An optical apparatus and a method for color scanning a surface of an article moving along a travel path axis make use of an imaging sensor unit including a digital color camera capable of generating highly focused color images, even when distance from surface to camera varies, by providing the camera with an objective defining an optical plane disposed in Scheimpflug configuration. A beam of collimated polychromatic light of an elongated cross-section is directed within a Scheimpflug scanning plane of focus and toward a scanning zone to form a reflected linear band of light onto the article surface of an intensity substantially uniform within the depth of sensing field. The reflected linear band of light is captured by the digital camera to generate a two-dimensional color image thereof, from which a single line color image data is extracted. The line data extraction is repeated as the article moves to generate successive line color image data, from which a two-dimensional color image of the article is built.
