Abstract: A method and apparatus are disclosed for measuring spatial dimensions of an object. The object is positioned between a radiation source and a radiation sensitive surface, such as between an X-ray unit and an X-ray film. The distance between the object and the X-ray unit is small relative to the distance between the object and the film. An the image of the object is produced on the film when radiation is emitted from the X-ray unit, and by virtue of the spacing of the object between the source and the film, the object is magnified, but is severely blurred. The image is then digitized and restored using two-dimensional deconvolution techniques to remove the blur, resulting in an enlarged, clear image. Edge-detection algorithms are then used to enable measurement of the spatial dimension. This permits accurate measurement of small internal dimensions of the object such as voids or cracks in bonded or welded components.

Abstract: A spring construction for use as an inner spring for a mattress or cushion. The spring is in the form of helical core including concave and convex side portions which when placed in adjacent rows overlap and intermesh to provide firm support for a body and aid in preventing sag and collapse of any individual spring.