Distance image acquisition apparatus and distance image acquisition method

• US 9,953,433 B2
• Filed: 09/22/2017
• Issued: 04/24/2018
• Est. Priority Date: 03/30/2015
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Takao, Hiroaki, Misawa, Takeshi, Kamiya, Takeshi, Masuda, Tomonori, Fujita, Koudai
• Primary Examiner(s): Wu, Jingge
• Application Number:
  US15/712,545
• Publication Number:
  US 20180012372A1
• Time in Patent Office: 214 Days
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/493 Extracting wanted echo signals
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A distance image acquisition apparatus includes a projection unit which projects a first pattern of structured light in a plurality of wavelength bandwidths, an imaging unit which is provided in parallel with and apart from the projection unit by a baseline length, performs imaging with sensitivities to a plurality of wavelength bandwidths, and generates a plurality of captured images corresponding to a plurality of wavelength bandwidths, a determination unit which determines whether or not a second pattern of structured light projected from another distance image acquisition apparatus is included in the captured images, and a pattern extraction unit which extracts the first pattern from a captured image determined as the second pattern being not included by the determination unit, and a distance image acquisition unit which acquires a distance image indicating a distance of a subject within a distance measurement region based on the first pattern.

Claims

1. A distance image acquisition apparatus comprising:

a projector which projects a first pattern of structured light distributed in a two-dimensional manner with respect to a subject within a distance measurement region in a plurality of wavelength bandwidths;

a camera which is provided in parallel with and apart from the projector by a baseline length, performs imaging with sensitivities to the plurality of wavelength bandwidths, and generates a plurality of captured images including the first pattern reflected from the subject and corresponding to the plurality of wavelength bandwidths; and

a processor configured to;

determine whether or not a second pattern of structured light projected from another distance image acquisition apparatus is included in the captured images;

extract the first pattern from at least a captured image determined as the second pattern being not included; and

acquire a distance image indicating a distance of the subject within the distance measurement region based on the first pattern extracted,

wherein the first pattern and the second pattern are dot patterns, and

in a case where the number of dots of a dot pattern in the captured image exceeds the number of dots of the first pattern projected from the projector, the processor determines that the second pattern is included in the captured image.

2. The distance image acquisition apparatus according to claim 1,

wherein the processor determines that the second pattern is included in a captured image in a wavelength bandwidth indicated by beacon information, which is received at the distance image acquisition apparatus, the beacon information indicating the wavelength bandwidth of projection of the second pattern from the another distance image acquisition apparatus.

3. The distance image acquisition apparatus according to claim 1, further comprising:

a light modulator which makes the first pattern be projected from the projector sequentially in the plurality of wavelength bandwidths,

wherein the camera performs imaging with a sensitivity only to a wavelength bandwidth of the first pattern during projection from the projector among the plurality of wavelength bandwidths in synchronization with switching of the wavelength bandwidths in the light modulator.

4. The distance image acquisition apparatus according to claim 1,

wherein the projector projects the first pattern simultaneously in the plurality of wavelength bandwidths.

5. The distance image acquisition apparatus according to claim 1,

wherein the camera has a plurality of types of light receiving elements having sensitivities to the plurality of wavelength bandwidths.

6. The distance image acquisition apparatus according to claim 1, further comprising:

a transmission wavelength bandwidth switching device which switches a transmission wavelength bandwidth of light entering the camera; and

a transmission wavelength bandwidth control unit which switches the transmission wavelength bandwidth of light entering the camera with the transmission wavelength bandwidth switching device to make the camera perform imaging with sensitivities to the plurality of wavelength bandwidths.

7. A distance image acquisition method comprising:

projecting a first pattern of structured light distributed in a two-dimensional manner with respect to a subject within a distance measurement region from a projector in a plurality of wavelength bandwidths;

performing imaging with sensitivities to the plurality of wavelength bandwidths with an camera provided in parallel with and apart from the projector by a baseline length, and generating a plurality of captured images including the first pattern reflected from the subject and corresponding to the plurality of wavelength bandwidths;

determining whether or not a second pattern of structured light projected from another distance image acquisition apparatus is included in the captured images;

extracting the first pattern from at least a captured image determined as the second pattern being not included; and

acquiring a distance image indicating a distance of the subject within the distance measurement region based on the extracted first pattern; and

in a case where the number of dots of a dot pattern in the captured image exceeds the number of dots of the first pattern projected from the projector, determining that the second pattern is included in the captured image,

wherein the first pattern and the second pattern are dot patterns.