Sir,?I must plead guilty to having performed many iridectomies unintentionally, and at the same time point out the cause of this little accident in most of my cases. This was a "bellying" of the blade of the Grafe's knife. If instead of the knife being, except at the point, of equal thickness and width there be a " belly " or greater width in the forepart of the blade, leaving the part near the...

In microtomy, faults of the cutting edge are an obvious and avoidable source of artifact. The purpose of this communication is to describe a simple apparatus for viewing and marking the cutting edge of the glass knives which are used in see-tioning for electron microscopy (1, 2). The apparatus consists of a monocular microscope with base, arm, body tube, coarse and fine adjustments, an annular ...

Image formation with partially coherent radiation is evaluated with the Hopkins formula and then applied to x-ray microscopy. Image characteristics expected from instruments with circular and annular pupils in partially coherent conditions are considered for two-point objects and a knife-edge object. The theoretically expected values for image characteristics that are easy accessible by an expe...

In this paper, a blind restoration method is presented to remove the blur in remote sensing images. An alternating minimization (AM) framework is employed to simultaneously recover the image and the point spread function (PSF), and an adaptive-norm prior is used to apply different constraints to smooth regions and edges. Moreover, with the use of the knife-edge features in remote sensing images...

The base sledge microtome presents a hazard to the operator due to the length of blade that is exposed. Manipulation of the carriage requires hand movements close to the knife edge and serious lacerations may result. A simple, effective guard has been devised, suitable for knives which have screw holes for handles at both ends. It consists of two perspex end-pieces (Fig. I), attached to the kni...

Motion blur in images is usually modeled as the convolution of a point spread function (PSF) and the original image represented as pixel intensities. The knife-edge function can be used to model various types of motion-blurs, and hence it allows for the construction of a PSF and accurate estimation of the degradation function without knowledge of the specific degradation model. This paper addre...

INTRODUCTION The accompanying article, written by John Murphy, a retired lawyer and lifelong outdoorsman from his beloved Colorado Rockies, draws the striking parallel between his experiences as a mountain climber and as a patient with metastatic melanoma facing the hope and uncertainty of experimental therapy. Both are life-threatening circumstances, demanding courage and hope, and challenging...