Microscopic shape from focus with optimal illumination

We present a novel method for compensating illumination artifacts in shape from focus reconstruction that does not require additional measurement time. Frequently applied in optical microscopy, shape from focus requires rich surface texture over the whole scene. This prerequisite is violated in saturated image regions. To overcome this limitation, we automatically compensate for the scene reflectance by means of a projector-camera system on a per-image basis. We iteratively adapt illumination in the first image and consecutively track the compensation pattern through the image stack to reduce measurement time. Despite the low measurement time, our experiments show that our method outperforms the standard shape from focus approach and is also superior to competing methods like high dynamic range imaging in terms of measurement time and accuracy.