Abstract: Minute surface unevenness formed on the surface of an object under inspection is detected, thereby improving the accuracy of an appearance inspection. A target surface in the sidewall region (21) of a tire (20) is illuminated by a red slit light from a first illuminating means (11) disposed in the direction of 45 degrees with respect to the normal line to the target surface. At the same time, the target surface is illuminated by a blue slit light from a second illuminating means (12) disposed in the direction of ?45 degrees with respect to the normal line. The illuminated surface is shot by a line camera (13) from the direction of the normal line. An R-component image and a B-component image are produced from the original image, and their respective luminance distribution waveforms are obtained. The surface unevenness formed on the target surface is detected on the basis of the luminance distribution waveforms.

Abstract: Minute surface unevenness formed on the surface of an object under inspection is detected, thereby improving the accuracy of an appearance inspection. A target surface in the sidewall region (21) of a tire (20) is illuminated by a red slit light from a first illuminating means (11) disposed in the direction of 45 degrees with respect to the normal line to the target surface. At the same time, the target surface is illuminated by a blue slit light from a second illuminating means (12) disposed in the direction of ?45 degrees with respect to the normal line. The illuminated surface is shot by a line camera (13) from the direction of the normal line. An R-component image and a B-component image are produced from the original image, and their respective luminance distribution waveforms are obtained. The surface unevenness formed on the target surface is detected on the basis of the luminance distribution waveforms.