The geometrical and physical properties of red peppers were studied for proper design of a red pepper processor. Mass, volume, roundness and compactness of red peppers were calculated from digital images. They were compared with real data and the relations of them were suggested. Roundness of red peppers was ranged from 0.2 to 0.5 and the average value was 0.349. Compactness of red peppers was ranged from 25 to 50 and the average value was 37.1. The regression equations to calculate the volume and mass of red pepper were obtained as y$\_$v/$\_$=/0.553$varkappa$$_1$+1.441$varkappa$$_2$-1.013$varkappa$$_3$(R=0.95) and y$\_$m/=0.252$varkappa$$_1$+0.938$varkappa$$_2$-0.499$varkappa$$_3$-1.5112 (R=0.93), y$\_$v/:volume(㎤), y$\_$m/:mass(g), $varkappa$$_1$: perimeter(cm), $varkappa$$_2$: area(㎠), $varkappa$$_3$: length of major axis(cm), respectively. The direction for aligning the red pepper in a machine processing was easily and perfectly recognized. The response time for digital image processing has to be reduced for more efficient operation. HSI and YIQ values could be useful for recognizing the red pepper from background.