Technical Explanations for the Object Depth Determination

Determination of object depth for various object classes on the basis of the processed scan data and multiple reflections

surface.

If the diameter of a plastic pipe or conduit is <50 mm (2 in), the reflections from the top and bottom surfaces are superimposed. The reflections then cannot be isolated. In this case, the mid point of the reflection in the processed cross section image is positioned slightly below the top surface of the pipe.

Multiple reflections are normally observed when wide, strongly reflective objects (e.g.

metal plates) are scanned. These reflections are a result of the radar waves bouncing back and forward between the concrete surface or the antenna and the object. The interval between these multiple reflections is a multiple of the distance between the object and the surface (antenna). As a result of this characteristic, multiple reflections can be identified as such, and not as real objects (ghost objects).

After processing, the reflections from the edges of a plate are normally stronger than those from its center. This is due to the strong scattering hyperbola at an edge, which becomes focused at this point.

A: Empty waste water pipe 70 mm (2¾ in) diameter

B: Empty plastic pipe 25 mm (1 in) diameter

C: Steel reinforcing bar 12 mm (# 4) diameter

D: Metal plate 170 mm (6¾ in) of width

Processed cross section with various objects at a depth of 70 mm (2¾ in)

Crosse section after application of depth-dependent gain showing various objects at a depth of 70 mm (2¾ in)

Depth

1) Multiple reflections

2) Mid point of reflection from upper surface of the object 3) Mid point of reflection from bottom surface of the object

Scanning w ith a X-Scan PS 1000 on concrete (2) w ith an overlay (1) of thickness (3)

"Overlay"

To activate the “Overlay” function make sure that the checkbox is activated.

N.B.: If using an overlay, you can generally obtain better results if you use the focus type

“Gained”.

"Thickness"

The “Thickness” value indicates the actual overlay thickness in [mm] (*). The display of the overlay thickness in the visualization is not to scale.

"Concrete"

The “Concrete” value indicates the relative permittivity of the overlay. Typical values of the parameter “Concrete” for the overlay are listed in the table below.

(*) NB: From a certain slice thickness depending on the value for “Concrete” of the material scanned and the overlay, focusing of the data through an overlay will no more provide reliable results, thus limiting the detection depth. In such a case, the general specifications are no longer valid.

The “Color Scheme” parameter lets you select a color scheme. There is a choice of nine color schemes. These allow you to change the appearance of the display or to adjust it to the prevailing lighting conditions, but have no other significance.

“Contrast”

Set a value between 1 and 100% to reduce or increase the contrast of the displayed image .

“3D Display Threshold”

The 3D view shows objects in the scanned material as isosurface. If the “3D Display Threshold” value is reduced, objects that provide only a very weak reflection, will also be displayed. In 2D, “3D Display Threshold” corresponds to the parameter “Contrast”.

"3D Transparency"

The 3D view also provides an image of cross sections. The “3D Transparency” setting lets you to vary the transparency of cross sections to make objects located behind another object visible.

"3D View"

The “3D View” defines the viewing angle from which to watch the data in 3D. It is possible to change the viewing angle at will by using the mouse to turn the 3D visualization. In addition, a presetting has been defined for every spatial direction.

“Object Smoothing”

If objects are aligned along one scan direction (x or y) and if these are longish objects, activate the checkbox for smoothing the objects.

It is not recommended to activate this filter if the objects are inclined relatively to the coordinate axes and if the objects’ shape is very irregular.

4.4.2 Section "Crosshair / Cross Section"

For illustration purposes, you’ll find below a few examples how to work with cross sections.

2D visualization of the low er steel reinforcing layer 3D visualization of the cross section (low er steel reinforcing layer) in the z-direction

3D visualization of the cross section in the y-direction 3D visualization of the cross section in the x-direction

3D visualization of the gained raw data as cross section im age in the y-direction. The color for the scan data is set to "grey".

3D visualization of the x and y-cross sections

4.5 Function Button "Config."

4.5.1 Section "Activate/Deactivate"

“Scan data” Use the checkboxes x and y to select the scan direction to display. Hiding the data of a scan direction may be helpful if objects laying in this

direction have no significance. Thus, objects in the other direction will be displayed more clearly.

“3D bounding box”

The “3D bounding box” indicates the maximum scan range of an

Imagescan. It is possible to hide the bounding box in x- or y- direction by deactivating the checkbox. Changing the coloration of the “3D bounding box” is possible using the parameter “Colors”.

“Grid” Use the checkbox “Grid” to activate/deactivate the display of the scan grid. Changing the coloration of the grid is possible using the parameter

“Colors”.

“Starting point” Use the checkbox “Starting point” to activate/deactivate the display of the starting point symbol (colored cone). Changing the coloration of the starting point is possible using the parameter “Colors”.

"Drill-hole marker"

Use the checkbox “Drill-hole markers” to activate/deactivate the display of the drill-hole markers defined before. Changing the coloration of the

“Drill-hole markers” is possible using the parameter “Colors”.

"Annotations" Use the checkbox “Annotations” to activate/deactivate the display of the

“Annotations” edited before. Changing the coloration of the “Annotations”

2D visualization of scan data in the x-direction 2D visualization of scan data in the y-direction

3D visualization of scan data in the x-direction 3D visualization of scan data in the y-direction

colors to the original values.

There is a choice of basic colors, user-defined colors and a continued color scheme.

Additionally, colors may also be indicated as RGB values. Enter the numerical value for the shade, saturation and brightness of colors.

“Scan data” For the 3D view, select a color for objects located in x- and y-direction.

“3D bounding box”

For the 3D view, select a color for “3D bounding boxes” in x- and y-direction.