Abstract: A meandering amount arithmetically operating device of a meandering amount measurement device calculates the meandering amount of a steel sheet using a drive side edge site zds(N) and a work side edge sites zws(N) at a current time when a measurement reliability determination unit determines that both the drive side edge site zds(N) and the work side edge sites zws(N) at the current time have high reliability. When only one of the drive side edge site zds(N) and the work side edge site zws(N) at the current time is determined to have high reliability, the other edge site is calculated by interpolation using the number of pixels W from a sheet width updating unit with the drive side edge sites zds(N) or the work side edge site zws(N) at the current time having high reliability as a reference.

Abstract: A position detection apparatus for a seam portion and a heating portion of a welded steel pipe, the position detection apparatus includes: a light source configured to irradiate the seam portion and the heating portion with light in a first wavelength range; an imaging unit having a plurality of different channels and configured to capture an image of each of the seam portion and the heating portion irradiated with the light by the light source; and an image processing unit configured to process the image captured by the imaging unit and to detect the position of each of the seam portion and the heating portion, wherein the imaging unit includes: a first channel capable of receiving the light in the first wavelength range; and a second channel capable of receiving light in a second wavelength range corresponding to radiation light from the heating portion.

Abstract: A calibration method for a temperature measurement device, the method including: measuring dispersed spectrum information of radiation energy from a black body furnace and dark current data with a first temperature measurement device and with a second temperature measurement device that is to be swapped with the first temperature measurement device, at each of a plurality of different temperatures; generating, using information thus measured, a second temperature measurement value to be measured by a second contact thermometer included in the second temperature measurement device, and a second dispersed spectrum information corresponding to the second temperature measurement value, from a first temperature measurement value measured by a first contact thermometer included in the first temperature measurement device and a first dispersed spectrum information corresponding to the first temperature measurement value; and determining, using the information thus generated, the basis spectrum and the calibration li