Methods of depth measurement and image fusion based on multi-focus micro-images

When a small object is measured by micro cameras, a sharp image of the whole object is impossible to be obtained because the depth of the object´s surface is different and the distance between different parts of the object´s surface maybe deeper than the depth of field of the micro camera. The camera is focused on different areas of the object´s surface and a series of multi-focus images are taken. The relative depths between the object surface´s different sub-regions will be got by comparing image sharpness evaluation function values of multi-focus images´ same sub-regions and considering the relative position between the camera and the object. Thus the surface depth is obtained. Multi-focus images´ sub-regions with maximum image sharpness evaluation function values are combined into an image. The experimental results verify the effectiveness of the proposed methods.