X-ray imaging methods for internal quality evaluation of agricultural produce

Abstract

A number of non-destructive methods for internal quality evaluation have been studied by different researchers over the past eight decades. X-ray and computed tomography imaging techniques are few of them which are gaining popularity now days in various fields of agriculture and food quality evaluation. These techniques, so far predominantly used in medical applications, have also been explored for internal quality inspection of various agricultural products non-destructively, when quality features are not visible on the surface of the products. Though, safety of operators and time required for tests are of concern, the non-destructive nature of these techniques has great potential for wide applications on agricultural produce. This paper presents insight of X-ray based non-destructive techniques such as X-ray imaging and Computed Tomography (CT). The concepts, properties, equipment and their parameters, systems and applications associated with the use of X-rays and CT for agricultural produce have been elaborated.

Assessment of bruise volumes in apples using X-ray computed tomography

“…As a result, X-ray techniques have been explored to detect several kinds of internal defects in agricultural products. These defects are often detectable with X-ray imaging because they change the tissue density locally or the distribution of the water content (Donis-González et al, 2014;Herremans et al, 2013Herremans et al, , 2014aHerremans et al, , 2014bKotwaliwale et al, 2014;Lammertyn et al, 2003). Bruise damage in apples is one of these defects that has been found to be detectable by using linescanning X-ray equipment (Diener et al, 1970;Schatzki et al, 1997).…”

In-line NDT with X-Ray CT combining sample rotation and translation

“…A first way to image a product's interior is through simple 2D radiographic projection, in which all features on the inside and outside of a product in 5 between an X-ray source and a detector are superimposed on one single image. Although some internal defects cannot be distinguished on these single point of view projection images, it is a fast way of imaging the interior of a product in-line and is used as such in a wide variety of application fields, going from weld and crack inspections on metallic parts, to soldering 10 inspection in electronics and contaminant detection in food products [1][2][3][4][5]. In X-ray computed tomography (CT) a series of these 2D radiographs, taken from multiple directions, can be combined to reconstruct a full 3D visualization of an object's interior.…”

“…ρ apple = 0.84 g/cm 3 . Indeed, by segmenting the apple tissue while excluding the core air space, it is possible to accurately determine the tissue volume and subsequently its 180 mass density by weighing the apple.…”

“…Again this parameter is highly dependent on the type and size of the sample, but can be estimated by looking at the 410 theoretical attenuation through a slab with a material and thickness representative for the sample under study, e.g. the Elstar apple can be modelled as a 6 cm thick slab of soft-tissue with a density of 0.8 g/cm 3 . The theoretical transmission through this slab can be calculated across several energy bins covering the complete X-ray tube's spectrum, followed by a back projection 415 of the attenuating mass and its associated error into a resolution element representative of a CT reconstruction [16,30].…”

Detección de Eurhizococcus colombianus (Hemiptera: Margarodidae) en mora por espectroscopía del infrarrojo cercano

“…En los últimos años, varias investigaciones a nivel mundial se han concentrado en el desarrollo o adaptación de mé-todos para la detección de insectos en su ambiente natural. Algunos de ellos incluyen el uso de sensores acústicos, microtomografía por rayos-X, radares armónicos, tomografía computarizada, resonancia magnética, ultrasonido y espectroscopia de infrarrojo cercano y visible (Mankin et al, 2000;Reynolds y Riley, 2002;O´Neal et al, 2004;Johnson et al, 2007;Kotwaliwale et al, 2011). La mayoría de equipos empleados para tal fin sólo pueden ser usados a escala de laboratorio, por lo que es necesario validarlos con el fin de desarrollar equipos portátiles con posibilidad de ser usados directamente en campo.…”