Abstract: An extraction section extracts, from each of a plurality of non-defective product images which show the appearance of the inspection target determined to be a non-defective product, the non-defective vector representing a feature of each non-defective product image. A generation section generates a transformation matrix by using a plurality of non-defective product vectors extracted by the extraction section. The transformation matrix is a matrix representing sequentially performing first mapping for mapping the feature vector to a feature space and second mapping for mapping a result of the first mapping to the whole space to which the feature vector belongs. An adjusting section adjusts each element of the transformation matrix generated by the generation section by using, as learning data, the feature vector extracted from a pseudo defect image.

Abstract: An extraction section extracts, from each of a plurality of non-defective product images which show the appearance of the inspection target determined to be a non-defective product, the non-defective vector representing a feature of each non-defective product image. A generation section generates a transformation matrix by using a plurality of non-defective product vectors extracted by the extraction section. The transformation matrix is a matrix representing sequentially performing first mapping for mapping the feature vector to a feature space and second mapping for mapping a result of the first mapping to the whole space to which the feature vector belongs. An adjusting section adjusts each element of the transformation matrix generated by the generation section by using, as learning data, the feature vector extracted from a pseudo defect image.

Abstract: An inspection apparatus according to the present invention comprises: a one-dimensional imaging unit for imaging a workpiece which is a three-dimensionally shaped test object; a first lens for causing light incident thereon from the test object to emerge as converging light; and a second lens, disposed between the first lens and the one-dimensional imaging unit, for focusing the light emerging from the first lens, wherein a chief ray of a bundle of rays incident on the first lens from the test object is parallel to the optical axis of the first lens, and the light containing the chief ray, incident from the test object, is focused through the first lens and the second lens onto the one-dimensional imaging unit for imaging.

Abstract: A method for producing an optical fiber preform is provided in which the variation of the outer diameter in the longitudinal direction is minimized and a target quantity of glass is accumulated as a whole. Based on a predetermined relationship between three variables: the outer diameter of a starting rod being a first variable, the outer diameter of an optical fiber preform a second variable, and the timing for ending the glass particles depositing process a third variable, the starting rod and burners are subjected to relative reciprocating movement so as to deposit glass particles on the starting rod until the timing for ending the depositing process, and then the resulting deposit body is vitrified. The third variable may be the traverse velocity, the glass particles deposition time, or the weight of a soot glass deposit body.

Abstract: A plurality of glass particle synthesizing burners are disposed opposite to a rotating starting rod. The starting rod and the glass particle synthesizing burners are relatively reciprocally moved to each other in parallel to the axial direction, so that glass particles synthesized by the burners are sequentially deposited on the surface of the starting rod. The movement is stopped and restarted repeatedly once or more than once during one reciprocal movement.

Abstract: An optical fiber is composed of silica glass and comprises a center core region doped with F element, a ring core region doped with GeO2, and an inner cladding region doped with F element; wherein a buffer layer composed of undoped SiO2 or SiO2 doped with one or both of P and Cl or a concentration gradient region in which GeO2 concentration radially decreases toward the boundary is provided between the center core region and the ring core region.

Abstract: A piercing inspection apparatus allows inspection of piercing of through-holes of a honeycomb structure having a number of parallel through-holes which extend therethrough from a first open end to a second open end of the honeycomb structure. The apparatus includes a lighting device which emits light onto the first open end of the honeycomb structure, so that the light passes through the through-holes, a telecentric optical system which converges the light emitted from the through-holes at the second open end to form inspection images corresponding to the through-holes, a camera which picks up the inspection images, and a monitor in which the picked up inspection images are indicated.

Abstract: An optical fiber is composed of silica glass and comprises a center core region doped with F element, a ring core region doped with GeO2, and an inner cladding region doped with F element; wherein a buffer layer composed of undoped SiO2 or SiO2 doped with one or both of P and Cl or a concentration gradient region in which GeO2 concentration radially decreases toward the boundary is provided between the center core region and the ring core region.

Abstract: In an optical fiber of this invention, the MFD is increased to effectively suppress the influence of nonlinear optical effects. A method of manufacturing the optical fiber effectively prevents bubble occurrence in a transparent preform, deformation of the preform, and flaws on the preform surface during the manufacture. The optical fiber has, from its center to the peripheral portion, a first core having a first refractive index n1, a second core having a second refractive index n2 (<n1), a first cladding having a third refractive index n3 (<n2), and a second cladding having a fourth refractive index n4 (>n3, <n2). The outer diameter of the second core is set to be 25 to 40 &mgr;m. Specifically, the refractive indices of the first and second claddings of the optical fiber preferably increase in the radial direction from the inner side thereof to the peripheral side thereof.

Abstract: An optical fiber is composed of silica glass and comprises a center core region doped with F element, a ring core region doped with GeO2, and an inner cladding region doped with F element; wherein a buffer layer composed of undoped SiO2 or SiO2 doped with one or both of P and Cl or a concentration gradient region in which GeO2 concentration radially decreases toward the boundary is provided between the center core region and the ring core region.

Abstract: In a method in which a rotating starting rod and glass particle synthesizing burners are relatively reciprocally moved in parallel with each other, so that while a turn-back position of the relative movement is shifted in a predetermined direction, glass particles (soot) are deposited on a surface of the starting rod to thereby produce a glass particles deposit, the deposition of soot is performed under a condition that an interval between a burner located at any one of both ends in a direction of the relative movement and a burner located adjacent thereto is shorter than another interval between any two of intermediate burners other than the two burners located at the both ends.

