object distance

An object's location is found using trilateration, a position-finding technique that measures the objects distance in relation to three reference points.

For concave mirrors, whether the image is virtual or real depends on how large the object distance is compared to the focal length.

This is by no means fixed: the subjective z is only vaguely related to the actual object distance, as is obvious in watching 3D film.

These vary small values of normal stereoacuity, expressed in differences of either object distances, or angle of disparity, makes it a hyperacuity.

For clear pictures, the focus is adjusted for distance, because at a different object distance the rays reach different parts of the lens with different angles.

For example k-Means clustering naturally optimizes object distances, and a distance-based internal criterion will likely overrate the resulting clustering.

The Gaussian mirror equation, also known as the mirror and lens equation, relates the object distance and image distance to the focal length :

Similarly to curved mirrors, thin lenses follow a simple equation that determines the location of the images given a particular focal length () and object distance ():

It was an early 3-D process of making and projecting pictures, using a conventional camera lens a with concave spherical lens attached to increase field without increasing object distance.

The main benefit of using optical power rather than focal length is that the lens-maker's equation has the object distance, image distance, and focal length all as reciprocals.

In his Kitab al-Mu'tabar, Abu'l-Barakat stated that the mover imparts a violent inclination (mayl qasri) on the moved and that this diminishes as the moving object distances itself from the mover.

In practice, objects at considerably different distances from the camera can still appear sharp (Ray 2000, 50); the range of object distances over which objects appear sharp is the depth of field ("DoF").

In film, photography and art, perceived object distance is manipulated by altering fundamental monocular cues used to discern the depth of an object in the scene such as aerial perspective, blurring, relative size and lighting.

"Macro" lenses were originally regular formula lenses optimized for close object distances, mounted on a long extension tube or bellows accessory to provide the necessary close focusing, but preventing focusing on distant objects.

The infinite depth of field means that image blur depends not on object distance, but on other factors, such as the distance from the aperture to the film plane, the aperture size, and the wavelength(s) of the light source.

Consider a general imaging system with object distance z, focal length of the thin lens f and an imaging distance z. The effect of the propagation in freespace acts as nearly a chirp convolution, that is, the formula of diffraction.

The output of this device is a boxcar output where the photodiodes are sequentially lit diode by diode as the object distance changes in relation to the sensor until either no diodes are lit, or all diodes are lit.

By optical convention, both object and image distances are positive for real images, so that in Figure 6, the object distance u increases to the left of the lens plane LP; the vertical axis uses the normal Cartesian convention, with values above the optical axis positive and those below the optical axis negative.