Research On Lineament Extraction Method In Geological Aspect

Lineament is linear expression that exists in artificial features and natural environment.In images, lineament is expressed through tonal change, brightness variation. Lineamentcontains a wealth of important geologic thematic information, such as linear structures, circlestructures, stratigraphic boundaries, geological body boundaries, seismic zone boundaries,mineralized alteration zone boundaries etc. As the carrier of lineament, satellite image is themost popular image resource and developing fast. The traditional way of lineament extractionin satellite image is visual interpretation, which is a quite subjective process, requiresexpertise and scientific skills, time consuming and expensive. To improve analysis efficiencyand reduce subjectivity, automatic extraction and interpretation is a pressing requirement. Thisthesis aimed to extract and utilize the lineaments in satellite images, using fusion method,edge extraction method, lineament statistics and analysis methods as key points. Researchresults and achievements were as follows:(1) A fusion method WBS was proposed. The fusion method was based on fast discretecurvelet transform via wrapping, the sub-band of low frequency was processed by theweighted average algorithm, the sub-band of middle frequency was processed by themaximum region edge detection algorithm, and the sub-band of the highest frequency wasprocessed by the maximum substitution algorithm. The experimental results show that, WBSis a suitable fusion method for high resolution satellite images with serious noise; itoutperforms traditional fusion methods in common image evaluation indicators and noisereduction evaluation indicators.(2) An edge detection method HSOD was proposed. The edge recognition was enhancedby using Gaussian high-pass filtering instead of low-pass filtering; OSTU method was usedfor edge point location, which made the threshold set automatically, and the combination ofstrong and weak thresholds reduced the loss of edge points; the edge connection method wasbased on the eight connection pathway, which made the strong edge points combined wellwith the weak edge points and formed more accurate and complete edges. The experimentalresults show that, HSOD outperforms traditional edge detection methods in evaluationindicators.(3) An automatic geological interpretation solution of satellite images was proposed.Based on the inner connection between lineament and geological anomaly field characteristics,the lineament extraction method proposed above, the statistic analysis methods, and theapplication solution of lineament in geologic area was systematically set up, which completed the solution of automatic interpretation for geology area. This solution was validated in tworesearch areas including Kalpin uplift in Xinjiang province and Hutouya polymetallic orefield of Qimantage in Qinghai province.