Improvement of stereoscopic images

Real or unreal?

In her final year Laure Leroy came to study at Mines Paristech under the Erasmus program, at the same time, she started working at the Robotics Centre (MINES ParisTech - CAOR)


By a Virtual Reality approach design objects entirely by means of computer applications is possible. The greatest claimed benefit thereof is that designers can modify virtual objects as many times as and to the extent they wish. When an object meets with their final approval, they can then decide to move on to building the real-world object, using the virtual one as a template.


But... Two nagging questions remain unanswered in Virtual Reality:

The first and somewhat obvious one is: “do the virtual creatures we get to see on the screen really correspond to the physical ones that we will end up with?” In other words, the issue is whether immersive design (and especially stereoscopic vision) can create a visual perception of a virtual object which closely matches the physical object at the end of a production chain.

The second question that inevitably comes to mind has to do with visual fatigue. In some instances, exposure to stereoscopic immersion techniques can be lengthy, and eye strain can become an issue. We propose a method for reducing eye strain induced by stereoscopic vision. After reviewing sources of eye strain linked to stereoscopic vision, we shall focus on one of these sources: images with high frequency contents associated with large disparities when the virtual object is far from the screen. We shall put forward an algorithm for removing the irritating high frequencies in high disparity zones (i.e. for virtual objects appearing far from the perceived location of the real screen). We shall elaborate on our testing protocol to establish that our processing reduces eye strain induced by stereoscopic vision, both objectively and subjectively. We shall subsequently quantify the positive effects of our algorithm on the relief of visual fatigue.

                          The high frequency is removed when the box is far of the screen


The treatment on the virtual test world:

           without treatment                                                                        with treatment


Perception test: Comparison between real and virtual shape:


The real word:
The virtual word:

We know that head tracking is essential to an accurate shape perception. It plays an even more significant role than stereoscopic vision itself. Monoscopic vision combined with head tracking is by far preferable to stereoscopic vision alone.  We also know that removing high frequencies linked to sharp relief details reduces visual fatigue in an unmistakable but also quantifiable way. So we have proposed an algorithm which processes stereoscopic images in such a manner that these unwanted high frequencies are eliminated.

Interpersonal exchanges and knowledge sharing

Laure Leroy studied in Brussels, at the “Ecole polytechnique – faculté des sciences appliquées” (Brussels University). In her final year she came to study at Mines Paristech under the Erasmus program, and, at the same time, she started working at the Robotics Centre (MINES ParisTech - CAOR). She had always wanted to engage in research somehow, but, when she started working there, she realized at once that this was where she would like to carry on with her favorite activity. So it was only natural that she should decide to stay and work on at the robotics centre.

                              Laure Leroy in the virtual reality room, in a car simulation


All along her studies, she was offered a lot of things to marvel at. Innovative breakthroughs were identified every day. Even so, when she got to work for the first time in the virtual reality world, she found it truly overwhelming, as so much new technology was all of a sudden unveiled and made available to her. This is a field of activity which encompasses a lot of wide-ranging disciplines and forms an intricate mixture of pure technology, mecatronics, computer hardware and software but also calls on domains of a totally different nature such as psychophysics, psychology, medicine, art, just to name a few… So when the virtual reality actors have a get together, it does not really come as a surprise that those encounters are, more often than not, rich in interpersonal exchanges and knowledge sharing.