Abstract: Methods and systems for determining information about an object are described. In one aspect, a method includes illuminating an object with a plurality of lines of light, the lines being spaced-apart along an axis, and acquiring a sequence of images of the lines of light while rotating the object about the axis. The method further includes, for each image, determining a location of an extremum for each of the lines of light. Furthermore, the method includes establishing a reference line based on the location of the extrema for a first plurality of the lines, calculating a deviation between the extrema of a second plurality of the lines and the reference line, and determining information about the shape of the object based on the calculated deviations.