Development of a Kinect-based Anthropometric Measurement. Application. Alvaro Espitia-Contreras. Pedro Sanchez-Caiman. Nueva Granada Mil. University.
Development of a Kinect-based Anthropometric Measurement Application Alvaro Espitia-Contreras
Pedro Sanchez-Caiman
Alvaro Uribe-Quevedo
Nueva Granada Mil. University Industrial Engineering*
ABSTRACT Anthropometry is known as the science that studies the human body dimensions, this measurements are acquire using special devices and techniques whose results are analyzed through statistics. Anthropometry plays an important role within the industrial design process in areas such as clothing, ergonomics, and biomechanics, where statistical data about body medians allow optimizing product design. Recently, image processing and hardware advances are allowing the development of applications that allow an user to preview wardrobe, costumes, games or advergames and even different types of environments according to the user measurements. This project proposes the development of a complimentary tool for acquiring user anthropometric data for characterizing users in the Mil. Nueva Granada University in Colombia, South America using Microsoft’s Kinect skeletal tracking for developing and assess the design of workspaces in several areas such as laboratories. Keywords: Anthropometric, Motion Capture, Industrial Design. Index Terms: H.5.2 [User Interfaces]: Ergonomics 1
INTRODUCTION
Most devices, tools or elements that people use on daily basis are designed using anthropometric dimensions for guaranteeing healthy and comfortable user experience. The development of ergonomic elements requires anthropometric profiles that are established through statistical analysis by acquire measurements using specials elements such as the caliper, stadiometer and scales, the goal is to measure body characteristics including linear dimensions, weight, volume, range of motion, etc. [1]. Currently, lationamerican anthropometric profiles does not fit the population of different latin countries, the main differences are find in terms of socioeconomic factors such as culture, age, gender, costumes, nourishment and life style, along with poblational growth [2]. This project presents the development of an interactive tool for taking anthropometric measurements using a kinect-based application as a complimentary alternative to available measurement devices, where users, while performing targeted movements are measured. The paper is organized in sections where, Section 2 presents the anthropometric characterization; Section 3 presents the methodology; Section 4 presents the results; and finally, Section 5 the Conclusions. ________________________________ *Email:{u2901569,pedro.sanchez,alvaro.uribe}@unimilitar.e du.co Universidad Militar Nueva Granada, KR 11 101 80, Bogota D.C., Colombia
2
ANTHROPOMETRY
Anthropometry consists of a series of technical measurements that quantitative expresses body dimensions [3]. Anthropometry is mainly categorized in static and dynamic, the first one is applied when measurements are taken directly over the body, while the second one describes the ranges of motion of the body [4]. The ample distribution of body dimensions results in nonrelevant measurements due to small genetics differences, however, other easily observable are variables that affect body dimensions due to age, gender, work habits and geographic location [5]. 2.1 Anthropometric points Anthropometric measurements take several body parts as reference points that allow obtaining relevant information regarding the region or segment being measured. These points are characterized for matching body segments that shape it, such as protuberances, edges, apophysis or segments that are easily found [6]. For the development of this project nine measurements height, breadth, vertical reach, shoulder height, elbow height, shoulder width, functional reach, iliac height and knee height. These measurements were chosen as they allow defining a basic anthropometric profile for designing ergonomic spaces through identifiable human body parts with the Kinect. 3
METHODOLOGY
The study was setup with a population of 370 students conformed by 177 women and 193 men where the measurements were taken by traditional means using specialized devices and then taken with the developed application-based on Kinect. 3.1 Development The development of the application was divided in four parts, Kinect interactions, graphic user interface design and development for data measurements, and finally, the data statistical analysis. During the development, each of the joint’s position was considered so the interactions were design accordingly to a motion capture area within the optimal Kinect tracking area. For improving the measurement experience, the application was designed to stimulate the user through messages informing when the measure was correctly taken and providing information about ergonomics. First, the users were measured at each position using measuring tapes, in order to obtain the data of the control group, then, they were asked to perform targeted motion involving extension of the legs and arms with a straight upper body. After both measurements were completed, the data was compared through an statistical analysis for generating the corresponding anthropometric profiles.
4
RESULTS
Table 2. Male anthropometric data MALE
The measurement process resulted in collected data from women and men with a 48% and 52% respective participation, the average age is 20 years old, and the measured Kinect data was compared with the control group measured with the special devices. Figure 1 presents a screen capture of the developed application where the measurements are shown so the user can perform the targeted positions for data acquisition. The interface feedbacks the user presenting an overlaid virtual skeleton that allows the user to correct his or her position during the measurement process.
