Re: 8Κ
Οι τηλεοράσεις 8K της Samsung δεν είναι αληθινές 8Κ
Οι τηλεοράσεις της Samsung χρησιμοποιούν τη τεχνική sub-pixel rendering για τη βελτίωση των γωνιών θέασης και τη μείωση των αντανακλάσεων.
Η τεχνική όμως αυτή έχει ως μειονέκτημα μειωμένη πραγματική ανάλυση που επηρεάζει τη λεπτομέρεια στην εικόνα.
Το αποτέλεσμα φαίνεται στις παρακάτω φωτογραφίες από την Samsung Q900R 8K LCD.
Notice how shadows and areas around the hairline pixellate. Here, the effective resolution is lower than 8K.
In the other example, you can see how it works. Pixels are controlled in clusters of four. With this shade of green, only one pixel is lit, while the three other pixels are either dimmed down or turned off. In the worst case scenario, you get 4K resolution but this will require special test patterns. With real content, you are more likely to see effective resolution somewhere between 4K and 8K.
Τα ίδια ισxύουν και για τις 4K τηλεοράσεις που χρησιμοποιούν την ίδια τεχνική sub-pixel rendering όπως η Samsung Q90 R.
As you may have guessed, sub-pixel rending does have drawbacks, with the main one being lower effective resolution when the wide viewing angle system is active. When examining the pixel structure more closely, we found that the LCD panel has a gate pattern that negatively affects picture details.
The photo to the right illustrates the same picture section from Samsung Q90R and Sony A9F, revealing that you some of the finer details (i.e. the pupil) in the picture are lost, and that color gradients or contrast transitions (around the hair) appear with dithering artefacts.
Στις 8Κ το φαινόμενο της μειωμένης πραγματικής ανάλυσης είναι πιο έντονο και πιο εμφανές για τον θεατή γιατί οι τηλεοράσεις έχουν μεγαλύτερα μεγέθη και ο θεατής καθεται πιο κοντά στην τηλεόραση
Για το λόγο αυτό η International Committee for Display Metrology (ICDM) έχει ανακοινώσει τα διεθνή πρότυπα για τη πιστοποίηση μια τηλεόρασης ως πραγματικής 8Κ.
"For a “real 8K” experience, pixels must be easily distinguishable from one another. According to the ICDM, Contrast Modulation (CM), which measures precisely if neighbouring pixels are distinguishable from one another- is the relevant way to measure and describe display resolution.
For any TV display to deliver the resolution indicated by its pixel count, the ICDM requires the minimum CM value to exceed a threshold of 25% for images and 50% for text. An 8K TV with a CM value that is lower than these required thresholds does not deliver real 8K, even though the TV may in fact have the sufficient number (7,680 x 4,320) of pixels"
Using as few as one-in-four pixels for 25% brightness will result in having lower CM values. Turning off pixels versus dimming them is a much lower-cost way to lower brightness at the expense of detail, HDR and colour. The customer is not getting a true 8K image nor brightness.
Samsung's Q900R is using one-in-four pixels producing a fly-screen effect. When you know what to look for the flyscreen effect – pixelation – becomes obvious as a much softer focus in dimmer areas and a loss of HDR detail.
Οne in four pixels turned off – notice fly screen effect in Samsung Q900R 8K
All pixels on using active dimming to 25% in LG 8K Nano panel
The left picture illustrates the quality if pixels are dimmed. The right illustrates the ‘holes’ if they are turned off leading to lower resolution
Για το λόγο αυτό η TCL ανακοίνωσε πως οι TCL 75X10 QLED 8K τηλεοράσεις της είναι πραγματικές 8Κ αφού έχουν πιστοποίηση από Κινεζικό Οργανισμό πιστοποίησης ενώ η LG ανακοίνωσε πως οι δικές της 8Κ τηλεοράσεις ξεπερνάνε το όριο του 25% που έχει θέσει η ICDM αφού φτάνουν το 90%.
www.flatpanelshd.com/review.php?subaction=showfull&id=1557215154
www.flatpanelshd.com/review.php?subaction=showfull&id=1557215154
www.flatpanelshd.com/news.php?subaction=showfull&id=1567494878
www.gadgetguy.com.au/lg-warns-of-real-8k-versus-fake-8k-tvs-how-to-tell
