Multi-Scale FPGA-Based Infrared Image Enhancement by Using RGF and CLAHE.

Infrared sensors capture thermal radiation emitted by objects. They can operate in all weather conditions and are thus employed in fields such as military surveillance, autonomous driving, and medical diagnostics. However, infrared imagery poses challenges such as low contrast and indistinct textures due to the long wavelength of infrared radiation and susceptibility to interference. In addition, complex enhancement algorithms make real-time processing challenging. To address these problems and improve visual quality, in this paper, we propose a multi-scale FPGA-based method for real-time enhancement of infrared images by using rolling guidance filter (RGF) and contrast-limited adaptive histogram equalization (CLAHE). Specifically, the original image is first decomposed into various scales of detail layers and a base layer using RGF. Secondly, we fuse detail layers of diverse scales, then enhance the detail information by using gain coefficients and employ CLAHE to improve the contrast of the base layer. Thirdly, we fuse the detail layers and base layer to obtain the image with global details of the input image. Finally, the proposed algorithm is implemented on an FPGA using advanced high-level synthesis tools. Comprehensive testing of our proposed method on the AXU15EG board demonstrates its effectiveness in significantly improving image contrast and enhancing detail information. At the same time, real-time enhancement at a speed of 147 FPS is achieved for infrared images with a resolution of 640 × 480.

Submarine cable monitoring system based on enhanced COTDR with simultaneous loss measurement and vibration monitoring ability.

A submarine cable monitoring system based on enhanced coherent optical time-domain reflectometry (E-COTDR) is realized. An improved optimal peak-seeking (OPS) based I/Q demodulation method is employed for simultaneous loss measurement and vibration monitoring. A single-end diagnosis range over 74km is achieved for the proposed E-COTDR, enabling the double-end cooperative system to have a single-span of 148km. For the multi-span cascaded cables over 1000km, the loss and vibration monitoring without fading zone is carried out for a single-span of 121km. The proposed system provides a reliable technical option for the next generation underwater cable monitoring applications.