- Email: [email protected]
Dara vestibular equipment onboard MIR
Acta Astronautica Vol. 43, Nos. 3-6, pp. 313-319, 1998 0 1998 Elsevia science Ltd. All r@ts resewed
PII: SOW-5765(98)001635
Printed in Great Britain 0094-5765/98+
front matter
DARA VES’TIBULAR EQUIPMENT ONBOARD MIR P. Hofmamt’, A. Kellig’, H.-U. Hoffmann’, G. Ruyters’ ‘Kayser-Threde GmbH, Wolfratshauser Str. 48, D-81379 Mlinchen; ‘Deutsche Agentur fiir Raumfahrtangelegenheiten (DARA, German Space Agency) GmbH, Konigswinterer Str. 522-524, D-53227 Bonn
1. INTRODUCTIOU In space, the weightless environment provides a different stimulus to the otolith organs of the vestibular system, and the resulting signals no longer correspond with the visual and other sensory signals sent to the brain. This signal conflict causes disorientation. To study this and also to understand the vestibular adaptation to weightlessness, DARA has developed scientific equipment for vestibular and visuo-oculomotoric investigations. Especially, two video-oculography systems (monocular - VOG - and binocular - BIVOG, respectively) as well as stimuli such as an optokmetic stimulation device have successfully been employed onboard MIR in the frame of national and EIJKI~W~ missions since 1992. The monocular VOG was used by Klaus Plade during the MIR ‘92 mission, by Victor Polyakov during his record 15 months stay onboard MIR in 1993194 as well as by Ulf Merbold during EUROMIR ‘94. ‘Ihe binocular version was used by Thomas Reiter and Sergej Avdeyev during the 6 months EUROMIR ‘95 mission. PIs of the various experiments include H. Scherer and A. Clarke (PU Berlin), M. Dieterichs and S. Krafczyk (LMU Mthtchen) from Germany as well as C.H. Markham and S.G. Diamond from the United States. Video-Oculography (VOG) is a technique for examining the function of the human balance system located in the inner ear (vestibular system) and the visio-oculomotor interactions of the vestibular organ. The human eye movements are measured, recorded and evaluated by state-of-the-art video techniques. The method was Fist conceived and designed at the Vestibular Research Laboratory of the ENT Clinic in Steglitz. N Berlin(A. Clarke, H. Scherer). Kayser-Threde developed, manufactured and tested the facilities for space application under contract to DARA. Evaluation software was fit provided by the ENT Clinic, Berlin, later by our subcontractor Sensomotoric Instruments (SMI), Teltow. Optokinetic hardware to support visuo-oculomotoric investigations, has been shipped to MIR for EUROMIR ‘95 and has successfully been used in conjunction with VOG by ESA astronaut Thomas Reiter. Most recently, BIVOG aboard MIR will be reused in the frame of German/ Russian joint experiment sessions employing two Russian cosmonauts from august 1997 to January 1998.
2. VOG MIIR ‘92 VOG MIR ‘92 is realised by a CCD camera mounted on a lightweight mask. The mask is fixed to the head with a flexible frame onto which a triaxial linear accelerometer and three angular rate sensors are attached. A microphone and a head set are included for commentary and instruction. The video images and the digitally encoded accelerometer and rate sensor signals are recorded synchronously onto high quality videotape, and evaluated post flight on the ground with video imaging techniques. The system can be extended with caloric stimulations. This is done by attaching a head-mounted cold caloric stimulator to the head unit. It produces a cold air flow which is blown into the subject’s ear. The technical specification of the VOG MIR ‘92 system is summarised in table 1.
313
314
12th Man in Space Symposium-additional Measurement:
Technical Specijication and Characteristics
30 eye movement:
Resolution c 0. f e Sample Rate 2S Hz Linearity over _+300 < 0.3’
Video:
Hi-8 recorder resp. camera Resolution 756 (H) x 581 (V)
papers
Triaxial acceleration sensors: Range + 2 g Resol ttion +zi mg Sampling rate 50 Hz Angular rate sensors:
Range + loo0 ‘Is Resolution e 1 “Is amine rate 50 Hz
PCM en&et:
12 bit, 8 analog, Idigital
Caloric:
I2”C - 15 ‘C air temperature Air~w 3.5 Ilmin.
