Researchers led by Prof. WANG Yingjian from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS) developed a new, image-free moving object position method.
The approach, published in Optics Express, is with just several moment modulation patterns. It can directly obtain the centroid which represent the position of the moving object. The frame rate reached 7400Hz under the equivalent 256×256 pixel resolution camera. This data was pushed further in another study published on Optics Letters, in which scientists doubled the frame rate to more than 11kHz was under the same resolution. The quasi-real-time detection of the object's centroid coordinates was realized by utilizing the complementary characteristics of the light modulator.
The traditional moving object position method based on high-speed camera requires large data deposit and a big amount of computing power. That's obstacle to the achievement of long-duration object position.
The advantage of this image-free geometric moment extraction method is its fast and long-duration positioning of the moving object, according to the team. Compared with the traditional method, this technology, which is based on the principle of optical computation, reduces the data and computation requirements by more than two orders of magnitude.
"There is still another advantage," said Dr. SHI Dongfeng, corresponding author of the papers, "thanks to the single-pixel detector included in the experimental device (such as photomultiplier tube (PMT), Avalanche Photo Diode (APD), etc.), it can operate in infrared, terahertz and other bands with high signal-to-noise ratio."
The proposed approach provides a broad and efficient solution for real-time tracking fast-moving object.
Related researches have been funded by Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2020438), Foundation of Key Laboratory of Science and Technology Innovation of Chinese Academy of Sciences, and Youth Fund of Advanced Laser Technology Laboratory of Anhui Province (20192201).
(a) Experimental scenes, including the moving object (magnet) and moment modulation patterns. (b) Trajectory of the moving object. (c) Position coordinate curve. (Image by SHI Dongfeng)
Image-free geometric moment extraction method boasts the advantage of fast and long-duration positioning of the moving object. (Image by SHI Dongfeng)