Objectives sources

Having obtained the necessary information from subjective and objective sources, the next step is the development of a preliminary diagnostic assessment, including commentary when possible on the five major axes Diagnostic and Statistical Manual of Mental Disorders, 4th ed., revised (DSM-IV) [11]), as well as other differential diagnostic considerations (see Appendix A). The diagnostic assessment serves many purposes ... 

Figure 6-1 Spectrophotometric Curves of Colored Objects. Source From Hunter Associates Lab., Inc.

The next step is to combine management objectives, source information, and habitat data into geographically explicit portions that can be analyzed in a relative manner. 

It is possible to enter not only existing technical installations in the risk inventory, but planned installations as well. It can be determined how risk stress will be changed by planned installations and how by suitable location selection high risk values can be avoided. The risk inventory together with the proposed admissibility criteria thus becomes a planning instrument and an objective source of information for persons living in the risk area. 

Figure 5. Life cycle of an dynamically created object (Source own study).

In most cases, the source of the data is based on convenience, and when available, police data are sought as the more objective source. But in some cases - such as the study by Maycock et al. (1991) on the relationship between age, experience and crashes, and the study by McCartt et al. (2003) on the effects of graduated driver license on crash involvement - the researchers actually prefer to rely on drivers self reports because they are considered to be more valid for the specific issues tested in these studies. 

Figure 6.12 A comparison of a regular orthographic view with a full-section view of the same object. Source James H. Earle, Engineering Design Graphics, 5th Edition, Addison-Wesley Publishing Co., Boston MA, copyright 1987. Reprinted with permission of Pearson Education, Inc., Upper Saddle River, NJ.)...

In Dynamic Spatial Reconstructor at the expense of use 2D matrix of detectors there was the opportunity to use a divergent cone beam of source emission. This system had a number of lacks. In particular the number of projections is rigidly limited by the number of x-ray sources. The dispersion of source emission results in errors of data collected.. However the system confirmed basic advantages of application of conic beams and 2D matrices of detectors for collecting information about 3D object. 

The sensitivity curves are plots of maximum achieved sensitivity as a function of thickness of the object for a given focal spot size and source to detector distance. The best attainable sensitivity in image intensifier systems is a function of tube voltage, current, scattered radiation and the screen gamma. As a first step, stainless steel plates with thicknesses ranging from 5 mm-30 mm in steps of 5 mm were chosen. These plates had a length of 950 mm and width of 280 mm. The plate is positioned very close and at the center to the LI. tube. The extraneous... 

This research examines the feasibility of a technique based upon the CT principle using a microfocus X-ray source with an image intensifier while the examined object is being rotated The attainable enlargement is up to 200. The data to be processed is collected from the whole surface of the image intensifier by a frame grabber and noise suppression is performed. 

In a commercial CT system an X-ray source and a set of detectors rotate around the examined object Two main difficulties that typical CT method meets are challenged in this study ... 

X-ray source, Turntable with examined object, Detection system. 

To describe the X-ray imaging system the projection of 3D object points onto the 2D image plane, and nonlinear distortions inherent in the image detector system have to, be modelled. A parametric camera model based on a simple pinhole model to describe the projection in combination with a polynomal model of the nonlinear distortions is used to describe the X-ray imaging system. The parameters of the model are estimated using a two step approach. First the distortion parameters for fixed source and detector positions are calculated without any knowledge of the projection parameters. In a second step, the projection parameters are calculated for each image taken with the same source and detector positions but with different sample positions. 

The primary source energy can be switched between 6, 9 and 11 MeV. So it is possible to penetrate and examine up to 0.6 m solid steel objects. In front of the accelerator a collimator... 

Using the theorem that the sufficiency condition for mathematical correctness in 3D-reconstruction is fulfilled if all planes intersecting the object have to intersect the source-trajectory at least in one point [8], it is possible to generalise Feldkamp s method. Using projection data measured after changing the sotuce-trajectory from circular to spiral focus orbit it is possible to reconstruct the sample volume in a better way with the Wang algorithm [9]. 

Equations 1 and 2 shows that the distance b between the radiation source and the object has big influence on the X-ray image [8]. Therefore you have to find a compromise between a small geometrical unsharpness and a sufficient high magnification to archive an optimal... 

Other limitation for the spatial resolution can be found in the detector. A limited number of pixels in the camera array can be a reason for pure resolution in the case of a big field of view. For example, if field of view should be 10 by 10 nun with camera division 512x512 pixels the pixel size will be approximately 20 microns. To improve the relation of the field of view and the spatial resolution a mega-pixel sensor can be used. One more limitation for the spatial resolution is in mechanical movement (rotation) of the object, camera and source. In the case of a mechanical movement all displacements and rotations should be done with accuracy better than the spatial resolution in any tested place of the object. In the case of big-size assemblies and PCB s it is difficult to avoid vibrations, axle play and object non-planarity during testing. 

During testing a depth resolution of 50-80 micron and a lateral resolution of 20-40 micron was achieved. The spatial resolution was limited not mainly hy source or camera properties, but by the accuracy of compensation of the instrumental errors in the object movements and misalignments. According to this results a mote precision object rotation system and mote stable specimen holding can do further improvements in the space resolution of microlaminography. 

It is shown how phase contrast X-ray microtomography can be realised with a (commercial) polychromatic X-ray microfocus tomograph provided the source size and the resolution of the detector are sufficiently small and the distance between source and detector is sufficiently large. The technique opens perspectives for high resolution tomography of light objects... 

For this experiment, as well as for the microtomography ( 3.2) we used the commercial desktop microtomography system Skyscan 1072 [5], the setup of which is sketched in Figure 1. For this instrument, which is designed to study relatively large objects with a diameter up to 50 mm, the source size is 8 pm, the distance source-detector is about 50 cm and the effective resolution of the detector is about 80 pm. For this system and this object, the global effective resolution a is estimated to be of the order of 50 to 100 pm [6]. 

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