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#1 2012-03-02 16:18:27

mgg
Member
Registered: 2011-06-24
Posts: 24

some help understanding Multi-band level.

From the APG documentation:

Multi-band level: Lets you adjust the influence zone for each input pixel. Each pixel will double its influence zone for each supplemental level. For example, at level 2, each pixel acts on a span of 2 pixels in the final rendering, 4 pixels at level 3, 8 pixels at level 4... Level 0 represents the maximal influence zone (depending on the size of the input images). The negative levels let you reduce this area based on the maximum area. -4, the default value, seems to be the best choice in the majority of cases, if the color correction is enabled.

I'm missing something.  From experience, it seems that a value of 0 provides the best blending.  The second sentence seems to say a larger positive number blends over a larger area.  The last seems to say, a negative number decreases the area.  The middle sentence says 0 is maximum.... am I the only one that is confused?

My aim here is to get the best blending between images.  I used to have terrible issues with vertical banding - which careful vignetting correction in Camera Raw helps a lot.  Using "0" for Multi-band helps as well but sometimes I still end up with very subtle bands in some pictures in some places.   There is no lens profile in ACR for my camera (Panasonic G3 with either lens), so I'm going to use their tools to create a profile: maybe that will get me better vignetting correction.

So is "0" truly the best value to use for this situation?
tnx
mgg

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#2 2012-03-02 16:38:31

mediavets
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From: Isleham, Cambridgeshire, UK.
Registered: 2007-11-14
Posts: 9742
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Re: some help understanding Multi-band level.

mgg wrote:

There is no lens profile in ACR for my camera (Panasonic G3 with either lens), so I'm going to use their tools to create a profile: maybe that will get me better vignetting correction.

mgg

Does DxO support your camera/lens combinations? If so it may provide good/better vignetting correction.

http://www.dxo.com/uk/photo

Last edited by mediavets (2012-03-02 16:38:53)


Andrew Stephens
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#3 2012-03-02 16:46:54

mgg
Member
Registered: 2011-06-24
Posts: 24

Re: some help understanding Multi-band level.

The G3 and 14-42 lens is supported, but the 45-200 lens isn't even listed as a future.......

tnx
mgg

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#4 2012-03-06 21:28:39

mgg
Member
Registered: 2011-06-24
Posts: 24

Re: some help understanding Multi-band level.

So,  no one truly understands that paragraph?  Or everyone understands it except me?

"Multi-band level: Lets you adjust the influence zone for each input pixel. Each pixel will double its influence zone for each supplemental level. For example, at level 2, each pixel acts on a span of 2 pixels in the final rendering, 4 pixels at level 3, 8 pixels at level 4... Level 0 represents the maximal influence zone (depending on the size of the input images). The negative levels let you reduce this area based on the maximum area. -4, the default value, seems to be the best choice in the majority of cases, if the color correction is enabled."

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#5 2012-03-12 21:40:11

DrSlony
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From: London, United Kingdom
Registered: 2007-11-03
Posts: 2259
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Re: some help understanding Multi-band level.

I too would like a clarification of "The negative levels let you reduce this area based on the maximum area."
In the case of a 4000x3000 photo,
...
-4 ? (if 0 is 2048, then this is 128?)
-3 ? (if 0 is 2048, then this is 256?)
-2 ? (if 0 is 2048, then this is 512?)
-1 ? (if 0 is 2048, then this is 1024?)
0 max (2048? "Level 0 represents the maximal influence zone (depending on the size of the input images)")
1 1
2 2
3 4
4 8
5 16
6 32
7 64
8 128
9 256
10 512
11 1024
12 2048
13 4096 (larger than image, so doesn't exist)

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#6 2012-03-13 09:15:48

AlexandreJ
Kolor CEO
From: Francin, France
Registered: 2005-11-14
Posts: 7917
Website

Re: some help understanding Multi-band level.

Really good explaination DrSlony. Thanks.
One note : if you have APG, you can go to exposure fusion dialog box where you can see in live the influence of this value ( multiband level slider at the bottom ).

