Guo Yinjing

Ultrasonic Imaging Detective System Based on Spread Spectrum Technology

In this paper introduce spared spectrum technology into ultrasonic imaging. Analyze how to modulate ultrasonic with the spread spectrum technology, introduce imagining restoration method, and then use this technology to detective the structure of five mine wells. Firstly, use pseudorandom codes to modulate ultrasonic signal before it is sent out, and then demodulate echo to obtain the time difference. Secondly, apply gradual linear iterative method and QR decomposition of least squares method to restore image. Analyze the image with computer we can obtain the structure of objects. Experiment verified introduce spared spectrum technology into ultrasonic imaging can improve the resolution and accuracy.

A compression algorithm for ECG based on integer lifting scheme wavelet transform

In view of the shortcomes of conventional ElectroCardioGram (ECG) compression algorithms, such as high complexity of operation and distortion of reconstructed signal, a new ECG compression encoding algorithm based on Set Partitioning In Hierarchical Trees (SPIHT) is brought out after studying the integer lifting scheme wavelet transform in detail. The proposed algorithm modifies zero-tree structure of SPIHT, establishes single dimensional wavelet coefficient tree of ECG signals and enhances the efficiency of SPIHT-encoding by distributing bits rationally, improving zero-tree set and ameliorating classifying method. For this improved algorithm, floating-point computation and storage are left out of consideration and it is easy to be implemented by hardware and software. Experimental results prove that the new algorithm has admirable features of low complexity, high speed and good performance in signal reconstruction. High compression ratio is obtained with high signal fidelity as well.