was at the

Takanawa Campus Area of Tokai University with

four members of the Tokai University Takanawa

Campus Basketball Club. Although these plays have

an average of more than 6 years playing organized

basketball, they have played for fun, not

competitively; in other words, they are less-skilled

players. On the other hand, the other experiment was

conducted at Yokogoshi Athletic Center in Niigata

city. The players belonged to the Apple Sports

College Basketball Course, U23 of Niigata Albirex

BB (Apple Sports College). They won the national

basketball championship tournament in vocational

school in 2018. The team members aim to be

professional basketball players, so we consider them

skilled players.

We recorded five scenarios:

1. Free throws

2. One-on-one (fixed camera)

3. Another one-on-one (tracking camera)

4. Two-on-two (Takanawa)

5. Two-on-two (Niigata)

We chose these five scenarios because we want to

study eye movements and player actions in various

scenarios that occur in basketball games.

Realization of Highly Realistic Broadcast that Includes the Eye Movements of Basketball Players

235

3 EXPERIMENT

3.1 Free Throws

The experimenter shot a free throw from the free-

throw line while wearing the wireless eye movement

measurement device. Figure 1 shows the layout of the

free-throw experiment. The eye movement

measurement focused on before and right after

shooting. Three video cameras were set up: one at the

center circle, another at the end line, and the third on

one of the sideline.

Figure 2 shows the scene of before and after the

player shoots a free throw. The top of the image is the

field-of-view image of the wireless eye-movement

measurement devices that superimposes the

movement of the line of sight, and the bottom three

are from the three video cameras (The capital “C” is

the camera number).

Figure 1: Layout of free throws.

Figure 2: A scene of before and after the player shoots a

free throw.

3.2 One-on-One (Fixed Camera)

In this experiment, two players participated in one-

on-one play in which each was on offense and defense

three times. Figure 3 shows the layout with fixed

cameras. The players each wore a wireless eye

movement measurement device, and three fixed video

cameras were set up at the center circle, end line, and

sideline of the court. The upper part of Fig. 4 shows

the eye movements on the field-of-view images of

both the offensive and defensive players. The bottom

part of Fig. 4 shows the three different images from

the three video cameras recorded at the different

angles. By viewing the action from these three video

cameras, spectators will be able to understand the

players’ movements easily, such as the location of

each player, the timing of the dribbling, the shooting,

and so on.

Figure 3: Layout of one-on-one (fixed camera).

Figure 4: Eye and body movement of two players.

3.3 One-on-One (Tracking Camera)

In the second experiment of one-on-one, each video

camera tracked each player. Figure 5 shows the layout

of this experiment. Three video cameras were set up:

one at the center circle and one on each sideline.

Camera 1 followed the offensive player, camera 2

followed the defensive player, and camera 3 recorded

half of the court. The upper part of Fig. 6 shows eye

movements of both the offensive and defensive

players.

icSPORTS 2020 - 8th International Conference on Sport Sciences Research and Technology Support

236

Figure 5: Layout of one-on-one (tracking camera).

Figure 6: Eye and body movement of two players.

3.4 Two-on-Two (Takanawa)

In this experiment, offense and defense alternated,

starting with a pass from a person off the court to one

of the two players.

Figure 7 shows the layout of two-on-two

experiment at Takanawa. Two of the players, one

offensive and one defensive player, wore a wireless

eye movement measurement device, and three

cameras were set up: one at the center circle (camera

1) and one on each sideline (cameras 2 and 3). All

three cameras were fixed. Figs.8 and 9 show the eye

movements of both the offensive and defensive

players.

Figure 7: Layout of two-on-two (Takanawa).

Figure 8: A scene of two-on-two with eye movement

(Takanawa).

Figure 9: A scene of two-on-two with eye movement

(Takanawa).

3.5 Two-on-Two (Niigata)

In this experiment, offense and defense alternated,

starting with a pass from a person off the court to one

of the two players on offense, as in Takanawa’s

experiment.

Figure10: Layout of two-on-two (Niigata).

Realization of Highly Realistic Broadcast that Includes the Eye Movements of Basketball Players

237

Figure 11: A scene of two-on-two with eye movement

(Niigata).

Figure 12: A scene of two-on-two with eye movement

(Niigata).

Figure 10 shows the layout of the two-on-two at

Niigata. Two of the players, an offensive player and a

defensive player, wore a wireless eye movement

measurement device, and three cameras were set up:

one at the center circle (camera 2) and one on each

sideline (cameras 1 and 3). Camera 3 tracked one

offensive player while (cameras 1 and 2 were fixed).

