Image Sensors Meet LEDs

Kamakura, Koji

doi:10.1587/transcom.2016lci0001

Cited by 18 publications

(7 citation statements)

References 39 publications

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“…We listed the data transmission rates in OOK and the proposed STC when an LED array or a rotary LED transmitter is used in Table III. A LED array transmitter refers to a matrix of LEDs [6]. When the camera shooting speed remains constant, the rotary LED transmitter improves communication speed compared to an LED array transmitter with the same number of LEDs.…”

Section: B Experimental Resultsmentioning

confidence: 99%

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Simplified Alamouti-Type Space-Time Coding for Image Sensor Communication Using Rotary LED Transmitter

2022

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This study proposes a simplified Alamouti-type space-time coding (STC), improving the performance of image sensor communication (ISC) using a rotary LED transmitter. The rotary LED transmitter was developed to increase the data rate of ISC using afterimages of LED lights. The transmitter simultaneously causes the LEDs to blink and rotates them around a vertical axis. Owing to the movement of the blinking LEDs that occurs within the exposure time of the camera, multiple blinking states are captured as afterimages, thus increasing the amount of information that can be received per image. However, with increasing communication distance, the size of the LED light captured on the image sensor decreases. In this case, it is difficult to distinguish each LED blinking state, leading to a degradation of the demodulation performance. To overcome this problem, the proposed STC encodes adjacent angular afterimages as symbol pairs and transmits these symbol pairs using two symbol times. In addition, we simplified the data decoding process by using normalized LED luminance values. We evaluate the demodulation performance of the proposed method through experiments. Compared with conventional coding methods, the proposed STC requires no channel estimation and significantly improves the demodulation performance.

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Section: B Experimental Resultsmentioning

confidence: 99%

“…communication. In ISC, the receiver camera captures the blinking states of the LEDs and outputs them as an image [6]. Because the data are demodulated from a two-dimensional (2D) image, an image processing technique can spatially separate the signal and non-signal light sources.…”

Section: Introductionmentioning

confidence: 99%

Simplified Alamouti-Type Space-Time Coding for Image Sensor Communication Using Rotary LED Transmitter

2022

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“…In ISC, the camera captures LED lights as an image. Because the optical signals and noise can be separated by image processing, ISC has excellent noise immunity [2,3]. However, the communication speed of ISC depends on the camera shooting speed.…”

Section: Introductionmentioning

confidence: 99%

A study on detection of rotary LED transmitter for image sensor communication

et al. 2022

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This study focuses on a rotary LED transmitter (RLT) for image sensor communication (ISC). RLT is a device that improves the transmission rate by utilizing the afterimages generated by moving the LEDs while blinking. When RLT is used in a real environment, the receiver needs to detect the position of the transmitter and the afterimages of lights on the captured image before data demodulation. This paper proposes a method for detecting the position of RLT and the coordinates of afterimages for ISC using RLT. Experimental results show that the proposed method operates correctly without false detection of them in the range of short distances.

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“…The focus of this research is image sensor communication (ISC), which generally refers to the VLC system using a camera as the receiving device [2,3,4]. ISC captures optical signals, which are sent by LEDs, as images and performs image processing to demodulate the data.…”

Section: Introductionmentioning

confidence: 99%

Sequential maximum likelihood decoding incorporating reliability determination for image sensor communication

et al. 2020

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In this study, the sequential maximum likelihood decoding (S-MLD) for image sensor based visible light communication, referred to as image sensor communication, is proposed. The conventional system cannot correctly decode degraded captured images. To overcome this problem, S-MLD partitions the LED area on the image into two segments and sequentially creates pseudo-captured images, which imitate all possible LED blinking patterns. This approach is based on MLD for each segment. Moreover, reliability determination is incorporated to improve communication quality. We performed computer simulations and confirmed that S-MLD exhibits superior decoding performance and approximately 90% computational cost reduction compared to the previous MLD.

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Image Sensors Meet LEDs

Cited by 18 publications

References 39 publications

Simplified Alamouti-Type Space-Time Coding for Image Sensor Communication Using Rotary LED Transmitter

Simplified Alamouti-Type Space-Time Coding for Image Sensor Communication Using Rotary LED Transmitter

A study on detection of rotary LED transmitter for image sensor communication

Sequential maximum likelihood decoding incorporating reliability determination for image sensor communication

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