| virtual image | <microscopy> Such as seen in a mirror or through a magnifier. A virtual image has no real existence in space as does a real image from a lens. It does have a definite location, however, caused by the angles of divergence of the rays received by the eye. This can be shown by the common school experiment of placing a pin coincident with its mirror image behind a sheet of glass acting as a partial mirror. Its location can also be placed in design by extrapolating backwards to a focus. If a magnifier is used as it should be, with the object at its focus, the virtual image is at infinity. The same is true for a microscope focused for the relaxed eye. See: distance of virtual image. (05 Aug 1998) |
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| visual image | A collection of foci corresponding to all the luminous points of an object. (05 Mar 2000) |
| retinal image | A real image formed on the retina. (05 Mar 2000) |
| mental image | A picture of an object not present, produced in the mind by memory or imagination. (05 Mar 2000) |
| phase image | A magnetic resonance image showing only phase shift information, to detect motion. (05 Mar 2000) |
| mirror image | A representation of an object or part thereof as its reflected image in a glass mirror. (05 Mar 2000) |
| mirror-image cell | A cell whose nuclei have identical features and are placed in the cytoplasm in similar fashion, a binucleate form of Reed-Sternberg cell often found in Hodgkin's disease; the twin nuclei are disposed in relation to an imaginary plane between them like a single nucleus together with its image in a mirror. (05 Mar 2000) |
| mirror image dextrocardia | Perfect right to left congenital reversal of the heart sometimes with other congenital abnormalities, sometimes normal except for position. (05 Mar 2000) |
| motor image | The image of body movements. (05 Mar 2000) |
| conoscopic image | <microscopy> The interference pattern and diffraction image seen at the back aperture of the objective lens. The conoscopic image provides a two-dimensional projection of the rays travelling in three dimensions in the specimen space. (05 Aug 1998) |
| positive image | <microscopy> A developed image in which dark areas correspond to dark areas of the original subject. (05 Aug 1998) |
| heteronymous image | A double image in physiological diplopia, when fixation is directed beyond an object; the right image arises from the left eye, while the left image arises from the right eye; i.e., there is a crossed diplopia. (05 Mar 2000) |
| sensory image | An image based on one or more types of sensation. (05 Mar 2000) |
| hypnagogic image | Imagery occurring between wakefulness and sleep. (05 Mar 2000) |
| hypnopompic image | <psychology> Imagery occurring after the sleeping state and before complete wakefulness; similar to hypnagogic imagery except for the time of occurrence. (05 Mar 2000) |