In Dec 2023, Tesla unveiled a demo video of its Optimus Gen2 humanoid robot. With faster mobility, environmental recognition & memory, precise neural network vision, and dexterous dual-arm coordination for complex tasks, the robot showcased capabilities once thought reserved for science fiction.
Elon Musk boldly predicted that robotic demand will far outpace green vehicles in the years ahead. Many experts agree – 2024 could be the start of the "embodied AI" era, with the global humanoid robot market potentially ballooning to $34.43 billion by 2030 (The Insight Partners).

Let’s explore this fascinating frontier today.
What Are Intelligent Humanoid Robots?
Artificial General Intelligence (AGI) requires emergent intelligence, autonomous agency, functional visibility, and physical embodiment. While today's large language models excel at the first two, they lack the latter qualities of environmental perception and physical instantiation. Intelligent robots are viewed as the most promising path to achieving those missing pieces of the AGI puzzle.
Intelligent humanoid robots are designed with human-like forms and functions – anthropomorphic limbs, mobility skills, sensory perception, learning, and cognition. They represent the pinnacle of complexity and control challenges among all types of robots. Humanoid robots are often used to assist or substitute humans in various tasks. With bipedal locomotion mirroring humans, these robots can seamlessly collaborate alongside people in real-world settings.
Why Design Them to Be Humanoid?
Our world's tools and infrastructure have been molded around human usage. By mimicking our form, humanoid robots can operate within existing environments without major overhauls. But their human-inspired design goes beyond just practical integration – the human body itself is an engineering marvel. Our physiques grant incredible flexibility, facilitating diverse mobility and adaptability across environments. Current imitation learning techniques allow humanoid robots to replicate our fluid movements and manipulation skills, rapidly mastering complex physical tasks.
Are Humanoid Robots Equivalent to Embodied AI?
Embodied AI refers to intelligent systems that perceive and act based on a physical body, interacting with the environment to acquire information, make decisions, and take actions, thus generating intelligent behaviors and adaptivity. Embodied AI does not have to be human-like. Humanoid robots are just one physical form of them.
The focus of embodied AI is capabilities like perception, cognition, learning, decision-making, and interaction with the environment. Humanoid robots refer to intelligent robots with human-like external features and motion abilities. They can walk on two legs, coordinate arms and body to function, and communicate with humans.
Components of Intelligent Humanoid Robots
Intelligent humanoid robots are engineered to emulate the human "perception-cognition-decision-execution" cycle. They contain mechanical body structures and actuated limbs akin to our musculoskeletal system. Sensor suites mimic our senses like vision, touch, and proprioception. Control architectures evoke the brain, cerebellum, and brain stem, governing cognition, decision-making, and motor control. Some even have interaction modules for communication akin to our social intelligence.

Ideally, intelligent humanoid robots resemble humans in form (anthropomorphic features, expressions), behaviors (motions, gestures), perception, and intellect (understanding, reasoning, speaking), and can interact with humans naturally.
Next, we’ll take a deeper look at their perception system.
Visual Perception Systems of Humanoid Robots
Humanoid robots rely on their perception systems – sensor arrays analogous to our senses – to gather information about their external environment and internal states. Common sensors include vision, touch/force, displacement & orientation sensors. Among these, vision sensors are paramount, as sight enables core reasoning about the world.
Vision System: The Eyes of Humanoid Robots
Just as over 80% of human knowledge is visually acquired, with half of the cerebral cortex involved in vision, advanced visual perception is vital for humanoid robots.

To operate in human environments, they must identify faces, detect objects, and ultimately understand their surroundings similar to humans. This starts from vision sensors like cameras and radar that provide optical images and depth data, to computer vision algorithms that process this raw sensory data into higher-level representations for intelligent planning, object recognition, navigation, pedestrian prediction, and more.
2D Vision vs. 3D Vision
Current leading humanoid robots typically integrate advanced machine vision systems, combining multimodal sensing with AI algorithms to enable perception, task execution, safety, and obstacle avoidance. These vision systems can be categorized into 2D and 3D varieties based on the image dimensions.
2D machine vision acquires 2D images and locates targets in x, y, rotation. It provides analysis based on contrast in grayscale or RGB images. However, it lacks 3D spatial information like height, surface orientation, volume, etc. 2D is also susceptible to lighting variations and struggles with moving objects. 3D machine vision provides richer target information, locating targets in x, y, z plus pitch, yaw, and roll. It reconstructs the 3D stereoscopic world of human eyesight. 2D and 3D excel in different scenarios, not in outright replacement.
Different Vision Solutions for Humanoid Robots
Given humanoid robots' lofty needs for wide field-of-view, high speed, and high accuracy perception in human environments, the technology approaches are still being actively pioneered. Different companies are taking diverse technical strategies. Popular humanoid robot vision solutions include Stereo Vision and ToF.
Stereo Vision uses two or more cameras to triangulate 3D scene information from multiple vantage points. For example, Tesla's Optimus robot employs an 8-camera vision system that combines algorithmic image processing for tasks like object detection and environment mapping. Time-of-flight (ToF) sensors like those used in Boston Dynamics' Atlas measure the time for light to travel to objects and reflect, enabling area scan imaging and depth perception without precision timing requirements. Notably, many current humanoid robots use multimodal fusion, combining cameras, LiDAR, etc. with infrared sensors, sonar, etc.
On the algorithm front, vision understanding leverages techniques like image segmentation, 3D reconstruction, and feature extraction. Meanwhile, visual navigation relies heavily on SLAM (simultaneous localization and mapping)