1. A surface measurement module for 3-D triangulation-based image acquisition of a surface-under-inspection and under observation by at least one camera, said module comprising: (a) a casing housing an optical system comprising a plurality of lens elements positioned between a fixed-pattern optic and a light source; (b) an output of said fixed-pattern optic comprising a multi-frequency pattern comprising a plurality of pixels representing at least a first and second superimposed sinusoid projected simultaneously, each of the sinusoids represented by the pixels having a unique temporal frequency and each of the pixels projected to satisfy I n p = A p + ∑ k = 1 K ⁢ B k p ⁢ cos ⁡ ( 2 ⁢ ⁢ π ⁢ ⁢ f k ⁢ y p + 2 ⁢ π ⁢ ⁢ k ⁢ ⁢ n N ) ⁢ Eq. ⁢ ( 1.1 ) where I n p is an intensity of a pixel for an n th projected image in a particular moment in time; K is an integer representing a number of component sinusoids, each component sinusoid having a distinct temporal frequency, said output comprising at least N projected patterns; a parameter B k p represents constants that determine an amplitude or signal strength of said component sinusoids; A p is a scalar; f k is a spatial frequency of a k th sinusoid corresponding to a temporal frequency k; and y p represents a spatial coordinate in an image projected as a result of said output; (c) a shifting element to temporally change said output of said fixed-pattern optic during projection onto said surface-under-inspection; (d) a plurality of images captured of said output of said fixed-pattern optic during projection onto said surface-under-inspection are used for the image acquisition; and (e) wherein said casing also houses said shifting element.