Abstract: A tube-shaped, GeO2-doped silica glass pipe having a high refractive index is prepared (step S2), a cylindrical silica glass rod doped with F element is inserted inside the GeO2-doped silica glass pipe (step S3), and the GeO2-doped silica glass pipe and silica glass rod in thus inserted state are heated so as to be unified (step S4). Further, thus formed assembly is inserted inside the a pure silica glass pipe (step S5), and they are heated so as to be unified (step S6), whereby an optical fiber preform is manufactured.

Abstract: In a elongating process, diameter gauges 20, 25 are provided at two locations of upstream measurement position P1 and downstream measurement position P2 which are in a taper portion 1b of an optical fiber preform 1, and fixed target diameters D10, D20 are set for the respective positions. Then a feed speed V1 of starting preform 1a is controlled based on a deviation (D1−D10) of measured diameter D1 at the measurement position P1, while a take-up speed V2 of elongated preform 1c is controlled based on a deviation (D2−D20) of measured diameter D2 at the measurement position P2. This decreases a time lag of control over the outside diameter of the elongated preform 1c and it thus becomes feasible to control the outside diameter in good response and with accuracy. Accordingly, an optical fiber preform elongating method and elongating apparatus are substantiated with improved elongating accuracy of the optical fiber preform and with improved productivity thereof.

Abstract: A tube-shaped, GeO2-doped silica glass pipe having a high refractive index is prepared (step S2), a cylindrical silica glass rod doped with F element is inserted inside the GeO2-doped silica glass pipe (step S3), and the GeO2-doped silica glass pipe and silica glass rod in thus inserted state are heated so as to be unified (step S4). Further, thus formed assembly is inserted inside the a pure silica glass pipe (step S5), and they are heated so as to be unified (step S6), whereby an optical fiber preform is manufactured.

Abstract: A method for producing an optical fiber preform is provided in which the variation of the outer diameter in the longitudinal direction is minimized and a target quantity of glass is accumulated as a whole. Based on a predetermined relationship between three variables: the outer diameter of a starting rod being a first variable, the outer diameter of an optical fiber preform a second variable, and the timing for ending the glass particles depositing process a third variable, the starting rod and burners are subjected to relative reciprocating movement so as to deposit glass particles on the starting rod until the timing for ending the depositing process, and then the resulting deposit body is vitrified. The third variable may be the traverse velocity, the glass particles deposition time, or the weight of a soot glass deposit body.

Abstract: An apparatus inputs an image of a regularly latticed-patterns. The inputted image data is transformed into frequency data by the Fourier transformation. The frequency data is restored into image data after it is processed. The processing of the frequency data includes a process for removing a frequency component corresponding to the latticed patterns. The processing of the frequency data further includes a process for removing a frequency component corresponding to a shape of an area of the latticed patterns. The processed data is used for detecting and examining a defect. It is possible to examine a defect accurately.

Abstract: A plurality of glass particle synthesizing burners are disposed opposite to a rotating starting rod. The starting rod and the glass particle synthesizing burners are relatively reciprocally moved to each other in parallel to the axial direction, so that glass particles synthesized by the burners are sequentially deposited on the surface of the starting rod. The movement is stopped and restarted repeatedly once or more than once during one reciprocal movement.

Abstract: The present invention relates to a dispersion-shifted optical fiber which comprises a structure for effectively eliminating the causes of deterioration in characteristics at the making stage thereof and is suitable for wavelength division multiplexing transmission. In the dispersion-shifted optical fiber according to the present invention, impurities to be added and the contents thereof are adjusted so as to reduce viscosity difference at each interface between individual glass regions. As a consequence of this structure, occurrence of structural irregularity and glass defect are effectively restrained in the vicinity of the interfaces between the regions.

Abstract: In an optical fiber of this invention, the MFD is increased to effectively suppress the influence of nonlinear optical effects. A method of manufacturing the optical fiber effectively prevents bubble occurrence in a transparent preform, deformation of the preform, and flaws on the preform surface during the manufacture. The optical fiber has, from its center to the peripheral portion, a first core having a first refractive index n1, a second core having a second refractive index n2 (<n1), a first cladding having a third refractive index n3 (<n2), and a second cladding having a fourth refractive index n4 (>n3, <n2). The outer diameter of the second cladding is set to be 25 to 40 &mgr;m. Specifically, the refractive indices of the first and second claddings of the optical fiber preferably increase in the radial direction from the inner side thereof to the peripheral side thereof.

Abstract: A dispersion-shifted fiber includes structure configured to effectively reduce nonlinear optical effects and transmission loss caused by structural mismatching. A core region in the dispersion-shifted fiber includes an inner core and an outer core, which are both glass areas. The inner core is doped with a predetermined amount of fluorine, having an average relative refractive index difference &Dgr;n1. The outer core is disposed between the inner core and the cladding region and is doped with a predetermined amount of germanium dioxide, having an average relative refractive index difference &Dgr;n2(&Dgr;n2>&Dgr;n1), such that the viscosity ratio between the inner core and the outer core at a drawing temperature is set within a predetermined range, thereby effectively restraining structural mismatching from occurring at the boundary between these glass regions.