A novel method for 3D reconstruction in tight and restricted space based on improved line-structured light

•The precise measurement technology of the inner surface of small hollow objects has not been widely researched. The components of the existing endoscope three-dimensional measuring probe are complex, expensive and not performed well in accuracy. Thus, a novel method and a miniaturized endoscopic 3D sensor is introduced.•In this paper, a new sensor for endoscopic three-dimensional measurement is designed, with good robustness and low cost. It fills the gap of the principle of linear structured light in 3D endoscope. It should be mentioned that, this work has been applied an aircraft engine blade surface defects detection, and the system has been applied to industrial sites, which has broad application prospects.•The sensor probe prototype has a maximum 6mm in thickness. It is mainly based on improved line-structured light, which performs better in robustness and measurement accuracy than coded projection. Especially, the components are inexpensive and easily available, which reduces the manufacturing cost and easily to popularize in industry. Correspondingly, to ensure the sensor measurement accuracy, we also proposed a calibration method for a miniature line-structured light system based on specially designed planar targets. It should be noted that the 3D extension of the line-structured light system relies on the movement of the translation stage. Taking full account of the characteristics of the sensor prototype, a high-precision direction calibration method of the translation stage based on joint multi-calibration position noise estimation is proposed.