Power supply:
12 V16.SA max, 4.2 A nominal
Mass:
Electronics box: 8.f kg Head unit including caloric module: 2.3 kg
Table 1:
Technical Specification of VOG MIR ‘92
The VOG MIR 92 hardware was improved for the EUROMIR 94 mission. A new head unit was shipped to MIR. A snap-in mechanism now allowed to exchange cameras from one eye to the other, to attach new hardware stimulation components, to exchange illumination diodes (e.g. from “visible” 880 nm diodes used during MB92 to “invisible” 950 nm diodes later on). The hardware is described in more detail in ref. [l] and IS), and depicted in figure 1 as shown below.
3. OKS VOG The optokmetic stimulator as developed for EUROMIR 95 consists of an optokinetic calibration and stinndation assembly, which fits the snapin mechanism as described above. The head-mounted monitor is a high resolution VGA black-white video monitor. A wide angle optics assures a large field of view of -90“. OKS VOG measures one eye while stimulating the other. For the generation and control of the stimulation patterns a PC with dedicated video processor is used. The image or stimulation patterns as well as the motion parameters, direction and speed, can be controlled by the PCkeyhoard using a menu. Since the generation and control of the stimulation patterns is done with a PC with dedicated video processor, various stimulating patterns as well as many motion programs can be realised. The modular overall concept is described in detail in ref. [2 1. The software implemented in the 95 light OKS system is a rotating roll pattern with a movable bar. This bar can be oriented by the subject using a roll potentiometer box to indicate the subjective visual vertical. The values are recorded on the OKS computer and on the VOG tape recorder (angle of bar, time, event, dition of roll pattern. status line). The OKS VGG hardware, as used during the EUROMIR 95 mission, is shown in figure 1. It consists of the VOG MIR ‘92 Head Unit with attached optokinetic assembly (head mounted monitor with an associated optical system attached to the face mask), the hand-held control unit, the VOG MIR ‘92 electronic box and the OKS electronic box. The latter is mainly comprised of a “cheque” card PC System (EPSON), a dedicated video board and the video monitor electronics.
12th Man in Space Symposium-additional
papers
Fig 1: The complete OKS VOG model as used during EUROMIR 95 for experiment D-38. The hardware is powered via the central power supply WE on board MIR (not shown). The specification of the OKS system is shown below. Field-of-view:
-90” wide angle optics magnification -30x
Display:
1” black + white VGA monitor (spot size 30 p resolution loo0 lines in the center, band with 5 Hz to 30 MHz)
Display pattern:
any (software programmable, implemented for EUROMIR ‘95: roll pattern with moveable bar
Pattern velocity:
any (Stan&d: 0 to Wlsec
Image Frequency:
60 Hzframe mode
Image Processing:
special graphic processing board in 386 PC system
horizontal, vertical, torsional)
Table 2: Specification of the OKS System
During the EUROMIR 95 mission the experiment D-38 (experimenters: M. Dieterichs, S. Krafczyk, J. Philipp) were done in
4. BIVOG BIVOG is an upgraded binocular version of VOG. Both eye images are obtained by CCD cameras via infrared mirrors. Thus, free-field-of-view, as well as experiments where visible light is occluded are possible. The video pictures are recorded on a professional studio quality Betacam recorder, which has been modified to be able to simultaneously record two black-white images. Similar to VOG. acceleration and rate sensors are mounted on a head frame and the data are recorded. A dictaphone (to guide the experimenter), an eye monitor (to focus) and a calibration unit are part of the new BIVOG system. A bite board can be attached to fix the camera to the skull.
315
316
12th Man in Space Symposium-additional
papers
Much development effort had to be invested into the new binocular face mask (IR) mirrors and coatings, diodes and illumination arrangements, selection of a small IR sensitive camera, optical arrangements etc.)
