Quick question: What is the difference between interpolating and blending?

jellysandwich · 8th March 2005, 01:51

Googles didn't help much

jellysandwich

trevlac · 8th March 2005, 03:18

Depends on the context. For deinterlacing I believe these mean the same thing. For resizing, they would not. Lanczos would be interpolation, bilinear would be blend.

BTW: Interpolate usually means calculating a new pixel value between and by using other pixels. If certain conditions are met, the calculation can be rather accurate. The secret is that the surounding pixels are not evenly weighted (not a simple average), and many are used. "A simple average" i would take as the general meaning of blend.

Unfortunately, for deinterlacing, there is not enough information to do a proper interpolation. AKA the frame rate is too low.

For deinterlacing ... other math magic has to me used. Like motion compensation.

At least that's my take ..

jellysandwich · 8th March 2005, 05:40

Hmm, that's a bit weird since the reason I'm asking
is because of Decomb's blend=true/false option...

jellysandwich

E-Male · 8th March 2005, 05:45

AFAIK(!):

blending means taking 2 or more pixels (or other sources) and combine them (for example by averaging)

interpolating means that you take 2 sources a and c and reconstruct b from them (trying to get d would be extrapolating)

so depending on the context it should be the same

jellysandwich · 8th March 2005, 05:46

To avoid making a new thread...

What is this called, and how can I get rid of it?

http://whitevoid.myvnc.com/stuff/this.JPG

The left picture is the source, unmodified. After
trying a bunch of plugins and scripts, I always end
up getting something like the right picture. At first,
I thought it was blending, but now I'm not so sure,
since I can't seem to get rid of it no matter what I
do... You can imagine what the previous/next frames
are.

Anyway, I'd like to make/use a script/plugin that
chooses either the previous or the next frame, instead
of having to use a combination of both. Is that
possible?

jellysandwich

tritical · 8th March 2005, 06:31

Pretty sure that part of the hellsing intro contains blended fields (you can verify it by using separatefields() and examining them), which is what is causing the effect in your pics...

Manao · 8th March 2005, 07:12

Blending and interpolating are totally different in the context of deinterlacing :

- blending : you merge both fields together ( hence it's a very basic kind of spatio temporal interpolation ). You will likely end up with ghosts on fast action scenes.

- interpolation : you discard one field and reconstruct it with the other, spatially ( so only spatial interpolation ). No ghosts ( except of course if the source has got blended fields, but that's another matter ), but less details too.

jellysandwich · 9th March 2005, 00:31

Quote:

Originally posted by tritical
Pretty sure that part of the hellsing intro contains blended fields (you can verify it by using separatefields() and examining them), which is what is causing the effect in your pics...

Ok, I just checked it, and I think you're right.

So, let me rephrase my previous question then...
Is there a way of getting rid of those blended
fields by using the next/previous unblended fields?

Manao, thanks, your explanation helped a lot.

jellysandwich

Guest · 9th March 2005, 00:37

Do a search on "blended fields".

jellysandwich · 9th March 2005, 00:38

Of course there is. I got it, thanks a bunch.

jellysandwich

8th March 2005, 01:51	#1 \| Link
jellysandwich Registered User Join Date: Mar 2004 Posts: 247	Quick question: What is the difference between interpolating and blending? Googles didn't help much jellysandwich

8th March 2005, 05:46	#5 \| Link
jellysandwich Registered User Join Date: Mar 2004 Posts: 247	Another question To avoid making a new thread... What is this called, and how can I get rid of it? http://whitevoid.myvnc.com/stuff/this.JPG The left picture is the source, unmodified. After trying a bunch of plugins and scripts, I always end up getting something like the right picture. At first, I thought it was blending, but now I'm not so sure, since I can't seem to get rid of it no matter what I do... You can imagine what the previous/next frames are. Anyway, I'd like to make/use a script/plugin that chooses either the previous or the next frame, instead of having to use a combination of both. Is that possible? jellysandwich

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8th March 2005, 03:18	#2 \| Link
trevlac budala Join Date: Oct 2003 Location: U.S. Posts: 545	Depends on the context. For deinterlacing I believe these mean the same thing. For resizing, they would not. Lanczos would be interpolation, bilinear would be blend. BTW: Interpolate usually means calculating a new pixel value between and by using other pixels. If certain conditions are met, the calculation can be rather accurate. The secret is that the surounding pixels are not evenly weighted (not a simple average), and many are used. "A simple average" i would take as the general meaning of blend. Unfortunately, for deinterlacing, there is not enough information to do a proper interpolation. AKA the frame rate is too low. For deinterlacing ... other math magic has to me used. Like motion compensation. At least that's my take ..

8th March 2005, 05:40	#3 \| Link
jellysandwich Registered User Join Date: Mar 2004 Posts: 247	Hmm, that's a bit weird since the reason I'm asking is because of Decomb's blend=true/false option... jellysandwich

8th March 2005, 05:45	#4 \| Link
E-Male mad computer-scientist Join Date: Mar 2002 Posts: 1,375	AFAIK(!): blending means taking 2 or more pixels (or other sources) and combine them (for example by averaging) interpolating means that you take 2 sources a and c and reconstruct b from them (trying to get d would be extrapolating) so depending on the context it should be the same

8th March 2005, 06:31	#6 \| Link
tritical Registered User Join Date: Dec 2003 Location: MO, US Posts: 999	Pretty sure that part of the hellsing intro contains blended fields (you can verify it by using separatefields() and examining them), which is what is causing the effect in your pics...

8th March 2005, 07:12	#7 \| Link
Manao Registered User Join Date: Jan 2002 Location: France Posts: 2,856	Blending and interpolating are totally different in the context of deinterlacing : - blending : you merge both fields together ( hence it's a very basic kind of spatio temporal interpolation ). You will likely end up with ghosts on fast action scenes. - interpolation : you discard one field and reconstruct it with the other, spatially ( so only spatial interpolation ). No ghosts ( except of course if the source has got blended fields, but that's another matter ), but less details too.

9th March 2005, 00:37	#9 \| Link
Guest Guest Join Date: Jan 2002 Posts: 21,901	Do a search on "blended fields".

9th March 2005, 00:38	#10 \| Link
jellysandwich Registered User Join Date: Mar 2004 Posts: 247	Of course there is. I got it, thanks a bunch. jellysandwich