SVS was born to address the needs of modern Police forces:

• Protect the life of Police Operators: every day thousand of policeman risk their life on the scenes of road accidents; the traditional systems (manual measurement) force a team of at least two agents to spend a long time on the road measuring distances, in a condition of serious vulnerability.
  The SVS system requires only one operator, allowing other agents to monitor traffic and to perform other necessary tasks. The result? Accident survey time is minimized, personnel safety is maximum. How valuable are the policemen's lives, and their families' future? How much will the little cost of SVS affect your balance sheet?
  
  
• Speed up traffic normalization: benefits for the whole community are huge. SVS allows for fast traffic normalization, with tremendous benefits for the public and for the local economy. Also consider the great image return: a modern Police force with state-of-the-art technology.
  
  
• Increase accident survey accuracy: the standard surveying process involves numerous operations to be carried out with maximum attention, in the most adverse environmental situation. Manual measurements are physiologically affected by errors, even for most experienced operators; the tape itself can be a source of errors because of its elasticity or because of environmental conditions (wind, heat). Moreover, the operator might accidentally leave some measurements behind, thus affecting the accuracy of accident reconstruction. SVS solves all these problems: the operator simply has to take pictures - what could be easier?
  
  
• Make accident reporting an easy task: advantages of using SVS are not evident only on scene of an accident; no more manual measurement input, no more triangulations, no more hand-drawn scene reconstruction! At the end of processing SVS automatically produces a report containing distances between all interesting points, and the planimetry (at chosen scale) of the scene in DXF format, compatible with most CAD softwares (such as AUTOCAD). You don't own AUTOCAD? No problem: SVS version 5 features SKYCAD, our powerful and easy-to-use CAD system. Shapes of vehicles and other objects on the scene of the accident can be easily imported on an existing cartography, speeding up the production of high-quality planimetric reports.
  
  
• Recover your investment: SVS features powerful report generation; a complete, detailed and accurate report can be sold to involved parties (lawyers, for example). SVS will soon become a source of income.

Photogrammetry means "measuring by means of photographs"; this science exists since centuries, its bases were thrown even before the invention of photography. SVS uses short radius photogrammetry to measure 3D positions of objects on the accident's scene, by means of pictures taken in-place with a standard digital camera. SVS features advanced distortion elimination functions, thus allowing the use of standard digital cameras instead of professional metric cameras.


A few pictures of the scene, taken with a digital camera are good enough to obtain an accurate, in-scale reconstruction.

Operators don't need to take any measurement, thanks to a reference shape, of known dimension, that must be positioned on road surface; the only condition is that the reference shape appears in each picture.

The reference shape is built in solid aluminium, and once folded back it fits perfectly in your car's boot.

This is the sequence of actions to perform:

• place (in an arbitrary position) the reference target on the road surface
• take pictures (from arbitrary positions) using a calibrated digital camera
• back in the office, import images into SVS, perform computations.

Next picture shows a window from SVS, with a list of images used for computations, and a thumbnail of selected image.



Chosen images can be viewed full size (up to 4 simultaneously), to allow accurate sampling of interesting points.

Sampling is done by clicking on the picture, selecting the same points that would have been manualy measured on the road, i.e. vehicles margins, road signs, lines, road margins etc. Points not laying on the road plane can be sampled as well, allowing to perform 3D measurements.

To facilitate point sampling, SVS features a magnified collimator that allows to click on each feature with maximum accuracy; this tools is also used to achieve sub-pixel precision, overriding camera resolution limitations.



Points selected on each image are then associated to correspondig real objects, previously defined, or created on-the-fly; all elements on the scene (vehicles, signs, debris) will be rendered as shapes in the planimetry in DXF format.

Each sampled point is marked on the images with a small circle and a text label.

After sampling all necessary points, the operator simply need to click a button to start the computation.

Once computations are complete (it takes a few seconds), SVS generates a raw scheme representing the geometric entities corresponding to the real objects, the position from where pictures where taken, and the position of the reference shape (red cross); grey lines represent the field visible in each picture.



This raw scheme allows the operator to verify that all objects are where they should be, and that no gross mistake has been done; it also allows evaluation of the overall survey geometry, including position from where pictures where taken.

Of course, it is possible to repeat calculations after adding or removing elements, and visually verify the achieved results; when stopping a session, all data are saved to disk, so it is possible to complete a reconstruction in several sessions.



Next picture shows the planimetry, in DXF format, produced after computations.

The planimetry can be imported in any CAD software, to be modified by adding elements or to enhance the presentation.

The main purpose of SVS is to compute with the maximum precision the relative positions of all elements in the scene, producing a schematic but complete planimetry of the area.

The operator can then insert shapes from CAD libraries, such as trees, people, signs, etc.

SVS features various pre-defined shapes, and allows the user to define custom shapes using a set of keywords.

SVS also generates a report containing relative distances of all sampled points; this report is available in several formats, including HTML and MS Excel.

It is also possible to define reference points, i.e. fixed points whose coordinates are know in a global system (e.g. city map): using these reference points it is possible to automatically position the planimetry into an existing cartography.

• Compact digital camera: easy to use, extremely cheap
  
• reference shape: foldable, solid aluminium
  
• SVS software: software does not break! Our support plan ensures that the system is always up to date and working fine.