Figure.2: BIVOG as fist used during EUROMIR ‘95
The complete BIVOG system is depicted in figure 2. The BIVOG electronics box is an upgrade of the previous hardware, but rather large, because it also serves as a storage box for head unit assembly, monitor and a calibration unit (not shown in the figure). We have chosen not to control the experiment flow via microprocessor control but via simple on/off switches, and to guide the experiments through the session with an integrated dictaphone. A good quality self standing monitor (BIMON) has been developed. This is used to adjust the set-up. As storage system, a modified Betacam recorder has been selected. Its drawbacks for use on board MIR (mass, volume of recorder and tapes) are overcompensated by its superior quality. The recorder was modified to allow to record two black and white video images on a single tape. Finally, evaluation on ground has substantially been improved by our subcontractor SMI. The BIVOG system is designed to allow additional attachments. The BIVOG electronics box has supplementary power outlets for a system video camcorder (scene pictures, or the new humid air caloric system as described elsewhere [Ref. 1,2D. The detailed specification of the BIVOG (and VOG) system (from a science point of view) is shown below (table 3).
12th Man in Space Symposium-additional
317
papers
Vertical
horizontal
Torsional
SpatialResolution
0.03 deg.
0.02 deg.
0. I deg.
LinearityError
max.
max.
k3.2% FSR
max. 9~1.4%FSR
GO deg.
&ZSdeg.
ti0 deg.
Temporal Resolution
50 Hz (PAL)
50 Hz (PAL)
25 Hz (PAL)
Video:
yQ&
ti.86 Measurement
FSR
Range
Hi-8 recorder one camera blw 756 (H) x 581 (V) BIVOG: Betacam SP recorder twocameras b/w 752 (H) x 582 (V) Triaxialacceleration sensor:
Range Resolution Sampling rate
Angular rate seA.sors:
Range Resolution Sampling rate
PCM encoder:
12 bit, 8 analog. I digital
e2g
cl O/s 50 Hz
Table 3: Specification of the BIVOG (and VGG) System During EURIMIR 95 this hardware has been used by three different scientific groups: USA-17 (C. H. Markham and S.G: Diamond, A. Clarke and H. Scherer) and D-38 (M. Dieterichs, S. Krafcxyk and J. Philipp).
5. STATUS OF FLIGHT HARDWARE AND SUPPLEMENTS For all pieces of hardware as described above three models exist, a flight. training, and qualification model. All models are basically identical. The trainings model can serve as a flight spare model, after suitable refurbishment, if required. All equipment worked very well during their usage aboard MIR. with few occasional small problems as can be expected. The scientific results are described elsewhere (e.g. ref. [31, [4]. see also present conference). Various supplements exist on ground. A new humid air caloric system is available as an engineering model which can straight-forward be shipped to MIR [2]. The specification is shown below (table 4).
Temperature:
warm stimulus44 “C cold stimulus30 “C
Airflow:
approx. 3.5 Umin
Stimuli:
CN cs WN CD WD
cold. normal cold, strong warm, normal cold dry (OptiOMl) warm dry (optional)
Table 4 Specification of the optional humid air caloric stimulation system
12th Man in Space Symposium-additional
318
Also a BIVOG optophysiological colour display is available. This display in VGA quality which can be used in conjunction with perform various types of optokinetic stimulations to the eye, and be performed using a standard computer. Besides applications ophthalmological research, the equipment can also be applied analysis, virtual reality display, etc..
papers
system is comprised of a colour TFI 6.5” LCD the BIVtXi face mask. This device allows to to display any pictures and patterns which can in the field of vestibular, neurological and in research areas such as psychology, stress
Two models built to flight standard and one trainings model are available. As an option the system can be coupled with an eye-tracking hardware (PC board) and software. The specification is shown below (table 5).
Field of view:
f200
Display:
640 x 480 pixels, TFT Colour VGA monitor, 95 x 130 mm’
Dimensions: (light occluding tube)
38Ox210x14Smm’
Mass:
-2.0 kg
Table 5: Specifications - VOG Optophysiological Color Display
Last but not least BIVOG has standard computer and video interfaces to allow to transmit all data to ground. Using a new communication interface unit (named BDD), developed by KT under contracts from DARA and ESA for the German MIR 97 mission, video and sensor data can synchronously be mixed and transmitted to ground in high quality. The BDD hardware uses the Russian Loutch satellites. It is a bidirectional system, and also allows direct communication from ground stations in Germany, e.g. GSOC, Germany to MIR.
