Pan-tilt Head Research Articles

Can Hyperspectral Imaging and Neural Network Classification Be Used for Ore Grade Discrimination at the Point of Excavation?

This work determines whether hyperspectral imaging is suitable for discriminating ore from waste at the point of excavation. A prototype scanning system was developed for this study. This system combined hyperspectral cameras and a three-dimensional LiDAR, mounted on a pan-tilt head, and a positioning system which determined the spatial location of the resultant hyperspectral data cube. This system was used to obtain scans both in the laboratory and at a gold mine in Western Australia. Samples from this mine site were assayed to determine their gold concentration and were scanned using the hyperspectral apparatus in the laboratory to create a library of labelled reference spectra. This library was used as (i) the reference set for spectral angle mapper classification and (ii) a training set for a convolutional neural network classifier. Both classification approaches were found to classify ore and waste on the scanned face with good accuracy when compared to the mine geological model. Greater resolution on the classification of ore grade quality was compromised by the quality and quantity of training data. The work provides evidence that an excavator-mounted hyperspectral system could be used to guide a human or autonomous excavator operator to selectively dig ore and minimise dilution.

A minimally invasive capture system for the safe and compassionate live-trapping of jaguar and puma

Live trapping of large carnivores can have counter-productive effects on the animal’s health and postrelease behavior. Nonetheless, trapping may be necessary for scientific inquiry, wildlife management and conservation. Capture methods should be efficient, selective, compassionate, and safe for both animals and people. Here, I review the methods used to capture the largest American felids, jaguars and pumas, and propose the use of a minimally invasive capture system (MICS). The device consists of a blowgun remotely controlled by means of cameras and a swiveling 2-way pan-tilt head. The blowgun is monitored by video camera and triggered from a distance of up to 400 m and is capable of shooting darts with high accuracy at distances of about 12 m. This method was developed a decade ago but has not been used despite clear advantages over traditional methods. The use of a MICS can be cheaper, lower in human investment, higher in efficiency and selectivity, and safer and more compassionate than the traditional methods used. The main disadvantages are related to manufacturing, as it must be custom built made by a specialized professional. In addition, any adjustments or repairs must also be handled by a specialist. Nevertheless, these challenges should not discourage the use of MICS, as ethical considerations are of growing importance worldwide when working with wild species. The use of MICS for the live-capture of wild jaguars and pumas (or other medium and large carnivores) deserves further consideration, testing, and discussion.

Panoramic view of the heat flux inside an insulated vehicle by infrared thermography

An IR camera is mounted on a pan-tilt head and automatically driven to map the temperature of the inner walls of the insulated container on a refrigerated vehicle. The vehicle is introduced in a test chamber where special conditions are applied, in such a way to maintain an inner-outer temperature difference of around 25 C. The objective of this work is that of complementing the qualitative results obtained by infrared thermography, with an evaluation of the heat flux flowing through the wall.

Heliostat Shape and Orientation by Edge Detection

The heliostats of central receiver solar power plants reach dimensions up to 150 m2 with focal lengths up to 1000 m. Their optical properties and tracking accuracy have great influence on the power plant efficiency and need to be monitored both at plant start up and during operation. Up to now, there are few efficient and fast measurement techniques that allow the heliostat properties to be measured. Flux density measurements and close-range photogrammetry are possible approaches, yet they do not fulfill the requirement to be accurate, inexpensive, and fast at the same time. In this paper, we present a noncontact measurement principle, which uses edge detection to extract the heliostat and facet vertices. This information is used to calculate the surface normals. Furthermore, the corners can replace retroreflective targets generally used in close-range photogrammetry, thus, enabling a fast and completely automatic evaluation of the three-dimensional heliostat structure. The pictures are provided by a digital camera, which is mounted on a pan tilt head on top of the central receiver tower, offering visibility to all heliostats and allowing the automated qualification of whole heliostat fields in a short period of time. It is shown that measurement uncertainties in heliostat orientation for the investigated heliostat are below 4 mrad in 80% of the relevant heliostat positions. Heliostat orientation is available within three minutes. Photogrammetric measurements based on edge detection at a 40 m2 CESA-1 heliostat at the Plataforma Solar de Almerìa exhibit an accuracy of 1.6 mrad for a single-facet normal vector with the results being available within 30 min. The reduced measurement time allows the economic characterization of entire heliostat fields. The lower accuracy compared with manual photogrammetry with retroreflective targets is still sufficient to detect facet misalignments in existing heliostat fields.

