Orientation (computer vision)

About: Orientation (computer vision) is a research topic. Over the lifetime, 17196 publications have been published within this topic receiving 358181 citations.

Method and system for Doppler ultrasound measurement of blood flow

Abstract: A method and system for providing Doppler data that is corrected for misalignment between the flow direction within a vessel and the beam orientation of the ultrasound probe. A conventional ultrasonic Doppler color mapping system is adapted to include a system to measure and record the free space position and orientation of the ultrasonic probe, as well as a system to generate and record the experiment time. A set of 2D image planes is acquired, each plane labelled with time, position, and orientation data. A structural representation according to the acquired data is used to determine the flow direction for the imaged vessel structure. Based on this identified flow direction, and the orientation and position information for each acquired 2D slice, the 2D Doppler signals are appropriately transformed into corrected velocity values. These corrected velocity values may then be used to construct a 3D flow field as a function of time.

Method for representing virtual information in a view of a real environment

Abstract: A method for representing virtual information in a view of a real environment comprises providing a virtual object having a global position and orientation with respect to a geographic global coordinate system, with first pose data on the global position and orientation of the virtual object, in a database of a server, taking an image of a real environment by a mobile device and providing second pose data as to at which position and with which orientation with respect to the geographic global coordinate system the image was taken. The method further includes displaying the image on a display of the mobile device, accessing the virtual object in the database and positioning the virtual object in the image on the basis of the first and second pose data, manipulating the virtual object or adding a further virtual object, and providing the manipulated virtual object with modified first pose data or the further virtual object with third pose data in the database.

Registration of terrestrial laser scanner data using imagery

Abstract: Building 3D models using terrestrial laser scanner (TLS) data is currently an active area of research, especially in the fields of heritage recording and site documentation. Multiple TLS scans are often required to generate an occlusion-free 3D model in situations where the object to be recorded has a complex geometry. The first task associated with building 3D models from laser scanner data in such cases is to transform the data from the scanner’s local coordinate system into a uniform Cartesian reference datum, which requires sufficient overlap between the scans. Many TLS systems are now supplied with an SLR-type digital camera, such that the scene to be scanned can also be photographed. The provision of overlapping imagery offers an alternative, photogrammetric means to achieve point cloud registration between adjacent scans. The images from the digital camera mounted on top of the laser scanner are used to first relatively orient the network of images, and then to transfer this orientation to the TLS stations to provide exterior orientation. The proposed approach, called the IBR method for Image-Based Registration, offers a one-step registration of the point clouds from each scanner position. In the case of multiple scans, exterior orientation is simultaneously determined for all TLS stations by bundle adjustment. This paper outlines the IBR method and discusses test results obtained with the approach. It will be shown that the photogrammetric orientation process for TLS point cloud registration is efficient and accurate, and offers a viable alternative to other approaches, such as the well-known iterative closest point algorithm.

Photogrammetric performance of an ultra light weight swinglet uav

Abstract: . Low cost mapping using UAV technology is becoming a trendy topic. Many systems exist where a simple camera can be deployed to take images, generally georeferenced with a GPS chip and MEMS attitude sensors. The step from using those images as information picture to photogrammetric products with geo-reference, such as digital terrain model (DTM) or orthophotos is not so big. New development in the field of image correlation allow matching rapidly and accurately images together, build a relative orientation of an image block, extract a DTM and produce orthoimage through a web server. The following paper focuses on the photogrammetric performance of an ultra light UAV equipped with a compact 12Mpix camera combined with online data processes provided by Pix4D. First, the step of image orientation is studied with the camera calibration step, thus the DTM extraction will be compared with conventional results from conventional photogrammetric software, new generation technique of pixel correlation and with reference data issued from high density laser scanning. The quality of orthoimage is presented in terms of quality and geometric accuracy.

Orientation of 3-D structures in medical images

Abstract: A tensor-based moment function method and a principal-axes method were investigated for registering 3-D test images to a standard image using translation, scale, and orientation. These methods were applied at two image resolutions to test discretization effects. At the higher resolution, both methods were found to perform well in cases where the test image could be described as an affine transform of the standard. At low resolutions, however, and when the test image was not an affine transform of the standard, only the principal-axes-based method performed adequately. The problem of quantifying the left ventricular function from gated blood pool single-photo emission computed tomographic images is considered. >