The upper parts of Figs.11 and 12 show the eye

movements of the offensive and defensive players.

4 RESULTS

4.1 Free Throws

The player scored four goals out of ten free throws.

The results show that the focal point is around the

support frame line on the backboard before a shoot

(Figs. 13 and 14). When a free throw is successful,

the focal point almost the same from before to after

shooting (Fig. 13). On the other hand, when a shot is

unsuccessful, a player’s focus moved after the ball

was released (Fig. 14). This indicates that it is

important to focus on a specific area constantly.

Although the players adopted various shooting

forms, this experiment proved that focusing on a

specific point without moving the eyes during

shooting is one of the most important factors for

players.

Figure 13: The focal point of before and after (successful

shot).

Figure 14: The focal point of before and after (unsuccessful

shot).

4.2 One-on-One (Fixed Camera)

This one-on-one fixed camera recording method can

show both body movements and eye movements at

the same time. For example, Fig. 4 shows the

offensive player (Player 2) looking at the floor right

before he started to dribble (circle 5 in the figure).

Video camera 1 (sideline) proved this movement,

such as the downward movement of the player's head.

This is because the offensive player checked the feet

of the defensive player and tried to pull out while

dribbling.

4.3 One-on-One (Tracking Camera)

The aim of this one-on-one tracking experiment was

to clarify the movement of each player to a much

greater extent than the experiment with a one-on-one

fixed camera. We assumed that the offensive player

looked for a moment at his intended route before he

started to dribble (Fig. 6). However, there are some

considerations about this eye movement. Although

some people may think it is to decide whether to

attack immediately, this eye movement may instead

have been a feint. The tracking recording method will

icSPORTS 2020 - 8th International Conference on Sport Sciences Research and Technology Support

238

be able to clarify the player’s intent. The two video

cameras are tracking the respective players. These

tracking cameras reveal what the offensive player and

the defensive player are trying to do.

In this tracking method, the spectators can watch

the players’ eye movements as well as their body

movements specifically at the same time. In other

words, this tracking system can show spectators the

characteristics of various playing styles.

4.4 Two-on-Two (Takanawa)

The offensive player looked for a moment at his

intended route before he started to dribble. This is the

same as the result of the one-on-one (tracking

camera) experiment. Also, most of the offensive

players' eyes were on the defensive player (Fig. 8) and

the goal even when the player passed to his teammate

(Fig. 9).

4.5 Two-on-Two (Niigata)

Based on the result of the Takanawa two-on-two

experiment, the predicted result of the Niigata

experiment was that the offensive player would focus

on his opponent or in the direction of his teammate

while dribbling. However, the result of Niigata

experiment was that the offensive player looked for a

moment at his opponent when receiving the ball and

then started to dribble (Fig. 11). After that, the

offensive player was always looking at his teammate

while dribbling (Fig. 12).

5 DISCUSSION

First, the purpose of this study was not to statistically

analyze basketball skills to improve athletic

performance but rather to identify new ways to

present those skills to new spectators. Although

people need to accept a new way of life until the

COVID-19 pandemic is over, this is an opportune

time to adopt new ways to spectate. More and more,

people will watch various sports on TV or on the

Internet. What these spectators desire is quality and

reality, as well as more information. The various eye-

tracking studies have investigated the important

relationship between athletic performance and eye

movements to pass or take a successful shot.

Especially, sports involving a ball and a goal demand

quick decisions and instant transitions from defense

to offense compared to other kinds of sports. By

revealing the eye and body movements of players, it

becomes clear to spectators what they are looking at,

what they are paying attention to, and when and

where they are feinting. Therefore, both tracking and

fixed video recordings are necessary to achieve

spectators' desires. The tracking recording watches an

individual player who has the ball, and the fixed

recording is to understand what the other players are

doing.

Second, the results of free-throw experiments

proved the importance of QE, such as gaze fixation.

However, QE is one of the factors involved in making

a successful shot. To acquire the effects of QE, it is

first necessary to set up a training period for the

acquisition of movements before implementing the

QE training. (Mizusaki et al., 2013). According to the

basketball textbook mentioned above, players who

learn to shoot and to move correctly during their

developmental years will grow into great shooters as

they develop. And the position of the ball during free-

throw shooting changes as the muscular develops

(2014).

