Image processing device, imaging device, computer-readable device, and image processing method for processing a fluorescence image

1. An image processing device comprising:

a normal-light-image storage unit that stores therein each picture signal of a normal light image of an observed region, the normal light image being captured by a normal-light imaging unit that receives normal light from the observed region via a plurality of color filters having different spectral characteristics;

a fluorescence-image storage unit that stores therein each picture signal of a fluorescence image of the observed region, the fluorescence image being captured by a fluorescence imaging unit that receives fluorescence generated from the observed region irradiated with excitation light;

a uniform-image generating unit that extracts each picture signal corresponding to a specific color filter, which is one of the plurality of color filters and transmits light in a wavelength band for which a light absorption property of a contrast region in the observed region is low, from among each picture signal of the normal light image stored in the normal-light-image storage unit, and generates a uniform image of a wavelength-band component corresponding to the specific color filter based on each extracted picture signal; and

a correction processing unit that corrects each picture signal of the fluorescence image stored in the fluorescence-image storage unit by using the uniform image;

wherein the plurality of color filters include a plurality of red light filters that transmit red light, a plurality of green filters that transmit green light, and a plurality of blue filters that transmit blue light, and

the red light filters among the plurality of color filters serve as the specific color filter; and

wherein:

the uniform-image generating unit includes:

a signal extracting unit that extracts each picture signal corresponding to the red light filter from among each picture signal of the normal light image stored in the normal-light-image storage unit; and

an interpolation processing unit that performs an interpolation process of each picture signal extracted by the signal extracting unit to generate the uniform image of a wavelength-band component corresponding to the red light filter.

2. The image processing device according to claim 1 , wherein

the plurality of color filters include a plurality of red light filters that transmit red light, a plurality of green light filters that transmit green light, a plurality of blue light filters that transmit blue light, and a plurality of infrared light filters that transmit infrared light, and

the infrared light filters in the plurality of color filters serve as the specific color filter.

3. The image processing device according to claim 2 , wherein

the uniform-image generating unit includes

a signal extracting unit that extracts each picture signal corresponding to the infrared light filter from among each picture signal of the normal light image stored in the normal-light-image storage unit; and

an interpolation processing unit that performs an interpolation process of each picture signal extracted by the signal extracting unit to generate the uniform image of a wavelength-band component corresponding to the infrared light filter.

4. The image processing device according to claim 1 , wherein the correction processing unit includes

a standardization processing unit that performs a standardization process on luminance of the fluorescence image by dividing a picture signal of the fluorescence image by a picture signal of the uniform image for each corresponding pixel between the uniform image and the fluorescence image.

5. The image processing device according to claim 1 , wherein

the correction processing unit includes

an offset processing unit that performs an offset process of uniformly adding a predetermined value to each picture signal of the uniform image, and

the correction processing unit corrects each picture signal of the fluorescence image by using the uniform image subjected to the offset process.

6. The image processing device according to claim 1 , wherein

the correction processing unit includes

a clipping processing unit that performs a clipping process of comparing a signal value of each picture signal of the uniform image with a predetermined reference value of the picture signal and replacing a signal value larger than the reference value with the reference value, and

the correction processing unit corrects each picture signal of the fluorescence image by using the uniform image subjected to the clipping process.

7. An imaging device comprising:

a light source unit that switchably applies normal light and excitation light to an observed region;

a normal-light imaging unit that includes a plurality of color filters having different spectral characteristics and captures a normal light image of the observed region by receiving, via the plurality of color filters, normal light from the observed region irradiated with the normal light;

a fluorescence imaging unit that captures a fluorescence image of the observed region by receiving fluorescence generated from the observed region irradiated with the excitation light;

a uniform-image generating unit that extracts each picture signal corresponding to a specific color filter, which is one of the plurality of color filters and transmits light in a wavelength band for which a light absorption property of a contrast region in the observed region is low, from among each picture signal of the normal light image captured by the normal-light imaging unit, and generates a uniform image of a wavelength-band component corresponding to the specific color filter based on each extracted picture signal; and

a correction processing unit that corrects each picture signal of the fluorescence image captured by the fluorescence imaging unit by using the uniform image;

wherein the plurality of color filters include a plurality of red light filters that transmit red light, a plurality of green filters that transmit green light, and a plurality of blue filters that transmit blue light, and

the red light filters among the plurality of color filters serve as the specific color filter; and

wherein:

the uniform-image generating unit includes:

a signal extracting unit that extracts each picture signal corresponding to the red light filter from among each picture signal of the normal light image stored in the normal-light-image storage unit; and

an interpolation processing unit that performs an interpolation process of each picture signal extracted by the signal extracting unit to generate the uniform image of a wavelength-band component corresponding to the red light filter.

8. A computer readable device recording programmed instructions for performing an image processing, wherein the instructions, when executed by a computer, cause the computer to perform:

acquiring each picture signal of a normal light image of an observed region, the normal light image being captured by a normal-light imaging unit that receives normal light from the observed region via a plurality of color filters having different spectral characteristics, and each picture signal of a fluorescence image of the observed region, the fluorescence image being captured by a fluoresce imaging unit that receives fluorescence generated from the observed region irradiated with excitation light;

extracting each picture signal corresponding to a specific color filter, which is one of the plurality of color filters and transmits light in a wavelength band for which a light absorption property of a contrast region in the observed region is low;

generating a uniform image of a wavelength-band component corresponding to the specific color filter based on each picture signal extracted at the extracting; and

correcting each picture signal of the fluorescence image by using the uniform image;

wherein the plurality of color filters include a plurality of red light filters that transmit red light, a plurality of green filters that transmit green light, and a plurality of blue filters that transmit blue light, and

the red light filters among the plurality of color filters serve as the specific color filter; and

wherein the extracting comprises extracting each picture signal corresponding to the red light filter from among each picture signal of the normal light image; and

wherein the instructions, when executed by the computer, further cause the computer to perform an interpolation process that performs an interpolation of each picture signal extracted by the signal extracting process to generate the uniform image of a wavelength-band component corresponding to the red light filter.

9. An image processing method comprising:

acquiring each picture signal of a normal light image of an observed region, the normal light image being captured by a normal-light imaging unit that receives normal light from the observed region via a plurality of color filters having different spectral characteristics, and each picture signal of a fluorescence image of the observed region, the fluorescence image being captured by a fluoresce imaging unit that receives fluorescence generated from the observed region irradiated with excitation light;

extracting each picture signal corresponding to a specific color filter, which is one of the plurality of color filters and transmits light in a wavelength band for which a light absorption property of a contrast region in the observed region is low;

generating a uniform image of a wavelength-band component corresponding to the specific color filter based on each picture signal extracted at the extracting; and

correcting each picture signal of the fluorescence image by using the uniform image;

wherein the plurality of color filters include a plurality of red light filters that transmit red light, a plurality of green filters that transmit green light, and a plurality of blue filters that transmit blue light, and

the red light filters among the plurality of color filters serve as the specific color filter; and

wherein the extracting comprises extracting each picture signal corresponding to the red light filter from among each picture signal of the normal light image; and

wherein the method further comprises an interpolation process that performs an interpolation of each picture signal extracted by the signal extracting process to generate the uniform image of a wavelength-band component corresponding to the red light filter.