Method for screening and compressing data collected by seismic exploration wireless node detector

Abstract

The invention discloses a method for screening and compressing data acquired by seismic exploration wireless node detectors, which comprises the following steps of: S1, setting the proportion of the number of detectors needing to return data to the total number of detectors, and then screening all the detectors to determine the detectors needing to return data; s2, carrying out secondary extraction and compression on the quantized discrete data, and taking the quantized discrete data as to-be-transmitted data; and S3, high-precision data to be transmitted are converted into low-precision data, and the low-precision data are transmitted back through a wireless network. According to the method, a sparse copy of the acquired data can be generated in real time, so that the acquired data can be possibly transmitted back to the seismograph in real time through a wireless network, a seismograph operator is assisted to make a decision on whether complementary measurement is needed in time, and the exploration data acquisition quality is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of geological exploration, and in particular to a method for screening and compressing data collected by a wireless node detector for seismic exploration. Background Art

[0002] All seismic exploration data in seismic exploration need to be stored in a storage medium in a certain format to facilitate on-site quality control and post-processing, interpretation and other processes. According to different instrument types, the data acquisition process also has certain differences. For example, all data of wired detectors are collected from the acquisition equipment to the mainframe of the seismic exploration instrument using cables, and the original seismic exploration data is generated in real time on site, and quality control is carried out. It is submitted for processing and interpretation according to the production schedule cycle; the data of wireless node detectors stores continuous data (all data during the excitation and standby periods) in the device's own memory in real time during the acquisition process. After completing the excitation acquisition process, all node devices are recovered to the data download device and all data are downloaded. Then the continuous data is separated according to the excitation time recorded in the host and synthesized into the original seismic exploration data. The current common seismic data storage format is 32-bit floating point data, that is, each data sample of seismic exploration data occupies 32 binary bits.

[0003] Traditional geological exploration relies on a large number of cables to transmit the data collected by the detectors to the seismographs. Due to the heavy cables and inconvenient installation, wireless node detectors that do not require cables are increasingly being used in geological exploration. In traditional wired data acquisition systems, seismograph operators can see in real time the data collected by each node detector after the shot is fired, and thus determine whether the collected data meets the requirements. This real-time decision is very important in certain scenarios. For example, when laying detectors along a highway, if a large truck happens to pass by when the shot is fired, the interference to the collected signal may be very large, causing the current shot to become a waste shot. If supplementary measurements cannot be made in time at this time, the overall acquisition quality may be greatly affected.

[0004] During the current field data collection process, wireless node geophones first collect data at the construction site, and then special equipment is used to centrally export the data collected by all node geophones during the construction interval. In this way, the seismograph cannot obtain the data of each geophone in real time, and cannot judge the collection quality of the geophone after the current shot is fired, resulting in the failure to timely re-measure the data of the waste shot, which greatly reduces the quality of the exploration data. Due to the large number of wireless node geophones, the total amount of data collected by all node geophones after each shot is fired is large. If the data collected by each node geophone is transmitted back to the seismograph in real time through the wireless network, it will cause the wireless network transmission burden to be too heavy, and it will also consume a lot of node energy, which is not economically cost-effective. Summary of the invention

[0005] In view of the shortcomings of the existing technology, the method proposed in the present invention mainly filters and compresses the data collected by the node detectors. On the basis of ensuring that the seismograph operator can make a real-time decision on whether to conduct additional measurements based on the returned data, the amount of data required to be returned is reduced as much as possible, so as to reduce the transmission burden of the wireless network and reduce the energy consumption of the nodes.

[0006] The present invention provides the following technical solutions:

[0007] A method for screening and compressing data collected by a seismic exploration wireless node detector comprises the following steps:

[0008] S1, setting the ratio of the detectors that need to transmit data back to the total number of detectors, and then screening all the detectors to determine the detectors that need to transmit data back.

[0009] Furthermore, the method further comprises the steps of:

[0010] S2, after the node detector performs analog-to-digital conversion and stores the data, the quantized discrete data is subjected to secondary decimation and compression, that is, a sample point data is uniformly extracted every n sample data as the data to be transmitted.

[0011] Furthermore, the method further comprises the steps of:

[0012] S3 converts the high-precision data to be transmitted into low-precision data and then transmits it back through the wireless network.

