TECHNICAL FIELD

This invention relates to the field of electronic imaging. More specifically, to new and useful apparatus, methods, and systems for three-dimensional (3D) imaging using image capturing devices and projected light.

BACKGROUND

Capturing 3D images, images where every pixel contains the distance to a point in the imaged scene, is of growing importance in imaging applications to manufacturing, 3D object scanning, and augmented reality.

As the field of three-dimensional (3D) imaging continues to grow rapidly as an area of technological interest with numerous applications, including applications in construction, manufacturing, research, entertainment, and medicine. A number of these applications require 3D image capture that can perform imaging in real-time and in-situ. Current 3D image capture solutions that meet these criteria are often too power-hungry to perform effectively. Also, providing a novel solution to reduce power consumption for 3D image capture systems is not only useful for current applications but is also potentially capable of opening up new fields of application as well.

Thus, there is a need in the field of 3D imaging to create new and useful methods for capturing the 3D images in accordance with the various application of a 3D image capture system. The embodiments of the present application provide such new and useful methods for capturing 3D images.

BRIEF SUMMARY

The present invention comprises an apparatus for 3D imaging, several methods for producing 3D images using the apparatus, projector subassemblies and related methods, and methods for controlling the projector used in the assembly.

The 3D sensing apparatus comprises two cameras for 3D sensing, a projector of a pre-defined pattern, an optional color camera, and one or more processors for controlling the cameras and projector and processing and/or transmitting data to a host computer. The cameras are preferably synchronized to trigger image capture simultaneously.

The 3D sensing apparatus contains an optoelectronic subassembly for projecting a pattern of light onto the scene in from of the apparatus. One embodiment of the projector uses a laser diode, one or more optical elements to create and focus the pattern, and a photodiode positioned within the housing for monitoring emitted light. Another embodiment of the projector uses an array of light emitting elements arranged on a semiconductor substrate, one or more optical elements to focus and/or create copies of the pattern embedded on the semiconductor substrate, and, optionally, a photodiode positioned within the housing for monitoring emitted light. Methods for producing the optoelectronic subassembly are described.

Methods for capturing 3D images using the apparatus are preferably provided by the invention. One method produces depth images by correlating image regions in one captured image with image regions in a second image. A second method produces depth images by correlating image regions in a first image with image regions in a second image and image regions in a captured reference image of the pattern. A third method produces depth by selecting images from one of the two depth sensing cameras, then correlating image regions from this image with a captured reference image of the pattern. A fourth method produces depth by training a machine learning system to recognize image regions in a captured reference image, then evaluating the machine learning system on captured images. The methods preferably utilize pre-processing steps that reduce error in and enhance the received images. The methods may be carried out on an embedded processor within the apparatus or after the images have been transmitted to a host computer.

The invention preferably captures imagery in such a way as to conserve power expended during operation of the processors, cameras, or projector. Power management may be conducted based on information about scene coverage, scene closeness, apparatus movement, or depth sensing frame rate.

The invention preferably utilizes methods for ensuring the eye safety of the projector. The invention also preferably utilizes methods for controlling the power emitted by the projector, heating up the projector more rapidly than its steady state duty cycle would allow, and synchronizing the projector illumination with the exposure interval of the cameras.