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#7 2012-03-13 14:32:26

klausesser
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From: Düsseldorf, Germany
Registered: 2006-05-22
Posts: 6443
Website

Re: some help understanding Multi-band level.

mgg wrote:

.... am I the only one that is confused?

No. Definitely not . . . cool I also can only guess what´s meant here in detail and what setting does which influence on our working.

best, Klaus


If you want something you´ve never had,
then you´ve got to do something you´ve never done.

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#8 2012-03-14 22:40:34

DrSlony
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From: London, United Kingdom
Registered: 2007-11-03
Posts: 2259
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Re: some help understanding Multi-band level.

AlexandreJ: explanation? I was asking big_smile

The exposure fusion dialog only allows one to use negative numbers: -10 to 0.

If you confirm what I wrote, it would mean that the negative range actually does the same thing as the positive range, just 'from the other end', so no problem really.

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#9 2012-03-15 16:05:22

AlexandreJ
Kolor CEO
From: Francin, France
Registered: 2005-11-14
Posts: 7917
Website

Re: some help understanding Multi-band level.

A pyramid has a level ( height ). This level ( height ) depends on input image size. For a 4000x3000 photos, the level is around 12 ( or 13 depending on the rounding ) : let's say 12.
+X means : X levels from the bottom : Example : 5 means 5 levels, so the blending will occurs over 16 pixes around edges.
-Y means : Y levels from the top. Example -2 means do all levels except last 2. In this case, 10, so everything is smooth at 512 pixels at least.

Of course, both positives values and negative values are the same. For a 12 levels pyramid : 5 = -7, 8 = -4, etc.
0 is an exception : it means all levels.

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#10 2012-03-15 17:51:18

gkaefer
Member
From: Salzburg
Registered: 2009-06-09
Posts: 2678
Website

Re: some help understanding Multi-band level.

AlexandreJ wrote:

A pyramid has a level ( height ). This level ( height ) depends on input image size. For a 4000x3000 photos, the level is around 12 ( or 13 depending on the rounding ) : let's say 12.
+X means : X levels from the bottom : Example : 5 means 5 levels, so the blending will occurs over 16 pixes around edges.
-Y means : Y levels from the top. Example -2 means do all levels except last 2. In this case, 10, so everything is smooth at 512 pixels at least.

Of course, both positives values and negative values are the same. For a 12 levels pyramid : 5 = -7, 8 = -4, etc.
0 is an exception : it means all levels.

hm. ok now I should say I'm wiser...
... but sorry cant follow the calculation

ok asume a height of 12 and a value of +X = 5 ... how do you get to 16pixels. and how to use this If I asume +X =6 ???
Georg

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#11 2012-03-15 19:39:26

lumelix
Member
From: Basel Switzerland
Registered: 2010-10-25
Posts: 405

Re: some help understanding Multi-band level.

Alexandre
A picture says more than thousand words smile
I think that kolor should illustrate this tricky thing with the pyramid graphically, so that we can understand this definitely.
I have seen something like this in the wiki earlier, but I couldn't find it again.

Last edited by lumelix (2012-03-15 22:36:17)


Regards
Martin

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#12 2012-03-18 18:39:15

DrSlony
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From: London, United Kingdom
Registered: 2007-11-03
Posts: 2259
Website

Re: some help understanding Multi-band level.

Alexandre you explained it very well now, thank you.

gkaefer the 5th level covers 16 pixels. See my post #5

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#13 2012-03-19 09:01:58

AlexandreJ
Kolor CEO
From: Francin, France
Registered: 2005-11-14
Posts: 7917
Website

Re: some help understanding Multi-band level.

BTW : we are working on the documentation to make this part full and better understandable :
WIP here : http://www.autopano.net/wiki-en/action/ … ing_engine

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#14 2012-03-19 16:13:20

gkaefer
Member
From: Salzburg
Registered: 2009-06-09
Posts: 2678
Website

Re: some help understanding Multi-band level.

