Jenga-Playing Robot

In the basement of MIT's Building 3, a robot is carefully contemplating its next move. It gently pokes at a tower of blocks, looking for the best block to extract without toppling the tower, in a solitary, slow-moving, yet surprisingly agile game of Jenga. The robot, developed by MIT engineers, is equipped with a soft-pronged gripper, a force-sensing wrist cuff, and an external camera, all of which it uses to see and feel the tower and its individual blocks.

As the robot carefully pushes against a block, a computer takes in visual and tactile feedback from its camera and cuff, and compares these measurements to moves that the robot previously made. It also considers the outcomes of those moves, whether a block, in a certain configuration and pushed with a certain amount of force, was successfully extracted or not. In real-time, the robot then learns whether to keep pushing or move to a new block, in order to keep the tower from falling.

More information:

https://www.sciencedaily.com/releases/2019/01/190131101016.htm

Dexterous and Sentient Hand Prosthesis

A female Swedish patient with hand amputation has become the first recipient of an osseo-neuromuscular implant to control a dexterous hand prosthesis. In a pioneering surgery, titanium implants were placed in the two forearm bones (radius and ulnar), from which electrodes to nerves and muscle were extended to extract signals to control a robotic hand and to provide tactile sensations. This makes it the first clinically viable, dexterous and sentient prosthetic hand usable in real life. Conventional prosthetic hands rely on electrodes placed over the skin to extract control signals from the underlying stump muscles. These superficial electrodes deliver limited and unreliable signals that only allow control of a couple of gross movements (opening and closing the hand). Richer and more reliable information can be obtained by implanting electrodes in all remaining muscle in the stump instead. Sixteen electrodes were implanted in this first patient in order to achieve more dexterous control of a novel prosthetic hand developed in Italy by the Scuola Superiore Sant'Anna and Prensilia.

Current prosthetic hands have also limited sensory feedback. They do not provide tactile or kinesthetic sensation, so the user can only rely on vision while using the prosthesis. Users cannot tell how strongly an object is grasped, or even when contact has been made. By implanting electrodes in the nerves that used to be connected to the lost biological sensors of the hand, researchers can electrically stimulate these nerves in a similar manner as information conveyed by the biological hand. This results in the patient perceiving sensations originating in the new prosthetic hand, as it is equipped with sensors that drive the stimulation of the nerve to deliver such sensations. One of the most important aspects of this work is that this is the first technology usable in daily life. This means it is not limited to a research laboratory. The patient is following a rehabilitation program to regain the strength in her forearm bones to be able to fully load the prosthetic hand. In parallel, she is also relearning how to control her missing hand using virtual reality, and in few weeks, she will be using a prosthetic hand with increasing function and sensations in her daily life.

More information:

https://www.sciencedaily.com/releases/2019/02/190205185204.htm

BCI Converts Brain Signals into Recognizable Speech

A team of researchers at Columbia University has developed a speech brain-computer interface system that translates brain signals into intelligible, recognizable speech. By monitoring someone’s brain activity, the system can reconstruct the words a person hears with unprecedented clarity. This could lead to new ways for computers to communicate directly with the brain, and lays the groundwork for helping people who cannot speak. Early efforts to decode brain signals researchers focused on simple computer models that analyzed spectrograms, which are visual representations of sound frequencies. But because this approach has failed to produce anything resembling intelligible speech, the team turned instead to a vocoder, a computer algorithm that can synthesize speech after being trained on recordings of people talking. This is the same technology used by Amazon Echo and Apple Siri to give verbal responses to our questions. 

Researchers asked epilepsy patients already undergoing brain surgery to listen to sentences spoken by different people, while they measured patterns of brain activity. These neural patterns trained the vocoder. Next, they asked those same patients to listen to speakers reciting digits between 0 to 9, while recording brain signals that could then be run through the vocoder. The sound produced by the vocoder in response to those signals was analyzed and cleaned up by neural networks, a type of artificial intelligence that mimics the structure of neurons in the biological brain. The end result was a robotic-sounding voice reciting a sequence of numbers. To test the accuracy of the recording, the scientists tasked individuals to listen to the recording and report what they heard. They found that people could understand and repeat the sounds about 75% of the time, which is well above and beyond any previous attempts.

More information:

www.sci-news.com/othersciences/neuroscience/brain-computer-interface-brain-signals-speech-06862.html

Multicolor Holography for Compact 3D displays

Researchers have developed a new approach to multicolor holography that could be used to make 3D color displays for augmented reality glasses, smartphones or heads-up displays without any bulky optical components. Researchers from Duke University, USA encoded a multicolor image onto a 300-by-300 micron hologram in a 2D waveguide structure, a very thin structure that guides light. The computer-generated hologram produces complex multicolor holographic images when the grating coupler is illuminated by red, green and blue light. The new fabrication method encodes holograms in a material that is compatible with integrated photonics technology. This means that the holographic devices are easy to mass manufacture with the same fabrication methods used to make computer chips.

The hologram producing elements could be incorporated into tiny chip-based devices that also house the light sources required to create the 3D images. The new multicolor holography technique is based on computer-generated holograms. Unlike traditional holography, which requires a physical object and laser beams to create the interference pattern necessary to form a holographic image, computer-generated holography generates interference patterns digitally. Computer generated holograms provide high-resolution 3D images, but it has proven difficult to create them in more than one color. The Duke team overcame this challenge by fabricating a grating and a binary hologram in a waveguide made of a light-sensitive material known as photoresist. They developed a way to integrate the interference patterns for red, green and blue into a single binary hologram pattern.

More information:

https://www.sciencedaily.com/releases/2019/01/190124141544.htm

Laser Transmits Audio Directly Into a Person’s Ear

Scientists have figured out how to use a laser to transmit audio, ranging from music to speech, to a person across a room without any receiver equipment, a potential breakthrough for the future of audio and communication. The system can be used from some distance away to beam information directly to someone’s ear. It is the first system that uses lasers that are fully safe for the eyes and skin to localize an audible signal to a particular person in any setting. MIT developed two different methods to transmit tones, music, and recorded speech via a laser. Both techniques take advantage of something called the photoacoustic effect, which is the formation of sound waves as the result of a material absorbing light. 

That material was water vapor in the air. For one of their methods, the researchers swept a laser beam at the speed of sound, changing the length of the sweeps to encode different audible pitches. This technique allowed them to transmit sound to a person more than 8.2 feet away at a volume of 60 decibels (about the loudness of background music or a conversation in a restaurant) without anyone between the source of the sound and the target hearing it. For the other method, they encoded an audio message by adjusting a laser beams power which produced a quieter but clearer result. further research will allow them to scale up the transmission distance, which could make the technique useful in dangerous situations, such during a mass shooting.

More information:

https://futurism.com/the-byte/laser-beam-speech-mit/