This paper presents a high resolution optical surveillance system which integrated an omni-directional imager as an event finder/ system trigger. The omni-directional optics, a fish-eye camera in this study, provides a wider field of view (FOV) which can monitor widely range continuously without scanning mechanism but offers sufficient information which includes sign of field event and direction and then drive high resolution surveillance camera for detail imaging. To archive an optical triggering surveillance system, the scale-invariant feature transform (SIFT) is implemented to detect features both from images taken by omni-directional imager and the high resolution surveillance camera. Considering the FOV of high resolution surveillance system is narrow, to ensure the pointing of high resolution surveillance system, feature matching is also implemented in this system to identify the images obtained by high resolution surveillance system are identical to the existing omni-directional image obtained from fish-eye camera. This provides a robust and accurate solution to the problem of optical radar surveillance system localization in unknown environments. An experiment is performed on outdoor image sequences with demonstrating the efficiency of our algorithm.
In this paper, a multi-camera DIC system with semi-circular configuration which can capture images from three different view angles at the same time is introduced. The multi-camera DIC system associated calibration method is proposed, the internal- and external- parameters of all system’s cameras by utilizing a planar plate with circular marks on it. A cracked cylindrical were reconstructed with images obtained by the proposed three-camera systems, with the help of digital image correlation method is also demonstrated and discussed.
The digital image correlation (DIC) method has been well recognized as a simple, accurate and efficient method for
mechanical behavior evaluation. However, very few researches have concentrated on the relationship between the
characteristics of the camera lens and the measurement error of the DIC method. The modulation transfer function (MTF)
has commonly used for evaluation of the resolution capability of camera lens. In practice, when the DIC method is
used, it is possible that the captured images become too blur to analyze when the object is out of the focus of the camera
lens or the object deviates from the line-of-view of the camera. In this paper, the traditional MTF calibration specimen
was replaced by a pre-arranged speckle pattern on the specimen. For DIC images grabbed from several selected locations
both approaching and departing from the focus of the camera lens, corresponding MTF curves were obtained from the
pre-arranged speckle pattern. The displacement measurement errors of the DIC method were then estimated by those
obtained MTF curves.
Chip sorter is one of packaging facilities in chip manufactory. Defects will occur for a few of chips during
manufacturing processes. If the size of chip defects is larger than a criterion of impacting chip quality, these flawed
chips have to be detected and removed. Defects inspection system is usually developed with frame CCD imagers.
There're some drawbacks for this system, such as mechanism of pause type for image acquisition, complicated
acquisition control, easy damage for moving components, etc. And acquired images per chip have to be processed in
radiometry and geometry and then pieced together before inspection. These processes impact the accuracy and
efficiency of defects inspection. So approaches of image acquisition system and its opto-mechanical module will be
critical for inspection system.
In this article, design and characterization of a new image acquisition system and its opto-mechanical module are
presented. Defects with size of greater than 15μm have to be inspected. Inspection performance shall be greater than
0.6 m/sec. Thus image acquisition system shall have the characteristics of having (1) the resolution of 5μm and 10μm
for optical lens and linear CCD imager respectively; (2) the lens magnification of 2; (3) the line rate of greater than 120
kHz for imager output. The design of structure and outlines for new system and module are also described in this work.
Proposed system has advantages of such as transporting chips in constant speed to acquire images, using one image only
per chip for inspection, no image-mosaic process, simplifying the control of image acquisition. And the inspection
efficiency and accuracy will be substantially improved.