1. A fringe light projection method for use with a system for measuring three-dimensional surface-geometry of an object comprising steps of: a) projecting a first triangular coded fringe pattern onto a surface of the object at a specified pitch and along a first direction to produce a first distorted fringe pattern on the object surface; b) capturing, from along a second direction from the projected triangular coded fringe pattern, a first fringe-pattern image of the first distorted fringe pattern; c) projecting at least one additional triangular coded fringe pattern onto a surface of the object at the specified pitch having a phase step relative to each other triangular coded fringe pattern and along the first direction to produce a corresponding at least one additional distorted fringe pattern on the object surface; d) capturing, from along the second direction from the projected triangular coded fringe pattern, at least one additional fringe pattern image corresponding to the at least one additional distorted fringe pattern; e) calculating a distribution of intensity ratios based on the first and the at least one additional fringe-pattern image; and f) calculating a height distribution relative to a pre-determined reference plane, whereby the three-dimensional surface geometry of the object may be determined.