Technique, analysis routines, and application of direct push-driven in situ color logging

Color data are a useful proxy for soil/sediment parameterization since they reflect material characteristics. We introduce direct push color logging for real-time and depth-resolved, in situ colorimetric record of colors in unconsolidated sediments in terrestrial environments. Until now, no routines exist on how to handle highly resolved (mm-scale) data. To develop such routine, we transform colorimetric data (CIEXYZ) into color surrogates of selected color spaces (CIExyZ, \({\text{CIE}}L^{*} a^{*} b^{*}\), \({\text{CIE}}L^{*} c^{*} h^{*}\), sRGB). We obtain interpretable color logs over depth by filtering with Haar and Daublet4 wavelet functions. We verify the approach, according to repeatability of in situ sediment color measurements, with related lithological determination gathered by state-of-the-art direct push-based cone penetration testing and soil sampling data. The developed routine is appropriate for unambiguous transformation of color data into interpretable color surrogates and filtering small-scale variability. We observe that soil color logs are repeatable and proved to correlate with lithological/chemical changes. Thus, the technique allows enhanced profiling by means of providing a reproducible high-resolution parameter for analysis of soil/sediment characteristics. This opens potential new areas of application and new outputs for in situ-obtained colorimetric data in and beyond geotechnical site characterization.