Depth-sensing technology using a negative microlens array

In this study, an optical depth-sensing system whose focus distance was equal to its object distance was constructed by using a lens with a shortened depth of field. In addition to a mechanical control lens that captured two-dimensional images, a set of negative microlens array films used to shorten the depth of field was installed in this system. The developed system can scan a region and obtain the relationship curve between the focus distance and the motor step. Depth information is acquired by discerning the sharpness of the object's outline and determining whether the captured object is in focus. The motor step is initialized when the object is in focus. The optical path of the developed system is simple, and its volume is minimal; thus, the developed system is suitable for being combined with cell phone lenses.