## 3 Digital Image Acquisition, Processing and Modelling Reconstruction
### Digital Image Acquisition Devices
\begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Imaging Techniques** & **Camera Setup** & **Advantages** & **Disadvantages** \\ \hline \multirow{8}{*}{Dynamic imaging techniques} & & Measures shape of large aggregate quantity. & \\  & & Use two cameras to capture images at different magnifications depending on the size of the collection. & Expensive. \\  & & Use two cameras to capture images at different magnifications depending on the size of the collection. & Assume the idealized ellipsoid as particle shape. \\  & & & Use two cameras to capture images at particle shape. & No texture addressed. \\  & & & Depending on the size of the collection. & \\ \hline \multirow{2}{*}{WipShape} & Two orthogonal cameras & 3D measurement of the shape of large aggregates. & No texture addressed. \\  & & & Use one camera magnification to take images of all aggregate sizes. & Use one camera magnification to take images of all aggregate sizes. \\ \hline \multirow{2}{*}{UIAIA} & Three orthogonal positioned cameras & 3D measurement of the shape of large aggregates. & Use one camera magnification to take images of all aggregate sizes. \\ \hline \multirow{2}{*}{LAAS} & \multirow{2}{*}{One CCD camera} & Measure three dimensions of aggregates. & Use the same scan to analyze aggregates with different sizes. \\ \hline \multirow{4}{*}{AIMS II} & \multirow{2}{*}{One camera with microscope} & Capture images at different resolutions with a microscope depending on the size of the aggregates. & Expensive. \\  & & & Use the same scan to analyze aggregates with different sizes. \\ \cline{2-5}  & & & Use same shape, angularity, and texture. & \\  & & & Acquire images using different scanning methods depending on the size of the aggregate. & The calculation is based on the 2D outline of aggregates. \\ \hline \multirow{2}{*}{OSAAS} & \multirow{2}{*}{Two digital cameras} & Measurement of 3D points on the aggregate surface. & Expensive. \\  & & & Use the same camera to analyze all sizes. & Measure the shape of relatively small amounts of aggregates. \\ \hline \multirow{2}{*}{X-ray CT} & \multirow{2}{*}{X-ray} & Obtain the voxels of aggregate. & Expensive. \\  & & & Use the same camera to analyze all sizes. & Measure the shape of relatively small amounts of aggregates. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._proposed another improved Aggregate Image Measurement System (AIMS II), which uses a closed dark box to eliminate the influence of ambient light and LED technology to overcome the disadvantage of difficult control of light intensity. The AIMS II automatically captures different resolutions of images according to the size of the aggregates through its digital camera with an autofocus microscope. The system is able to measure the 3D size of aggregates to determine parameters such as sphericity and aspect ratio and calculates the aggregates' angularity of various sizes by the gradient method and coarse aggregates texture by the wavelet method. The Fourier Transform interferometry system (FTI) uses a CCD camera to capture the aggregate images, which further generates the 3D coordinates of the aggregate top surface, whose shape is determined by the sphericity, flatness ratio and elongation. [PERSON] et al. [84] compared the characteristics of different aggregate image measurement techniques and quantified the morphological features of different types of aggregates using AIMS II, a first-generation University of Illinois aggregate image analyzer (UIAIA), and a FTI system. The three aggregate imaging systems were evaluated. The results show that AIMS II provides a more direct and scientific measurement of the aggregate morphological features than traditional methods. AIMS has objectivity and reliability and can perform an accurate and comprehensive analysis of aggregate morphological characteristics and pavement texture characteristics. The X-ray CT 3D reconstruction system for aggregates has been designed and developed in the last 20 years [85].