Texture MTF is a method to measure the sharpness of a digital camera and lens by capturing the image of a target of known characteristics. It purports to better evaluate the perception of fine details in low contrast areas of the image – what is referred to as ‘texture’ – in the presence of noise reduction, sharpening or other non-linear processing performed by the camera before writing data to file.
![](https://i0.wp.com/www.strollswithmydog.com/wordpress/wp-content/uploads/DeadLeavesInput.png?resize=300%2C297&ssl=1)
The Modulation Transfer Function (MTF) of an imaging system represents its spatial frequency response, from which many metrics related to perceived sharpness are derived: MTF50, SQF, SQRI, CMT Acutance etc. In these pages we have used to good effect the slanted edge method to obtain accurate estimates of a system’s MTF curves in the past.[1]
In this article we will explore proposed methods to determine Texture MTF and/or estimate the Optical Transfer Function of the imaging system under test from a reference power-law Power Spectrum target. All three rely on variations of the ratio of captured to reference image in the frequency domain: straight Fourier Transforms; Power Spectral Density; and Cross Power Density. In so doing we will develop some intuitions about their strengths and weaknesses. Continue reading Introduction to Texture MTF