Abstract: While an insert shaft (11) disposed with a wide angle lens (15) at a top end thereof is being inserted into a hole to inspect a wall surface of the hole on the basis of an image photographed through the wide angle lens (15), gas is injected into the innermost recess of the hole along the outer circumferential surface of the insert shaft (11) by a gas injection mechanism (19). The gas injection mechanism (19) is provided with a guide (13) configured to surround a top end portion of the insert shaft (11) and form a gas injection passage (R) extending in the longitudinal direction of the insert shaft (11) between the inner circumferential surface of the guide (13) and the outer circumferential surface of the insert shaft (11), and a gas supply unit (14c) configured to supply gas to an inner space of the guide (13).

Abstract: An image processing method includes a step of extracting an inner circle and an outer circle from an annular image, a step of obtaining the center for the extracted inner circle and the extracted outer circle respectively, and a step of moving a processing center serving as a reference in the polar coordinate conversion gradually between the center of the inner circle and the center of the outer circle to convert the circular image into a panoramic development image. According thereto, when an annular image of a side wall surface of a hole imaged by an omnidirectional imaging device (10) is converted into a panoramic development image according to a polar coordinate conversion, a distortion resulted from a position deviation occurred between an optical axis (L1) of the omnidirectional imaging device (10) and a central axis (L2) of the hole (H) can be corrected.

Abstract: While an insert shaft (11) disposed with a wide angle lens (15) at a top end thereof is being inserted into a hole to inspect a wall surface of the hole on the basis of an image photographed through the wide angle lens (15), gas is injected into the innermost recess of the hole along the outer circumferential surface of the insert shaft (11) by a gas injection mechanism (19). The gas injection mechanism (19) is provided with a guide (13) configured to surround a top end portion of the insert shaft (11) and form a gas injection passage (R) extending in the longitudinal direction of the insert shaft (11) between the inner circumferential surface of the guide (13) and the outer circumferential surface of the insert shaft (11), and a gas supply unit (14c) configured to supply gas to an inner space of the guide (13).

Abstract: An image processing method includes a step of extracting an inner circle and an outer circle from an annular image, a step of obtaining the center for the extracted inner circle and the extracted outer circle respectively, and a step of moving a processing center serving as a reference in the polar coordinate conversion gradually between the center of the inner circle and the center of the outer circle to convert the circular image into a panoramic development image. According thereto, when an annular image of a side wall surface of a hole imaged by an omnidirectional imaging device (10) is converted into a panoramic development image according to a polar coordinate conversion, a distortion resulted from a position deviation occurred between an optical axis (L1) of the omnidirectional imaging device (10) and a central axis (L2) of the hole (H) can be corrected.