TRADITIONAL METHOD
KINECT
MEDIAN
P5
P 95
D ST
MEDIAN
P5
P 95
HEIGHT
174.40
164.00
185.00
6.40
165.80
155.20
179.30
8.50
BREADTH
172.50
158.70
183.60
7.30
148.70
108.70
180.00
20.50
VERTICAL REACH
215.00
200.00
230.60
11.60
195.90
140.00
223.20
25.40
SHOULDER HEIGHT
144.50
135.00
156.00
9.70
136.90
123.20
154.60
11.60
ELBOW HEIGHT
109.70
101.00
118.00
7.10
108.20
98.00
118.00
8.60
SHOULDER WIDTH
45.80
37.00
52.00
4.60
37.30
31.60
51.00
6.40
FUNCTIONAL REACH
63.70
56.00
73.30
5.30
59.70
50.30
70.00
8.50
ILIAC HEIGHT
95.90
87.00
105.00
9.40
94.10
80.90
103.10
9.70
KNEE HEIGHT
52.70
47.00
58.00
3.50
47.00
40.00
57.00
6.40
5
D ST
CONCLUSION
The Kinect sensor proved to be a suitable for taking anthropometric measurements when considering body points as the head, shoulders, elbows and knees when facing the sensors. The comparison of the measured data with the control group and other anthropometric data, allows concluding that Kinect data is reliable being within a normal mean differences and variance difference, even though small errors occur due to illumination, sensor distance and clothing. Future works will focus on improving sensor tracking and adding more tracked points with a gamified system for providing and encouraging user participation. H 0 : µ1 = µ 2
Test of Homogeneity of Variances
H1: There are significant differences in variance between the two measures
Figure 1: Developed application
After the anthropometric data was obtained with the Kinect, an statistical analysis was performed resulting in smaller values compared to those obtained with the special devices with the control group. The data was compared to other anthropometric data for its validation, and errors obtained after comparing the information can be attributed to several factors such as, userKinect distance, room illumination, clothing and shoes that altered some recognized joints.
Levene Statistic 1.578
Height
df2 144
Sig. .051
The critical level (Sig) in the Levene statistic is 0.51; therefore, the null hypothesis of equal variances is accepted. Functional reach Levene Statistic 1.393
Table 1. Female anthropometric data
df1 20
df2 151
Sig. .134
The critical level (Sig) in the Levene statistic is 0.134, so the null hypothesis of equal variances is accepted.
FEMALE TRADITIONAL METHOD
df1 25
KINECT
MEDIAN
P5
P 95
D ST
MEDIAN
P5
P 95
D ST
HEIGHT
161.50
150.0
173.00
14.00
156.50
142.20
174.20
10.20
BREADTH
156.50
129.70
172.10
17.00
138.40
96.10
175,0.00
26.10
VERTICAL REACH
197.70
182.90
217.00
20.00
186.00
136.60
217.10
24.10
SHOULDER HEIGHT
135.50
121.90
147.10
14.50
128.70
113.10
151.10
14.60
ELBOW HEIGHT
103.70
95.00
112.20
12.60
102.10
88.70
120.00
11.80
SHOULDER WIDTH
39.30
30.60
46.00
5.20
34.90
27.30
46.00
8.40
FUNCTIONAL REACH
58.90
51.00
67.00
7.10
58.00
45.30
70.10
8.10
ILIAC HEIGHT
92.20
82.30
102.10
9.70
90.30
74.00
107.30
13.60
KNEE HEIGHT
48.70
41.00
55.10
5.90
46.10
37.20
56.10
6.50
REFERENCES [1] [2] [3] [4] [5] [6]
Antropometría Aplicada y Espacio de Trabajo. [Online]. Available: http://www.virtual.unal.edu.co/cursos/sedes/manizales/4100002/lecc iones/lecturas/EstudioOperaciones/ANTROPOMETRIA.pdf Physiological Assessment of Human Fitness. Peter J. Maud y Carl Foster (Eds.). Human Kinetics Publishers. Champaign, Illinois. Cap.11, pp. 205-219, 1995. D. Oborne, J. David. Ergonomía en acción. La adaptación del medio de trabajo al hombre. s.l.: Trillas, 1990, pp. 402. Ergonomía y Antropometría. [Online]. Available: http://ergomobiliariohuelva.blogspot.com D. Oborne, J. David. Ergonomía en acción. La adaptación del medio de trabajo al hombre. s.l.: Trillas, 1990, pp. 402. Leiva Suárez, A. J. (s.f.). Manual de control médico de la actividad física.