6. OUTLDOK At present KT is working on improvements of the BIVOG equipment. The following major activities can be reported: l
l
l
An ultralight face mask based on the principle of the existing BIVOG concept. The BIVOCl performance is not degraded. ‘Ihe free-field-of-view is extended, at the expense of the possibility darkening with a metal cover. (A black cloth may be used instead.). This hardware is mainly for use in ground laboratories, and exists as a prototype. An improved colour display attached to BIVOG is breadboarded. Some compromises with respect to the eye evaluation performances and the field-of-view of the display area may have to be made. This system is aimed at “virtual reality type” applications, while allowing good quality eye measurements. This system will also be partially suited to optokinetic applications, but with reduced field of view. Most important new IR sensitive detectors have become available based on CMOS instead of CCD technology. These &vices allow e.g. a pm-evaluation “on chip”. Using these concepts and the fast progress in computing power and storage capacity, a next generation BIVOG can be real&d with quasi on-line evaluation (no more video recorder necessary) and higher sampling rates 0 200 Hz). We believe that these concepts should be real&d for a next generation BIVOG, which may - as part of NASA’s Human Research Facility - become the 3D eye tracking system for the early utilisation phase of the International Space Station. First results, as also reported by A. Clarke during this conference, are very promising. Only minor hardware adaptations, e.g. of the BIVOG face mask seem necessary.
12th Man in Space Symposium-additional
papers
7.SUMMARY We have described the vestibular and visuo-oculomotoric equipment which has been developed under various DARA contracts since 1991, and used aboard MIR in the frame of the following missions: l German MIIR ‘92 mission (VOG) l Extensions 1.0MIR ‘92, e.g. the use of VOG by V.Polyakov during his record stay in space from 1993 to 1994 l EUROMIR ‘94 (VOG) . EUROMIR ‘95 (VOG,OKS and BIVOG) l Joint Germa.n /Russian experiments in 1997/98 (BIVOG) The hardware is supplemented by various stimuli and measurements. New developments for a next generation BIVOG, which may become the Space Station 3D eye tracking system, have shortly been addressed.
8.ACKNOWLEDGEMENTS All VOG systems have been developed by Kayser-Threde under contracts to DARA. Various companies in the new “Lander” have contributed to the project (IMT, Dresden; SMI. Teltow; VRS. Leipzig)
ESA is acknowledged for using VOG during their EUROMIR 1994/95 projects, and support for the ongoing experiments. In particular we thank Chr. Nitzschke (DARA), our PI’s (H. Scherer, A. Clarke, ENT Laboratory, FU Berlin; C.H. Markham, S.G. Diamond, UCLA, USA; M. Dieterichs, S. Krafczyk, J. Philipp, LMU Munich), the EUROMIR project (in particular R.-D. Andresen. J. Schiemamr. B. Elmann-Larsen) as well as our Russian partners (V. Pol,yakov. IBMP; Mrs. T. Batentschuk-Tusko. RSC) for the good cooperation and support.
9.REFERENCES 111
“Video-0culography (VOG) on MIR ‘92”; J. Burfeindt, P. Hofmann. A. Kellig. P. Rank, 6th European Symposium on Life Sciences Research in Space; Arcachon. France, 26.9.-1.10.1993
PI
“Recent Developments of DARA Visuo-Vestibular Equipment for MB?‘; P. Hofmann, C. Kessler, A. Kellig, W. Teiwes. B. Seeliinder; IAF-Congress; Jerusalem, Israel, 9.-14.10.1994
131
‘The Three-Dimensional VOG during Prolonged Microgravity”; A. Clarke, J. Grigull, W. Krzok, H. Schere.r, 6th European Symposium on Life Sciences Research in Space, Trondheim, Norway; ESA SP-390 (October 1996); p. 83-87
141
‘The Effect of Hypogravity on Spontaneous Eye Torsion during Space Missions and on Subsequent Ocular Counterroling on Earth”; C.H. Markham, S. G. Diamond; 6th European Symposium on Life Sciences Research in Space; Trondheim, Norway; ESA SP-390 (October 1996); p. 89-93
PI
