Total Immersion: An Introduction to Factors Affecting Headset Quality/VR Immersion

Written by Marc Demar

As the release of the Somnium VR1 approaches, we’ve chosen to take a step back and examine some key factors that influence immersion quality, including Field of View (FOV), visual clarity/brightness, resolution, sweet spot, comfort, and more. This will serve as an introductory overview rather than an exhaustive technical exploration. For those seeking in-depth analyses and headset reviews, Artur Sychov’s (founder and CEO of Somnium Space) YouTube channel, Artur’s Tech Tales, may be of interest.

Let’s clarify one thing: possessing the top-of-the-line headset doesn’t guarantee a satisfying immersive experience if the virtual environment lacks realism. While this may be subjective, the closer the virtual world resembles reality, the more convincingly my brain perceives it as genuine. By “realistic,” I don’t necessarily mean replicating physical reality precisely. Drop me onto a fictional planet inhabited by ferocious spaghetti creatures—so long as it appears realistic rather than cartoonish, you’ve captured my attention. Or rather, you’ve captivated my brain. Realism is one of the reasons why I love Somnium Space, but I am digressing.

This article focuses on headset hardware rather than the realism of virtual environments and explores the factors that contribute to or detract from the immersive experience.

Field of View (FOV)

Field of View, which is measured in degrees, is the panoramic extent of the virtual world visible to the user at any given moment. A wider FOV enhances immersion by mimicking the natural human field of vision, creating a more realistic and enveloping experience. Users are less likely to perceive the boundaries of the display, leading to an extended sense of presence within the virtual environment. Limited FOV can create a “tunnel vision” effect, which limits the user’s sense of presence.

Based on some of the VR1 numbers shared by Artur Sychov, we know that the VR1 will have quite an impressive FOV.

FOV measurements by Artur Sychov

FOV is split into horizontal field of view (hFOV) and vertical field of view (vFOV). FOV’s typically differ from person to person, depending on face shape and IPD (Interpupillary Distance, distance between a person’s pupils), which is why FOV is best given as a range. But based on reported numbers by Artur, in ideal cases the hFOV can be pushed to 130 degrees and even beyond. vFOV sits at around 105 degrees.

But FOV does not stand on its own. An impressive FOV can be totally negated if it does not go hand in hand with a high visual fidelity.

Visual Fidelity

Visual clarity, color accuracy, color vibrancy, detail resolution, and overall realism are fundamental aspects that directly impact the immersive quality.

Visual clarity refers to the sharpness and crispness of images, ensuring that details are clearly discernible without blurring or distortion. Color vibrancy pertains to the richness, saturation, and accuracy of colors displayed. Colors should be rendered faithfully to their real-world counterparts, with vibrant and accurately reproduced hues.

Seems simple enough, doesn’t it? However, constructing an optical stack with both a wide FOV and exceptional visual fidelity across the entire field is no small task. Numerous challenges must be addressed, including distortions like geometric distortions (warping, stretching), chromatic aberration (color fringing or blurring around object edges), not to mention the potential for lens flares and glares.

Also, there is a trade-off between FOV and resolution. As FOV increases, maintaining high resolution becomes a challenge due to limitations in current display technologies. The wider the FOV, the more challenging it becomes to maintain pixel density, potentially compromising visual clarity. Striking the right balance between FOV and resolution is crucial for delivering an optimal VR experience that combines immersion with visual fidelity.

The good news is that the Somnium VR1 appears to have gone the extra mile when designing and building their optical stack, meaning that the VR1 will be able to deliver extraordinary visual fidelity combined with high FOV. Additionally, VR1 users will have the ability to customize and employ various rendering profiles to tailor the rendering precisely to their preferences. This flexibility is invaluable as individual users vary in their perceptions of visual fidelity. Users will have the option to select from a range of warping profiles and fine-tune settings such as FOV, software focal distance, contrast, brightness, gamma, hue, resolution, refresh rate, local dimming, and more.

Artur testing VR1 (on the left) versus an ‘unknown PCVR headset’ for brightness. Test was done in the same room, same scene in VR (Steam VR home) looking at the same spot in the sky. Both headsets had local dimming off, brightness set at 100%. The verdict? The VR1 is super bright!

