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A densitometer is a device that measures the degree of darkness (the optical density) of a photographic or semitransparent material or of a reflecting surface. [1] The densitometer is basically a light source aimed at a photoelectric cell . [ 2 ]
According to the principle of operation of the densitometer, one can have: spot densitometry: the value of light absorption is measured at a single spot; line densitometry: the values of successive spots along a dimension are expressed as a graph
The ultrasonic density meter calculates the sonic velocity by using the known distance between the transmitter and receiver and the measured transit time. The measuring instrument can now calculate the density, as it is dependent on the sound velocity.
The granularity measurement [2] involves the use of an optical aperture, 10-50 micrometers in diameter, and in the recording of thousands of optical density readings. The standard deviation of this series of measurements is known as the granularity [ 2 ] [ 3 ] of the measured transmission surface, optical film, or photographic film , in ...
U-tube with piezo-electric actuator Digital density measuring principle. The oscillating U-tube is a technique to determine the density of liquids and gases based on an electronic measurement of the frequency of oscillation, from which the density value is calculated.
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In any event it must pass through film processing and possibly printing equipment before reaching the telecine machine and, in all cases, the overall gamma for the entire film-using system must be 1.0 so that, for example, sections of film may be inter-cut with live transmissions. One example of this is, of course, the many sections of ...
The amount of bone mineral content, bone structure, and bone strength can be reflected better by velocity and amplitude attenuation and has a good correlation with DEXA. The method is easy to operate, safe and harmless, and low in price. The instrument used was an ultrasonic bone densitometer. [14] [15]