AlexandreJ wrote:

BTW : we are working on the documentation to make this part full and better understandable :
WIP here : http://www.autopano.net/wiki-en/action/ … ing_engine

Hi Alexandre,

looking at the new docu of your link and in special at the image

http://www.autopano.net/wiki-en/action/ … vel_en.png

I've following question:

the size in poxel of the influence zone is the common denominator between the + and the - values.

why not using a scale from 1 to 12 (or 0 to 11) where the smallest is representing the 1 pixel and the highest the 4096 pixel?

with current scaling I have 21 possible values I can set but 9 of them can be set with 2 different values (the -10 and the +2 is representing the 2 pixel, the -9 and the +3 is representing the 4pixel etc. and I assume using +2 or the -10 will give the same result, because both are using the influence zone of 2 pixels?

Liebe Grüße,
Georg

Last edited by gkaefer (2012-03-19 16:14:35)

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#15 2012-03-19 16:16:30

gkaefer
Member
From: Salzburg
Registered: 2009-06-09
Posts: 2678
Website

Re: some help understanding Multi-band level.

DrSlony wrote:

Alexandre you explained it very well now, thank you.

gkaefer the 5th level covers 16 pixels. See my post #5

thanks - got it ;-)

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#16 2012-03-19 18:10:54

klausesser
Member
From: Düsseldorf, Germany
Registered: 2006-05-22
Posts: 6443
Website

Re: some help understanding Multi-band level.

AlexandreJ wrote:

BTW : we are working on the documentation to make this part full and better understandable :
WIP here : http://www.autopano.net/wiki-en/action/ … ing_engine

Well explained! Thank you. As i understand level "0" is the best to use in my case with the sky images? So Vincèn was right?
When i use it the borders seem become a bit sharper than with -4 (default).

best, Klaus

The best result i got is this one - using -4 but some anchors:


Uploaded Images


If you want something you´ve never had,
then you´ve got to do something you´ve never done.

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#17 2012-03-21 11:12:52

[bo]
community overseer
From: Bulgaria
Registered: 2006-05-05
Posts: 1839

Re: some help understanding Multi-band level.

OT: I've never seen more icons on the dock or desktop! Amazing! How do you work and find things smile


Some of my panoramas, posted in the Autopano Pro flickr group.

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#18 2012-03-21 14:27:15

AlexandreJ
Kolor CEO
From: Francin, France
Registered: 2005-11-14
Posts: 7917
Website

Re: some help understanding Multi-band level.

gkaefer wrote:

the size in poxel of the influence zone is the common denominator between the + and the - values.

why not using a scale from 1 to 12 (or 0 to 11) where the smallest is representing the 1 pixel and the highest the 4096 pixel?

with current scaling I have 21 possible values I can set but 9 of them can be set with 2 different values (the -10 and the +2 is representing the 2 pixel, the -9 and the +3 is representing the 4pixel etc. and I assume using +2 or the -10 will give the same result, because both are using the influence zone of 2 pixels?

The pyramid has a variable max level ( sometimes, it can be only 8, other time, it can grow up to 12 or 13 ). So the total number of value can be larger of smaller than 21.
Depending on that, the association ( -something = +some other value ) changes. We want it simple without anyone knowing that there is something not constant around.
That's why we came up with a (-10 | 0 | +10 ) slider. We though also about 3 checks box ( small, normal, large uniformisation ), but that didn't give the accuracy I wanted.

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#19 2012-03-24 10:41:50

marzipano
Member
From: Richmond London UK
Registered: 2011-03-05
Posts: 125

Re: some help understanding Multi-band level.

AlexandreJ wrote:

gkaefer wrote:

the size in poxel of the influence zone is the common denominator between the + and the - values.

why not using a scale from 1 to 12 (or 0 to 11) where the smallest is representing the 1 pixel and the highest the 4096 pixel?

with current scaling I have 21 possible values I can set but 9 of them can be set with 2 different values (the -10 and the +2 is representing the 2 pixel, the -9 and the +3 is representing the 4pixel etc. and I assume using +2 or the -10 will give the same result, because both are using the influence zone of 2 pixels?

