Posts Tagged ‘image rendering’

Making of: step 3, the rendering

Thursday, March 11th, 2010

Last step before putting the image on-line: the rendering. The rendering is the process where the final image is actually generated in Autopano Giga after the panorama edition.

Thanks to Intel, we were able to take advantage of powerful hardware to render the image in record time. Let’s ponder a bit: we borrowed an Intel Server System SR2600UR that included 2 Intel Xeon processors 5500 series and 6 SSD hard drives of 160 GB each, allowing a much faster data writing than standard hard drives. With this hardware that would have certainly made a number of geeks jealous (16 cores, 24 GB RAM, 1 TB SSD), the rendering lasted only 3 hours and 14 minutes: an amazing performance. Two years ago for the record of Harlem 13 Gigapixels, we needed 48 hours for the rendering to complete; the image was two times smaller. You can read more about this in the case study written by Intel.

But the hardest part is yet to come…

It is true that, thanks to a good hardware and software that can exploit all available power, it is rather easy to create large images such as Paris 26 Gigapixels. But the necessary adjustments that have to be made thereafter can be numerous:
- First, the quality of the stitching was very good and there was virtually no assembly errors in the image of Paris.  But we had to better harmonize the colors in some areas of the sky. This is a real technological challenge.
- Second, our lawyer had the excellent idea of advising us to mask any areas that could be an invasion of privacy, including license plates and recognizable faces! We had to split the view into smaller pieces that could be edited in Photoshop. Note: Photoshop is internally limited to a size of 300,000 by 300,000 pixels. So the image of Paris could not be opened directly. I take this opportunity here to make an appeal to John Nack: “Hey John, in the next Photoshop, please raise this internal limit to 3,000,000, for example. ;) Thanks John!

We embarked on this great job of blurring or masking the said areas, something that is not so easy when the image you are working on is the size of two football fields! We developed a tool that can cut, and then easily reassemble such large images. It will soon be made available to the Autopano community.

We took advantage of the required retouching step to include a few surprises in the picture so that you can also have fun searching for little details everywhere! There are 10: we  let you discover them by yourself :) What? Easter eggs? Yes sir!

Along with the editing work, the website has been prepared and asks nothing more than to receive this giant image in its two versions:
- The default version, in Flash format, which includes interactive elements like an automatic visit. The Flash viewer used is KRPano, the same technology we use in our product Autopano Tour.
- The version in HDview format, accessible via the top-right button, does not offer the interactive features but offers a smoother experience while navigating inside the image.

Finally, we had to cope with one last issue: offer this experience to everyone regardless of server load. This website is made up from 600,000 files indeed. Our partner IPSyn helped us in geolocalized deployment on many servers around the world. With this, we should take the load :)

Have a nice visit to Paris and see you soon for new gigapixel adventures.