Imaging apparatus generating subject image from moire fringe image obtained by concentric pattern and method thereof

Patent metadata

Field	Value
Publication number	US-10928641-B2
Application number	US-201916535493-A
Country	US
Kind code	B2
Filing date	Aug 8, 2019
Priority date	Jun 17, 2015
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

The cost and power consumption of an imaging apparatus are reduced by facilitating detection of an incident angle of a light beam transmitted through a grating substrate. An image sensor converts an optical image captured by pixels arranged on an imaging surface and outputs the converted image signal. A modulator is configured to modulate intensity of light; and an image processing circuit performs image processing of the output image signal. The modulator has a grating substrate, a grating pattern formed on a back surface side of the grating substrate arranged in proximity to the light receiving surface of the image sensor; and a grating pattern formed on a front surface facing the back surface. Each of the grating patterns is constituted of a plurality of concentric circles. The modulator performs intensity modulation on the light transmitted through the grating pattern and outputs the modulated light to the image sensor.

First claim

The invention claimed is:

1. An imaging apparatus comprising:
an image sensor configured to convert light received by a plurality of pixels arranged in an array on a light receiving surface into an image signal and output the image signal;
a modulator arranged on a side closer to the light receiving surface of the image sensor and being configured to modulate the light; and
an image processing circuitry configured to perform image processing of the image signal output from the image sensor,
wherein the modulator includes two concentric patterns arranged so as to face each other,
the modulator is configured to modulate incident light by the two concentric patterns, and
the image sensor is configured to receive the light modulated by the modulator,
wherein a pitch of concentric circles in each of the two concentric patterns becomes narrower in a direction from a center of the concentric circles toward an outer side, and
wherein a center position of the concentric circles in each of the two concentric patterns are offset from each other.

2. The imaging apparatus according to claim 1 ,
wherein the image processing circuitry is configured to perform a two-dimensional Fourier transform on the image signal output from the image sensor, and calculate a frequency spectrum.

3. The imaging apparatus according to claim 1 ,
wherein the center position of the concentric circles in each of the two concentric patterns are offset from each other in a short side direction of an image output from the image processing circuitry.

4. The imaging apparatus according to claim 1 ,
wherein one of the two concentric patterns is formed of a cylindrical lens.

5. The imaging apparatus according to claim 1 ,
wherein the modulator includes a transparent substrate, and the concentric patterns are respectively formed on both surfaces of the transparent substrate.

6. An imaging apparatus configured to generate an image of a subject, comprising:
a modulator including a first concentric pattern and a second concentric pattern arranged so as to face each other, the modulator being configured to modulate light of the subject by the first concentric pattern and the second concentric pattern, and form an optical image that includes a moire fringe;
an image sensor configured to receive the optical image that includes the moire fringe formed by the modulator, convert the optical image into an image signal, and output the image signal; and
an image processing circuitry configured to perform image processing including a Fourier transform on the optical image that includes the moire fringe output from the image sensor, and generate the image of the subject,
wherein a center position of the concentric circles in the first concentric pattern and a center position of the concentric circles in the second concentric pattern are offset from each other.

7. The imaging apparatus according to claim 6 ,
wherein a pitch of concentric circles in each of the first concentric pattern and the second concentric pattern becomes narrower in a direction from a center of the concentric circles toward an outer side.

8. The imaging apparatus according to claim 6 ,
wherein the center position of the concentric circles in the first concentric pattern and the center position of the concentric circles in the second concentric pattern are offset from each other in a short side direction of an image output from the image processing circuitry.

9. The imaging apparatus according to claim 6 ,
wherein the first concentric pattern is positioned on a side closer to the image sensor, the second concentric pattern is positioned on a side closer to the subject, and the second concentric pattern is formed of a cylindrical lens.

10. The imaging apparatus according to claim 6 ,
wherein the modulator includes a transparent substrate, the first concentric pattern is formed on a surface of the transparent substrate facing a light receiving surface of the image sensor, and the second concentric pattern is formed on an opposite surface of the transparent substrate.

11. A method of generating an image for generating an image of a subject by using an image sensor, the method comprising the steps of:
forming an optical image that includes a moire fringe by modulating light of the subject, by using a modulator that includes a first concentric pattern and a second concentric pattern facing each other;
receiving the optical image that includes the moire fringe formed by the modulator, converting the optical image into an image signal, and outputting the image signal, by using the image sensor; and
generating the image of the subject by performing signal processing including a Fourier transform on the image signal of the optical image that includes the moire fringe output from the image sensor, by using an image processing circuitry,
wherein a center position of the concentric circles in the first concentric pattern and a center position of the concentric circles in the second concentric pattern are offset from each other.

12. The method of generating an image according to claim 11 ,
wherein a pitch of concentric circles in each of the first concentric pattern and the second concentric pattern becomes narrower in a direction from a center of the concentric circles toward an outer side.

13. The method of generating an image according to claim 11 ,
wherein the center position of the concentric circles in the first concentric pattern and the center position of the concentric circles in the second concentric pattern are offset from each other in a short side direction of an image output from the image processing circuitry.

14. The method of generating an image according to claim 11 ,
wherein the second concentric pattern is formed of a cylindrical lens.

15. The method of generating an image according to claim 11 ,
wherein the first concentric pattern is positioned on a side closer to the image sensor, the second concentric pattern is positioned on a side closer to the subject, and the second concentric pattern is formed of a cylindrical lens.

16. An imaging apparatus comprising:
an image sensor configured to convert light received by a plurality of pixels arranged in an array on a light receiving surface into an image signal and output the image signal;
a transmissive modulator arranged on a side closer to the light receiving surface of the image sensor and being configured to modulate the light; and
an image processing circuitry configured to perform image processing of the image signal output from the image sensor,
wherein a first concentric pattern is formed on one surface of the modulator, and the modulator is configured to modulate incident light by the first concentric pattern,
the image sensor receives the light modulated by the modulator and outputs the image signal that includes an image corresponding to the first concentric pattern,
the image processing circuitry is configured to:
input the image signal that includes the image corresponding to the first concentric pattern output from the image sensor;
generate an image of a second concentric pattern;
generate an image corresponding to the first concentric pattern contained in the input image signal, and generate a moire fringe image using the image of the second concentric pattern; and
perform processing including a two-dimensional Fourier transform on the generated moire fringe image, and generate an image.

17. The imaging apparatus according to claim 16 ,
wherein a pitch of concentric circles in the first concentric pattern becomes narrower in a directio

Assignees

• Maxell Ltd

Inventors

• Shimano Takeshi

Classifications

• H04N25/00

  Circuitry of solid-state image sensors [SSIS]; Control thereof · CPC title

• H04N23/60

  Control of cameras or camera modules · CPC title

• G02B27/4205 Primary

  having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant · CPC title

• G03B15/00

  Special procedures for taking photographs; Apparatus therefor · CPC title

• G02B27/4272

  having plural diffractive elements positioned sequentially along the optical path · CPC title