Third, the differences in eye movements were

expressed between two different players during two-

on-two, such as looking at the opponent or the goal

and glancing at a teammate. Based on this

experimental result, it is difficult to decide whether

these differences are attributable to the player’s skill

level. However, if cooperation among the players on

team is essential for scoring points, then the players

of Niigata could read the movements of their

teammates, check the situation instantly, and decide

where to attack easily by understanding the situation.

In other words, cooperation enables players to score

points. It is often thought that having a good scorer

(point getter) is an advantage, but in reality, a team

with a good balance of players is better for winning

than a team with a single standout player.

Fourth, the basketball textbook maintains that

passing requires a much higher level of judgment than

shooting or dribbling. It is an important skill that

supports team play and must be based on

communication between teammates, but also on

anticipation of defensive moves. The textbook shows

that the keys to offense are to keep the face up, keep

the vision wide, and be ready to react to the ball or to

the movement of teammates at any time. On the other

hand, the keys to defense are to keep the face up and

both the ball and the opponent in sight. Here, "keep

the face up" or "keep the vision wide" refers to

peripheral vision (2014). In the experiment, although

the eye movement camera of the offensive player

always captures the Niigata teammate, the Takanawa

player’s camera does not. And, Takanawa player’s

camera shows the floor and goal sometimes. This

result proved that skilled players demonstrate "keep

Realization of Highly Realistic Broadcast that Includes the Eye Movements of Basketball Players

239

the face up" and "keep the vision wide" as usual in

their practice time (Japan Basketball Association,

2014).

Next, Yaita et al. (2014) mentioned that play

involving post players has a lot to do with their ability

to compete and their ability to make situational

judgments. They need to be trained to understand how

to make good situational judgments in play involving

or related to post players. At least, the passer and the

post player should wear eye movement measurement

devices to clarify this situation. And, by putting

different pictures on one screen on the same timeline

(Figs. 5, 7, 9, and 10), the peripheral vision and eye

contact of both the passer and the post player can be

revealed. If all the players in the court wear the

devices and record 4K video cameras from 360

degrees, all the players’ eye and body movements will

be evident.

Finally, although we could gather real

experimental data from activity similar to a real game

rather than from experiments in the lab or limited play

performance situations, there will be more movement

or more players involved in a real game. We limited

the play performance area to a quarter of a basketball

court for the one-on-one and two-on-two experiments.

This is because the purpose of this research is not to

analyze basketball skills to improve athletic

performance, but rather to introduce to spectators the

allure of basketball, such as players’ decision making

and make quick transitions.

6 SUMMARY

We approached a new method of recording

performance videos by using a wireless eye

movement measurement device and 4K video and

then measured the eye movement of basketball

players during free throws, one-on-one (fixed and

tracking), and two-on-two play in order to identify

new ways to present the game to new spectators. The

results show the following: 1) focusing steadily on a

specific point during shooting is one of the important

factors in free throws; 2) in the one-on-one

experiments, a fixed camera can capture both body

and eye movements at the same time; 3) spectators

can watch a player’s eye and body movements

specifically at the same time by one-on-one tracking

camera method; and 4) eye movements during play

are completely different for expert players than for

less-skilled players. Although passing is not an

individual play or skill, a passer always needs a

receiver. In other words, basketball is not only about

individual skills but about teamwork.

The use of wireless eye movement measurement

devices and 4K technology allows us to watch the

body movements of players from different angles and

to simultaneously watch their eye movements in high

resolution. As a result, eye movements can be

observed and measured outside of the lab, i.e., on a

court, where players can move freely. In other words,

a wireless eye movement measurement device leads

to experiments that are similar to real games. These

techniques enable us to watch players move at

dizzying speed over a relatively small area and thus

to show the skills of basketball players. This study can

be extended to reveal the secrets of skill development

and spectators' observation points. At the same time,

the concerted visual and body movement movements

of players were investigated to determine the

processing mechanisms in the brains of superior

athletes. The results of this study are applicable not

only to sports but also to the analysis of human

behavior and the importance of concerted action

between vision and body movement.

ACKNOWLEDGEMENTS

This study was supported in part by the Hoso Bunka

Foundation (2018/2019 Grant Cycle). We would like

to thank Kento Nakajima for all the experiments and

also thank the players of the Basketball Club at the

Tokai University of Takanawa campus and Apple

Sports College Basketball Course, U23 of Niigata

Albirex BB for their kind cooperation in conducting

experiments.

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