Researchers have developed the primary megapixel photon-counting camera supported new-generation image sensor technology that uses single-photon avalanche diodes (SPADs). The new camera can detect single photons of sunshine at unprecedented speeds, a capability that would advance applications that need the fast acquisition of 3D images like augmented reality and LiDAR systems for autonomous vehicles.
“Thanks to its high resolution and skill to live depth, this new camera could make computer game more realistic and allow you to interact with augmented reality information during a more seamless manner,” said Edoardo Charbon from the Advanced Quantum Architecture Laboratory (AQUALab) at École Polytechnique fédérale de Lausanne (EPFL) in Switzerland. Charbon developed the thought for the new camera and is that the founder and head of AQUALab, where the image sensor was designed.
In Optica, The Optical Society’s (OSA) journal for high-impact research, the researchers describe how they created one among the littlest SPAD pixels ever devised and reduced the facility consumption of every pixel to but 1 microwatt while maintaining speed and timing precision. The new camera can acquire images at up to 24,000 frames per second. For comparison, 30 frames per second is that the standard rate wont to record video for television.
“For transportation applications, this new camera could help achieve unprecedented levels of autonomy and safety by enabling multiple low-power LiDAR devices to be used on a vehicle, providing fast, high-resolution 3D view of the environment,” said first author, Kazuhiro Morimoto from Canon Inc. in Japan. “In a somewhat more distant future, quantum communication, sensing, and computing could all enjoy photon-counting cameras with multi-megapixel resolution.”
A new quite sensor 3d image
In but 20 years, SPAD sensors have advanced from a novelty to versions that are standard in most smartphone cameras and lots of household devices. This technology’s success comes from the very fact that SPAD sensors are extremely efficient at detecting single photons and converting them into electrical signals that are stored during a digital memory. an outsized format camera is often created by building an array of pixels that every contain a SPAD.
In the new work, the researchers drew on 15 years of SPAD research at the AQUALab in EPFL to make a particularly fast, high-resolution camera that leverages SPAD technology for advanced imaging. The new camera detects single photons and converts them into electrical signals at a record rate of about 150 million times per second. Each SPAD sensor is often finely controlled to permit light certain as little as 3.8 nanoseconds, roughly four billionths of a second. This quick ‘shutter speed’ can capture extremely fast motion or be wont to increase the dynamic range — the difference between the darkest and lightest tones — of an acquired image.
The researchers created extremely small SPAD pixels and designed for low power consumption by employing a feedback mechanism that nearly immediately quenches the avalanche of electrons triggered by photon detection. This improves the general performance and reliability of the pixels. They also used enhanced layout techniques to pack the SPAD sensors tighter, thus upping the detection area density and enabling a camera with 1,000,000 pixels.
The researchers then applied sophisticated microcircuit design techniques to make a particularly uniform distribution of fast electrical signals over the large-scale pixel array. They showed that the shutter speeds varied by only 3 percent over the million pixels, demonstrating that this sensor could feasibly be made using available mass-production techniques.
High-speed 3D imaging
The camera’s speed makes it possible to live the time a photon hits the sensor very precisely. This information is often wont to calculate how long it takes individual photons to travel the space from a source to the camera, referred to as time-of-flight. Combining time-of-flight information with the power to capture 1,000,000 pixels simultaneously enables the extremely high-speed reconstruction of 3D images.
The researchers used the new camera to work out the time-of-flight of photons emitted from a laser source and reflected by a target. They also captured complex scenes that are difficult for other imaging techniques to live, like an object viewed through a partially transparent window, and that they used the camera to accumulate conventional pictures with unprecedented dynamic ranges. In the future, they decide to further improve the performance and timing resolution of the camera and to further miniaturize the components to form it more practical for the spread of applications.