Systems level model integration and embodiment: a case study with gaze control

Systems level model integration and embodiment: a case study with gaze control

A remote-controlled teleinjection system for the low-stress capture of large mammals

To recapture trap-shy Eurasian lynx (Lynx lynx) in Switzerland, we developed a selective and minimally invasive capture system (MICS). The device consists of a blowgun remotely controlled by means of 2 built-in cameras and a swiveling 2-way pan-tilt head. The blowgun is monitored and triggered from a distance of up to 400 m and is capable of shooting darts with high accuracy at distances of about 12 m. We darted lynx at kill sites, but the system generally can be used in any situation where a medium to large mammal stands still for a moment at a predictable distance. The MICS allows selection of specific individuals, thereby avoiding capture of nontarget animals. As there is no holding device, risk of injuries due to capture is minimized. Preliminary data on hematology and serum cortisol levels furthermore indicated that captures with the MICS induced less stress than captures with either box traps or foot-snares. We believe this new system opens new possibilities to capture cautious animals and provides considerable progress regarding animal welfare considerations.

EMS-Vision: a perceptual system for autonomous vehicles

The paper gives a survey on the new Expectation-based Multifocal Saccadic vision (EMS-vision) system for autonomous vehicle guidance developed at the Universitat der Bundeswehr Munchen (UBM). EMS-Vision is the third generation dynamic vision system following the 4-D approach. Its core element is a new camera arrangement, mounted on a high bandwidth pan-tilt head for active gaze control. Central knowledge representation and a hierarchical system architecture allow efficient activation and control of behavioral capabilities for perception and action. The system has been implemented on commercial off-the-shelf (COTS) hardware components in both UBM test vehicles VaMoRs and VaMP Results from autonomous turnoff maneuvers, performed on army proving grounds, are discussed.

Statistical mosaics for tracking

A method of robust feature-detection is proposed for visual tracking with a pan-tilt head. Even with good foreground models, the tracking process is liable to be disrupted by strong features in the background. Previous researchers have shown that the disruption can be somewhat suppressed by the use of image-subtraction. Building on this idea, a more powerful statistical model of background intensity is proposed in which a Gaussian mixture distribution is fitted to each of the pixels on a ‘virtual’ image plane. A fitting algorithm of the ‘Expectation-Maximisation’ type proves to be particularly effective here. Practical tests with contour tracking show marked improvement over image subtraction methods. Since the burden of computation is off-line, the online tracking process can run in real-time, at video field-rate.

A housing to eliminate heat of a mercury-vapor lamp used for fluorescence microscopy.

The housing was designed to utilize the high intrinsic output of the General Electric A-H6 high pressure mercury-vapor lamp while completely eliminating the considerable heat radiated by the lamp. The housing consists of a box, 4 1/2 × 5 × 6 inches, fabricated from 1/4 inch aluminum sheeting. Radiant heat is conducted away from the lamp house by an auxiliary cooling coil of 14 inch copper tubing through which water from the main jacket is circulated. The housing was designed for mounting in a table top which positions the necessary water lines below the table top and out of the way, but it can be mounted on a photographic pan-tilt head for use in the conventional manner. The General Electric 250 watt Uviarc UA-2 lamp, which has a useful peak at the 365 mμ band, can be used in this lamp house providing some slight modifications to the housing are made. The UA-2 lamp requires no water cooling.