The dead leaves pattern is very useful to obtain an SFR from a stochastic pattern and can be used to measure texture loss due to noise reduction or compression in images and video streams. In this paper, we present results from experiments that use the pattern and different analysis approaches to measure the dynamic range of a camera system as well as to describe the dependency of the SFR on object contrast and light intensity. The results can be used to improve the understanding of the performance of modern camera systems. These systems work adaptively and are scene aware but are not well described by standard image quality metrics.
Aliasing is a well-known effect in imaging which leads potentially to disturbing artefacts on structures. While the high pixel count of todays devices helps to reduce this effect, at the same time optical anti-aliasing filter are more often removed from sensor stacks to improve on system SFR and quantum efficiency. While the artefact is easy to see, an objective measurement and quantification of aliasing is not standardised or established. In this paper we show an extension to existing SFR measurement procedures described in ISO12233 which can measure and quantify the existence of aliasing in the imaging system. It utilises the harmonic Siemens star of the s-SFR method and can be included into existing systems, so does not require the capture of additional images.
The technology to let a camera automatically focus on the main object is more than 40 years old. We have a look at todays cameras and their auto focus performance. All tests are performed from the end-user perspective, so with final hardware and without access to the internal processing. With this information engineers get a better understanding on what to expect from todays cameras and how to design test procedures for system with auto focus systems. As an international standard is on its way, we also support the efforts of ISO with this work. We check for repeatability, accuracy and timing of the auto focus systems more than 300 camera systems and compare the different technologies behind it.