A measurement system includes a cylindrical mirror, a light source, a photosensitive array, and a processor. The light source is configured and positioned with respect to the cylindrical mirror such that light from the light source is reflected from the cylindrical mirror as a circular arc on an object surface. The photosensitive array is positioned with respect to the cylindrical mirror to detect the circular arc on the object surface. The processor is in communication with the photosensitive array and is configured to detect a break in the circular arc and to measure a substance applied to the object surface based on an image detected by the photosensitive array.