Regardless of the existence of advanced style and production strategies, lenses can still differ substantially in imaging quality because of producing errors. Because of the growing requirement in the efficiency of imaging of lenses, the characterization by the help of the Modulation Transfer Feature, or MTF tests, as the premier criterion for objectively reviewing is more and more utilized.
The optical market uses this specification as a meaningful quality function for the unbiased assessment of optical systems.
The MTF defines how the picture contrast varies with spatial regularities. It is expressed as the ratio of comparison in the image to compare in the object as a function of spatial regularity of a line grid with cosinus practical transmission. Spatial frequency is shared in terms of line pairs per millimeter. The MTF incorporates image resolution and comparison into a common representation.
An additional feature of an MTF determining instrument is, that it allows system screening in scenarios comparable to real applications. Area angle positions, distances between objects, spooky ranges, as well as photo planes can be replicated or simulated in the examination of an optical system.
Determining concept
The MTF dimension is based upon the evaluation of the test graph image, offered by the lens under test. As a test chart an edge or space, or hair cross, is used.
The test chart image is taken with the highest accuracy as well as reviewed by an image handling system utilizing the according to mathematical algorithms.
The Fourier improvement of the line spread feature results in the complicated optical transfer function. The MTF is the magnitude of the Fourier improvement of the line spread feature.
Measuring procedure
- The MTF measurements can be done in interactive or in automatic mode.
- The automated mode is used for the serial examination of a specimen of the very same type.
- The interactive setting is utilized for the assessment of unique sampling.
- In the interactive mode, the MTF is displayed in actual time on the PC display.
- The outcomes of interactive dimensions can be stored as well as stood for together with layouts in determining procedures.
In the completely automatic gauging mode, measuring design templates are processed instantly. Determining design templates can be produced easily by the operator.
After the beginning, the complete dimension escapes fully automated.
