Araguaney Solar vehicle telemetry system

In an automotive prototype, having a telemetry system is of great importance since it allows measuring and recording its behavior under real operating conditions. For this reason, a telemetry system was developed, composed of hardware and software stages. For the system's development process, first, the variables to be measured were defined, and the data transmission networks and communication stages were chosen. Both the RF communication cards and the 915 MHz band were chosen.

For this application, we use data packet formats, communication protocols, encryption algorithms, and Red Solomon coding to increase the transmitted data's reliability and efficiency. The radio system developed comprises a transmitter chipset (CC1101), coupling networks, amplifiers, duplexers, and an antenna (see Fig. 1). The transfer of information to the transmitter and receiver card is done through the CAN 2.0 protocol and the telemetry card, as shown in Fig.1.Transmitter and receiver card Figure 2.

using chip CC1101.

Communication protocol CC1101

The information packets coming from the CAN bus are transferred to the RF module via SPI protocol. The captured information is stored in registers depending on the packet type. These packets are assigned an identification command,

Fig.2. Control card of transmitter and length, and CRC16 polymode, encrypted using AES. After

the receiver based on chip CC1101 passing through this process, the packets are separated into

128-byte blocks. Each block is encoded using Reed Solomon, forming three blocks of 160 bytes to which an identifier is assigned. The new block encoding is transferred via SPI to the chipset in 256-byte blocks. The maximum data buffer size of the CC1101 is 256 bytes.

At the hardware level, the telemetry system has the following characteristics:

- Modulation type: 2-FSK.

Communication technique: FHSS 510 hops/s.

- ∆f = 80 KHz.

- Fc = 915 MHz.

- Rb = 125 kbps.

- Modulation index: 0.64.

- Channel frequency: 200 kHz.

- Number of channels 16.

- Minimum output power: +0dBm.

- Maximum output power: +27dBm.

- Sensitivity: -86.5 dBm.

- Network losses: 2dB.

- Free space losses 97.748dB.

- Maximum range: 1Km

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Three-dimensional hyperspetral camera based on near-infrared single-pixel imaging

This work presents the development of a multi-spectral vision system that combines different technologies detecting radiation in the visible spectrum (380-750 nm wavelengths), in the near-infrared NIR (1550 nm wavelengths), in the thermal spectrum band 1.4µm, and 77 GHz millimeter band. The main motivation of the this work is to propose a new hyperspectral approach to overcome the limitations present in commercial vision systems, such as the high amount of memory needed to generate images, the low quantum efficiency of silicon sensors, noise due to disturbance of the visible spectrum, limitations caused by foggy or low visibility conditions, and the difficulty to determine the depth information for objects in the image. Therefore, we propose a hybrid vision system that combines the capabilities offered by RADAR technology at the a range of tens or hundreds of meters, the ability to trace surfaces and operate under low visibility conditions, using a vision system based on single-pixel imaging (SPI) operating in the near-infrared NIR (@ 1550 nm) part of the spectra and Time-of-flight (ToF) based system using an InGaAs high quantum efficiency detector (QE(λ)>80 @ 1550 nm wavelength). Furthermore, SPI systems have a high intrinsic compression capacity at the hardware level, so less memory is needed for image generation, reaching PSNR values > 20 db (the PSNR level acceptable image quality in the industry is between 20 and 50 dB). Developing a system with these characteristics offers a high advantage for applications such as drones, autonomous vehicles, and other techniques that operate with 2D/3D vision or video systems. For the implementation of the system, a structured lighting SPI architecture was developed using an array of 32 x 32 NIR LEDs emitting radiation in the wavelength of 1550 nm that operates in combination with other technologies such as an 80 GHz millimeter band radar, a Time-of-flight system based on four pulsed lasers, a 32 x 24 thermal camera sensor, and a camera with northern vision capability. The developed vision system has an operating range of 37.5 mm to 5 m with a maximum spatial resolution of 10 mm in the distance range below 1 m. As a single-pixel image processing strategy, the Orthogonal Matching Pursuit (OMP) compressed sensing algorithm supported on a GPU architecture is used to achieve a processing times of below 30 ms, which corresponds to a 24 frame/sec video rate.

