This paper proposes a large depth-of-field (DOF) imaging method, which uses an image acquisition system equipped with a liquid lens. This paper also establishes the relationship between the focusing distance and the current value to estimate the object distance. The proposed method firstly uses a liquid lens to capture multi-focus images. Then the different objects in the scene are segmented by image processing algorithm. Then we apply an effective blur estimation algorithm on each object to determine the clearest image from all multi-focus images and obtain the corresponding current value. Finally, the clear images of different objects are combined to obtain a large DOF image, and meanwhile, the distances of different objects can be estimated, respectively. Experimental results show that the proposed method can effectively achieve large DOF imaging and measure approximate object distances.
Camouflaged objects can hide into the surrounding environments by changing their appearances. It is difficult to discover them with traditional detection methods. To address the problem, this paper proposes an effective checkerboard projection method for high-speed camouflage detection. Specifically, the projector illuminates two complementary checkerboard patterns onto the monitoring region, meanwhile the camera records the deformed patterns. Then we develop an image analysis algorithm to extract the local variations of the deformed patterns, which can indicate the locations and contours of camouflaged objects. Both simulations and experiments verify that the proposed method can effectively detect the objects camouflaged in complex environments with the advantages of high speed, good robustness, and easy to use.
Fringe projection technique has been widely used for three-dimensional (3D) shape measurement. However, it remains challenging to achieve high-speed measurement. A two-wavelength phase-shifting profilometry method with only four patterns is presented. Specifically, all these four patterns contain two wavelength components. The short wavelength component was used to compute the wrapped phase map, while the long one was used to unwrap the wrapped phase map. The performance of the proposed method was validated by both simulation study and experimental results.
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