What is a Stereo Photo?

What is a Stereo Photo?

… but edited a little.

Have you ever wanted to create your very own 3D photos from cameras or devices you already own? While 3D scanning technology has been around since the 80s, most of the early methods were either too crude (like contact-based scanners with articulated arms) or way too complex (like laser triangulation arrays). Lucky for us, that’s no longer the case.

With today’s technology, it’s much easier to make your own 3D models without any fancy equipment. This is the magic of stereo photos and videos. How exactly does it work?


Stereoscopy — how we see with two eyes

Depending on the person you ask, this phenomenon can be referred to in a myriad of terms — stereoscopy, stereopsis or simply 3D pictures, among others. In any case, it’s a concept that most of us use in our daily lives, even if we aren’t aware of it.

The word “stereo” actually originates from Ancient Greek and means “relating to space”. By forming a composite image from the two images that our eyes see (thankfully your brain does this automatically) we can estimate how close or far objects in our view are. This is what we call depth perception.

Have you ever noticed how flat your vision may appear when one eye is closed?

A normal picture on paper, film or a computer screen is only one-eyed, meaning it is captured one lens and cannot convey a truly spatial perception–resulting in a flat picture. By taking two lenses and imitating the way your two eyes see, stereoscopy creates a spatial image.

This is how your eyes see. Boom.

Creating the illusion of depth from flat images

No matter how detailed or how beautifully rendered an image or video is, any 2D media is still perceived by our brains as flat. The simplest way to create the illusion of depth is to take two photos of a single subject that are slightly offset from each other. By putting these images together, we can come up with a composite image (AKA stereo photo) that simulates how our eyes work.

The two necessarily individual views can be generated in several ways. We can produce them like the original stereo artists did by first drawing one, and then the other single view. We can also take exposures of a static scene one after the other with a normal single lens camera as long as the subject stays completely still. You’ve probably seen an example of this technique in old-fashioned 3D images. You know, the ones that require the viewer to wear blue and red-tinted glasses.

The easiest way to make a stereo image out of two parallel views is by simply crossing your eyes. Nowadays there are much more sophisticated ways to view stereo images and videos with your Looking Glass Display, especially with a little help from creators in our community.

Viewing stereo photos and video using the Looking Glass

If you already have a pair of photos captured from offset perspectives, then you can use the Looking Glass to view the resulting stereo photo. Creators from our community have demonstrated time and again that they want to port a whole archive of stereoscopic images into the Looking Glass. A company called Triaxes has put together a whole suite of tools, and recently updated their version of StereoTracer to support the conversion of stereo photos to something you can view inside a Looking Glass. What the program does is calculate the depth map image from a stereoscopic photo.

StereoTracer works with a user-drawn depth map and automatically calculates one or two depth maps out of a stereopair for further 3D sequence rendering. Recently, Mr. Masuji Suto has also added Looking Glass support directly to his popular StereoPhotoMaker (SPM) softwareand using similar techniques to Triaxes, is able to generate a depth map from a right/left stereo photography pair. While we’re at it. here is an in-depth tutorial on how to use StereoPhotoMaker.

Combined with our proprietary lightfield technology, the Looking Glass can now display a converted stereo photo as close as possible to how it would look like in the real world. With the aforementioned tools by Triaxes & Masuji-san, Looking Glass users can view stereo photos from different angles and see the variations in depth of the features in the photo. There’s no eye-tracking trickery here — the lightfield holographic display actually shows how the stereo photo looks like from different angles.

Depth map conversion in StereoPhotoMaker…
… the final result

Stereoscopic imaging is a decades-old technique, but modern technology is showing that there is so much more than we can do using the same principles. Using lightfield technology, the Looking Glass display can easily create (or re-create!) advanced stereoscopic images.

For further reading, we recommend heading over to Missy’s iPhone Portrait Mode > Looking Glass blog post where she goes in-depth about how you can use iPhone 7+/8+/X/XS to take portrait-mode photos and have display on the Looking Glass using StereoPhotoMaker’s web tools!

Have you taken any stereoscopic images and would like to see how they look in a Looking Glass? Get a Looking Glass display and see for yourself. In the coming week, Missy will be publishing a post about how to extract your depth map, edit in Photoshop, and convert your rgb+depth map into a quilt to be viewed on the Looking Glass. Stay tuned.

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