The possibility of using x-ray radiographic imaging for detecting intenal defects in apples has been investigated. Four hundred to seven hundred each of five Washington State cultivars [Red and Golden Delicious (RD< GD), Fuji (FJ), Granny Smith (GS) and Braeburn (BR)], both defect free and with assorted internal defects (bruises, senescence browning, rot, insect damage and watercore), were imaged using film and on-line line-scanning x-ray equipment. Both axial (stem-to-calyx) and radial images were obtained. The resulting images were presented to human operators, both as still shots and by scrolling them across the screen of a PC at rates approximating that of a commercial packing line. Good recognition [greater than 50% recognized, less than 10% false positives] could generally be obtained on selected cultivars when still shots were inspected. Apple orientation was required for recognition of watercore and rot. However, recognition rapidly fell off as scrolling speeds across the screens approached commercial rates. It is concluded that such inspection may be possible using machine recognition, but probably cannot be achieved using human operators.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.