US 12,604,073 B2Granted

Device and filter array used in system for generating spectral images corresponding to N wavelength bands where N is an integer greater than or equal to four

AssigneePanasonic Intellectual Property Management Co., Ltd.

InventorsMotoki Yako, Atsushi Ishikawa

Life of this patent

Estimating the term…

Loading patent…

Abstract

A device used in a system for generating spectral images corresponding to four or more wavelength bands includes optical filters different in spectral transmittance and an image sensor that detects light through the optical filters, in which when the wavelength bands are given numbers in an ascending or descending order of a central wavelength, the image sensor outputs i-th mask data by detecting only light corresponding to an i-th wavelength band and outputs j-th mask data by detecting only light corresponding to a j-th wavelength band among the wavelength bands, a correlation coefficient between the i-th and j-th mask data is greater than or equal to 0.8 in a combination where |i−j| is 1, and is equal to or less than 0.8 in at least one combination where |i−j| is greater than or equal to 2 and less than or equal to N−1.

Claims6

Dependent claims

A device used in a system for generating spectral images corresponding to N wavelength bands where N is an integer greater than or equal to 4, the device comprising:

optical filters that are different from one another in spectral transmittance;
and
an image sensor that detects light that has passed through the optical filters,
wherein
the image sensor outputs i-th mask data corresponding to a pixel value distribution corresponding to an i-th wavelength band among the N wavelength bands by detecting only light corresponding to the i-th wavelength band where i is an integer greater than or equal to 1 and less than or equal to N and outputs j-th mask data corresponding to a pixel value distribution corresponding to a j-th wavelength band among the N wavelength bands by detecting only light corresponding to the j-th wavelength band where j is an integer greater than or equal to 1 and less than or equal to N,
a correlation coefficient rij between the i-th mask data and the j-th mask data is expressed as follows:
r
ij
=
❘
"\[LeftBracketingBar]"
∑
m
⁢
∑
n
⁢
(
i
mn
-
i
0
)
⁢
(
j
mn
-
j
0
)
(
∑
m
⁢
∑
n
⁢
(
i
mn
-
i
0
)
2
)
⁢
(
∑
m
⁢
∑
n
⁢
(
j
mn
-
j
0
)
2
)
❘
"\[RightBracketingBar]"
where imn and jmn are a pixel value of a pixel at an m-th row and an n-th column of the i-th mask data and a pixel value of a pixel at an m-th row and an n-th column of the j-th mask data, respectively, i0 and j0 are an average of pixel values of the i-th mask data and an average of pixel values of the j-th mask data, respectively, and the N wavelength bands are given numbers in an ascending or descending order of a central wavelength,
the correlation coefficient rij satisfies rij>0.8 in a combination of the i-th mask data and the j-th mask data in which |i−j| is 1, and
the correlation coefficient rij satisfies rij≤0.8 in at least one combination of the i-th mask data and the j-th mask data in which |i−j| is greater than or equal to 2 and less than or equal to N−1.

67 more elements

A method for manufacturing a filter array used in a system for generating spectral images corresponding to N wavelength bands where N is an integer greater than or equal to 4, the filter array including optical filters that are different from one another in spectral transmittance, the method comprising:

calculating a correlation coefficient between the spectral images of a target concerning all combinations of two different wavelength bands among the N wavelength bands;
and
designing a transmittance distribution of the optical filters for each of the N wavelength bands on a basis of the correlation coefficient, wherein
in the calculating the correlation coefficient, the correlation coefficient is calculated such that a correlation coefficient rij between an i-th transmittance distribution of the optical filters concerning light of an i-th wavelength band among the N wavelength bands where i is an integer greater than or equal to 1 and less than or equal to N and a j-th transmittance distribution of the optical filters concerning light of a j-th wavelength band among the N wavelength bands where j is an integer greater than or equal to 1 and less than or equal to N is expressed as follows:
r
ij
=
❘
"\[LeftBracketingBar]"
∑
m
⁢
∑
n
⁢
(
i
mn
-
i
0
)
⁢
(
j
mn
-
j
0
)
(
∑
m
⁢
∑
n
⁢
(
i
mn
-
i
0
)
2
)
⁢
(
∑
m
⁢
∑
n
⁢
(
j
mn
-
j
0
)
2
)
❘
"\[RightBracketingBar]"
where imn and imn are transmittance of an optical filter at an m-th row and an n-th column in the transmittance distribution of the optical filters concerning the light of the i-th wavelength band and transmittance of an optical filter at an m-th row and an n-th column in the transmittance distribution of the optical filters concerning the light of the j-th wavelength band, respectively, i0 and j0 are an average of transmittances of the i-th transmittance distribution and an average of transmittances of the i-th transmittance distribution, respectively, and the N wavelength bands are given numbers in an ascending or descending order of a central wavelength,
the correlation coefficient rij satisfies rij>0.8 in a combination of the i-th transmittance distribution and the i-th transmittance distribution in which |i−j| is 1, and
the correlation coefficient rij satisfies rij<0.8 in at least one combination of the i-th transmittance distribution and the i-th transmittance distribution in which |i−j| is greater than or equal to 2 and less than or equal to N−1.

65 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/675,123Filed 27 May 2024 · continuation
Priority: JP 2021-1995568 Dec 2021
Published: US 2024/0314409 A119 Sep 2024
Granted: 14 Apr 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

H04N 23/12
For generating image signals from different wavelengths: with one sensor only
G01J 3/24
Using diffraction elements, e.g. grating: using gratings profiled to favour a specific order
G01J 3/26
Generating the spectrum; Monochromators: using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
G01J 3/2803
Investigating the spectrum: using photoelectric array detector