‘DAR4 Vestibular Equipment Aboard the MIR Station”; P. Hofmann. A. Kellig; 6th European Symposium on Life Sciences Research in Space; Trondheim, Norway; ESA SP-390 (October 1996); p. 119.,124
319
PII: SOW-5765(98)001635
Printed in Great Britain 0094-5765/98+
front matter
DARA VES’TIBULAR EQUIPMENT ONBOARD MIR P. Hofmamt’, A. Kellig’, H.-U. Hoffmann’, G. Ruyters’ ‘Kayser-Threde GmbH, Wolfratshauser Str. 48, D-81379 Mlinchen; ‘Deutsche Agentur fiir Raumfahrtangelegenheiten (DARA, German Space Agency) GmbH, Konigswinterer Str. 522-524, D-53227 Bonn
1. INTRODUCTIOU In space, the weightless environment provides a different stimulus to the otolith organs of the vestibular system, and the resulting signals no longer correspond with the visual and other sensory signals sent to the brain. This signal conflict causes disorientation. To study this and also to understand the vestibular adaptation to weightlessness, DARA has developed scientific equipment for vestibular and visuo-oculomotoric investigations. Especially, two video-oculography systems (monocular - VOG - and binocular - BIVOG, respectively) as well as stimuli such as an optokmetic stimulation device have successfully been employed onboard MIR in the frame of national and EIJKI~W~ missions since 1992. The monocular VOG was used by Klaus Plade during the MIR ‘92 mission, by Victor Polyakov during his record 15 months stay onboard MIR in 1993194 as well as by Ulf Merbold during EUROMIR ‘94. ‘Ihe binocular version was used by Thomas Reiter and Sergej Avdeyev during the 6 months EUROMIR ‘95 mission. PIs of the various experiments include H. Scherer and A. Clarke (PU Berlin), M. Dieterichs and S. Krafczyk (LMU Mthtchen) from Germany as well as C.H. Markham and S.G. Diamond from the United States. Video-Oculography (VOG) is a technique for examining the function of the human balance system located in the inner ear (vestibular system) and the visio-oculomotor interactions of the vestibular organ. The human eye movements are measured, recorded and evaluated by state-of-the-art video techniques. The method was Fist conceived and designed at the Vestibular Research Laboratory of the ENT Clinic in Steglitz. N Berlin(A. Clarke, H. Scherer). Kayser-Threde developed, manufactured and tested the facilities for space application under contract to DARA. Evaluation software was fit provided by the ENT Clinic, Berlin, later by our subcontractor Sensomotoric Instruments (SMI), Teltow. Optokinetic hardware to support visuo-oculomotoric investigations, has been shipped to MIR for EUROMIR ‘95 and has successfully been used in conjunction with VOG by ESA astronaut Thomas Reiter. Most recently, BIVOG aboard MIR will be reused in the frame of German/ Russian joint experiment sessions employing two Russian cosmonauts from august 1997 to January 1998.
2. VOG MIIR ‘92 VOG MIR ‘92 is realised by a CCD camera mounted on a lightweight mask. The mask is fixed to the head with a flexible frame onto which a triaxial linear accelerometer and three angular rate sensors are attached. A microphone and a head set are included for commentary and instruction. The video images and the digitally encoded accelerometer and rate sensor signals are recorded synchronously onto high quality videotape, and evaluated post flight on the ground with video imaging techniques. The system can be extended with caloric stimulations. This is done by attaching a head-mounted cold caloric stimulator to the head unit. It produces a cold air flow which is blown into the subject’s ear. The technical specification of the VOG MIR ‘92 system is summarised in table 1.
313
314
12th Man in Space Symposium-additional Measurement:
Technical Specijication and Characteristics
30 eye movement:
Resolution c 0. f e Sample Rate 2S Hz Linearity over _+300 < 0.3’
Video:
Hi-8 recorder resp. camera Resolution 756 (H) x 581 (V)
papers
Triaxial acceleration sensors: Range + 2 g Resol ttion +zi mg Sampling rate 50 Hz Angular rate sensors:
Range + loo0 ‘Is Resolution e 1 “Is amine rate 50 Hz
PCM en&et:
12 bit, 8 analog, Idigital
Caloric:
I2”C - 15 ‘C air temperature Air~w 3.5 Ilmin.
