Fluoroscopic image density correction method, and image processing device

An image processing device comprising:

• a scanner that acquires a reference fluoroscopic image generated from a radiation detection medium, which is radially disposed on the entirety of an outer circumference of a reference pipe having a reference welded portion, in case where a radiation source is disposed on a central axis of the reference pipe and radiation originating from the radiation source is detected by the radiation detection medium, wherein the reference fluoroscopic image captured at each point along a selected length of the reference pipe is a single captured image of said outer circumference at the point along the length of the reference pipe, and a weld inspection fluoroscopic image generated from the radiation detection medium, which is radially disposed on the entirety of an outer circumference of an inspection target pipe, in case where a radiation source is disposed inside an inspection target pipe having an inspection target welded portion and radiation originating from the radiation source is detected by the radiation detection medium at the time of weld inspection, wherein the weld inspection fluoroscopic image captured at each point along a selected length of the inspection target pipe is a single captured image of said outer circumference at the point along the length of the inspection target pipe;
• a computer configured to
• generate a reference density profile, which indicates a relationship between signal values and coordinates on the reference fluoroscopic image in a direction along the outer circumference of the reference pipe, on the basis of the reference fluoroscopic image, and generating a weld inspection density profile, which indicates a relationship between signal values and coordinates on the weld inspection fluoroscopic image in a direction along the outer circumference of the inspection target pipe, on the basis of the weld inspection fluoroscopic image,
• calculate weld inspection density correction information for correcting density irregularities in the weld inspection fluoroscopic image in the direction along the outer circumference of the inspection target pipe, on the basis of the reference density profile and the weld inspection density profile;
• and a density correction unit that corrects the density irregularities in the weld inspection fluoroscopic image in the direction along the outer circumference of the inspection target pipe, on the basis of the weld inspection density correction information.