Future applications NIR-SPI hyperspectral system

The last decade has promoted different detection technologies adapted to different conditions in rainy, fog, or low-visible scenarios. The object detection under scattering conditions has converter in a challenge to which they have proposed some solution as use of the RADAR or LIDAR . A point important to considerer in a scattering condition is the elastic Mie scattering effects which in NIR spectrum decreases, for which a NIR-SPI system is a solution efficiency with low-cost and integration which in recent years have improved, reaching processing times close to real-time and capacity of 3D images. Therefore, these offer an advantage for its integration in systems perception using today in different vehicles, where it doesn't need to have a high-quality image for application as vision sensors detect and avoid obstacles, 2D/3D pre-mapping, or navigation applications.

Our NIR-SPI system developed if adopted in UAVs (see Fig. 1) offers a solution to perform better visualization of the scene in outdoor conditions. If compared to conventional vision systems that usually use RGB sensors operating in the visible spectrum. As explained, conventional systems operating in the VIS range present much higher image degradation in scattering conditions than those operating in the NIR part of the spectra. The integration of our NIR-SPI system into UAVs increases spectral capacity detection. In addition, it provides fast deployment at remote or challenging locations, being essential for many civil and military applications such as post-disaster relief assistance. Therefore, we believe that the NIR-SPI system presented has a great potential to be used in similar applications. Furthermore, SPI could be an alternative to the use of LIDAR technology.

Fig. 1. Future applications NIR-SPI hyperspectral system recues Drone

SPI applications are not limited to vision sensors, but new applications have also been developed. For example, in VR/AR systems, we can cite MEMSEye system that works using SPI and MEMS mirror to a generation of 3D images (see Fig .2b), and applications in holography . Others applications that are studied is adaption as vision system for ROVs or underwater, SPI-RADAR (see Fig.2c), and hyper-spectral . This later field of application has great importance in the area medical [241] (see Fig. 2d), the space exploration , and CubeSat.

Fig.2. Overview of new fields for applications system vision SPI: (a) SPI-LIDAR , (b) VR/AR , (c) SPI-RADAR , (d) SPI-medical.

Single-pixel image reconstruction using active near-infrared illumination in rainy conditions

RGB silicon-based image sensors operating in the visible (VIS) part of the spectra (with wavelengths between 400 and 700 nm) are highly susceptible to outdoor environmental conditions. They are forced to deal with scattering effects caused by the interaction of light with micrometer size particles in the rain, fog, or smoke, limiting the depth of visibility. Using longer wavelengths, e.g., near infra-red (NIR) radiation with wavelengths of around 1550~nm, would result in less light attenuation effects, eliminating most of Rayleigh scattering and leaving predominantly elastic Mie scattering effects, where the size of the scattering particles is comparable to the used illumination wavelengths. Motivated by the latter, this work proposes a vision system based on NIR active illumination and single-pixel imaging (SPI) using an array of 8 x 8 NIR-LEDs and a single Indium Gallium Arsenide (InGaAs) detector device with high detection efficiency for the wavelength range of interest. The proposed system uses a fusion of the super-resolution convolutional neural networks (CS-SRCNN) and the wavelet method, adapted to different Hadamard active illumination scan patterns for 2D image reconstruction.With the objective of evaluating the NIR-SPI 2D image reconstruction capabilities in scattering environments with rain, we carried out an evaluation of the quality of the reconstructed images using figures of merit such as Structural Similarity Index Measure (SSIM) and Peak Signal-to-Noise Ratio (PSNR) in scenarios of laboratory that simulate different conditions of background illumination and droplet size to test its feasibility as a vision sensor.

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SPIE Future Sensing Technologies 2021, Nov. 14, 2021.

https://doi.org/10.1117/12.2601118.