Video Techniques: Measurement of Resolution of Camera Systems, 1993 Techniques
|Publication Date:||16 March 1995|
The fundamental basis for making a measurement of resolution of a camera system is to reproduce a suitable test chart with the equipment under test. This test chart shall include a pattern that has a sufficient amount of fine detail so that a quantitative observation can be made of the amount of this detail in the reproduced picture. This is usually done by incorporating in the chart a series of lines having graduated widths. The reproduced image of this test chart is then observed on a picture tube or other suitable reproducing device. The point in the picture where the lines are no longer visible as separately defined images gives a measure of the system performance with respect to resolution. A quantitative method of measuring the horizontal resolution response of a camera system is based upon the oscilloscope display of the camera output voltage obtained from any single scan line across the vertical wedges of the resolution chart image. By choosing lines that occur at suitable times, the amplitude of the resulting signal can be plotted as a function of the line number of the chart.
NOTE - The horizontal resolution response characteristic described above is also referred to as the depth of modulation. The term modulation transfer function (MTF), or optical transfer function (OTF), is strictly defined as sine wave frequency response, and should not be used when referring to the response of the television camera to optical square wave patterns.