Background subtraction operations

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Background subtraction operations

junsheng
As to the uneven illuminative image stack from X-ray transmission, it is
difficult to substract a proper backgroud per image. I'm planning to do
the z-direction median filter and trying to generate a backgroud from
the stack. Can anybody point me to a plugin which can do this?


Cheers,
Junsheng Wang
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Re: Background subtraction operations

Gabriel Landini
On Tuesday 17 January 2006 09:40, Wang, Junsheng wrote:
> As to the uneven illuminative image stack from X-ray transmission, it is
> difficult to substract a proper backgroud per image. I'm planning to do
> the z-direction median filter and trying to generate a backgroud from
> the stack. Can anybody point me to a plugin which can do this?

Without having any other clues about the problem, I do not understand the
problem. If you have an  uneven exposure of X rays what has the median image
of the stack have to do with the uneven nature of the background?

If you have a pixel which has not been exposed in the majority of the frames
(i.e. there is an object between the xray source and the detector) taking the
median guarantees that one of those pixels will be forming part of the median
image. You would be then use those pixels for "background correction". Is
that the correct way of doing background correction?

Can you just take a shot without the specimen and correct from that image
alone?

Cheers,

Gabriel
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Re: Background subtraction operations

junsheng
In reply to this post by junsheng
Hello,
 
Thank you for your reply. The noise in my Images is partly because of the uneven exposure of X-rays at each shot. Another big problem is the unstable exposure of X-ray on the specimen at different shot because the short exposure time. So I can't correct the it from the image without specimen. I did XY-2D median filter on each image in the stack to remove the uneven exposure of X-ray at each shot. After that, I plan to do z-median filter to generate a background to remove noise from unstable exposure.
 
Best wishes,
Junsheng

________________________________

From: ImageJ Interest Group 代表 Gabriel Landini
Sent: 2006-1-21 (星期六) 12:51
To: [hidden email]
Subject: Re: Background subtraction operations



On Tuesday 17 January 2006 09:40, Wang, Junsheng wrote:
> As to the uneven illuminative image stack from X-ray transmission, it is
> difficult to substract a proper backgroud per image. I'm planning to do
> the z-direction median filter and trying to generate a backgroud from
> the stack. Can anybody point me to a plugin which can do this?

Without having any other clues about the problem, I do not understand the
problem. If you have an  uneven exposure of X rays what has the median image
of the stack have to do with the uneven nature of the background?

If you have a pixel which has not been exposed in the majority of the frames
(i.e. there is an object between the xray source and the detector) taking the
median guarantees that one of those pixels will be forming part of the median
image. You would be then use those pixels for "background correction". Is
that the correct way of doing background correction?

Can you just take a shot without the specimen and correct from that image
alone?

Cheers,

Gabriel