Abstract: Method and apparatus for determining the velocity of an object in a given direction without contacting the object, by: directing coherent radiation to the object in a direction substantially perpendicular to the given direction to cause radiation to be scattered from the object to produce a speckle pattern exhibiting a speckle spectrum, the speckle pattern at a location spaced from the object having a time dependency which is a function of movement of the object, detecting the speckle pattern intensity at the location spaced from the object, producing a first signal representative of the detected speckle intensity, and producing, from the first signal, a time-dependent intensity signal having a value which is weighted as a function of the frequency of the first signal.

Abstract: For measuring the speed of movement of one phase in another, and particularly the rate of sedimentation of corpuscles in blood plasma, a container is filled with a blood sample, a light beam is directed through the container and an image of a vertical plane in the container traversed by the beam is formed in a measuring plane, the light intensity at two vertically spaced regions of the measuring plane is measured, the container is moved until a certain light intensity relationship exists between the two regions, indicating that the image of the boundary of the one phase in the other phase is located between the regions, and after a selected time interval the container is raised until the same light intensity relationship is established between the two regions and the distance through which the container has been raised is indicated.

Abstract: For enabling a quasimonochromatic high intensity light beam to be produced by a source having a lamp equipped with a cold light mirror, a heat protection filter in the light beam path and a system for cooling the heat protection filter, the source is further provided with an interference filter and projection optics located in the beam path downstream of the heat protection filter, and the interference filter is disposed in the optics.