Images of sediment cores are often acquired to preserve primary color information, before such profiles are altered by subsequent sampling and destructive analyses. In many cases, however, no post-processing of these images is undertaken to extract information, despite the fact that image processing can be used to describe and measure structures within the sample. Improvements of RGB (Red/Green/Blue) cameras and image processing algorithms now enable acquisition of high-resolution, metrically calibrated pictures called ortho-images, which have great potential. The way to obtain such ortho-images is by processing several raw images. We propose a semi-automated method that uses metrically calibrated targets to create the ortho-image, using Agisoft Photoscan software and a Python script. The method was tested on sediment cores up to 1.5 m long. It was compared to an approach without markers, one that uses only image matching. The proposed method showed better resolution and less distortion (GSD: 59 µm, RMSE: 7–18 µm). Images acquired without calibrated targets can still be used, by manually positioning points that can then be metrically calibrated. This approach is very useful for smartphone images taken in the field. There are many potential applications for such images of sediment cores, for instance as metric stratigraphic logs to facilitate description of the profile by unit, to study and measure structures (e.g. laminae, instantaneous deposits), or use of image registration or data fusion to create spatial landmarks for non-destructive sensors or destructive laboratory analyses. High-resolution metrically calibrated RGB images of sediment cores are simple to acquire and can play an important role in paleoclimate and paleoenvironmental studies.

在随后的采样和破坏性分析改变这些剖面之前，通常获取沉积物核心的图像以保留原色信息。然而，在许多情况下，尽管图像处理可用于描述和测量样本内的结构，但并未对这些图像进行后处理以提取信息。RGB（红/绿/蓝）相机和图像处理算法的改进现在可以获取高分辨率、度量校准的图像，称为正射图像，具有巨大的潜力。获得这种正射图像的方法是处理几个原始图像。我们提出了一种半自动方法，该方法使用度量校准的目标来创建正射图像，使用 Agisoft Photoscan 软件和 Python 脚本。该方法在长达 1.5 m 的沉积岩心上进行了测试。它与一种没有标记的方法进行了比较，一种只使用图像匹配的方法。所提出的方法显示出更好的分辨率和更少的失真（GSD：59 µm，RMSE：7-18 µm）。通过手动定位可以进行度量校准的点，仍然可以使用在没有校准目标的情况下获取的图像。这种方法对于在现场拍摄的智能手机图像非常有用。沉积岩心的此类图像有许多潜在的应用，例如作为公制地层测井以促进按单元描述剖面，研究和测量结构（例如层状、瞬时沉积物），或使用图像配准或数据融合来创建非破坏性传感器或破坏性实验室分析的空间地标。