Dataset for, "Modelling of longitudinally cut carrot curling induced by the vascular cylinder-cortex interference pressure"

Data collection method:

Fifty-two fresh Nantes carrots (Brookfield Farm, Lancashire, UK) of varying sizes were stored in zip lock bags in a refrigerator at 3°C. Each carrot was labelled and marked with a pen at positions 10 mm and 20 mm from the crown end and then in intervals of 20 mm until the tip end. The diameters at the marked position were measured with a vernier calliper which achieved an accuracy of 0.02 mm. The length and mass of each carrot was also recorded using a ruler to the nearest mm and a scale (OPKS009, One Home Collection) of resolution 1 g respectively. The mass recorded was used to measure evaporable moisture content. Each carrot was chopped in half with a sharp chef’s knife. Each carrot half was clamped lightly on a lab stand such that the cut plane was levelled with the 18 megapixel camera (Coolpix S9400, Nikkon, fitted with a Nikkor 18x wide optical zoom lens VR set to 25mm focus (or zero-zoom)). The setup was levelled using a spirit level on the cut surface at the crown tip. One image was taken for each carrot half before being stored in a zip lock bag in the refrigerator (AUCL 4884W) at 3°C. The bags counteract the dried refrigerator’s natural convection, which prolongs the lifespan of the carrots by lowering the root vegetables’ hydration. The halves were placed along the vertical edge of the bags to ensure the curling action of carrots can occur as naturally as possible. The procedure was repeated for all carrot halves on the 3rd and 7th day after the initial cut. The measurement workspace made use of a blue background to maximise the contrast of carrots when applying a thresholding algorithm to the images. Zhang’s method of camera calibration was used to ensure real straight lines remain straight on the image. A printed checkerboard pattern of 63 10-mm squares was printed on card held in line with the plane of the carrot centreline in the images to allow removal of this distortion. To segment the carrot half from the image background, Otsu’s method was utilised to generate binary images of each carrot. A MATLAB script was written to extract from the image the upper edge of a carrot half as a position vector, from which the radius of curvature could be estimated using the second-order Kása circle fitting procedure.

Data processing and preparation activities:

N/A

Technical details and requirements:

The code to extract both the images and finite element results were run with MATLAB v. 2020. Ansys R2 v. 2020 was used to model the single-curvature model.