Apple Computer, Inc. released iPhone X on November 3, 2017. One of iPhone X’s new features was a new authentication system, called Face ID, a face recognition system, which allowed users to unlock their phone by looking at its front screen.
Face ID and the Animoji feature are made possible by its TrueDepth camera system on iPhone X and newer models. It is found in the notch at the top of the iPhone’s front screen.
TrueDepth uses an LED dot projector to shine predetermined ‘structured light’ patterns comprised of more than 30,000 invisible (infrared) dots onto a user’s face.
An infrared camera, also contained in the notch, captures the dot pattern, and turns the information into a dynamic 3D depth map of the user’s face. This data is sent to the iPhone’s Bionic chip to confirm a match, allowing the user’s phone to become unlocked.
This depth map is also for a variety of security purposes, such as logging on to banking and credit card sites. However the same information can be useful for personal entertainment features, such as interacting with Snapchat or Tiktok, and communicating with other iPhone users via Memojis, in real time.
This depth tracking information can also be used with Epic Software’s free Live Link Face, as well as a number of other content creation apps, to drive real-time facial motion capture animation using dynamic combinations of 52 ARKit (AR Kit) ‘blend shapes’ or ‘morph targets’ triggered by the user’s facial motion in real-time. These blend shape combinations are retargeted on to a 3D character’s face, in real-time for live performance and streaming, via Twitch or Youtube.
In addition to its real-time capabilities, Live Link Face also can record video and depth information for offline processing. After recording one or more takes, the video and depth sent to a networked PC for processing by MetaHuman Animator (MA). MA uses machine learning to analyze and retarget the captured expressions for remarkably lifelike animation of the faces of 3D MetaHuman characters.
Animators are not limited to the various MetaHuman characters Epic Software has created. A free plugin for Unreal Engine called “mesh to MetaHuman” lets users convert an OBJ format 3D file of their characters’ heads into a MetaHuman head.
The TrueDepth systems on iPhone models 13 and newer use a different TrueDepth sensing technology, purportedly utilizing three, rather than four dot projector patterns. Though iPhone 13 and newer still do a great job for security and personal entertainment purposes, it is less than ideal for motion capture content creation.
Indeed, the TrueDepth camera systems on iPhone models X through 12 are superior to those sensors found in 13 and newer. These images clearly illustrate the quality differences between TrueDepth captures on 12 and 13:
iPhone 12 Pro: data as point cloud, object about 25cm from phone
iPhone 13 Pro: data as point cloud, same setup. (Notice the the noisier, bumpier, and less accurate depth data, especially the area highlighted in red.)
For more discussion on this topic, please visit this page on Apple’s Developer Forums:
The resolution of the TrueDepth sensor on iPhone X is 7 MP and its processor is the A11 Bionic chip. iPhone 11 and 12 both feature a 12 MP sensor. 11 uses the A13 Bionic chip, and 12 uses the A14 Bionic chip.
Of these three phones, only 12 supports Wi-Fi 6, which is hugely important when doing production work with MetaHuman Animator, since the capture files generated can be sizable. They will take a LONG time to transfer to a networked PC for processing, if you are using one of the less robust Wi-Fi standards. (Transfer to a networked PC requires Wi-Fi, not a Lightning or USB-C cable).
TP-Link makes several reasonably priced Wi-Fi 6 routers. If you decide to use your iPhone 16 rather than 12, despite the less robust TrueDepth sensing, you can use a router that supports Wi-Fi 7 for faster phone to network transfer speeds.
MetaHuman Animator does not officially support iPhone X and 11, users have reported getting it those older models to work. Of course, iPhone X is less than ideal due to its 7 MP TrueDepth resolution, CPU speed, and Wi-Fi data transfer speeds.
In terms of weight, iPhone 12 mini is an ideal choice for use with our FaceCam iPhone HMC. Though some of our customers use the 12 mini without our optional Counterweight, other users prefer the counterweight, all the same.
The counterweight should be removed for stunts and fast motions, since the increased overall helmet weight can make the helmet less stable, under those circumstances.
12 mini is an ideal choice if you will be capturing a facial expression during acrobatic and rapid motions, since it is the lightest iPhone that has a TrueDepth Sensor and doesn’t require a counterweight.
If you will be using our FaceCam for VTubing or other live performance, iPhone 12’s superior TrueDepth capabilities will help you get better results.
Should you rush out and buy an iPhone 12?
Not necessarily. If you have access to one of the newer phones, you might as well try that, first. Once you have gotten that working, you will probably want to ‘up your game’ by picking up a used or refurbished iPhone 12. There are several reputable resellers on eBay, and you can also purchase from sites like BackMarket.
If you will not be using the phone’s cellular service, you needn’t be too concerned about which carrier your phone supports. Most sellers of used iPhones offer a range of prices, generally depending upon the aesthetic condition and available RAM of the various used phones.
If you have access to various phone models, 12 and newer, you might want to install Epic Software’s free Live Link Face app and use the preview feature to get a qualitative sense of the depth capture offered by the different phones.
How TrueDepth works:
- How Apple's iPhone X TrueDepth Camera Works
- Using an Infrared Camera to Show How Face ID Works
- What is a TrueDepth camera? All about the iPhone camera feature
- iPhone 15 Camera Feature People Don't Talk About | Apple's Game Changer
Comparison of different TrueDepth sensors:
- Are the TrueDepth sensors of iPhone X to 12 equal?
- TrueDepth Camera on iPhone13 products - lower accuracy of depth data?
- Which iPhone is best for facial motion capture ?? march 2022
- iPhone 13 and 14 depth data accuracy? iPhone 12 and iPad Pro is fine
iPhone Model Comparisons:
MetaHuman Animator and TrueDepth:
- Animating with Live Link
- MetaHuman and iPhone
- MetaHuman Animator x iPhone | Scan YOUR Face in Unreal Engine 5