Image postprocessing

Fig. 5.5a,b. Image postprocessing subtraction of pre- from post-contrast high resolution CE-MRA improves signal suppression from stationary tissue. Notice a mild blurring (smoothing) of the edges of the carotid arch and the proximal subclavian arteries, due to respiration and pulsations... 

Figure 4. Left - topography of microtomed cross-section through a multilayer polyolefin packaging film. Centre - raw thermal conductivity contrast image. Right - thermal conductivity image postprocessing with trained neural net program.

Tremendous advances in scanner technology introduced in the recent years made cardiac CT a clinical reality. Automated software has reduced image postprocessing time to a few minutes. Coronary tree extraction allows obtaining projections of the CT dataset that resemble the views familiar from catheterization angiography. But application of the method today is confined to a selected range of patients. This is due to the many restrictions that prevail. 

In comparison with traditional radiography testing ISONIC system allows to provide image analysis and printout with different sensitivity thresholds at the postprocessing stage... 

It is to be taken into account that there is a difference between ultrasonic and radiography defect imaging, so the ultrasonic image recognition knowledge required for the person interpreting the inspection results. The ISONIC postprocessing mode allows to ease sueh interpretation because it s maximally approached to inspection standards. 

Pomerantz SR, Harris GJ, Desai HJ, Lev MH. Computed tomography angiograph and computed tomography perfusion in ischemic stroke a step-hy-step approach to image acquisition and three-dimensional postprocessing. Semin Ultrasound CT MR 2006 27 243-270. 

PIV has also been applied to gas-liquid systems (Reese and Fan, 1994 Lin et al, 1996) to study the flow structure in bubble columns. A specific complication here is caused by the presence of the gas bubbles. On the basis of a prior knowledge of the size distribution of the tracer particles and the gas bubbles it is possible to discriminate bubbles from particles and thus phase-specific postprocessing of the images can be undertaken whereby both the flow pattern of the bubbles and the liquid in principle can be obtained. Particle image velocimetry has also been applied (Chen and Fan, 1992) to study the flow structure in 3D gas-liquid-solid fluidized beds. 

Postprocessing suppression methods (see Postprocessing and selective detection-based methods, p. 325) have particular relevance to imaging since insufficient apodization and truncation can result in ringing over a large portion of the spectrum. This is often the case in spectroscopic imaging using multiple spin-echoes. ... 

Widely different approaches can be found in the literature. Some authors work with bandfiltered radiation (infrared, chemiluminescence bands) whereas others capture broadband light (usually, in the visible range). Nevertheless, in the end, feature-extraction methods are applied in most cases that is, the images collected are postprocessed to calculate a few selected magnitudes. 

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