How is MTF value calculated?
How is MTF value calculated?
The MTF, or Modulation Transfer Function, is defined as the ratio of the image contrast to the target contrast, expressed as a function of spatial frequency. That is, MTF(u) = C'(u) / C(u). C is the contrast in the target, C’ is the corresponding contrast in the image.
What are the units of MTF?
Spatial Frequency Units
| MTF Unit | Equation |
|---|---|
| Cycles/Pixel (C/P) | |
| Cycles/Distance (cycles/mm or cycles/inch) | \frac{MTF(C/P)}{\text{pixel pitch}} |
| Line Widths/Picture Height (LW/PH) | 2 \times MTF\bigl(\frac{LP}{PH}\bigr) ; 2 \times MTF\bigl(\frac{C}{P}\bigr) \times PH |
How do you calculate line pairs per millimeter?
A line pair consists of a dark line and a bright line. So if one line is 5 microns wide, then a line pair will be 10 microns wide and there would be 1 mm/10 microns = 100 line pairs per millimeter.
What is MTF value?
Modulation Transfer Function or “MTF” is a measurement of the optical performance potential of a lens. A MTF chart plots the contrast and resolution of a lens from the center to its edges against a “perfect” lens that would transmit 100% of the light that passes through it.
What is MTF as a percentage?
MTF is usually normalized to 100% at very low frequencies. But it can go above 100% with interesting results. Contrast levels from 100% to 2% are illustrated on the right for a variable frequency sine pattern. Contrast is moderately attenuated for MTF = 50% and severely attenuated for MTF = 10%.
What is MTF PSF?
A point spread function (PSF) or modulation transfer function (MTF) is a measure of how well focused a satellite imaging sensor is. The MTF is simply the normalized Fourier Transform of the PSF. Therefore, when one function is obtained, so is the other.
What does LP mm mean?
Line Pairs per Millimeter
Lp/mm (Line Pairs per Millimeter) Units used to measure image intensifier resolution. Usually determined from a 1951 U.S. Air Force Resolving Power Test Target. The target is a series of different-sized patterns composed of three horizontal and three vertical lines.
How do you convert pixels to line pairs per millimeter?
For monochrome applications the pixel size is multiplied by factor 1.41 (=square root of two). The result is the diagonal of the pixel. For color applications you can generally use factor 2. The result is 1000 / ( pixel size * factor) for the value “lines per millimeter”.
What is MTF SFR?
The relative contrast at a given spatial frequency (output contrast/input contrast) is called the Modulation Transfer Function (MTF) or Spatial Frequency Response (SFR). It is the key to measuring sharpness.
