Preliminary results indicate that the achievable resolution in directions parallel to the camera, thus including the beam direction, are compatible with the quality control requirements. We reconstruct images of a point source having a broad energy spectrum compatible with the up-mentioned application. realistic Compton camera prototype designed for hadrontherapy on-line monitoring. In this work we apply a recently developed filtered backprojection algorithm to data simulated from a. It allows a considerable improvement in detection compared to a standard gamma-camera but also requires more sophisticated image reconstruction techniques. The Compton camera is an imaging device relevant for the detection of prompt photons produced during nuclear fragmentation in hadrontherapy. Journal Compilation 2006 The Remote Sensing and Photogrammetry Society and Blackwell Publishing Ltd. Finally, an example of the automatic calibration process, which is implemented in the iWitness system, is presented for the case of multiple zoom settings of a consumer-grade digital camera. Accuracy aspects are also touched upon and the impact of chromatic aberration is discussed. The second is a new approach to initial value determination for relative orientation, which then supports fully automatic initial network exterior orientation and subsequent bundle adjustment with self-calibration. The first is exploitation of RGB colour attributes in the design of automatically detected and identified coded targets. Two innovations are central to the developed process. This paper describes a new method for automatic camera calibration, which is suited to colour digital cameras. The paper is an updated version of Luhmann (2014) new experimental investigations on the effect of lengthĬonsumer-grade digital cameras have become commonplace and with calibration there is significant potential for their use in photogrammetric applications. Spherical targets do not show better results Larger than usually assumed, and must be compensated for high-accuracy applications. It can be stated that the eccentricity is Based on numerical simulations, the eccentricity in the image is further quantified and investigated.įinally, the resulting effect in 3D space is estimated for stereo and multi-image intersections. It then describes the geometrical projection model in order to demonstrate theĮccentricity in image space. Use and measurement of circular and spherical targets. best-fitĮllipses), the calculated ellipse centre does not correspond to the desired target centre in 3D space. As a result, if measurement methods based on ellipses are used to detect the target (e.g. Both types of targetsĪre imaged with an elliptical contour. Respect to the true imaged circle centre, it can also be shown that the a similar effect exists for spherical targets. While it is commonly known that flat circular targets can have a significant displacement of the elliptical image centre with This paper discusses a feature of projective geometry which causes eccentricity in the image measurement of circular and spherical Arduino-based triggering systems appeared to beįeasible, and they have the potential to be extended to more complicated triggering systems. Presented values include both camera-based and trigger-based desynchronization. Corresponding mean values for the four wireless triggering systems varied between 7.92 and 9.42 μs. As a result, the wired system indicated an 8.91 μs mean triggering time differenceīetween two cameras. Triggering accuracy of global shutter cameras. In order to validate the synchronizationĪccuracy, we developed a prototype of a rotating trigger detection system (named RoTriDeS). Our wireless systems utilize 315 MHz or 434 MHz frequencies with noise filtering capacitors. Variations of Arduino-based low-cost remote trigger systems designed to provide a synchronous trigger signal for industrial cameras. In this paper, we describe one wired and four wireless Accurate synchronizationĮnables 3D measurements of moving objects or from a moving platform. Synchronous triggering is an important task that allows simultaneous data capture from multiple cameras.
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