Power supply:
12 V16.SA max, 4.2 A nominal
Mass:
Electronics box: 8.f kg Head unit including caloric module: 2.3 kg
Table 1:
Technical Specification of VOG MIR ‘92
The VOG MIR 92 hardware was improved for the EUROMIR 94 mission. A new head unit was shipped to MIR. A snap-in mechanism now allowed to exchange cameras from one eye to the other, to attach new hardware stimulation components, to exchange illumination diodes (e.g. from “visible” 880 nm diodes used during MB92 to “invisible” 950 nm diodes later on). The hardware is described in more detail in ref. [l] and IS), and depicted in figure 1 as shown below.
3. OKS VOG The optokmetic stimulator as developed for EUROMIR 95 consists of an optokinetic calibration and stinndation assembly, which fits the snapin mechanism as described above. The head-mounted monitor is a high resolution VGA black-white video monitor. A wide angle optics assures a large field of view of -90“. OKS VOG measures one eye while stimulating the other. For the generation and control of the stimulation patterns a PC with dedicated video processor is used. The image or stimulation patterns as well as the motion parameters, direction and speed, can be controlled by the PCkeyhoard using a menu. Since the generation and control of the stimulation patterns is done with a PC with dedicated video processor, various stimulating patterns as well as many motion programs can be realised. The modular overall concept is described in detail in ref. [2 1. The software implemented in the 95 light OKS system is a rotating roll pattern with a movable bar. This bar can be oriented by the subject using a roll potentiometer box to indicate the subjective visual vertical. The values are recorded on the OKS computer and on the VOG tape recorder (angle of bar, time, event, dition of roll pattern. status line). The OKS VGG hardware, as used during the EUROMIR 95 mission, is shown in figure 1. It consists of the VOG MIR ‘92 Head Unit with attached optokinetic assembly (head mounted monitor with an associated optical system attached to the face mask), the hand-held control unit, the VOG MIR ‘92 electronic box and the OKS electronic box. The latter is mainly comprised of a “cheque” card PC System (EPSON), a dedicated video board and the video monitor electronics.
12th Man in Space Symposium-additional
papers
Fig 1: The complete OKS VOG model as used during EUROMIR 95 for experiment D-38. The hardware is powered via the central power supply WE on board MIR (not shown). The specification of the OKS system is shown below. Field-of-view:
-90” wide angle optics magnification -30x
Display:
1” black + white VGA monitor (spot size 30 p resolution loo0 lines in the center, band with 5 Hz to 30 MHz)
Display pattern:
any (software programmable, implemented for EUROMIR ‘95: roll pattern with moveable bar
Pattern velocity:
any (Stan&d: 0 to Wlsec
Image Frequency:
60 Hzframe mode
Image Processing:
special graphic processing board in 386 PC system
horizontal, vertical, torsional)
Table 2: Specification of the OKS System
During the EUROMIR 95 mission the experiment D-38 (experimenters: M. Dieterichs, S. Krafczyk, J. Philipp) were done in
4. BIVOG BIVOG is an upgraded binocular version of VOG. Both eye images are obtained by CCD cameras via infrared mirrors. Thus, free-field-of-view, as well as experiments where visible light is occluded are possible. The video pictures are recorded on a professional studio quality Betacam recorder, which has been modified to be able to simultaneously record two black-white images. Similar to VOG. acceleration and rate sensors are mounted on a head frame and the data are recorded. A dictaphone (to guide the experimenter), an eye monitor (to focus) and a calibration unit are part of the new BIVOG system. A bite board can be attached to fix the camera to the skull.
315
316
12th Man in Space Symposium-additional
papers
Much development effort had to be invested into the new binocular face mask (IR) mirrors and coatings, diodes and illumination arrangements, selection of a small IR sensitive camera, optical arrangements etc.)
