Images of copper wires with various diameters for validating root image analysis

This image set of copper wires was used for ground truth measurements to validate  RhizoVision Explorer, and open-source software for image analysis of plant roots, as described further below. 

Preprint of the manuscript:

Seethepalli, A., Dhakal, K., Griffiths, M., Guo, H., Freschet, G. T., York, L. M. (2021). RhizoVision Explorer: Open-source software for root image analysis and measurement standardization. bioRxiv: 2021.2004.2011.439359. doi: https://doi.org/10.1101/2021.04.11.439359

Methods:

Copper wire samples with average lengths of 30.48 cm and various diameter wire gauges (American Wire Gauge 40, 32, 28, 22, 16, and 10; with the diameter ranging from 0.09–2.59 mm) were used for the validation. For each gauge, two wires were used for a total of 12 wires. The diameter of each wire was measured with a digital micrometer and the length was measured by fitting string to the length of the wire, then measured with a ruler. The surface area and volume for each wire were calculated assuming the wires were cylinders. The average diameter for scans containing multiple wires was calculated as the weighted diameter based on the length of each wire in the scan. The wires were then scanned on an Epson Expression 12000XL flatbed scanner with a transparency unit (overhead light), as common practice for root imaging. The images were digitized at 600 dpi as 16-bit grayscale images and then saved as TIFF (tagged image file format). Scans were taken in 28 combinations from individual wires to all as shown in order to achieve variation in total length, average diameter, total surface area, and total volume.

The ZIP file contains these 28 images, as well as a CSV file containing the ground truth data measured or calculated as described above.