[0013] Furthermore, the proportion of the detectors that need to transmit back data accounts for 5%-30% of the total number of detectors.

[0014] Furthermore, the screening method of the detector is one of manual setting, random assignment by random assignment algorithm, or a combination of the two.

[0015] Furthermore, the manual setting is that the seismograph operator specifies the ratio before data acquisition and manually sets the detectors that need to send back data.

[0016] Furthermore, the random assignment algorithm randomly assigns detectors that need to transmit back data in a set ratio using a random assignment algorithm.

[0017] Furthermore, the low-precision data is 16-bit floating-point data.

[0018] Furthermore, the value of n is 5-20, preferably 10.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention discloses a method for screening and compressing data collected by a wireless node detector for seismic exploration. The present invention can screen and compress the data collected by the wireless detector and generate a sparse copy of the collected data in real time, thereby compressing the amount of data that needs to be transmitted through a wireless self-organizing network, making it possible to transmit the collected data back to the seismograph in real time through the wireless network, thereby assisting the seismograph operator to make a timely decision on whether to make a supplementary measurement, thereby greatly improving the quality of exploration data collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a layout diagram of the seismograph and node detectors of the present invention.

[0023] Figure 2 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] For ease of understanding, the present invention uses a specific example to illustrate how the data to be transmitted back is screened and compressed. It should be noted that the data transmitted back through the wireless self-organizing network is only used by the seismograph operator to determine whether additional measurement is needed, and the initial data collected by the detector will be read by a dedicated device during the construction interval.

[0027] Example 1

[0028] The preset conditions and scenarios of the technical solution of the present invention are described as follows:

[0029] After the seismic exploration personnel have deployed the wireless node detectors at reasonable locations, the source vehicle will perform seismic excitation according to the designed location points, and the node detectors will collect seismic signals. The wireless node detectors are equipped with communication modules, and the nodes form a wireless self-organizing network. The data collected by each node can be transmitted back to the seismograph through the wireless self-organizing network. However, due to the large number of node detectors, it is very difficult to require all detectors to transmit the collected data back to the seismograph after each shot is excited, and the node energy consumption is extremely high. The present invention proposes the following method to achieve partial return of collected data, which can help the seismograph operator make a decision on whether to make a supplementary measurement while minimizing the burden on the wireless network.

[0030] The present invention provides a method for screening and compressing data collected by a wireless node detector for seismic exploration. The node detector is configured as follows: Figure 1 In the topology shown in the figure, M*N node detectors are evenly arranged along the network of M rows and N columns, with the seismograph at the far left. Each node detector is equipped with a communication module, and all detectors form a complete wireless self-organizing network. The data to be returned is transmitted to the seismograph by the wireless self-organizing network.

[0031] Furthermore, as a specific implementation method, in order to ensure the quality of seismic exploration data, node detectors are usually arranged relatively densely. However, if it is only for the seismograph operator to make a decision on whether to conduct a supplementary measurement, it is not necessary for all node detectors to transmit data back to the seismograph. In the present invention, the proportion of detectors that need to transmit data back to the total number of detectors is first set, and then the detectors are screened using the following two methods: (1) the seismograph operator specifies the proportion before data collection and manually sets the detectors that need to transmit data back; (2) a random assignment method is adopted, and a random assignment algorithm is used to randomly assign the detectors that need to transmit data back according to the set proportion. After screening the node detectors, the amount of data that needs to be transmitted back will be greatly reduced. For example, when the ratio is set to 10%, after screening, the amount of data that needs to be transmitted back can be saved by about 90%.

[0032] Specifically, as a specific implementation method, the node detectors that need to return information are screened out from all the M*N node detectors. In this example, the screening ratio is set to be 10%.

[0033] There are two screening methods: (1) 1st, 11th, 21st, …┖ M*N*10％┚*10+1 The detector with the highest value will be selected and its collected data will be further processed, while the data of other detectors will not be processed; (2) randomly select ┖M*N*10%┚ detectors from M*N detectors. ┖·┚ represents the rounding down operation of floating point numbers. Random selection is a commonly used and mature method and will not be described here.

