Database of hyperspectral images of phosphorus in soil.
The database is made up of the images associated with the hyperspectral cube of each sample, and four tables: the first describes the properties of the soil used to obtain the mixtures, the second the composition of the fertilizer used, the third describes the soil-fertilizer ratio to make up the samples, and the fourth was the laboratory analysis of the total phosphorus content of the analyzed samples. Hyperspectral images can be used to quantify the concentration of total phosphorus in soil samples. 152 soil samples were prepared, and a hyperspectral cube made up of 145 images in the VIS-NIR bands, between 420 and 1000 nm, was obtained from each of them. The images obtained were taken with the Bayspec OCIF Series hyperspectral camera, in push-broom function, using a platform that includes an illumination system that offers a continuous spectrum in the range of interest. The samples were prepared with a soil from the Santander de Quilichao region, Cauca, Colombia, and mixed with known concentrations of P2O5 fertilizer, so that a total mass of 50 g was obtained. Each sample was deposited in a round black plastic container, 6 cm in diameter and a depth of 1 cm. The soil samples were analyzed in the laboratory to establish the concentration of total phosphorus.
Steps to reproduce
Hyperspectral cubes of 152 prepared soil and fertilizer samples were captured. The samples were homogeneous mixtures obtained from a cultivated soil in the region of the Department of Cauca - Colombia and the DAP di-ammonium phosphate fertilizer (P2O5), with a high content of phosphorus and frequently used in the area. Both the soil and the fertilizer were previously subjected to a spraying and screening process. During the capture of the hyperspectral cubes there was no interference from light sources, other than of those integrated into the platform's artificial lighting system. In addition, a prior process of calibrating the lighting of the camera was carried out, in which the maximum (white reference adjustment) and minimum (black reference adjustment) reflectance values are established, following the directions of the camera manufacturer. In this fashion, the acquired images are adjusted, and the gain and exposure time values are set. The height of the camera ensures that the field of view covers the area of interest, while the scan speed during the push-broom progressive scan has been adjusted so that the aspect ratio (width and length) of the image matches the sample image.