Figure.2: BIVOG as fist used during EUROMIR ‘95
The complete BIVOG system is depicted in figure 2. The BIVOG electronics box is an upgrade of the previous hardware, but rather large, because it also serves as a storage box for head unit assembly, monitor and a calibration unit (not shown in the figure). We have chosen not to control the experiment flow via microprocessor control but via simple on/off switches, and to guide the experiments through the session with an integrated dictaphone. A good quality self standing monitor (BIMON) has been developed. This is used to adjust the set-up. As storage system, a modified Betacam recorder has been selected. Its drawbacks for use on board MIR (mass, volume of recorder and tapes) are overcompensated by its superior quality. The recorder was modified to allow to record two black and white video images on a single tape. Finally, evaluation on ground has substantially been improved by our subcontractor SMI. The BIVOG system is designed to allow additional attachments. The BIVOG electronics box has supplementary power outlets for a system video camcorder (scene pictures, or the new humid air caloric system as described elsewhere [Ref. 1,2D. The detailed specification of the BIVOG (and VOG) system (from a science point of view) is shown below (table 3).
12th Man in Space Symposium-additional
317
papers
Vertical
horizontal
Torsional
SpatialResolution
0.03 deg.
0.02 deg.
0. I deg.
LinearityError
max.
max.
k3.2% FSR
max. 9~1.4%FSR
GO deg.
&ZSdeg.
ti0 deg.
Temporal Resolution
50 Hz (PAL)
50 Hz (PAL)
25 Hz (PAL)
Video:
yQ&
ti.86 Measurement
FSR
Range
Hi-8 recorder one camera blw 756 (H) x 581 (V) BIVOG: Betacam SP recorder twocameras b/w 752 (H) x 582 (V) Triaxialacceleration sensor:
Range Resolution Sampling rate
Angular rate seA.sors:
Range Resolution Sampling rate
PCM encoder:
12 bit, 8 analog. I digital
e2g
cl O/s 50 Hz
Table 3: Specification of the BIVOG (and VGG) System During EURIMIR 95 this hardware has been used by three different scientific groups: USA-17 (C. H. Markham and S.G: Diamond, A. Clarke and H. Scherer) and D-38 (M. Dieterichs, S. Krafcxyk and J. Philipp).
5. STATUS OF FLIGHT HARDWARE AND SUPPLEMENTS For all pieces of hardware as described above three models exist, a flight. training, and qualification model. All models are basically identical. The trainings model can serve as a flight spare model, after suitable refurbishment, if required. All equipment worked very well during their usage aboard MIR. with few occasional small problems as can be expected. The scientific results are described elsewhere (e.g. ref. [31, [4]. see also present conference). Various supplements exist on ground. A new humid air caloric system is available as an engineering model which can straight-forward be shipped to MIR [2]. The specification is shown below (table 4).
Temperature:
warm stimulus44 “C cold stimulus30 “C
Airflow:
approx. 3.5 Umin
Stimuli:
CN cs WN CD WD
cold. normal cold, strong warm, normal cold dry (OptiOMl) warm dry (optional)
Table 4 Specification of the optional humid air caloric stimulation system
12th Man in Space Symposium-additional
318
Also a BIVOG optophysiological colour display is available. This display in VGA quality which can be used in conjunction with perform various types of optokinetic stimulations to the eye, and be performed using a standard computer. Besides applications ophthalmological research, the equipment can also be applied analysis, virtual reality display, etc..
papers
system is comprised of a colour TFI 6.5” LCD the BIVtXi face mask. This device allows to to display any pictures and patterns which can in the field of vestibular, neurological and in research areas such as psychology, stress
Two models built to flight standard and one trainings model are available. As an option the system can be coupled with an eye-tracking hardware (PC board) and software. The specification is shown below (table 5).
Field of view:
f200
Display:
640 x 480 pixels, TFT Colour VGA monitor, 95 x 130 mm’
Dimensions: (light occluding tube)
38Ox210x14Smm’
Mass:
-2.0 kg
Table 5: Specifications - VOG Optophysiological Color Display
Last but not least BIVOG has standard computer and video interfaces to allow to transmit all data to ground. Using a new communication interface unit (named BDD), developed by KT under contracts from DARA and ESA for the German MIR 97 mission, video and sensor data can synchronously be mixed and transmitted to ground in high quality. The BDD hardware uses the Russian Loutch satellites. It is a bidirectional system, and also allows direct communication from ground stations in Germany, e.g. GSOC, Germany to MIR.
