“Grand Priz”, SilkyEvCam® Event-based Vision Camera Application Idea and Algorithm Contest 2024
"How to conduct experiments that capture the essence of physics in a simple and inexpensive way" YANOYANOWAKUWAKU (Kota Igarashi, Yuka Kobayashi and Ryoya Kobayashi) (Nagaoka National College of Technology)
managerDigest
(1) Outline of the proposal
The communication method using visible light such as LED (visible light communication) has excellent features that it is resistant to electromagnetic noise, can ensure high security, and can be used freely by anyone without interfering with wireless communication, but it has a problem that the communication range is limited because the communication distance depends on the strength of the light source.
In addition, Visible Light Communication using a conventional frame-based camera has the following issues: limited information transmission volume due to low time resolution, increased power consumption due to improved camera performance for increased transmission volume, and motion blur (“blurring” of images that occurs when the subject moves fast) and image degradation in low-light environments.
This proposal aims to solve the problems of Visible Light Communication using a conventional frame-based camera by using an event-based vision camera (hereinafter referred to as “event camera”) that has high temporal resolution and can sense changes in luminance with a wide dynamic range (ratio of minimum and maximum detectable luminance) even under low light conditions, while taking advantage of the excellent features of Visible Light Communication.
(2) Algorithm of Visual Light Communication using an event camera
Figure 2 shows an algorithm for reading a signal consisting of a sequence of binary data of 1s and 0s with an event camera. The figure shows an example of reading the signal 0101100 with an event camera. Since an event camera only acquires increasing/decreasing light intensity, the signal 0101100 is created by turning on/off a light source such as an LED, and the event camera detects the change of the light intensity signal from 0 to 1 or from 1 to 0, so that the signal is switched to 1 if the signal before the switch is 0 and to 0 if the signal before the switch is 1.
On the other hand, the proposed method cannot read a signal with two or more 1's, such as 0110, but we have demonstrated that the proposed method can solve this problem with a clever algorithm. Various coding/modulation schemes have been experimentally tried, and experiments have demonstrated that actual communication is possible, including algorithms for error detection and correction. It is also an experiment to demonstrate the feasibility of one-to-N communication, whereas the existing visible light communication devices are for communication between two points.
The upper part: Signal, and the lower part is EVS camera
Visible light communication using an event camera is a new application field of event cameras (cameras that only capture events such as movement and changes), and this proposal is an excellent expression of the concept and was selected as the Grand Prize winner.
(3) Introduction of the team
We are a team brought together by our laboratory. We are interested in an event-based vision camera that can capture only moving objects, and our representative, Mr. Igarashi, has gathered together students who are studying image processing.
(4) Comments on the award
The development using a special camera that only captures moving objects was a very new experience for us. We was surprised that the SDK was well prepared even though the device is not yet widely used. It was difficult to come up with ideas and to implement functions with little information, but we are surely able to improve my ability. In the future, We would like to contribute to the social implementation of this camera through the field of robotics. We am very much looking forward to contributing to the implementation of this camera in society through the field of robotics.
