trinamiX accuses Apple of infringing Face ID skin-detection patents

Germany-based BASF subsidiary trinamiX has sued Apple in U.S. federal court, alleging that Face ID technology in newer iPhones and iPads infringes seven patents covering techniques for distinguishing human skin from masks and other materials during facial authentication.

The lawsuit, filed September 3 in the U.S. District Court for the Western District of Texas, alleges that Apple incorporated patented material and skin detection technology into Face ID without authorization.

The case was filed by trinamiX GmbH and trinamiX Sensing LLC.

The dispute is narrower than simply that trinamiX invented Face ID or facial anti-spoofing technology generally.

Apple introduced Face ID with the iPhone X in 2017, and trinamiX acknowledges in its complaint that the original system did not use the technology covered by the patents it is asserting.

Instead, trinamiX says Apple later modified Face ID to incorporate technology that can determine properties of the material presented to the camera, including whether a detected face consists of human skin.

According to the complaint, the allegedly infringing technology is now used in a variety of iPhone 15, iPhone 16 and iPhone 17 models, iPad Pro devices and other Apple products.

trinamiX alleges Apple “knew or should have known” that updating its devices to use Face ID with material and skin detection would infringe its patents.

The technology is intended to address presentation attacks against facial authentication systems.

A photograph can potentially be rejected by determining that the presented face lacks three-dimensional depth. More sophisticated attacks can use three-dimensional masks or replicas that reproduce the geometry of a real face.

trinamiX’s technology goes a step further by analyzing how projected light is reflected from an object. Those reflections can provide information not only about an object’s distance and shape, but also about properties of its surface material.

In a biometric authentication system, the resulting information can be used to determine whether what appears to be a face behaves optically like human skin rather than silicone, plastic or another material.

The claims describe systems using combinations of near-infrared cameras, structured-light projectors, lasers known as vertical cavity surface emitting lasers and processing that examines characteristics of reflected light.

One of the face unlock patents describes detecting a face, projecting an illumination pattern onto it and examining the reflected pattern both for three-dimensional depth and for a material classification.

A dependent claim specifies using a machine learning model trained to distinguish human skin from nonbiological materials.

Another patent describes determining material properties including scattering, translucency and transparency from reflected light. Its claims cover structured light systems using a camera, laser source and diffractive optical element.

Those components have substantial similarities to the hardware Apple uses for Face ID, but that alone does not establish infringement.

Apple says its TrueDepth camera projects and reads thousands of infrared dots to build a depth map of a user’s face while also capturing an infrared image. The resulting data is processed by neural networks within the Secure Enclave to compare the detected face with the enrolled user.

Apple has also said since the original introduction of Face ID that the system uses an additional neural network specifically trained to detect and resist spoofing attempts involving photographs and masks.

What Apple’s public security documentation does not say is that Face ID classifies the material of a detected face or determines that a surface is human skin by analyzing the intensity or shape of reflected infrared light.

That distinction is likely to be central to the infringement dispute.

If newer Face ID implementations use reflected light information to derive a skin or material classification of the kind described in the trinamiX patents, the technology could fall much closer to the asserted claims.

Apple could argue, however, that its anti-spoofing system reaches its decisions through different analysis of infrared images, depth information or other characteristics without performing the patented material classification steps.

Apple had publicly documented structured-light facial authentication and anti-spoofing before the dates claimed by trinamiX’s asserted patents.

An Apple patent family claiming priority to September 2018 describes facial authentication using both flood infrared illumination and patterned infrared illumination, with the patterned light providing three-dimensional depth information.

The application predates the March 2019 date of trinamiX’s earlier asserted patent family.

That does not by itself determine whether trinamiX’s later material detection inventions are valid or whether Apple infringes them. It does, however, underscore that the lawsuit is not fundamentally about who invented infrared structured-light facial authentication.

The contested technology is the additional use of information in the reflected light to identify material characteristics and, ultimately, distinguish a real human face from a sophisticated physical replica.

trinamiX says its work grew out of BASF research into organic solar cells beginning around 2010 that led to development of three-dimensional and material sensing technology.

BASF says trinamiX GmbH was founded in 2015 as a wholly owned subsidiary. The company develops biometric imaging and mobile near-infrared spectroscopy technology and holds more than 800 patents and patent applications.

The lawsuit seeks unspecified monetary damages and an order preventing further infringement.

The case could ultimately turn on technology that cannot readily be determined from an iPhone teardown.

While the TrueDepth system’s infrared camera and structured-light components are well documented, the lawsuit raises the less visible question of what information Apple’s Face ID software derives from those sensors before determining that the face in front of the device is genuine.

Article Topics

Apple  |  biometric liveness detection  |  Face ID  |  lawsuits  |  patents  |  skin detection  |  trinamiX