| Summary: | 碩士 === 國立交通大學 === 電機學院電信學程 === 101 === In nighttime surveillance, there is usually not enough natural ambient light for image capturing, and an IR illuminator is often used to partially resolve the problem. However, improper intensity/location of an illuminator may result in object images which are too dark or bright so that image quality is not satisfactory even for human perception. Using multiple-intensity IR-illuminator can produce a number of different light intensities to help the generation of images with different degrees of exposure, from which well-exposed images can be chosen, and increase the number of good quality images. The goal of this thesis is to develop an automatic calibration method for a synchronous multiple-intensity IR-illuminator, which may be used in different environments for capturing images of objects at various locations, so that quality images, e.g., those with good contrast, will be included in the images captured with selected illumination intensities. In other words, by reducing the number of improperly illuminated images, more informative images (and more useful image analysis results) can be obtained. Experimental results shows that the proposed automatic calibration method can indeed achieve the above improvement for the performance of automatic face detection. Potential applications which may also benefit from such calibration include license plate identification, image integration for a high dynamic range (HDR) representation …etc.
|
|---|
