A method of measuring the inside diameter of a hollow body of revolution that is transparent or translucent and that is defined by an inside face and an outside face, the body presenting an axis of revolution along a vertical axis (z), the method consisting in: - illuminating the hollow body on one side by means of a light source so that the incident light rays (Ii) pass through the hollow body along at least one cross-section perpendicular to the axis of revolution and in which the inside diameter is to be measured along a measurement axis (x), the light source presenting two light boundaries (9 1, 9 2) spaced apart along the measurement axis (x); - from the side of the hollow body that is opposite from its illuminated side, and by acting along an optical axis (y) that is perpendicular to the vertical axis (z) and perpendicular to the measurement axis (x), recovering the light rays that are reflected and refracted by the hollow body so as to form at least one image in which there appear light transitions (T1, T2); and - processing the image so as to determine the measurement of the inside diameter of the hollow body, the method being characterized in that it consists in: - illuminating the hollow body by means of a diffuse light source having light boundaries (9 1, 9 2) on either side of the optical axis (y) created in the image, two light transitions (T 1, T 2) that are spaced apart from each other and diametrically opposite relative to the vertical axis (z), corresponding to emerging light rays that propagate along respective lines tangential to the inside face and perpendicular to the diameter, said light boundaries (9 1, 9 2) lying along the measurement axis (x) strictly between the position of an internal limiting incident light ray (I 3) and the position of an external limiting incident light ray (I 4), the internal limiting incident light ray (I 3) generating the emerging light ray (E 3) that is only refracted on passing through the hollow body and that is situated farthest from the optical axis (y), while the external limiting incident light ray (I 4) generates the emerging light ray (E 4) that is reflected by the inside face of the hollow body and that is the closest to the optical axis; and - processing the image so as to determine the distance along the measurement axis (x) between the two light transitions (T 1, T 2) in order to determine the measurement for the inside diameter of the hollow body. - illuminating the hollow body on one side by means of a light source so that the incident light rays (Ii) pass through the hollow body along at least one cross-section perpendicular to the axis of revolution and in which the inside diameter is to be measured along a measurement axis (x), the light source presenting two light boundaries (9 1, 9 2) spaced apart along the measurement axis (x); - from the side of the hollow body that is opposite from its illuminated side, and by acting along an optical axis (y) that is perpendicular to the vertical axis (z) and perpendicular to the measurement axis (x), recovering the light rays that are reflected and refracted by the hollow body so as to form at least one image in which there appear light transitions (T1, T2); and - processing the image so as to determine the measurement of the inside diameter of the hollow body, - illuminating the hollow body by means of a diffuse light source having light boundaries (9 1, 9 2) on either side of the optical axis (y) created in the image, two light transitions (T 1, T 2) that are spaced apart from each other and diametrically opposite relative to the vertical axis (z), corresponding to emerging light rays that propagate along respective lines tangential to the inside face and perpendicular to the diameter, said light boundaries (9 1, 9 2) lying along the measurement axis (x) strictly between the position of an internal limiting incident light ray (I 3) and the position of an external limiting incident light ray (I 4), the internal limiting incident light ray (I 3) generating the emerging light ray (E 3) that is only refracted on passing through the hollow body and that is situated farthest from the optical axis (y), while the external limiting incident light ray (I 4) generates the emerging light ray (E 4) that is reflected by the inside face of the hollow body and that is the closest to the optical axis; and - processing the image so as to determine the distance along the measurement axis (x) between the two light transitions (T 1, T 2) in order to determine the measurement for the inside diameter of the hollow body.