
Light source KPIs
Why are CCT or CIE chromaticity coordinates not always the best parameters for designing your test requirements?
Why are CCT or CIE chromaticity coordinates not always the best parameters for designing your test requirements?
The method is suitable for all scenarios where it is essential to examine only a part of the whole imaging system, like both lens and sensor comparison.
The International Organization for Standardization published a revision of “ISO 12233 Photography — Electronic still picture imaging — Resolution and spatial frequency responses” in February 2014.
The Signal to Noise ratio (SNR) is a well known and commonly used metric to describe the noise behavior of a digital camera.
More and more cameras provide a so-called High Dynamic Range (HDR) mode these days. If the scene that you want to get onto your memory card has a too strong contrast, this mode will help to maintain the shadows while keeping the highlight.
Noise is an important parameter in image quality evaluation. Occurring as a random signal variation for each pixel, noise has its source in the physical characteristic of light (photon-shot noise) and technical limitations of the sensor (dark current and read noise).
A standard photometer basically works with a silicon detector in combination with a v(λ) filter to correct for the spectral sensitivity of the human eye. The output current of the detector is directly related to the measured photometric measure value.
One important message we cannot give enough is "pixel count is not resolution". We see resolution as the capability of an imaging system to reproduce spatial frequencies. The higher the frequencies that can be transferred into image content, the higher the resolution.
The ISO standards often specify requirements for the surrounding conditions when testing a camera. As the ISO group for Photography tries to keep these requirements consistent for all standards we summarize the important aspects in this "TechNote".