From b61d222ad9a2ff4b1ef9f82eff81bf09dd04654f Mon Sep 17 00:00:00 2001 From: "Simon A. Eugster" Date: Thu, 6 Jan 2011 13:11:54 +0000 Subject: [PATCH] Light Graffiti effect: Better explanations, parameter for nonlinear dimming added svn path=/trunk/kdenlive/; revision=5278 --- effects/frei0r_lightgraffiti.xml | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/effects/frei0r_lightgraffiti.xml b/effects/frei0r_lightgraffiti.xml index 9ff83bca..68c20030 100644 --- a/effects/frei0r_lightgraffiti.xml +++ b/effects/frei0r_lightgraffiti.xml @@ -8,21 +8,21 @@ Sensitivity - For slowly moving light source try to use a higher sensitivity to obtain smoother results.]]> + For slowly moving light source try to use a lower sensitivity to obtain a better exposure.]]> Brightness Threshold - R+G+B) a light source needs to be in order to be recognized as light source.
+ R+G+B) does a pixel need to be in order to be recognized as a light source?
Increasing this threshold requires brighter light sources (i.e. more white or less color, respectively) but prevents some «false alarms» where semi-bright parts, e.g. hands where colors can change quite a lot compared to the background, are incorrectly recognized as light source.]]> Difference Threshold - max(dR, dG, dB)) relative to the calculated background.
- Increasing this threshold makes it harder for light sources to be accepted on bright backgrounds, but decreases the danger of noise counting as light source.]]> + max(dR, dG, dB)), in order to be recognized as light source?
+ Increasing this threshold makes it harder for light sources to be accepted on bright backgrounds, but decreases the danger of noise or generally bright spots counting as light source.]]> Difference Sum Threshold - dR + dG + dB).
+ relative to the background image (dR + dG + dB) have to change until a pixel is recognized as a light source?.
Raising this value might, in some cases, avoid that some light objects lit by the light source are added to the light mask.]]> @@ -31,23 +31,34 @@ Background Weight - Strength of the (calculated) background image. Setting it to 100 paints the light mask directly over the background, without any person in the image if the video starts with a «clean» background image. + Strength of the (calculated) background image. Setting it to 100 paints the light mask directly over the background, without the painting person in the image if the video starts with a «clean» background image. (See the α parameter.) - α - - If the background does not change, then try to use 0 (requires the first frame to represent background only, without your light sources).]]> + α + + The Light Graffiti remembers the first frame of the clip it is applied to, so the clip should always start with the painter outside of the video. If the background constantly changes, e.g. on a street, try to set α > 0 to calculate an average background image.]]> Show brightness statistics + + Example: To adjust the brightness threshold, check this box and adjust the threshold until the whole light source is highlighted. Repeat the same with the other parameters. Only parts that are highlighted in all thresholds will count as light source.]]> Show background difference statistics + + Show background difference sum statistics + Transparent Background + Makes the background transparent, allowing to apply a composite effect and paint the light mask over a completely different video. + + + Nonlinear dimming + If normal dimming does not look natural enough, try this one. - Reset the mask + Reset + Resets the light mask and the background image. This is necessary e.g. if you apply this effect to a clip in the timeline and then move the timeline cursor from outside of the clip to the middle of it. The effect receives this frame in the middle as first frame and uses it as background image. For proper threshold adjusting move the timeline cursor to the beginning of the clip, check the Reset box and uncheck it again. -- 2.39.2