#Objektiv test full

P.862 was later complemented with Recommendations ITU-T P.862.1 (mapping of PESQ scores to a MOS scale), ITU-T P.862.2 (wideband measurements) and ITU-T P.862.3 (application guide).

#Objektiv test full

ITU-T’s family of full reference objective voice quality measurements started in 1997 with Recommendation ITU-T P.861 (PSQM), which was superseded by ITU-T P.862 (PESQ) in 2001. The three companies merged their approaches to one single model, which was adopted as Recommendation ITU-T P.863. In May 2010, ITU-T selected candidate models from three companies (OPTICOM, SwissQual / Rohde & Schwarz and TNO ( Netherlands Organisation for Applied Scientific Research)). In mid-2009, a competition was started to evaluate several candidate models. The POLQA activities started in ITU-T in early 2006 under the working title P.OLQA. POLQA also targets the assessment of speech signals recorded acoustically by an artificial head with mouth and ear simulators. Similarly to P.862, POLQA supports measurements in the common telephony band (300–3400 Hz), but in addition it has a second operational mode for assessing HD-Voice in wideband and super-wideband speech signals (50–14000 Hz). Further improvements target the handling of time called signals and signals with many delay variations. POLQA avoids weaknesses of the current P.862 model and is extended towards handling of higher bandwidth audio signals. POLQA is the successor of PESQ (Recommendation ITU-T P.862). POLQA uses real speech as a test stimulus for assessing telephony networks. Usually, a Mean Opinion Score (MOS) is predicted. The predictions of those objective measures should come as close as possible to subjective quality scores as obtained in subjective listening tests. The CAs increase to 1.6px at 55mm f/2.8 but this is still nowhere excessive.POLQA covers a model to predict speech quality, by means of digital speech signal analysis. In the 18-35mm range they stay at or below 1px on the average pixel at the image borders. Lateral CA (color shadows at the image borders) are well controlled for a standard zoom lens. If you want to know more about the MTF50 figures you may check out the corresponding Per picture height (LW/PH) which can be taken as a measure for sharpness. Please note that the MTF results are not directly comparable across the different systems!īelow is a simplified summary of the formal findings. Otherwise the corners will be defocused - thus visually soft. While the technical figures are impressive at 18mm, we have to note that the lens suffers from a high amount of field curvature at 18mm - the focus plane 'bends' towards the front in the image corners making it necessary to stop down quite a bit get everything into focus. The sweet spot of the lens is at 18mm and the weakest spot is around 35mm - albeit on a very high level. The extreme corners show no softness at all tested apertures and focal lengths as well. The border quality is easily on a very good level and it even touches excellent levels in the lower zoom range. The center performance is generally excellent except at f/11 where diffraction takes a slight toll. The Fujinon produced very impressive resolution figures in the MTF lab. Please note that vignetting compensation is also a lossy procedure because it increases the corner (sensor-)noise. However, it isn't really an issue anymore when stopping down to f/5.6. aperture there's a strong light falloff especially at 18mm but also at and beyond 35mm. In RAW mode - thus with disabled distortion and vignetting compensation - it is a different story. Vignetting is another aspect which is usually auto-corrected.

Move the mouse cursor over the focal length text marks below to observe the respective distortions Zooming in, the distortion decreases to a slight barrel distortion level at 23mm and a slight pincushion distortion at longer focal lengths. The Fujinon shows a rather massive amount of barrel distortion at the short end (4.6%) so it is a bit under-designed here. However, it is still interesting to check the original distortion characteristic - after all the auto-correction is a lossy procedure.

These days image distortion is usually taken care of by the camera or by RAW converters so from a user perspective there isn't much to worry about there.