| CPC G01B 9/02091 (2013.01) [A61B 5/0066 (2013.01); G01B 9/0203 (2013.01); G01B 9/02084 (2013.01)] | 10 Claims |
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1. A method for operating an optical tomographic imaging apparatus, the optical tomographic imaging apparatus comprising:
a light source;
a splitter that splits light emitted from the light source into first light and second light;
a translucent tube that is inserted into a biological tubular element;
an imaging unit that includes an optical fiber having a proximal end optically coupled to the splitter, and an optical part provided at a distal end of the optical fiber, and that emits the first light guided by the optical fiber from the optical part toward an inner wall of the biological tubular element through the translucent tube, and obtain reflected light of the first light returning from the biological tubular element via the translucent tube, from the optical part through the optical fiber;
an optical distance adjustment unit that includes a movable reference mirror, and is capable of obtaining reference light by reflecting the second light on the reference mirror, and adjusting an optical distance of the second light by moving the reference mirror;
an optical coupler that causes the reflected light and the reference light to interfere with each other, and obtains interference light;
a detector that detects the interference light of the reflected light and the reference light and photoelectrically converts the interference light to generate an analog signal corresponding to the interference light;
a converter that receives the analog signal from the detector and converts the analog signal into a digital signal;
a Fourier transform unit that performs Fourier transform on the digital signal obtained by the converter to obtain a light intensity distribution chart with respect to an optical distance difference between an optical distance of the reflected light and an optical distance of the reference light;
an image display;
an image processor that deletes data corresponding to an intensity corresponding to the artifact from the digital data Fourier-transformed by Fourier transform unit, so that an image without the artifact is displayed on the image display; and
a controller, wherein the imaging unit, the optical distance adjustment unit, the image processor, and the image display are configured to be controlled by the controller,
the method comprising executing, by the controller:
(a) an initial setting step of controlling the optical distance adjustment unit to set an optical distance of the reference light substantially equally to an optical distance of the reflected light, the optical distance of the reference light being an optical distance that light emitted from the light source travels until reaching the detector after being reflected by the reference mirror, and the optical distance of the reflected light being an optical distance obtained by adding a first optical distance from the light source to a distal end of the optical part and a second optical distance from the distal end of the optical part to the detector;
(b) an imaging step of, after the initial setting step, operating the imaging unit to image the biological tubular element though the translucent tube by detecting the reflected light by the detector;
(c) a reference mirror adjustment step of, after the imaging step, controlling the optical distance adjustment unit to move the reference mirror to make the optical distance of the reference light shorter than the optical distance of the reflected light, so that i) the image portion of reflected light from the biological tubular element and the image portion of reflected light from the translucent tube are enlarged and ii) an image portion of an artifact caused by the reflected light from the optical part is reduced, whereby fitting the image portion of the artifact within an inside of the image portion of the reflected light from the translucent tube;
(d) a magnification adjustment step of, after the reference mirror adjustment step, controlling the image processor to delete the data corresponding to the intensity corresponding to the artifact, and then, decrease size of the image portion of the reflected light from the biological tubular element and the image portion of the reflected light from the translucent tube to size before the enlargement; and
(e) a display step of, after the magnification adjustment step, causing the image display to display the image portion of the reflected light from the biological tubular element and the image portion of the reflected light from the translucent tube.
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