The pyramid has a variable max level ( sometimes, it can be only 8, other time, it can grow up to 12 or 13 ). So the total number of value can be larger of smaller than 21.
Depending on that, the association ( -something = +some other value ) changes. We want it simple without anyone knowing that there is something not constant around.
That's why we came up with a (-10 | 0 | +10 ) slider. We though also about 3 checks box ( small, normal, large uniformisation ), but that didn't give the accuracy I wanted.

I understand how the current system is meant to work now but I would say it suffers from an unnecessary over-complication in using values both above and below zero. I cannot see why the slider cannot just go from 0 to 12 where 0 represents max blending equal to the pixel width of the image itself. Then 1=1/2 max 2=1/4 max 3=1/8 max and so on up to 12 or 13 as required. The actual pixel values themselves would not be that important but for a 4096 pixel width it would be 4096=0, 2048=1, 1024=2, 512=3, 256=4, 128=5, 64=6, 32=7, 16=8, 8=9, 4=10, 2=11, 1=12, 1=13

The current system is also not intuitive because in moving the slider from -1 to 0 to 1 (which are all next to each other on the scale) you move through a discontinuity for example where 0=4096 it goes 2048 to 4096 to 1. The slider goes from max to min in one jump there

regards,
Martin

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#20 2012-03-24 11:11:46

gkaefer
Member
From: Salzburg
Registered: 2009-06-09
Posts: 2678
Website

Re: some help understanding Multi-band level.

AlexandreJ wrote:

gkaefer wrote:

the size in poxel of the influence zone is the common denominator between the + and the - values.

why not using a scale from 1 to 12 (or 0 to 11) where the smallest is representing the 1 pixel and the highest the 4096 pixel?

with current scaling I have 21 possible values I can set but 9 of them can be set with 2 different values (the -10 and the +2 is representing the 2 pixel, the -9 and the +3 is representing the 4pixel etc. and I assume using +2 or the -10 will give the same result, because both are using the influence zone of 2 pixels?

The pyramid has a variable max level ( sometimes, it can be only 8, other time, it can grow up to 12 or 13 ). So the total number of value can be larger of smaller than 21.
Depending on that, the association ( -something = +some other value ) changes. We want it simple without anyone knowing that there is something not constant around.
That's why we came up with a (-10 | 0 | +10 ) slider. We though also about 3 checks box ( small, normal, large uniformisation ), but that didn't give the accuracy I wanted.

ok, got it. my impression is that the user currently does not know which size the currently used images does have, 4096, 2048 etc. and so user cant predict where the best results can be expected rather with minus rather with plus values. so its still a bit inefficient a try & error playing...

so a colorscale from green to red obove/down the (current) slider could help the user where the best results can be expected. the scale should be dynamically & dependant to the internally detected pixel size?

Liebe Gruesse,
Georg

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#21 2012-03-26 09:14:44

AlexandreJ
Kolor CEO
From: Francin, France
Registered: 2005-11-14
Posts: 7917
Website

Re: some help understanding Multi-band level.

Yes Gkaefer, perhaps, that's another option. We did this single slider for compacity goal. I agree with the discontinuity.
If you have another UI to propose, I didn't find anything better yet.

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#22 2012-03-27 12:20:34

marzipano
Member
From: Richmond London UK
Registered: 2011-03-05
Posts: 125

Re: some help understanding Multi-band level.

AlexandreJ wrote:

Yes Gkaefer, perhaps, that's another option. We did this single slider for compacity goal. I agree with the discontinuity.
If you have another UI to propose, I didn't find anything better yet.

As I proposed in my post #19 the use of 2 scales is an over-specification of the problem IMO. One scale with a slider going from 0 to +n is all that is required with each increment reducing the scope of the smoothing by an exponential factor of (1/2) to the power n

This is also the best solution in terms of "compacity" (compactness)

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