Imaging device, image processing device, image processing method, program, and recording medium

Patent metadata

Field	Value
Publication number	US-10269101-B2
Application number	US-201715783439-A
Country	US
Kind code	B2
Filing date	Oct 13, 2017
Priority date	Apr 16, 2015
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

A restoration processing unit performs a restoration process based on an optical transfer function of an optical system for a target image. The entire angle of view of the optical system is greater than 90 degrees. A light amount evaluation region of the optical system is a region in which a distance from the center of an image formation plane is not less than 80% of half of the length of a diagonal line of an imaging surface of an imaging element. When a first evaluation wavelength is used, the ratio of the amount of light in the light amount evaluation region to the amount of light in a region of the optical system corresponding to the center of the image formation plane is not less than 25%. When a second evaluation wavelength is used, the value of the MTF of the optical system acquired at half of the Nyquist frequency of the imaging element is not less than 15%.

First claim

What is claimed is:

1. An imaging device comprising:
an optical system;
an imaging sensor that receives imaging light through the optical system and outputs a target image; and
a processor configured to perform a restoration process based on an optical transfer function of the optical system for the target image, wherein:
an entire angle of view of the optical system is greater than 90 degrees;
a light amount evaluation region of the optical system is a region of the optical system in which a distance from a center of an image formation plane of the optical system in the image formation plane is equal to or greater than 80% of half of a length of a diagonal line of an imaging surface of the imaging sensor;
in a case in which a first evaluation wavelength including a wavelength component of 546.1 nm is used, a ratio of the amount of light in the light amount evaluation region to the amount of light in a region of the optical system corresponding to the center of the image formation plane is equal to or greater than 25%; and
in a case in which a second evaluation wavelength including a wavelength component of 406.0 nm, a wavelength component of 430.5 nm, a wavelength component of 471.2 nm, a wavelength component of 522.5 nm, a wavelength component of 577.5 nm, a wavelength component of 628.8 nm, a wavelength component of 669.5 nm, and a wavelength component of 694.0 nm is used, a value of an MTF of the optical system acquired at half of a Nyquist frequency of the imaging sensor is equal to or greater than 15%.

2. An imaging device comprising:
an optical system;
an imaging sensor that receives imaging light through the optical system and outputs a target image; and
a processor configured to perform a restoration process based on an optical transfer function of the optical system for the target image, wherein:
an entire angle of view of the optical system is greater than 90 degrees; and
the optical system satisfies the following expression:



H
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(

f
,
h

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1
2

⁢

(

1
-

1
-

4

S
⁢

⁢
N
⁢

⁢

R
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(
f
)

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R
2

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(
h
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where f indicates a spatial frequency of the target image,
h indicates a distance from a center of the target image,
H(f, h) indicates an OTF of the optical system,
R(h) indicates a ratio of the amount of light in a light amount evaluation region of the optical system to the amount of light in a region of the optical system corresponding to a center of an image formation plane of the optical system in a case in which the light amount evaluation region is a region of the optical system in which a distance from the center of the image formation plane in the image formation plane is equal to or greater than 80% of half of a length of a diagonal line of an imaging surface of the imaging sensor and a first evaluation wavelength including a wavelength component of 546.1 nm is used and satisfies 0≤R(h)≤1,
SNR(f) is represented by SNR(f)=S(f)/N(f),
S(f) indicates a mean square value of the amount of signal at the center of the target image expected in an assumed imaging condition, and
N(f) indicates a mean square value of the amount of noise expected in an assumed imaging condition.

3. An image processing device comprising a processor configured to:
acquire a target image;
acquire imaging device conditions indicating information of an optical system and an imaging sensor when the target image is captured; and
perform a restoration process based on an optical transfer function of the optical system for the target image in a case in which the imaging device conditions satisfy the following:
an entire angle of view of the optical system is greater than 90 degrees;
in a case in which a light amount evaluation region of the optical system is a region of the optical system in which a distance from a center of an image formation plane of the optical system in the image formation plane is equal to or greater than 80% of half of a length of a diagonal line of an imaging surface of the imaging sensor and a first evaluation wavelength including a wavelength component of 546.1 nm is used, a ratio of the amount of light in the light amount evaluation region to the amount of light in a region of the optical system corresponding to the center of the image formation plane is equal to or greater than 25%; and
in a case in which a second evaluation wavelength including a wavelength component of 406.0 nm, a wavelength component of 430.5 nm, a wavelength component of 471.2 nm, a wavelength component of 522.5 nm, a wavelength component of 577.5 nm, a wavelength component of 628.8 nm, a wavelength component of 669.5 nm, and a wavelength component of 694.0 nm is used, a value of an MTF of the optical system acquired at half of a Nyquist frequency of the imaging sensor is equal to or greater than 15%.

4. The image processing device according to claim 3 , wherein the value of the MTF is the smaller of the value of the MTF of the optical system in a sagittal direction and the value of the MTF in a tangential direction.

5. The image processing device according to claim 3 , wherein the processor is further configured to perform the restoration process in a case in which the imaging device conditions further satisfy the following:
in a case in which the first evaluation wavelength is used, the ratio of the amount of light in the light amount evaluation region to the amount of light in the region of the optical system corresponding to the center of the image formation plane is equal to or greater than 30%; and
in a case in which the second evaluation wavelength is used, the value of the MTF acquired at half of the Nyquist frequency of the imaging sensor is equal to or greater than 20%.

6. The image pro

Assignees

• Fujifilm Corp

Inventors

• Tanaka Takuya
• Naruse Yousuke

Classifications

• G08B13/19617

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