For efficient visual inspection of moving targets, such as walls, surfaces of structures, roads, assembly lines, and so on in real-time, inspection systems must have a simple yet robust design capable of operating at high speed. However, high-speed motion degrades image quality due to motion blur and defocusing which are conventionally compensated separately. In this research, we propose a focus adjustable motion-blur compensation method using one deformable mirror capable of back-and-forth movement and curvature bending. The deformable mirror, installed between a target and a 2D camera, simultaneously tracks the moving target and adjusts the focus to achieve high-quality images in real-time without image processing. Through the experiment using a camera having VGA resolution and frame rate of 30Hz, a deformable mirror with a pupil size of 10mm and 43 actuators for deformation and tip/tilt, and a moving target, the results showed that our system improved motion blur and focusing at the same time with only one device. As future work, entire system can be packaged into inspection system.
In this paper, motion-blur compensation method for micro fabricated objects using a galvanometer mirror with back-and-forth rotation is proposed. Motion-blur compensation is expected to extend exposure time without motion blur because longer exposure time can decrease the intensity of illumination to avoid shape expansion of a target object by heat of illumination. Dealing with this demand, a galvanometer mirror is installed between the target and a 2D high-speed camera, and controls the optical axis of the camera to follow the moving target. Each continuous images are taken during the motion of the stage, and finally taken images are integrated into one image by patching for detecting fabrication error using image processing. The experimental system that consists of a high-speed camera, a galvanometer mirror and a high-precision stage is developed and a 20mm=/s moving drilled silicon nitride sheet having holes of about 40 μm in diameter are lattice-shaped at a pitch of 60 μm is captured without motion blur by using this system. Comparing captured images with still images in diameter, roundness and curvature of the each holes, the effectiveness of this system is validated.
Currently, micro fabrication has gained popularity because of miniaturization and densification of devices. Accordingly, the importance of optical shape measurement to detect processing defects and verify the necessity of re-processing is increasing. On the other hand, conventional optical shape-sensing methods require complicated settings such as strict calibration and liquid immersion, and long examination durations; however, there is a requirement for a rapid examination method. Thus, in this research, we propose an optical shape-measuring method for drilled objects, using the light leakage through holes. Specifically, improved precision can be expected by scanning target holes illuminated by a monochromatic LED from the back with a micro pinhole installed on a high-precision stage, and detecting light using an area camera passing through the pinhole. Images are captured at every scanning step of the stage, and finally, one integrated image is generated. An advantage of this method is that even if the diameter of the pinhole is larger than the minimum step of the stage, the camera can detect the amount of light leakage; hence, a high-precision image can be captured by our method. Moreover, the proposed method reduces the labor required for setup and shortens the examination time because it does not require liquid immersion and strict calibration for each object. Through the experiment, we verified the proposed method using a pinhole having a diameter of 10 μm, and obtained the image of through holes. As future work, the scanning speed could be improved using multi-arrayed micro pinholes.