High accuracy pixel-wise spatial calibration of optical see-through glasses

Klemm, Martin; Seebacher, Fabian; Hoppe, Harald

doi:10.1016/j.cag.2017.02.001

Cited by 14 publications

(10 citation statements)

References 6 publications

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“…The experiment results suggested that the calibration refinement step accounting for the user's eye position was paramount to achieve accurate results also for eye positions different from the reference one for all those OST HMDs with finite focal distances (i.e., not parallax-free OST HMDs). This was in accordance with what was suggested by Owen et al [14] and contrary to what was hypothesized by Gilson et al and by [34] et al It should be also stressed that this assumption was clearly different from what was suggested in [20] (page 58), where the classification of the OST HMDs was made based on the level of complexity of the OST optical combiner: "these results show that the triangulation approach only works for OSTG with simple optics and that it is not a universal approach".…”

Section: Quantitative Evaluation Of Virtual-to-real Registration Accusupporting

confidence: 88%

“…This explained the values of the angular errors obtained. If we considered the absolute error at the distance where the validation checkerboard was placed (≈650 mm), our results were comparable to those obtained with the camera based triangulation approach proposed by Klemm et al [20]. The experiment results suggested that the calibration refinement step accounting for the user's eye position was paramount to achieve accurate results also for eye positions different from the reference one for all those OST HMDs with finite focal distances (i.e., not parallax-free OST HMDs).…”

Section: Quantitative Evaluation Of Virtual-to-real Registration Accusupporting

confidence: 83%

“…Indeed, the collimation optics of any OST HMDs, despite being essential to provide a reasonable FOV and a comfortable viewing distance for the virtual image, is a source of optical distortions such as radial and tangential distortions [35]. The same can be said for the optical combiner, particularly for waveguide based OST displays [20]. These optical distortions not only affect the shapes of the virtual objects perceived by the user, but they also distort the pattern of binocular disparities between the left and right virtual images, and therefore, they alter the stereoscopic perception of the virtual content [36].…”

Section: Resultsmentioning

confidence: 99%

“…Finally, in 2017, Klemm et al [20] presented an off-line automated camera based method that resulted in an optimized rendering frustum together with an arbitrary number of distortion maps determined from different viewpoints. Unfortunately, their triangulation approach only worked for OST HMDs with simple optics for which, as stated by the authors on page 57, the "pixel locations are independent from the eye position".…”

Section: Related Workmentioning

confidence: 99%

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Off-Line Camera-Based Calibration for Optical See-Through Head-Mounted Displays

et al. 2019

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In recent years, the entry into the market of self contained optical see-through headsets with integrated multi-sensor capabilities has led the way to innovative and technology driven augmented reality applications and has encouraged the adoption of these devices also across highly challenging medical and industrial settings. Despite this, the display calibration process of consumer level systems is still sub-optimal, particularly for those applications that require high accuracy in the spatial alignment between computer generated elements and a real-world scene. State-of-the-art manual and automated calibration procedures designed to estimate all the projection parameters are too complex for real application cases outside laboratory environments. This paper describes an off-line fast calibration procedure that only requires a camera to observe a planar pattern displayed on the see-through display. The camera that replaces the user’s eye must be placed within the eye-motion-box of the see-through display. The method exploits standard camera calibration and computer vision techniques to estimate the projection parameters of the display model for a generic position of the camera. At execution time, the projection parameters can then be refined through a planar homography that encapsulates the shift and scaling effect associated with the estimated relative translation from the old camera position to the current user’s eye position. Compared to classical SPAAM techniques that still rely on the human element and to other camera based calibration procedures, the proposed technique is flexible and easy to replicate in both laboratory environments and real-world settings.

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Section: Quantitative Evaluation Of Virtual-to-real Registration Accusupporting

confidence: 88%

Section: Quantitative Evaluation Of Virtual-to-real Registration Accusupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

See 2 more Smart Citations

Off-Line Camera-Based Calibration for Optical See-Through Head-Mounted Displays

et al. 2019

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“…To achieve high tracking accuracy, the optical elements used have to be calibrated. We used the high-precision, non-model-based camera calibration technique described in 26 for both camera calibration and the calibration of the HMOST glasses, as discussed in 27 . With this calibration technique, it was possible to achieve the maximum accuracy throughout the entire imaging process of the camera.…”

Section: Trackingmentioning

confidence: 99%

Electrode-free visual prosthesis/exoskeleton control using augmented reality glasses in a first proof-of-technical-concept study

Hazubski

Hoppe

Otte

2020

Sci Rep

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In the field of neuroprosthetics, the current state-of-the-art method involves controlling the prosthesis with electromyography (EMG) or electrooculography/electroencephalography (EOG/EEG). However, these systems are both expensive and time consuming to calibrate, susceptible to interference, and require a lengthy learning phase by the patient. Therefore, it is an open challenge to design more robust systems that are suitable for everyday use and meet the needs of patients. In this paper, we present a new concept of complete visual control for a prosthesis, an exoskeleton or another end effector using augmented reality (AR) glasses presented for the first time in a proof-of-concept study. By using AR glasses equipped with a monocular camera, a marker attached to the prosthesis is tracked. Minimal relative movements of the head with respect to the prosthesis are registered by tracking and used for control. Two possible control mechanisms including visual feedback are presented and implemented for both a motorized hand orthosis and a motorized hand prosthesis. Since the grasping process is mainly controlled by vision, the proposed approach appears to be natural and intuitive.

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