elcovision elsp auto-e · pdf fileelcovision elsp auto elcovision elsp auto is the automatic...

ELCOVISION ELSP Auto

ELCOVISION ELSP Auto is the automatic rectification module of ELCOVISION 10. It generates textures from oriented pictures onto a three-dimensional surface model. Until now this could be done with the simple ELCOVISION 10 ELSP which was also very comfortable but you had to work plane by plane and it was only semiautomatic when you used oriented pictures: You selected the definition points for planes manually and they were transferred into the ELSP. The program assigned the measuring points (points of reference) automatically. By working this way you also could define a unlimited number of planes and digital rectifications but it could take long times. Now with the auxiliary module ELSP Auto point drawings, line evaluations, digital terrain models and also volume models can be converted into a surface model. This surface model will be the base for all further processing. The program will process every surface in the drawing individually by picking each of the individual surfaces out of the model, checking which picture will be the best source for a rectification plane, creates an rectification plane on this picture, cuts out the valid plane range and transfers the digital rectified texture into the drawing. See the following two samples: First Sample: 3D Measurement And Visualisation Of a Whole Mountain. Step #1: Orientate The Pictures

ElCOVISION 10 ELSP Auto www.elcovision.com of 12

The first step is in common with the traditional 3D photogrammetry. You need to do the orientation process with the pictures. You can use as many pictures as your license of ELCOVISION 10 permits you to use. In this example a skiing pist was photographed from the opposite slope. In total there were 12 pictures used for this example. After finishing the orientation process the project was loaded into the AutoCAD environment. There was also a contour map of the slope available, we used it as base for the surface generation:

With the built in surface modeller of ELCOVISION it is very easy to convert this contour map into a surface model:


Step #2: Triangulate The Surface

In this step specify all of the drawing elements which are supposed to define the resulting surface. Now determine the "quality" of the points. At least define which kind of result you need: a closed surface or an open surface.

After the triangulation is done you can simplify the result for your needs. You can adjust the triangulation mesh from fine to wide seamlessly using a slider control: Fine meshed triangulation:

By using the slider control on the right side of the window you can choose the dense of the triangle mesh in real-time and nearly seamlessly.


Wide meshed triangulation:

The adjusted mesh is transferred into the AutoCAD by clicking [OK]:

Now everything is ready for texture generation.


Step #3: Calculate The Textures

Select all drawing entities by using all snap and select modes of AutoCAD. Select all of the pictures which are supposed to be valid texture sources.

After clicking [OK] the texturing process will start and after a view minutes you will get the following result:


Second Example: A 3D Orthophoto from a curved ceiling. The second example shows a typical task for protection of historical monuments. A dilapidated, monument protected hotel dining hall shall be documented and plans prepared for the restoration. In this example 116 pictures were used. Nearly all of them are close-ups to make smallest details visible and measurable. After the orientation process you can see the generated orientation points and the photos point of view using the ELCOVISON 10 project explorer:

There were enough objects points for the surface triangulation generated during the orientation process so we simply load them into AutoCAD and triangulate them using the ELCOVISION 10 surface generator:


After this ELCOVSION 10 can generate and map all textures onto this surface automatically:

This 3D texture now represents the basis for far detailed plans. Or you can do a projection of the entire ceiling:


In order to show you the accuracy in which ELCOVISION 10 proceeds, you can see the same detail twice below. In the first image you can see the borders of the original rectification planes:


Templates for the restoration of the painting can be produced by simply tracing the outlines which is very fast and simple:

Technical Information About The Projects "Mountain" "Dining Room" Number of images 12 116 Used cameras Fuji S2 Fuji S2, Leica R5 Elcovision Storage Place for the images 427 MB 3.9 GB Accuracy at object Better than 30 cm Better than 2 mm Number of textures generated 6425 1459 Kind of textures True colour images (24 Bit) 256 colour images (8 Bit)* Size of textures 100 MB 752 MB Time for texture generation** 20 min. 62 min. * 256 colours textures were used, since thereby the storage requirement sinks around 2/3. With true colour textures approx. 1,6 GB texture data would result. ** Used computer: Dell Dimension 8300: Pentium 4, 2.6 GHz; 1GB Ram

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