Observation device and observation method

An observation apparatus comprising:

• an interference optical system configured to split light output from a light source into object light and reference light, irradiate an observation object moving along a first direction with the object light, and combine and output the object light passed through the observation object and the reference light;
• a camera having an imaging plane configured to receive the object light and the reference light output from the interference optical system, and configured to image an interference intensity image generated by interference between the object light and the reference light on the imaging plane, and output time series data of the interference intensity image;
• and
• a computer configured to perform analysis based on the time series data of the interference intensity image, wherein
• the interference optical system includes:
• an irradiation optical system configured to, when the observation object is irradiated with the object light, focus the object light and irradiate a line-shaped region extending in a second direction perpendicular to the first direction in the observation object with the object light;
• and
• an imaging optical system configured to, when the object light passed through the observation object is guided to the imaging plane, set a positional relationship of Fourier transform between the observation object and the imaging plane in the first direction, and set a positional relationship conjugate to each other between the observation object and the imaging plane in the second direction, and wherein
• the object light and the reference light are incident on the imaging plane from directions different from each other,
• the computer is configured to generate a complex differential interference image of each of a plurality of positions and a plurality of light irradiation directions when performing focused irradiation of the object light on the observation object by the irradiation optical system based on the time series data of the interference intensity image, and generate a three-dimensional phase image of the observation object based on the complex differential interference image, and
• the computer is further configured to:
• acquire the time series data of the interference intensity image from the camera;
• generate, for each of the plurality of light irradiation directions, a complex amplitude image based on the time series data of the interference intensity image;
• generate, for each of the plurality of light irradiation directions, a complex amplitude image at each of the plurality of positions based on the complex amplitude image;
• perform, before, during, or after generating, for each of the plurality of light irradiation directions, the complex amplitude image at each of the plurality of positions, a phase conjugate operation on the complex amplitude image of each of the plurality of light irradiation directions to generate a complex amplitude image of each of the plurality of light irradiation directions when a relationship between light irradiation and imaging for the observation object is reversed;
• generate, for each of the plurality of positions, the complex differential interference image of each of the plurality of light irradiation directions based on the generated complex amplitude image of each of the plurality of light irradiation directions, and generate a two-dimensional phase image based on the complex differential interference image of each of the plurality of light irradiation directions;
• and
• generate the three-dimensional phase image based on the two-dimensional phase image at each of the plurality of positions, wherein
• when a phase image generated based on the complex amplitude image before performing the phase conjugate operation is set as a first phase image, and a phase image generated based on the complex amplitude image obtained by performing the phase conjugate operation is set as a second phase image, out of the plurality of positions, the computer is configured to generate the two-dimensional phase image mainly based on the first phase image at a position relatively close to the camera, and generate the two-dimensional phase image mainly based on the second phase image at a position relatively far from the camera.

An observation method comprising:

• performing an interference of causing object light and reference light to interfere with each other, by using an interference optical system configured to split light output from a light source into the object light and the reference light, irradiate an observation object moving along a first direction with the object light, and combine and output the object light passed through the observation object and the reference light;
• performing a modulation of setting respective optical frequencies of the object light and the reference light different from each other by a heterodyne frequency, by using a frequency shifter provided on an optical path of the object light or the reference light from splitting to combining in the interference optical system;
• performing an imaging of imaging an interference intensity image generated by interference between the object light and the reference light on an imaging plane, and outputting time series data of the interference intensity image, by using a camera having the imaging plane configured to receive the object light and the reference light output from the interference optical system;
• and
• performing analysis based on the time series data of the interference intensity image, wherein
• the interference optical system includes:
• an irradiation optical system configured to, when the observation object is irradiated with the object light, focus the object light and irradiate a line-shaped region extending in a second direction perpendicular to the first direction in the observation object with the object light;
• and
• an imaging optical system configured to, when the object light passed through the observation object is guided to the imaging plane, set a positional relationship of Fourier transform between the observation object and the imaging plane in the first direction, and set a positional relationship conjugate to each other between the observation object and the imaging plane in the second direction, and wherein
• the object light and the reference light are incident on the imaging plane coaxially with each other,
• the analysis includes generating a complex differential interference image of each of a plurality of positions and a plurality of light irradiation directions when performing focused irradiation of the object light on the observation object by the irradiation optical system based on the time series data of the interference intensity image, and generating a three-dimensional phase image of the observation object based on the complex differential interference image, and
• the analysis includes:
• performing an interference intensity image acquisition of acquiring the time series data of the interference intensity image from the camera;
• performing a first complex amplitude image generation of generating, for each of the plurality of light irradiation directions, a complex amplitude image based on the time series data of the interference intensity image;
• performing a second complex amplitude image generation of generating, for each of the plurality of light irradiation directions, a complex amplitude image at each of the plurality of positions based on the complex amplitude image;
• performing a phase conjugate operation of performing, before, during, or after a processing step by the second complex amplitude image generation, a phase conjugate operation on the complex amplitude image of each of the plurality of light irradiation directions to generate a complex amplitude image of each of the plurality of light irradiation directions when a relationship between light irradiation and imaging for the observation object is reversed;
• performing a two-dimensional phase image generation of generating, for each of the plurality of positions, the complex differential interference image of each of the plurality of light irradiation directions based on the complex amplitude image of each of the plurality of light irradiation directions generated by the second complex amplitude image generation or the phase conjugate operation, and generating a two-dimensional phase image based on the complex differential interference image of each of the plurality of light irradiation directions;
• and
• performing a three-dimensional phase image generation f generating the three-dimensional phase image based on the two-dimensional phase image at each of the plurality of positions, wherein
• when a phase image generated based on the complex amplitude image before performing the operation by the phase conjugate operation is set as a first phase image, and a phase image generated based on the complex amplitude image obtained by performing the operation by the phase conjugate operation is set as a second phase image, out of the plurality of positions, the two-dimensional phase image generation includes generating the two-dimensional phase image mainly based on the first phase image at a position relatively close to the camera, and generating the two-dimensional phase image mainly based on the second phase image at a position relatively far from the camera.

