Design And Realization Of The Simulation Algorithm On The Synthesis Of Directional Illumination Data

Vibrator, as a non-destructive source, is the main hypocenter in urban exploration, whether we can improve the SNR and the resolution of seismic data is the key point to sovle the problem of the underground structure detection by vibrators effectively. However, the conventional single vibrator has a low signal-to-noise ration, although it is low cost and simple; phased-array vibrator meets the requirement of high signal-to-noise ratio indeed and can produce any direction seismic waves at the same time, however, which would occur some problems in the practical applications such as high cost, complicated control, weak consistency, low efficient working and so on. Therefore, in order to improve the signal-to-noise ratio of vibrators, the directional illumination technology, which combining the strong points of single vibrator and phased-array vibrator, has practical significance. Then the study on the directional illumination technology theory and design the directional illumination synthesis method from simulate angle, and then achievement the goals of the simulation algorithm of directional illumination vibrator and of preliminary studies on directional illumination synthesis of field data, which not only provide us the basis on achievement the goals of the synthesis of directional illumination vibrator data under the condition of complex geology finally, but also provide necessary reference and experience for directional illumination synthesis method of the field data.Therefore, basing on directional illumination technology theory, the thesis first studies the synthetic method of the directional illumination vibrator according to different layer models, and then the SNR based on single vibrator directional illumination technology are calculated to indicate the improvement degree of SNR from quantitative angle., and finally primary discussion and research has been taken on the directional illumination synthesis method of field data Specific contents as follows:1 The lighting techniques theory is researched in this thesis, and a simulation method based on single vibrator directional illumination is designed according to the following three principles: effective testing method of seismic wave, calculation of improved SNR and related parameters selection. This method laid the foundations of both the simulation based on single vibrator directional illumination in different layer models and the synthesis of field directional illumination data. 2 The simulation algorithm of directional illumination vibrator signal in different layer medium models is realized, and a strong emphasis on the study of the influences on single vibrator Directional illumination is laid, these influences include vibrator numbers, intervals, delays and noise intensity. Delay is especially researched for it directly affect the direction of directional vibrator wave. Through a qualitative analysis on the contrast of single vibrator, phased-array vibrator and directional illumination technology, the directional illumination technology is validated better than single vibrator in the aspect of SNR, its advantage is obvious especially in low -SNR testing region.3 Based on different layer models such as horizontal monolayer, horizontal multilayer, inclined monolayer and so on, the SNR of reflection signals generated in single vibrator, phased-array vibrator and directional illumination vibrator are respectively calculated and compared. Furthermore, when vibrator number, vibrator interval, delay and some other parameters are changed, the SNR based on single vibrator directional illumination technology are calculated to indicate the improvement degree of SNR from quantitative angle. The results show that directional illumination technology can dramatically improve single vibrator SNR, however, the effect is inferior to phased-array vibrator. When the noise intensity is relatively small, compared to single vibrator SNR, the improvement degree is similar. But when the noise intensity is relatively large, the noise suppressing ability is inferior to phased-array vibrator. However, as directional illumination technology is generated by later data combining, when the vibrator number is increased, the SNR is better phased-array vibrator.4 Primary research has been taken on the Directional illumination synthesis method of field data, not only the related parameters are reasonable choosed, but also the improvement of SNR on the synthesis result is analyzed. The research proves that the directional illumination technology performs excellent SNR and it is flexible and efficient. Finally, the software is designed which implement the batch processing of mass data in measuring line.