US 9,310,184 B2 · Systems and methods for suppressing coherent structured illumination artifacts

Abstract

Methods and systems are provided for suppressing speckle and/or diffraction artifacts in coherent structured illumination sensing systems. A coherent radiation pattern forms an interference pattern at an illumination image plane and illuminates an object. Radiation scattered or otherwise emitted by the object is detected to produce a signal, which is integrated in time. Coherent artifact suppression is attained by using a spatial modulator, such as an acousto-optic device, to vary a phase gradient at the illumination image plane during the signal integration time. Various embodiments are provided for purposes including without limitation: preserving the depth of field of the coherent illumination; using the same acousto-optic device for pattern generation and coherent artifact suppression; electronically controlling the effective spatial coherence of the illumination system; and reducing errors due to coherent artifacts in a laser-based three dimensional imaging system.

Claims20

Dependent claims

A method of suppressing at least one of speckle and a diffraction artifact sensed by a detector, the method comprising:

illuminating an object with a first radiation, the first radiation forming an interference pattern at an illumination image plane, and the object producing a second radiation in response to the first radiation;
imparting a phase gradient across the first radiation at the illumination image plane, the phase gradient varying in time during an integration period;
sensing at least a portion of the second radiation with the detector so as to produce a signal representative of the sensed second radiation;
and
temporally integrating the signal over the integration period so as to reduce a deviation of the signal due to at least one of speckle and a diffraction artifact.

2 more elements

An apparatus for estimating a position of a location on an object in a three-dimensional scene, the apparatus suppressing at least one of speckle and a diffraction artifact and comprising:

a means for generating a first radiation;
a means for illuminating the object with the first radiation, the first radiation forming an interference pattern at an illumination image plane, and the object producing a second radiation in response to the first radiation;
a means for imparting a phase gradient across the first radiation, the phase gradient being at the illumination image plane and varying in time during an integration period;
a means for collecting at least a portion of the second radiation and forming an image of the illuminated object, the radiation portion propagating at an angle with respect to an axis orthogonal to the illumination image plane;
a means for sensing at least a portion of the image so as to produce a signal representative of the sensed image portion;
a means for temporally integrating the signal over an integration period so as to reduce a deviation of the signal due to at least one of speckle and a diffraction artifact;
and
a means for estimating the position of a location on the illuminated object using the temporally integrated signal.

5 more elements

Dependencies are inferred from the claim text.

Systems and methods for suppressing coherent structured illumination artifacts

Life of this patent

Systems and methods for suppressing coherent structured illumination artifacts

Life of this patent

Abstract

Claims20