ARTag, AprilTag and CALTag Fiducial Marker Systems: Comparison in a Presence of Partial Marker Occlusion and Rotation

Sagitov, Artur; Shabalina, Ksenia; Sabirova, Leysan; Li, Hongbing; Magid, Evgeni

doi:10.5220/0006478901820191

Cited by 30 publications

(13 citation statements)

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“…These approaches allow camera calibration in the presence of marker occlusions and rotations [17] and such features are especially important for autonomous self-calibration of a robot in real world operation conditions.…”

Section: Discussionmentioning

confidence: 99%

Experiments on mobile robot stereo vision system calibration under hardware imperfection

et al. 2018

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Abstract. Calibration is essential for any robot vision system for achieving high accuracy in deriving objects metric information. One of typical requirements for a stereo vison system in order to obtain better calibration results is to guarantee that both cameras keep the same vertical level. However, cameras may be displaced due to severe conditions of a robot operating or some other circumstances. This paper presents our experimental approach to the problem of a mobile robot stereo vision system calibration under a hardware imperfection. In our experiments, we used crawler-type mobile robot «Servosila Engineer». Stereo system cameras of the robot were displaced relative to each other, causing loss of surrounding environment information. We implemented and verified checkerboard and circle grid based calibration methods. The two methods comparison demonstrated that a circle grid based calibration should be preferred over a classical checkerboard calibration approach.

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Section: Discussionmentioning

confidence: 99%

Experiments on mobile robot stereo vision system calibration under hardware imperfection

et al. 2018

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“…CALTag is a self-identifying marker that could be accurately detected in the image. Compared to other markers, CALTag demonstrated better resistance to occlusion (e.g., CALTag size of 98 × 98 mm had an 88% recognition rate with 25.5% to 32.5% occlusion) [ 35 ].…”

Section: Pose Estimation Approachmentioning

confidence: 99%

Pose Estimation of Excavator Manipulator Based on Monocular Vision Marker System

Zhao

Tian

2021

Sensors

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Excavation is one of the broadest activities in the construction industry, often affected by safety and productivity. To address these problems, it is necessary for construction sites to automatically monitor the poses of excavator manipulators in real time. Based on computer vision (CV) technology, an approach, through a monocular camera and marker, was proposed to estimate the pose parameters (including orientation and position) of the excavator manipulator. To simulate the pose estimation process, a measurement system was established with a common camera and marker. Through comprehensive experiments and error analysis, this approach showed that the maximum detectable depth of the system is greater than 11 m, the orientation error is less than 8.5°, and the position error is less than 22 mm. A prototype of the system that proved the feasibility of the proposed method was tested. Furthermore, this study provides an alternative CV technology for monitoring construction machines.

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“…While such developments can be highly beneficial, many concerns may be raised, among the most important being related to safety: as demonstrated by recurring tragic fatalities, autonomous vehicles have an insufficient understanding of their environment despite state‐of‐the‐art on‐board sensor and computation technology. [ 5–9 ] In restricted environments like research labs or power plants, reliable localization and object identification by robots are ensured by labeling surfaces with fiducial markers , [ 10 ] patterns of black squares on white background similar to the well‐known QR codes. Fiducial markers would be an enormous aid for robots deployed in human‐populated spaces, but black‐on‐white grid patterns are aesthetically and architecturally disruptive.…”

Section: Introductionmentioning

confidence: 99%

Encoding Hidden Information onto Surfaces Using Polymerized Cholesteric Spherical Reflectors

Geng

Kizhakidathazhath

Lagerwall

2021

Adv Funct Materials

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The omnidirectional Bragg reflection of cholesteric liquid crystals molded into spheres turns them into narrow-band retroreflectors with distinct circular polarization. It is shown that these cholesteric spherical reflectors (CSRs) can encode information onto surfaces for far-field optical read-out without false positives, as the selective retroreflectivity allows the background to be easily subtracted. In order to hide the encoding from detection by the human eye, the retroreflection band is tuned to the near-UV or IR spectra, allowing ubiquitous deployment of CSRs in human-populated environments. This opens diverse application opportunities, for instance, in supporting safe robotic navigation and in augmented reality. A key breakthrough is our ability to permanently embed CSRs in a binder such that undesired scattering and reflections are minimized. This is achieved by realizing CSRs as shells that are polymerized from the liquid crystalline state. The resulting shrinkage around an incompressible fluid deforms the thinnest region of each shell such that it ruptures at a well-defined point. This leaves a single small hole in every CSR that gives access to the interior, allowing complete embedding in the binder with optimized refractive index, minimizing visibility.

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ARTag, AprilTag and CALTag Fiducial Marker Systems: Comparison in a Presence of Partial Marker Occlusion and Rotation

Cited by 30 publications

References 0 publications

Experiments on mobile robot stereo vision system calibration under hardware imperfection

Experiments on mobile robot stereo vision system calibration under hardware imperfection

Pose Estimation of Excavator Manipulator Based on Monocular Vision Marker System

Encoding Hidden Information onto Surfaces Using Polymerized Cholesteric Spherical Reflectors

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