Speckle structured light projection module based on holographic waveguide

Abstract

The invention relates to the field of 3D shape measurement. The invention provides a speckle structured light projection module based on a holographic waveguide, which includes a holographic waveguide unit, an array laser light source, a collimating lens and a diffractive optical element, wherein the holographic waveguide unit is composed of a holographic optical element and a waveguide base material. As a coupling input and output modulation device, the holographic optical element modulates the first speckle pattern emitted by the array laser light source into a total reflection waveguide transmission in the substrate, and then couples and outputs it to the collimator lens after a certain distance, and the diffractive optical element receives the collimated The light beam replicates and expands the first speckle pattern to form a high-density speckle lattice illumination, which is projected onto the scene to be tested. By adopting the holographic waveguide transmission method, the laser array light source can be separated from other optical modulation devices by a certain distance in space, so as to add a heat dissipation device for the light source, and ensure good heat dissipation characteristics while realizing a light and thin structure design.

Description

technical field [0001] The invention relates to the field of 3D shape measurement, in particular to a speckle structured light projection module based on a holographic waveguide. Background technique [0002] 3D shape measurement technology can collect the depth coordinate information of objects in the scene, providing additional data processing freedom for back-end development. With the popularity of mobile terminal devices and intelligent interactive devices, 3D measurement technology has increasingly become the core technology of the new generation of human-computer interaction, and has a wide range of applications in industrial inspection, security retail, somatosensory games, mobile payment, and biomedicine. prospect. [0003] Speckle structured light technology is currently a widely used 3D data acquisition solution. It uses coded random, pseudo-random or regularly arranged spot light clusters as optical probes, and projects them into the space scene. By comparing th...

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Problems solved by technology

Compact and thin projection modules and depth cameras have become an urgent research demand in the field; in addition, due to the compact installation and arrangement of various components in the miniaturized projection module, it will also face the problem of heat dissipation from the light source. Problems seriously restrict the development of speckle projection modules

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