Virtual Reality Cath Lab - Gear VR
Gear VR still imagery
We received a lot of feedback on the cardboard Virtual Reality experience, both positive and negative. The predominant negative was the softness or fuzziness of the images. Realizing that resolution was the reason for the softness, we decided to experiment with increasing the resolution. The basic resolution for Cardboard VR is device dependent, with the Samsung phone the resolution is 2560 x 1440. Using that resolution as the starting point we rendered out stereoscopic top/bottom images at 3840 x 1920. We noticed a very slight quality increase but realized that the field of view was still being scaled up in the viewer. Doubling the resolution resulted in failure to load the image. Another solution was needed to correct the problem.
Turning to the Oculus Gear VR headset, we experimented with various rendering engines in our 3D application. We discovered that using a stereoscopic camera with a field of view of 360 degrees that rendered out a cube 6x1 format was the answer.
The specialized camera renders the scene as a cube which is unfolded into a long strip. The software renders a left and right eye image of each cubic plane, then formats the image into a strip of 12 images, 6 for each eye. The resolution of each cube plane is 1536 x 1536 yielding a finish rendered strip 18432 x 1536-extremely high resolution. The beauty of this approach is that there was no distortion in each of the 6 planes of the cube. The Oculus software on the phone rebuilds the scene as a seamless stereoscopic image with incredible clarity. The realism is stunning, however, so are the render times! Not something you want to do on a slow computer.
The viewing procedure is straight forward. A directory needs to be created on the phone called Oculus. Inside that directory create a directory called 360photos. Finally create a new directory where you will copy the cube map to, it can be named anything. The cube map file needs to be named <cubemapfile>_VR.jpg. The append _VR is required. Place the phone in the Gear VR viewer, which will automatically launch the Oculus app. Looking at the 360 Photos tab, Tap the side button, then tap the My Photos tab on the left hand side menu panel to see the directory containing the cube map.
There are a number of Android apps and websites that also provide hosting and sharing services of panoramic images.
- Beautiful photorealistic renders with no compression artifacts or softness
- Easy to deploy on an Android phone
- Affordable GearVR headset
- Files can reside on the phone
- Slideshow capability
- High resolution and long render times
- Only supports rotational 3d movement, not translation
- Requires specific headset hardware
- No support for animation, however step through slideshows are supported
In our next blog we will discuss the process of creating a high interactive VR catheter lab in the HTC Vive environment.