In depth from defocus (DFD), when images are captured with different camera parameters, a relative magnification is induced between them. Image warping is a simpler solution to account for magnification than seemingly more accurate optical approaches. This work is an investigation into the effects of magnification on the accuracy of DFD. We comment on issues regarding scaling effect on relative...

The use of operating spectacles goes back just over one hundred years; the first were simple presbyopic corrections, later increased to over-correction and later coupled with the use of base-in prisms. Magnification was increased by displacement on the nose to increase the back vertex distance. About 1880, the limited magnification available with a single lens was overcome by the use of compoun...

I n this paper we tackle the problem of magnifying an image without incurring blurring, ringing or other artifacts common to classical schemes. The proposed iterative scheme starts with an initial magnified image generated by a process of selective interpolation. By placing suitable constraints on the final magnified image, which are convex in nature, we show that magnification can be posed as ...

Actually, there is first a small technical issue of mapping between texture coodinates, which might be defined on any arbitrary rectangle in 2D, and actual texel coordinates (e.g. numbers between 0 and 512 for a 512 × 512 texture image). This is handled as usual by a windowing transform, which can be conveniently represented with a transformation matrix: as mentioned last time, OpenGL even prov...

We have developed a novel method of calculating the radiological magnification of the hip using two separate radio-opaque markers. We recruited 74 patients undergoing radiological assessment following total hip replacement. Both the new double marker and a conventional single marker were used by the radiographer at the time of x-ray. The predicted magnification according to each marker was calc...

The present paper described the technique to evaluate digital resolution (DR), Visual Magnification (VM), onScreen Magnification (SM) and Useful magnification (US) in order to compare image quality and resolution for diagnostic purposes on computer assisted microscopes including Multi-Modal Miniature Microscopes-4M.The study was done on surgical pathology and cytological specimens comparing ana...

This study aims to quantify any cavity size change following removal of tooth-coloured restorations in vitro using unaided vision and 2.6 x magnification. Occlusal composite restorations were removed under simulated clinical conditions and changes in cavity size were measured, blind to method, using standardized photographs. The outline of the cavity was digitized and its area was used as a sur...