FRC Artefact /Noise

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Hi
I am using a LG 24" LCD PN : LM240W08 SLE1 based on 6Bit + FRC technology. The LCD suffers from inversion and FRC artefact/noise issue which is disturbing in the application it is to be used.Are there ways to avoid such a flicker.

Any reply....answers....
Waiting for the same

[Chief Blur Buster]

It's hard to avoid -- some panels, particularly TN panels, are prone to these artifacts -- sometimes amplified in strobed mode or low-Hz VRR mode.



Related: Inversion Artifact: Fine Checkerboard / Line In Solid Colors

For people who hate FRC artifacts or inversion artifacts, the use of an IPS panel is often the best. The 165 Hz IPS panels tend to be very a good compromise of high Hz and lack of FRC/inversion artifacts.

[open]

If this happens to be with gsync there have been similar issues in the past related to certain driver revisions. You could try older or newer drivers.

[Chief Blur Buster]

Inversion may increase/decrease with monitor firmware updates (pixel voltage fine-tuning on the scaler) but it's often present when running http://www.testufo.com at odd-pixel-per-frame steps (e.g. 7 pixels per frame). Amplifies when enabling ULMB.

Fiddle with pixels-per-second speed at http://www.testufo.com until pixels-per-frame becomes an odd number, and that's when inversion artifacts amplify (and even moreso in strobe mode)

Low framerates in FreeSync/GSYNC can also amplify inversion artifacts.

That's where good Low Frame Rate Conversion comes in.

The GSYNC update improves low frame rate compensation algorithms (doubles the refresh rate when framerates fall very low), e.g. running at 29fps will run the monitor at 58 Hz in a much more regular cadence, reducing the GSYNC flicker caused by asymmetric "every-other-refresh-cycle" displaytimes -- which can amplify inversion artifacts. Good "low frame rate compensation logic" can greatly reduce inversion-artifacts flicker during low frame rates.

In the past, low framerates often showed asymmetric refresh cycle times (e.g. 24fps GSYNC/FreeSync with a 30Hz minimum, used to show a 1/30sec refresh cycle immediately followed by a 1/120sec re-refreshing cycle -- which caused a weird flickering inversion artifact.

After proper Low Framerate Compensation logic (mostly a graphics driver responsibility) -- 24fps GSYNC/FreeSync now shows a 1/48sec refresh cycle immediately followed by a 1/48sec re-refresh cycle. Both phases (positive/negative) voltages of the inversion cycle are now given equal voltagetime. This greatly reduces inversion artifacts for consistent frame rates.

However, albiet reduced, it is not always possible to completely eliminate the checkerboard-patterning or lines-patterning inversion artifacts on TN LCD panels, especially for constant-speed motion especially at odd-pixel steps, especially in strobe mode (Try varying the speed settings at TestUFO until odd pixel steps occur). It can be very, very good (super faint / not detectable - at non-close viewing distances) -- in fact, you might not be able to see it anymore at least in non-strobed mode -- but it can never be perfect for TN-technology panels.

It is theoretically possible to create an intelligent motionspeed-adaptative inversion pattern with some kind of error-diffusion patterning, but I haven't seen this done on current TN panels. So there's often a checkerboard patterning or 1-pixel-thick vertical/horizontal line texturing in solid backgrounds. If you look closely, they can appear to "scroll" or "animate" even in a static image (it's just more noticeable during image motion at certain odd-pixel-step motionspeeds).

For more technical explanations of inversion (the LCD-protecting voltage-polarity swapping operation) and inversion artifacts (side effects of inversion) -- see the hyperlinks (Techmind/Lagom) at the top of http://www.testufo.com/inversion .... That said, VRR and strobing modes can sometimes amplify inversion artifacts.