The present invention belongs to the field of image spectrum detection, and specifically relates to a high-precision detection method for the contour of the
meniscus of liquid in a capillary tube. It comprises a
telecentric lens, an industrial camera, a displacement platform, a
light source, a capillary tube and a culture dish; the industrial camera, the capillary tube and the culture dish are respectively mounted on different displacement platforms. The
light source is provided with a rotating telescopic rod to achieve all-round movement. When photographing the contour of the
meniscus of liquid in the capillary tube, the
light source, the
meniscus of the capillary tube and the industrial camera are adjusted to be aligned on the same horizontal plane. Based on the principle of telecentric imaging and the principle of light
refraction, a
distortion correction function for the contour of the meniscus in the capillary tube is derived. The present invention uses an industrial camera in combination with a
telecentric lens, thereby avoiding the problem of shape
distortion caused by changes in the distance between the object and reducing the difficulty of image
distortion correction. The meniscus contour
distortion correction function derived based on the telecentric imaging principle can accurately calculate the actual value of the meniscus contour and restore the actual contour of the meniscus.