Is a Depth Camera in Agreement with an Electromagnetic Tracking Device when Measuring Head Position?

In this paper head position locating systems were analyzed. There were reviewed scientific articles with different proposed methods. The chosen system is with the camera located on the user head. The main parameters of the head positioning systems were analyzed. The procedure laid down in what order parameters are found. The diagram of the system and detail block diagram of the algorithm were provided. Realization of the algorithm used: edge detection method (Sobel), the adjustment algorithm (Subpixel). System is realized in Matlab and C# environment. Determine the optimal parameters for the algorithm execution. Execution of the algorithm in Matlab environment is 1.2 s and C # environment – 126 ms. During the examination of the longest executing algorithm segment, it was found that image filtering is carried out in 107 ms. It is noted that the uncertainty of the algorithm can be divided into static and measurement. The maximum static uncertainty while measuring head position parameters is 1.63 mm and orientation parameters – 0.16°. The maximum measurement uncertainty while measuring head position parameters is 4 mm and orientation parameters – 0.11°. Santrauka Nagrinėjamos galvos padėties pozicionavimo sistemos. Apžvelgti moksliniai straipsniai, kuriuose pateikiami įvairūs siūlomi metodai. Pasirinkta sistema, kai kamera pritvirtinama vartotojui ant galvos. Išskirti pagrindiniai galvos padėties nustatymo parametrai, nustatytas parametrų suradimo eiliškumas, pateikta sistemos schema ir detali algoritmo blokinė schema. Algoritmui įgyvendinti taikyti briaunų radimo (Sobel) ir algoritmo tikslinimo (Subpixel) metodai. Sistema įgyvendinta Matlab ir C# aplinkose. Nustatyti optimalūs algoritmo vykdymo parametrai. Naudojamo kompiuterio procesorius Intel Pentium dual core T4500 – 2,3 GHz. Vidutinis algoritmo veikimo laikas Matlab aplinkoje yra 1,2 s, o C# aplinkoje – 126 ms. Ištyrus algoritmo segmentų vykdymo laiką, pastebėta, kad ilgiausiai vykdomas vaizdo filtravimas – 107 ms. Parodyta, kad algoritmo neapibrėžtis galima suskirstyti į statines ir matavimo neapibrėžtis. Maksimali statinė neapibrėžtis, matuojant galvos pozicijos padėtį, yra 1,63 mm, matuojant orientacijos parametrus – 0,16°. Maksimali matavimo neapibrėžtis yra 4,0 mm, matuojant galvos padėties parametrus, ir 0,11° – orientacijos parametrus.

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Accuracy of an electromagnetic tracking device for measuring hip joint kinematics during gait: effects of metallic total hip replacement prosthesis, source-sensor distance and sensor orientation

Australasian Physical & Engineering Sciences in Medicine ◽

10.1007/bf03178714 ◽

2005 ◽

Vol 28 (3) ◽

pp. 184-189 ◽

Cited By ~ 6

Author(s):

S. Jaberzadeh ◽

S. Scutter ◽

M. Zoghi

Keyword(s):

Total Hip Replacement ◽

Hip Joint ◽

Hip Replacement ◽

Joint Kinematics ◽

Electromagnetic Tracking ◽

Total Hip ◽

Sensor Orientation ◽

Tracking Device ◽

Replacement Prosthesis

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PO-0856 SIMULTANEOUS USE OF AN ELECTROMAGNETIC TRACKING DEVICE AND A CONVENTIONAL FLAT-PANEL X-RAY IMAGER

Radiotherapy and Oncology ◽

10.1016/s0167-8140(12)71189-1 ◽

2012 ◽

Vol 103 ◽

pp. S334-S335

Author(s):

M.F. Fast ◽

E. Wisotzky ◽

U. Oelfke ◽

S. Nill

Keyword(s):

Electromagnetic Tracking ◽

Flat Panel ◽

X Ray ◽

Simultaneous Use ◽

Tracking Device

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Measurement of spinal range of motion in healthy individuals using an electromagnetic tracking device

Journal of Neurosurgery Spine ◽

10.3171/spi/2008/8/2/135 ◽

2008 ◽

Vol 8 (2) ◽

pp. 135-142 ◽

Cited By ~ 18

Author(s):

Chien-Jen Hsu ◽

Yi-Wen Chang ◽

Wen-Ying Chou ◽

Chou-Ping Chiou ◽

Wei-Ning Chang ◽

...

Keyword(s):

Lumbar Spine ◽

Range Of Motion ◽

Thoracic Spine ◽

Axial Rotation ◽

Electromagnetic Tracking ◽

Healthy Individuals ◽

Hip Joints ◽

Forward Bending ◽

Tracking Device ◽

Side Bending

Object The authors measured the range of motion (ROM) of the spine in healthy individuals by using an electromagnetic tracking device to evaluate the functional performance of the spine. Methods The authors used the Flock of Birds electromagnetic tracking device with 4 receiver units attached to C-7, T-12, S-1, and the midthigh region. Forward/backward bending, bilateral side bending, and axial rotation of the trunk were performed in 18 healthy individuals. Results The average ROM was calculated after 3 consecutive measurements. The thoracic spine generated the greatest angle in axial rotation and smallest angle in backward bending. The lumbar spine generated the greatest angle in forward bending and smallest angle in axial rotation. The hip joints generated the greatest angle in forward bending and smallest angle in backward bending. Additionally, 40% of forward-bending motion occurred in the lumbar spine and 40% occurred in the hip joints. Approximately 60% of backward bending occurred in the lumbar spine; 60% of axial rotation occurred in the thoracic spine; and 45% of side bending occurred in the thoracic spine. Conclusions The Flock of Birds electromagnetic tracking device cannot only measure the ROM of spine but also easily differentiate the 6-degree contributions by different segments.

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Determining Dual Euler Angles of the Ankle Complex in vivo Using “Flock of Birds” Electromagnetic Tracking Device

Journal of Biomechanical Engineering ◽

10.1115/1.1846072 ◽

2005 ◽

Vol 127 (1) ◽

pp. 98-107 ◽

Cited By ~ 9

Author(s):

Ning Ying ◽

Wangdo Kim

Keyword(s):

Three Dimensional ◽

Euler Angles ◽

Joint Motion ◽

Electromagnetic Tracking ◽

Kinematic Coupling ◽

Alternative Approach ◽

Ankle Complex ◽

Coupling Characteristics ◽

Tracking Device

The dual Euler angles method has been proposed as an alternative approach to describe the general spatial human joint motion. In this study, the dual Euler angles method was applied to study the three-dimensional motion of the ankle complex. The methodology for obtaining dual Euler angles of the ankle complex was developed by using a “Flock of Birds” electromagnetic tracking device. The repeatability of the methodology was studied based on the intertester and intratester variability analysis. Finally kinematic coupling characteristics of the ankle complex during dorsiflexion–plantarflexion, eversion–inversion, and abduction–adduction were analyzed according to the parameters of the dual Euler angles.

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