Image processing device, image processing system, image processing method, and imaging optical system group

Patent metadata

Field	Value
Publication number	US-10817995-B2
Application number	US-201916281109-A
Country	US
Kind code	B2
Filing date	Feb 21, 2019
Priority date	Aug 25, 2016
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

Provided are an image processing device, an image processing system, an image processing method, and an imaging optical system group capable of suppressing an increase in costs and appropriately restoring an image. In the imaging optical system, in a case where a first MTF curve M 1 indicating an MTF value in a first azimuth direction with respect to an amount of defocus from a focal position is compared with a second MTF curve M 2 indicating an MTF value in a second azimuth direction with respect to the amount of defocus from the focal position, a ratio of a peak value P 1 of the first MTF curve M 1 to a peak value P 2 of the second MTF curve M 2 is equal to or greater than 2, and a ratio of a half-value width HW 2 of the second MTF curve M 2 to a half-value width HW 1 of the first MTF curve M 1 is equal to or greater than 1.25. The restoration filter is a common filter corresponding to a representative value of transfer functions in a plurality of same type imaging optical systems.

First claim

What is claimed is:

1. An image processing device comprising:
a processor, configured to;
acquire an image;
acquire a restoration filter corresponding to a transfer function of an imaging optical system, having at least one lens, used for generating the image; and
perform restoration processing on the acquired image through the acquired restoration filter,
wherein in the imaging optical system, in a case where a first modulation transfer function (MTF) curve indicating an MTF value in a first azimuth direction with respect to an amount of defocus from a focal position during focusing on an optical axis is compared with a second MTF curve indicating an MTF value in a second azimuth direction with respect to the amount of defocus from the focal position, a peak value of the second MTF curve is less than a peak value of the first MTF curve, a ratio of the peak value of the first MTF curve to the peak value of the second MTF curve is equal to or greater than 2, a half-value width of the second MTF curve is greater than a half-value width of the first MTF curve, and a ratio of the half-value width of the second MTF curve to the half-value width of the first MTF curve is equal to or greater than 1.25, and wherein the restoration filter is a common filter corresponding to a representative value of transfer functions in a plurality of same type imaging optical systems including the imaging optical system.

2. The image processing device according to claim 1 ,
wherein the first azimuth direction is a circumferential direction of a circle centered on the optical axis of the imaging optical system, and the second azimuth direction is a radial direction of the circle.

3. The image processing device according to claim 1 ,
wherein the restoration filter is a zero-phase restoration filter that makes the restoration processing non-executable on the acquired image in terms of the phase.

4. The image processing device according to claim 1 ,
wherein the ratio of the peak value of the first MTF curve to the peak value of the second MTF curve is equal to or greater than 4.

5. The image processing device according to claim 1 ,
wherein the ratio of the peak value of the first MTF curve to the peak value of the second MTF curve is equal to or greater than 10.

6. The image processing device according to claim 1 ,
wherein the ratio of the half-value width of the second MTF curve to the half-value width of the first MTF curve is equal to or greater than 3.

7. An image processing system comprising:
an imaging optical system, having at least one lens, that, in a case where a first modulation transfer function (MTF) curve indicating an MTF value in a first azimuth direction with respect to an amount of defocus during focusing on an optical axis is compared with a second MTF curve indicating an MTF value in a second azimuth direction with respect to the amount of defocus, a peak value of the second MTF curve is less than a peak value of the first MTF curve, a ratio of the peak value of the first MTF curve to the peak value of the second MTF curve is equal to or greater than 2, a half-value width of the second MTF curve is greater than a half-value width of the first MTF curve, and a ratio of the half-value width of the second MTF curve to the half-value width of the first MTF curve is equal to or greater than 1.25;
a processor, configured to:
acquire an image generated by using the imaging optical system;
acquire a restoration filter which is a common filter corresponding to a representative value of transfer functions in a plurality of same type imaging optical systems including the imaging optical system, the restoration filter corresponding to the transfer function of the imaging optical system; and
perform restoration processing on the acquired image through the acquired restoration filter.

8. An image processing method comprising:
acquiring an image generated using an imaging optical system, having at least one lens, that, in a case where a first modulation transfer function (MTF) curve indicating an MTF value in a first azimuth direction with respect to an amount of defocus during focusing on an optical axis is compared with a second MTF curve indicating an MTF value in a second azimuth direction with respect to the amount of defocus, a peak value of the second MTF curve is less than a peak value of the first MTF curve, a ratio of the peak value of the first MTF curve to the peak value of the second MTF curve is equal to or greater than 2, a half-value width of the second MTF curve is greater than a half-value width of the first MTF curve, and a ratio of the half-value width of the second MTF curve to the half-value width of the first MTF curve is equal to or greater than 1.25; and
performing restoration processing on the acquired image through a restoration filter which is a common filter corresponding to a representative value of transfer functions in a plurality of same type imaging optical systems including the imaging optical system, the restoration filter corresponding to the transfer function of the imaging optical system.

9. An imaging optical system group comprising:
an imaging optical system, having at least one lens, that, in a case where a first modulation transfer function (MTF) curve indicating an MTF value in a first azimuth direction with respect to an amount of defocus during focusing on an optical axis is compared with a second MTF curve indicating an MTF value in a second azimuth direction with respect to the amount of defocus, a peak value of the second MTF curve is less than a peak value of the first MTF curve, a ratio of the peak value of the first MTF curve to the peak value of the second MTF curve is equal to or greater than 2, a half-value width of the second MTF curve is greater than a half-value width of the first MTF curve, and a ratio of the half-value width of the second MTF curve to the half-value width of the first MTF curve is equal to or greater than 1.25; and
a storage medium that stores a restoration filter which is a common filter corresponding to a representative value of transfer functions in a plurality of same type imaging optical systems including the imaging optical system, the restoration filter corresponding to the transfer function of the imaging optical system.

Assignees

• Fujifilm Corp

Inventors

• Kunugise Takashi
• Naruse Yousuke
• Hayashi Kenkichi

Classifications

• H04N23/67

  Focus control based on electronic image sensor signals · CPC title

• H04N25/615

  involving a transfer function modelling the optical system, e.g. optical transfer function [OTF], phase transfer function [PhTF] or modulation transfer function [MTF] · CPC title

• G06T5/20 Primary

  using local operators · CPC title

• H04N5/232

  Electricity · mapped topic

• G06T5/003

  Physics · mapped topic