[0034] Example 2

[0035] In geological exploration, in order to ensure the quality of exploration data, the accuracy of data collected by node detectors is generally high. However, if it is only for the seismograph operator to make a decision on whether to make additional measurements, it is not necessary to send back high-precision data.

[0036] The present invention provides a method for screening and compressing data collected by a seismic exploration wireless node detector. Figure 2 , the high-precision data stored in the node detector will first be converted into low-precision data and then transmitted back through the wireless network. For example, most high-precision digital signals require 32 bits, but only 16 bits are needed after conversion to low-precision data.

[0037] Specifically, as a specific implementation method, the data collected by the node detector has a higher precision after analog-to-digital conversion, which will occupy a larger space in the memory. In this example, the accuracy of the initial data collected by the detector is set to be higher, 32 bits. In the example of the present invention, for the node detectors selected in Example 1, the data accuracy is reduced so that each data occupies only 16 bits. There are mature methods for converting high-precision floating-point numbers to low-precision floating-point numbers in data processing, which will not be repeated here.

[0038] Example 3

[0039] In geological exploration, in order to ensure the quality of exploration data, when the node detector performs analog-to-digital conversion on the collected analog quantities, the sampling rate is generally above 1000 times per second, and some may reach 2000 times per second.

[0040] In order to further reduce the amount of data that needs to be transmitted back to the seismograph, the present invention provides a method for screening and compressing data collected by a seismic exploration wireless node detector. Figure 2 After the node detector performs analog-to-digital conversion and stores it, the quantized discrete data is subjected to secondary extraction and compression. The extracted data is equivalent to the original analog quantity being sampled at a low sampling rate. For example, if the original sampling rate is 1000 times per second, the secondary extraction and compression method is: for the data after the first sampling, one is uniformly extracted every N intervals, which is equivalent to the original analog quantity being sampled at a sampling rate of 1000 / N. In actual construction, the sampling interval of the secondary extraction can be set according to demand.

[0041] Specifically, as a specific implementation method, the node detector data processed by Example 2 is subjected to secondary extraction in the present invention. One sample point data is uniformly extracted every 10 sampling points as the data to be transmitted. The above method is equivalent to sampling the original analog quantity 200 times per second, which can ensure that the complete information of all seismic waves not greater than 100 Hz is retained, thereby meeting the judgment needs of the seismograph operator.

[0042] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for screening and compressing data collected by a wireless node detector for seismic exploration, characterized in that: The following steps are involved: S1, setting the ratio of the detectors that need to transmit data back to the total number of detectors, and then screening all the detectors to determine the detectors that need to transmit data back.

2. According to claim 1, a method for screening and compressing data collected by a seismic exploration wireless node detector is characterized in that: Also includes the steps: S2, performing secondary decimation compression on the quantized discrete data, that is, uniformly extracting a sample point data every n sample data as the data to be transmitted.

3. A method for screening and compressing data collected by a seismic exploration wireless node detector according to claim 1 or 2, characterized in that: Also includes the steps: S3 converts the high-precision data to be transmitted into low-precision data and then transmits it back through the wireless network.

4. The method for screening and compressing data collected by a wireless node detector for seismic exploration according to claim 1, characterized in that: The proportion of the detectors that need to transmit data back to the total number of detectors is 5%-30%.

5. The method for screening and compressing data collected by a wireless node detector for seismic exploration according to claim 1, characterized in that: The screening method of the detector is one of manual setting, random assignment by random assignment algorithm, or a combination of the two.

6. A method for screening and compressing data collected by a seismic exploration wireless node detector according to claim 5, characterized in that: The manual setting is that the seismograph operator specifies the ratio before data acquisition and manually sets the detectors that need to send back data.

7. A method for screening and compressing data collected by a seismic exploration wireless node detector according to claim 5, characterized in that: The random assignment algorithm randomly assigns detectors that need to transmit data back at random according to a set ratio using a random assignment algorithm.

8. The method for screening and compressing data collected by a wireless node detector for seismic exploration according to claim 2, characterized in that: The low-precision data is 16-bit floating-point data.

9. The method for screening and compressing data collected by a wireless node detector for seismic exploration according to claim 3, characterized in that: The value of n is 5-20.

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