Canon Inc. announced today that the company has developed the world's first1 single-photon avalanche diode (SPAD) image sensor with signal-amplifying pixels capable of capturing 1-megapixel images. SPAD image sensors are ideal for such applications as 2-dimensional cameras, which capture and develop still image and video in an extremely short span of time. These sensors also hold potential for use in 3-dimensional cameras due to their ability to obtain information about the distance between them and a subject as image data.
A SPAD sensor is a uniquely designed image sensor in which each pixel possesses an electronic element. When a single light particle, called a photon, reaches a pixel it is multiplied—as if creating an “avalanche”—that results in a single large electrical pulse. The ability to generate multiple electrons from a single photon provides such advantages as greater sensitivity during image capture and high precision distance measurement.
The SPAD image sensor developed by Canon overcomes the longstanding difficulties of achieving this effect with high pixel counts. By adopting new circuit technology, Canon's sensor uses a method known as photon counting to realize a digital image resolution of 1 megapixel. What's more, the sensor employs a global shutter that allows simultaneous control of exposure for every pixel. Exposure time can be shortened to as little as 3.8 nanoseconds2, making possible clear and distortion-free image capture. In addition, the sensor is capable of up to 24,000 frames per second (FPS) with 1 bit output, thus enabling slow-motion capture of fast movement within an extremely short time frame.
Thanks to its ability to capture fine details for the entirety of events and phenomena, this technology holds the potential for use in a wide variety of fields and applications including clear, safe and durable analysis of chemical reactions, natural phenomena including lightning strikes, falling objects, damage upon impact and other events that can't be observed with precision by the naked eye.
The sensor also features a high time resolution as precise as 100 picoseconds2, enabling it to determine the exact timing at which a photon reaches a pixel with ultra-high accuracy. Leveraging this functionality, the sensor is capable of Time of Flight distance measurement. What's more, with a high resolution of 1 megapixel and high-speed image capture, it is also able to accurately perform 3D distance measurements in situations where multiple subjects overlap—useful in such scenarios as a vehicle distance measurement for self-driving automobiles and grasping 3D spatial information for xR3 and similar devices.
Canon's development of a SPAD image sensor enables 3D cameras capable of recognizing depth information to achieve a resolution of 1 megapixel is expected to rapidly expand the use of such cameras as the “eyes” of high-performance robotic devices. Going forward, Canon will strive to anticipate the needs of industry by continuing to advance its innovative image sensor technology, further expand the possibilities of what is visible, spur evolution in science and industry through high-precision detection of information and contribute to the development of fields yet to be discovered.
- Among SPAD sensors. As of June 23, 2020. Based on Canon research.
- 1 nanosecond = one billionth of a second. 1 picosecond = 1 trillionth of a second.
- “xReality,” where x represents a variable for the unknown. Includes AR (augmented reality), MR (mixed reality), and VR (virtual reality).