Plenoptic cameras for three-dimensional imaging

The emergence of increasingly powerful sensors and the rapid growth in computing resources have enabled the intensive development of the 3D imaging we see today. In fact, the volumetric information provided by the scenes (or objects) observed provides additional information to the simple 2D image. In addition to applications for the general public (refocusing, change of point of view), it can be used, for example, to improve diagnostics for medical needs, to aid navigation by providing 3D knowledge of the terrain, and in industry to provide 3D visual assistance for robots, or to control industrial processes. These are non-contact techniques (profilometry, silhouetting) and non-inclusion techniques (3D images in biological tissue or materials).

In the field of cameraphones (cell phone cameras), which today account for 80% of the camera market, manufacturers have accelerated technological advances, notably by reducing pixel size to improve resolution. In 2015, 1.12 µm pixels were marketed, and 0.8 µm pixels are currently under development. Pixel size is approaching the wavelengths of the visible spectrum (0.4 to 0.8 µm), and will soon reach a physical limit. To increase the added value of their products, manufacturers are turning to more functionalization of these cameras. The development of cameraphones with 3D imaging or digital autofocus therefore makes perfect sense. It is estimated that, by 2021, the global market for 3D cameras will be worth almost $10.8 billion.

The instruments used for 3D imaging can be passive (plenoptic, stereoscopy) or active (laser triangulation, time-of-flight).

The plenoptic camera we're interested in here is a single-camera stereoscopic imaging system. This system incorporates a microlens array that can be located in the image plane of the main lens, or in an intermediate plane. Depending on the instrument's optical configuration, the system's spatial and depth resolutions, as well as its depth of field, will vary. Defining your needs will therefore help you choose the best configuration.