Image display colour

In colour Doppler, similar processing is applied across the image. The colour Doppler signals are shown as an overlay conventionally coded in shades of red for flow towards, and blue for flow away from the transducer (Fig. 1.3). Another way to display flow information depicts only the Doppler signal intensity as a power Doppler scan. It has higher sensitivity than frequency-based colour Doppler but lacks directional information and so is more useful for the small vessels, for example, in tumours, than for the portal vein where flow direction is important. 

A number of controls are provided to enable the user to tailor the colour, scale and orientation of the displayed image to highlight details of interest. Two types of colour map are available. The Default colour map is a cold-to-hot scheme in which with cold colours such as blue used for low amplitudes and hot colours such as red, yellow and white used for high amplitudes. The Mono colour map uses intensities of red, from black upwards, to indicate increasing amplitude. 

Analogously to STM, the image obtained in a force microscopy experiment is conventionally displayed on the computer screen as grey scales or false colour, with the lightest shades corresponding to peaks (or highest forces) and darkest shades corresponding to valleys (or lowest forces). 

Figure 2 FIRSEM (A, D F) and AFM (error B + C, height E + G) images of an ibidem observation of STA-7. The green box represents the area view in C-D and the blue box represents the area viewed in F-G. The magenta line represents the cross section displayed in (FI). Observable terraces are cloured green and terraces unobservable to the FIRSEM are coloured magenta...

Figure 3 displays a Band Ratio image (5/3, 7/3, 4/2), in which peridotite appears dark yellowish black colour. It is difficult to distinguish between gabbro and basalt, due to their similar reflectance properties. 

This set-up allows a pixel to be addressed at each intersection of a row and a column. This works line for nematic LCs in modest sized displays, i.e. up to 120 000 pixels, but beyond this size there is an increase in switching times and cross-talk between adjacent pixel elements leading to a loss in contrast. This problem can be overcome by using STN LCs, which are materials where the hehcal twist is increased to between 180° and 270°. These super twist LCs give a much sharper image than the 90° materials. This system is ideal for monochrome displays but even with these materials the response times start to get very slow with the several million pixels that are required for high contrast, full-colour displays. 

Fig. 5. BSE image of the view shown in Fig. 4(A). SI displays a light colour, whereas the surrounding S2 (medium grey) is characterized by a variable internal composition and complex zoning. S3 is a relatively homogeneous, late-generation pore-filling cement. Note the irregular dissolution boundary between S1 and S2, and between S2 and S3 (arrows). These cement relationships are typical of Tirrawarra Sandstones. Sample Ml-9598, Moorari 1, 2925.5 m.

ZHANG X and wardell ba (1997) A spatial extension of CIELAB for digital colour image production, Journal for the Society for Information Display. 

POINTER M R, ATTRIDGE G c and JACOBSON R E (2002) Food colour appearance jndged using images on a compnter display. The Imaging Science Journal 50, 23-35. 

This technique also has important applications in medicine. For example, it can be used for the spectral classification of a normal human liver cell versus a cancerous liver cell as shown in Figure 4.14. Both the normal human liver cell (E) and the cancerous liver cell (F) contain three dominant types of spectra, each of which is displayed as a distinct colour. However, when the two cells are compared quantitatively, as shown in the histogram area measurements, the abnormalities in the cancerous cell can be quantified objectively. Another example of the use of fluorescence microscopy in medicine is illustrated in Figure 4.15. Using confocal fluorescence imaging, the uptake and distribution of drug (in this case an anthracycline) can be profiled in tumour cells. 

Fig. 2.18 Ultrasonic images of the transmission measurements on cores 40KL, 47KL, GeoB2821-l and PS2567-2 retrieved from different terrigenous and biogenic sedimentation environments. Displayed are the colour-encoded instantaneous frequencies of the transmission seismograms and the lithology derived from visual core inspections.

Fig. 14.12 CT-images of a core section at 87 m below sea-floor (ODP Site 1248 from Hydrate Ridge) showing that gas hydrate is filling a vertical fracture (low density is displayed in dark and high density is shown by lighter colour). A CT-slice through the core B CT-overview of the core section documenting the dipping of the hydrate-filled fracture parallel to the core (from Ahegg et al. suhm.).

Figure 5.75 shows the fluorescence decay function in a selected pixel of the recorded data array and a double exponential Levenberg-Marquardt fit. The decay is clearly double-exponential and cannot be reasonably approximated by a single exponential decay. For the lifetime image, both lifetime components were weighted with their amplitude coefficients. This mean lifetime" is displayed as colour in the lifetime image in Fig. 5.74, left. 

Merging the components of the double-exponential decay into a mean lifetime does, of course, discard useful information. An example of using multiexponential decay data is shown in Fig. 5.74, right. It shows an image that displays the colour-coded ratio of the amplitude coefficients of both lifetime components. The ampli-... 

FIGURE 2.8 An individual trapped barium ion ( Ba ). Diffraction-limited image of its laser-induced resonance scattering. False-colour display of scattered intensity. A second ion placed 3 pm apart would show up in the lower right part of the figure, but was temporarily excited into its dark metastable state Ds/2. For a colour reproduction of this figure see the colour plate section, near the end of this book. 

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