Image quality parameters

In general, the performance of a radioscopic system should always be checked via test pieces with natural flaws. To ensure an additional comparability, standardized image quality indicators have to be used to control the essential image quality parameters such as spatial resolution (unsharpness) and contrast sensitivity. 

Experimental data relating the spatial frequency dependence of image quality parameters obtained from electrophotographic toner deposits with the toner particle size distributions are presented. 

The two image quality parameters introduced above are single values which are determined from single observations. 

Xie, Z., Wang, Z. Color Image Quahty Assessment Based on Image Quality Parameters Perceived by Human Vision System, pp. 1-4 (2010)... 

To evaluate the image quality of the processing system, one can determine classical parameters like spatial resolution, contrast resolution, dynamic range, local and global distortion. Guidelines for film digitization procedures have been well described now. Furthermore, a physical standard film for both equipment assessment and digitization calibration and control, will be available in a next future (4). 

In addition when it is necessary to process a large number of specimens per day, taking hours over a single specimen is clearly not a practical approach. The use of MRI to examine fresh, unfixed fetal rat and rabbit heads from embryo-fetal development (EFD) studies has already been proposed (6) (see Note 1) and the compromise between image quality and speed of acquisition that is necessary under these circumstances examined. MRI is now considered to have the potential to be an acceptable alternative to current methods after throughput was increased by scanning multiple specimens in parallel with careful optimization of scan parameters. 

Chemical composition is an important contributor to bone quality, a term that encompasses the effects of architecture, composition and remodeling dynamics. An important advantage of infrared (IR) and Raman imaging in bone studies is that they allow the imaging of parameters that measure tissue quality and competence. These are usually measured as band height or band area ratios, and in some cases as band widths. Although measures of tissue properties are similar in both IR and Raman spectroscopy, the IR metrics have been validated with other techniques. 

The correlation analyses of toner particle size and size distribution parameters and image quality characteristics of toner deposits as measured by the spectral dependence of contrast transfer function and noise show high coefficients of correlation Specifically the Wiener spectrum data appear to yield the weight geometric mean and standard deviation of the toner population in this study. Therefore the Wiener spectrum may be another analytical tool in characterizing particle populations. It must be pointed out that the analysis reported here is mainly empirical. Further work is needed to refine the models and to examine the limits of applicability of these tests. Factors such as particle clumping, non-uniform depositions and optical limitations are specific areas for examination. 

Radial mass profile analysis can be performed as described previously (Steven el al., 1984). An alignment program is used to refine the centerline of filaments or the center of spheres by adjusting diameter, amplitude, and orientation of a cylindrical or spherical model subtracted from the image pixels using as a quality parameter the root mean square (RMS) difference of image minus model computed over pixels near the chosen center. Following refinement of the centerline. 

Table 3.1 Correlations between Flour Quality Parameters and the Two Methods of Measuring Milling Efficiency Ash and Bran by Image Analysis...

CT Parameters and Image Quality Viewing the Axial Source Images CT Protocols for Skeletal Imaging 3D Image Reconstruction in Musculoskeletal CT 33 Metallic Implants and Casts 34... 

This chapter provides an overview of skeletal CT techniques, with an emphasis on radiation risks, CT parameters affecting image quality, and viewing and manipulating axial source images. Tables with specimen paediatric CT protocols are also provided. 

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