An observation method comprising:

• performing an interference of causing object light and reference light to interfere with each other, by using an interference optical system configured to split light output from a light source into the object light and the reference light, irradiate an observation object moving along a first direction with the object light, and combine and output the object light passed through the observation object and the reference light;
• performing an imaging of imaging an interference intensity image generated by interference between the object light and the reference light on an imaging plane, and outputting time series data of the interference intensity image, by using a camera having the imaging plane configured to receive the object light and the reference light output from the interference optical system;
• and
• performing analysis based on the time series data of the interference intensity image, wherein
• the interference optical system includes:
• an irradiation optical system configured to, when the observation object is irradiated with the object light, the object light and irradiate a line-shaped region extending in a second direction perpendicular to the first direction in the observation object with the object light;
• and
• an imaging optical system configured to, when the object light passed through the observation object is guided to the imaging plane, set a positional relationship of Fourier transform between the observation object and the imaging plane in the first direction, and set a positional relationship conjugate to each other between the observation object and the imaging plane in the second direction, and wherein
• the object light and the reference light are incident on the imaging plane from directions different from each other,
• the analysis includes generating a complex differential interference image of each of a plurality of positions and a plurality of light irradiation directions when performing focused irradiation of the object light on the observation object by the irradiation optical system based on the time series data of the interference intensity image, and generating a three-dimensional phase image of the observation object based on the complex differential interference image, and
• the analysis includes:
• performing an interference intensity image acquisition of acquiring the time series data of the interference intensity image from the camera;
• performing a first complex amplitude image generation of generating, for each of the plurality of light irradiation directions, a complex amplitude image based on the time series data of the interference intensity image;
• performing a second complex amplitude image generation of generating, for each of the plurality of light irradiation directions, a complex amplitude image at each of the plurality of positions based on the complex amplitude image;
• performing a phase conjugate operation of performing, before, during, or after a processing step by the second complex amplitude image generation, a phase conjugate operation on the complex amplitude image of each of the plurality of light irradiation directions to generate a complex amplitude image of each of the plurality of light irradiation directions when a relationship between light irradiation and imaging for the observation object is reversed;
• performing a two-dimensional phase image generation of generating, for each of the plurality of positions, the complex differential interference image of each of the plurality of light irradiation directions based on the complex amplitude image of each of the plurality of light irradiation directions generated by the second complex amplitude image generation or the phase conjugate operation, and generating a two-dimensional phase image based on the complex differential interference image of each of the plurality of light irradiation directions;
• and
• performing a three-dimensional phase image generation f generating the three-dimensional phase image based on the two-dimensional phase image at each of the plurality of positions, wherein
• when a phase image generated based on the complex amplitude image before performing the operation by the phase conjugate operation is set as a first phase image, and a phase image generated based on the complex amplitude image obtained by performing the operation by the phase conjugate operation is set as a second phase image, out of the plurality of positions, the two-dimensional phase image generation includes generating the two-dimensional phase image mainly based on the first phase image at a position relatively close to the camera, and generating the two-dimensional phase image mainly based on the second phase image at a position relatively far from the camera.