6. OUTLDOK At present KT is working on improvements of the BIVOG equipment. The following major activities can be reported: l
l
l
An ultralight face mask based on the principle of the existing BIVOG concept. The BIVOCl performance is not degraded. ‘Ihe free-field-of-view is extended, at the expense of the possibility darkening with a metal cover. (A black cloth may be used instead.). This hardware is mainly for use in ground laboratories, and exists as a prototype. An improved colour display attached to BIVOG is breadboarded. Some compromises with respect to the eye evaluation performances and the field-of-view of the display area may have to be made. This system is aimed at “virtual reality type” applications, while allowing good quality eye measurements. This system will also be partially suited to optokinetic applications, but with reduced field of view. Most important new IR sensitive detectors have become available based on CMOS instead of CCD technology. These &vices allow e.g. a pm-evaluation “on chip”. Using these concepts and the fast progress in computing power and storage capacity, a next generation BIVOG can be real&d with quasi on-line evaluation (no more video recorder necessary) and higher sampling rates 0 200 Hz). We believe that these concepts should be real&d for a next generation BIVOG, which may - as part of NASA’s Human Research Facility - become the 3D eye tracking system for the early utilisation phase of the International Space Station. First results, as also reported by A. Clarke during this conference, are very promising. Only minor hardware adaptations, e.g. of the BIVOG face mask seem necessary.
12th Man in Space Symposium-additional
papers
7.SUMMARY We have described the vestibular and visuo-oculomotoric equipment which has been developed under various DARA contracts since 1991, and used aboard MIR in the frame of the following missions: l German MIIR ‘92 mission (VOG) l Extensions 1.0MIR ‘92, e.g. the use of VOG by V.Polyakov during his record stay in space from 1993 to 1994 l EUROMIR ‘94 (VOG) . EUROMIR ‘95 (VOG,OKS and BIVOG) l Joint Germa.n /Russian experiments in 1997/98 (BIVOG) The hardware is supplemented by various stimuli and measurements. New developments for a next generation BIVOG, which may become the Space Station 3D eye tracking system, have shortly been addressed.
8.ACKNOWLEDGEMENTS All VOG systems have been developed by Kayser-Threde under contracts to DARA. Various companies in the new “Lander” have contributed to the project (IMT, Dresden; SMI. Teltow; VRS. Leipzig)
ESA is acknowledged for using VOG during their EUROMIR 1994/95 projects, and support for the ongoing experiments. In particular we thank Chr. Nitzschke (DARA), our PI’s (H. Scherer, A. Clarke, ENT Laboratory, FU Berlin; C.H. Markham, S.G. Diamond, UCLA, USA; M. Dieterichs, S. Krafczyk, J. Philipp, LMU Munich), the EUROMIR project (in particular R.-D. Andresen. J. Schiemamr. B. Elmann-Larsen) as well as our Russian partners (V. Pol,yakov. IBMP; Mrs. T. Batentschuk-Tusko. RSC) for the good cooperation and support.
9.REFERENCES 111
“Video-0culography (VOG) on MIR ‘92”; J. Burfeindt, P. Hofmann. A. Kellig. P. Rank, 6th European Symposium on Life Sciences Research in Space; Arcachon. France, 26.9.-1.10.1993
PI
“Recent Developments of DARA Visuo-Vestibular Equipment for MB?‘; P. Hofmann, C. Kessler, A. Kellig, W. Teiwes. B. Seeliinder; IAF-Congress; Jerusalem, Israel, 9.-14.10.1994
131
‘The Three-Dimensional VOG during Prolonged Microgravity”; A. Clarke, J. Grigull, W. Krzok, H. Schere.r, 6th European Symposium on Life Sciences Research in Space, Trondheim, Norway; ESA SP-390 (October 1996); p. 83-87
141
‘The Effect of Hypogravity on Spontaneous Eye Torsion during Space Missions and on Subsequent Ocular Counterroling on Earth”; C.H. Markham, S. G. Diamond; 6th European Symposium on Life Sciences Research in Space; Trondheim, Norway; ESA SP-390 (October 1996); p. 89-93
PI
‘DAR4 Vestibular Equipment Aboard the MIR Station”; P. Hofmann. A. Kellig; 6th European Symposium on Life Sciences Research in Space; Trondheim, Norway; ESA SP-390 (October 1996); p. 119.,124
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