Apparatus, system, and method of estimating spectrum of object

1. An image capturing apparatus, comprising:

an optical system configured to focus lights from an object to generate optical information;

a filtering device including filters or filter areas that respectively have spectral characteristics different from one another, wherein:

the filtering device includes at least three filters or filter areas, and

at least two filters or filter areas of the filtering device are configured to have transmittance greater than a predetermined value throughout a wavelength range subject for estimation;

a sensor configured to form a plurality of types of spectral image based on the optical information; and

a processor configured to estimate a line spectrum of the object using spectral images of the at least two filters or filter areas having transmittance greater than the predetermined value, wherein

when the processor determines that at least one spectral image of at least three spectral images corresponding to the at least three filters or filter areas of the filtering device is not output, the processor switches to a line spectrum mode to estimate the line spectrum of the object.

2. The image capturing apparatus of claim 1 , wherein the processor estimates the line spectrum of the object using a ratio in output intensity between or among the spectral images of the at least two filters or filter areas having transmittance greater than the predetermined value.

3. The image capturing apparatus of claim 2 , wherein the predetermined value is 0%.

4. The image capturing apparatus of claim 2 , wherein the predetermined value is 5%.

5. The image capturing apparatus of claim 1 , wherein the optical system includes:

a first optical system, wherein the filtering device is provided near a diaphragm position of the first optical system; and

a second optical system provided between the first optical system and the sensor and configured to have a plurality of lenses being arranged in a substantially parallel in a direction of a two-dimensional surface of the sensor.

6. The image capturing apparatus of claim 1 , wherein the processor estimates a reflection spectral image or an illumination spectral image of the object.

7. A color inspection system, comprising:

the image capturing apparatus of claim 1 ; and

an information processing apparatus configured to obtain spectral data indicating the estimated line spectrum of the object from the image capturing apparatus, and to inspect color of the object based on the spectral data.

8. An image capturing system, comprising:

an image capturing apparatus including:

an optical system configured to focus lights from an object to generate optical information;

a filtering device including filters or filter areas that respectively have spectral characteristics different from one another, wherein:

the filtering device includes at least three filters or filter areas, and

at least two filters or filter areas of the filtering device are configured to have transmittance greater than a predetermined value throughout a wavelength range subject for estimation; and

a sensor configured to form a plurality of types of spectral image based on the optical information; and

an information processing apparatus including a processor, the processor being configured to estimate a line spectrum of the object using spectral images of the at least two filters or filter areas having transmittance greater than the predetermined value, wherein

when the processor determines that at least one spectral image of at least three spectral images corresponding to the at least three filters or filter areas of the filtering device is not output, the processor switches to a line spectrum mode to estimate the line spectrum of the object.

9. The image capturing system of claim 8 , wherein the processor of the information processing apparatus estimates the line spectrum of the object using a ratio in output intensity between or among the spectral images of the at least two filters or filter areas having transmittance greater than the predetermined value.

10. A method of estimating a spectrum of an object, comprising:

obtaining, by a processor, a plurality of types of spectral image, the plurality of types of spectral image being generated by passing lights through filtering device having m items of filters or filter areas that respectively have spectral characteristics different from one another, wherein at least n items of filters or filter areas of the filtering device are configured to have transmittance greater than a predetermine value throughout a wavelength range subject for estimation;

determining, by the processor, whether there is no output of spectral image for (m-n) items of spectral images;

switching, by the processor, to a line spectrum mode when the determining determines that there is no output of spectral image for (m-n) items of spectral images; and

estimating, by the processor, a line spectrum of the object using spectral images of the at least n items of filters or filter areas having transmittance greater than the predetermined value;

areas have transmittance greater than the predetermined value at any wavelength throughout the wavelength range subject for the estimation.

11. The method of claim 10 , further comprising:

inspecting color of the object based on spectral data, the spectral data indicating the estimated line spectrum of the object.

12. The image capturing apparatus of claim 1 , wherein the at least two filters or filter areas have transmittance greater than the predetermined value at any wavelength throughout the wavelength range subject for the estimation.