Line-scan imaging

Fig. 1.2. Line-scan image and gray-scale image. The two images represent the same set of data collected by STM on a Si(lll)-7X7 surface with steps. Dimensions 100 X 125 A . (Reproduced from Becker et al.. 1985a, with permission.)...

Figure 6.30 In situ STM x-t line scan image of a stepped HOPG surface in the system HOPG(0001)/10-2 M AgC104 + 1 M HCIO4 at T = 298 K [6.1921. / = 5 nA Pt-Ir tip. Substrate potential A = 0 mV is modulated by an ac amplitude of 80 mV.

A closely related technique can be used for multi-slice imaging (Fig. 6.2.7) [Fral]. The scheme of Fig. 6.2.5(c) is appended by further slice-selective 90° pulses with different centre frequencies, so that the magnetization of other slices is selected [Fral]. In this way, the otherwise necessary recycle delay can effectively be used for acquisition of additional slices. However, the contrast in each slice is affected by a different Ty weight, because is different for each slice. The technique can readily be adapted to line-scan imaging by applying successive slice-selective pulses in orthogonal gradients [Finl]. 

Fig. 7, Line scan image from a vascular smooth muscle cell. Image shows a spark originating at a site towards the edge of the cell. The line scan has had the background subtracted and it has been colorized in order to clearly visualise the spark. In this image time is in the horizontal direction and distance across the cell is in the vertical direction. Beneath the line scan is the averaged fluorescence signal, measured from the section of the line scan indicated by the bar. The figure also shows an example of a STOC to demonstrate the similarity in the time course of these events, (taken from figure 1, Nelson et 0.11995).

Dyck [8.104] reported that a 1024 x 64 element silicon imager, which can be used both in both the storage and time-delay-integration (TDI) modes, has shown high saturation capability (10 electrons per pixel) with a total surface uniformity of 1-3 % and a 50% quantum efficiency when operated in the storage mode. The rms noise was less than 200 electrons per pixel but the actual value was not reported. When operated in the TDI mode as a line scan imager the sensitivity was said to increase by a factor of 64 over a simple line scan image sensor of equal size elements (20 pm x 20 pm). 

A variety of methods have been developed to image materials based on their Raman contrast. The methods can be classified broadly as source scanning approaches or as wide-field source illumination approaches and are diagrammed in Fig. 2, Figure 2A describes point-scan Raman imaging, whereas Fig. 2B shows line-scan imaging and Fig. 2C shows the wide-field approach. 

The point-scanning technique can be extended by using an approach described as line-scan imaging [12,13]. This method employs cylindrical optics or scanning mechanisms to distribute a laser beam in one dimension, whereas the other dimension maintains the size... 

In addition, the spatial resolution parallel to the laser line is the convolution of the microscope magnification by the pixel size. As a result, submicron spatial resolution is achievable in one spatial dimension. In the dimension perpendicular to the laser line, the spatial resolution of the image continues to be limited by the width of the laser line on the sample convolved by the scanning precision of the instrument. Although line-scan imaging has not been as widely explored as point-scan imaging, it has been demonstrated in several applications [12-15] and line-scan Raman imaging systems are commercially available. 

Equations (2) and (3) indicate that in comparison with scanning techniques, wide-field imaging is performed in less time than point-or line-scan imaging when m is less than n or /n, respectively ... 

Figure 4 Video micrograph (A) and Raman chemical image (B) of a monocrystalline silicon substrate with amorphous silicon deposited in a pattern on the substrate surface obtained using a commercial line-scan imaging system. 

Chemical micro-imaging of composition (line scans, image mapping)... 

Dealing with animal products, Chao s team [144-146] investigated broiler wholesomeness (skin tumors detection, diseases, etc.) using a HS-multispectral line-scan imager. 

Chao, K. et al. (2007) Hyperspectral-multispectral line-scan imaging system for automated poultry carcass inspection applications for food safety. Poult. Sci, 86 (11), 2450-2460. 

Chao, K., Yang, C.C., and Kim, M.S. (2010) Spectral line-scan imaging system for high-speed non-destructive wholesomeness inspection of broilers. Trends Food Sci. Technol, 21 (3), 129-137. 

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