Sweet Spot

The “sweet spot” in the context of VR headsets refers to a specific area within the headset’s lenses where the image appears the clearest and sharpest. When users wear VR headsets, they look through lenses that magnify the virtual image displayed on the screen. However, due to the curvature of the lenses and the nature of optics, the clarity of the image may vary across different parts of the lens surface.

In the sweet spot, the user’s eyes are aligned with the optical axis of the lenses, resulting in minimal distortion, blurring, or aberrations. This area typically corresponds to the center portion of the lens. When the user positions their eyes within the sweet spot, they experience the highest level of visual fidelity and immersion, with sharp, clear images and accurate representation of details.

Achieving a large sweet spot is a desirable feature in VR headset design, as it enhances the overall user experience by providing consistent clarity and immersion across a wide range of viewing angles. Headsets with a smaller sweet spot may require users to make more frequent adjustments to maintain optimal visual quality during prolonged use.

The Somnium VR1 excels in this area as well, combining a big sweet spot with no distortion.

Through the lens pictures of the Somnium VR1, made with a professional grade camera. It shows a very sharp image in the majority of the grid which indicates a big sweet spot and no distortions

Audio/Microphones

Quality microphones play a crucial role in enhancing immersion. Somnium Space shares this sentiment, evident in the video by Artur. The VR1 microphones deliver great sound quality, devoid of any noise.

Many people ask me about the quality of the microphone of @SomniumSpace #VR1 headset.

As a #SocialVR enthusiast and a Social VR platform, having good microphones on our #PCVR headset is a top priority.

Here is a latest sample of audio quality I have just recorded wearing VR1 pic.twitter.com/JL4mEYjEQs
— Artur Sychov ᯅ (@ASychov) January 24, 2024

Comfort and Weight

The physical comfort of VR headsets is paramount to sustaining user immersion over extended periods. Factors such as weight, fit, and overall design directly influence the user’s comfort level. A comfortable headset minimizes distractions, allowing users to focus on the virtual experience without the encumbrance of physical discomfort.

Somnium Space acknowledges this and has experimented with different designs of face masks and head straps. Moreover, what sets the Somnium VR1 apart is its modularity, enabling the interchangeability of various components, including the head strap. This ensures that optimal solutions will be accessible to all users. What one user finds extremely comfortable in a head strap may not be as comfortable for another user. The ability to swap out this aspect of the headset is a significant advantage. That being said, the out of the box solution is likely to provide good comfort for the majority of users.

Artur testing facemask a head strap prototypes

Full Body Perception

Full body perception goes beyond the realm of the headset, encompassing the representation of the user’s entire body within the virtual environment. When users feel like active participants with a full representation of their bodies, designers can craft interactions and environments that align with the user’s expectations, enhancing the overall sense of presence. From gestural interactions to realistic body movements, full body perception contributes to a more authentic and engaging virtual experience.

Somnium Space as a VR platform is forging the future in this respect. Apart from supporting full body tracking, it integrates with the famous Teslasuit, a full-body haptic suit designed for VR experiences. It incorporates a combination of haptic feedback, motion capture, and biometric systems to provide users with a more immersive and interactive VR experience.

But this is a topic for another article.

Conclusion

The pursuit of total immersion in virtual reality involves a meticulous consideration of various factors, each playing a crucial role in shaping the user’s experience. FOV, visual fidelity, resolution, audio, comfort, and full-body perception collectively contribute to the depth and authenticity of VR immersion.

Navigating the equilibrium among these elements is a delicate choreography. Drawing from reports and early reviews of the Somnium VR1, we are convinced that Somnium has succeeded in pushing the limits of each facet. The anticipated immersive experience with the VR1 is certainly something to look forward to. Hence, we, at the Somnium Times, will unquestionably place an order for one.

Marc Demar
A @somniumspace native, editor of the @somniumtimes, and believer in the future of decentralized, persistent, immersive VR. He’s also an avid traveler, trader and writer. His personal X account is @marcdemar1