Table 1.

Comparison of different imaging mediums used for radiography

S. No.	Imaging medium	Advantage/Limitation	Agricultural product/ commodity and application	Reference
1	Photographic plate/ film	High resolution, cheap, easy to use, needs development, no instantaneous results, storage requires physical space.	Wheat, corn, sorghum (insect infestation), Apple (Bruised apple sorting)	Milner et al. (1950), Kirkpatrick and Wilbur (1965), Mills and Wilbur (1967), Diener et al. (1970), Sharifi and Mills (1971a, b), Stermer (1972), Schatzki and Fine (1988), Keagy and Schatzki (1991)
	Fast industrial radiography film	Fine grain and high resolution	Mango (seed weevil detection), Apple (Watercore damage), Tree ring measurement	Thomas et al. (1995), Schatzki et al. (1997) and Okochi et al. (2007)
	Digitizing the radiography film	Ease of storage and retrieval and possibility of image processing. Cannot be online, digitization requires special effort and device	Pistachio nuts (Worm damage), Almonds, Wheat, Citrus, peach, guava (infestation)	Keagy et al. (1996), Casasent et al. (1998), Kim and Schatzki (2001), Fornal et al. (2007), Jiang et al. (2008), Haff and Slaughter (2004)
2	Photodiode	Solid state device, digital output, device requires cooling, resolution not as good.	Lettuce heads (differentiate mature from immature heads), grain (infestation), scattered radiation measurement, Apple (watercore)	Lenker and Adrian (1971), Stermer (1972), Zwiggelaar et al. (1997), Schatzki et al. (1997)
3	Camera	Solid state device, digital output, available in variety of resolutions, real time analysis possible, expensive, special triggering systems required if used online	Wheat (insect infestation), detection of soft materials by selective energy of X-ray transmission imaging, pecan quality evaluation	Schatzki and Fine (1988), Zwiggelaar et al. (1997), Kotwaliwale et al. (2007a, b)
	Line scan camera	More suitable for imaging while the sample is moving on a conveyor, available in variety of resolutions, real time analysis possible. The sample needs to be placed under radiation for a longer time compared to area scan cameras.	Detection of Apple watercore, quarantine inspections for detecting alien pests in imported fruits	Kim and Schatzki (2000), Jiang et al. (2008)
4	Intensifiers/ Fluoroscopes/Intensifier coupled to CCD camera/ Combination of fluoroscope, B/W digital camera, and image digitizer		Wheat (insect infestation), wheat and corn flow rate, wheat infestation, horticultural peat (detection of glass contamination), wheat infestation, wheat fungal infection	Karunakaran et al. (2003b), Arslan et al.(2000), Haff and Slaughter (2004), Ayalew et al. (2004), Karunakaran et al. (2004c, 2004d), Neethirajan et al. (2006a) and Narvankar et al. (2009), Morita et al. (1997)