Introduction

We use image-based methods to capture 3D rigid forms of biological organisms in fields. Photogrammetry and stereo vision are combined to reconstruct high quality models while alleviating the burden of data capture.

Image-based methods are chosen because cameras are suitable for in situ usage. Unlike the controllable environment in laboratory, the field work brings more challenges to the task of form capture. First, the lack of electric power makes it infeasible to use most kinds of popular scanning techniques. Second, the targets are usually animals alive, which are typically moving when their forms are being captured, therefore it must be quick enough to setup and operate the instruments. Third, people often have to walk, run or climb hill to find and chase the animals, which requires light weighted instruments.

Both photogrammetry and stereo vision methods can be used to reconstruct from a set of object images specially taken. As shown in figure 1, the photogrammetric method usually reconstruct simple model with very limited samples; while the stereo vision method can produce denser samples. However, stereo vision method is not as easy to use in the field as its counterpart because of the requirement of a calibrated stereo rig.


Figure 1. Reconstructed 3D form of the carapace of Aldabrachelys gigantea. A. photography of the tortoise. B. reconstructed 3D form with photogrammetric method: (1) textured model, (2) untextured model, and (3) wireframe model. C. reconstructed 3D form with stereo vision method: (1) textured model, (2) untextured model, and (3) wireframe model.

A 'hybrid' method extends the photogrammetric method by combining it with stereo vision to compute a spatially dense model. As shown in figure 2, the model reconstructed with the hybrid method is comparative to that with stereo vision while the data taking processing is almost as easy as the photogrammetric method.


Figure 2. Reconstructed 3D form of the carapace of Geochelone porteri. A. photography of the tortoise. B. textured mapped model with photogrammetric method. C. textured model with the hybrid method.

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  • Pipeline

  • User Guide

  • Using digital images to reconstruct three-dimensional biological forms: a new tool for morphological studies. Chiari Y, Wang B, Rushmeier H, Caccone A. Biological Journal of the Linnean Society, 95(2), Pages 425 - 436, 2008. [PDF]

  • On April 21 2008, Eos Systems Inc. released Photomodeler Scanner, a software supporting dense surface modeling. The software uses similar ideas to ours for data capturing and processing; and it can be used to reconstruct the carapace instead. See Eos website for more details.

Contact

This webpage is kept updated and renewed. For any technical problem or general question about the methodologies, their possible applications and the content of our paper, please contact Ylenia Chiari (yle at yleniachiari dot it) or Bing Wang (bing dot wang at yale dot edu).

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