RESUMEN
BACKGROUND: Multi-channel acquisition systems of brain neural signals can provide a powerful tool with a wide range of information for the clinical application of brain computer interfaces. High-throughput implantable systems are limited by size and power consumption, posing challenges to system design. OBJECTIVE: To acquire more comprehensive neural signals and wirelessly transmit high-throughput brain neural signals, a FPGA-based acquisition system for multi-channel brain nerve signals has been developed. And the Bluetooth transmission with low-power technology are utilized. METHODS: To wirelessly transmit large amount of data with limited Bluetooth bandwidth and improve the accuracy of neural signal decoding, an improved sharing run length encoding (SRLE) is proposed to compress the spike data of brain neural signal to improve the transmission efficiency of the system. The functional prototype has been developed, which consists of multi-channel data acquisition chips, FPGA main control module with the improved SRLE, a wireless data transmitter, a wireless data receiver and an upper computer. And the developed functional prototype was tested for spike detection of brain neural signal by animal experiments. RESULTS: From the animal experiments, it shows that the system can successfully collect and transmit brain nerve signals. And the improved SRLE algorithm has an excellent compression effect with the average compression rate of 5.94%, compared to the double run-length encoding, the FDR encoding, and the traditional run-length encoding. CONCLUSION: The developed system, incorporating the improved SRLE algorithm, is capable of wirelessly capturing spike signals with 1024 channels, thereby realizing the implantable systems of High-throughput brain neural signals.
RESUMEN
OBJECTIVES: The puncture needle of an intelligent puncture robot must accurately reach the target location early in the diagnosis of benign and malignant nodules and in the puncture ablation of malignant tumors. To track the position and the orientation of the puncture needle tip, an electromagnetic tracking system based on adaptive adjustment of excitation intensity and lock-in amplification is proposed. METHODS: The system includes a time-sharing excitation device with multiple magnetic sources, a magnetic sensor, a signal processing device based on dual-phase lock-in amplifiers and a computing platform in the upper computer. With adaptive adjustment of excitation intensity, the time-sharing excitation device uses a microcontroller to control a direct digital synthesizer. Based on feedback from the magnetic sensor, the microcontroller time-shares the power amplifier to generate the required excitation current. Dual-phase lock-in amplifiers demodulate the magnetic sensor output after preamplification and filtering. Through analog-to-digital conversion and the serial interface, the digital signal is sent to the computing platform for solving by neighborhood particle swarm optimization algorithm, and the position and orientation of the puncture needle fixed with the magnetic sensor are obtained. RESULTS: The experimental results within a 300 mm×300 mm×300 mm space show average position errors of 0.4467 cm (X-axis), 0.4154 cm (Y-axis), and 0.3766 cm (Z-axis). The overall average position error is 0.4129 cm, with a root mean square error of 0.4970 cm. CONCLUSIONS: The proposed electromagnetic tracking system can track the needle position and orientation of puncture robots in real-time, thereby enhancing puncture success rates and reducing puncture times.