Optical method and apparatus for measuring objects

A sawing inspection system to measure dimensions of a cant that has been cut into pieces is disclosed. The system includes a housing having a window， an image sensor， a first mirror， and a second mirror. The first mirror includes a concave parabolic reflective surface and a focal point， and the second mirror includes a flat， reflective surface. The focal point is where parallel rays of light that enter the housing through the window and reflect off of the concave parabolic reflective surface intersect. The second mirror is positioned to reflect toward the focal point the parallel rays of light reflected by the first mirror. The image sensor is located at the focal point. At least one of the first mirror， the second mirror， and the image sensor is movable relative to the others to remove parallax error from the measurement of the pieces of the cant.