<div>Roberto,</div><div><br></div><div>I may have confused these with the values in 0028|1051 and 0028|1050. There are valid cases to use the slope/intercept to rescale the data. Sorry for the noise.</div><div><br></div>
<div>- Wes<br><br><div class="gmail_quote">On Wed, Jan 4, 2012 at 1:02 AM, Roberto Laurita <span dir="ltr"><<a href="mailto:roberto.laurita@gmail.com">roberto.laurita@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<p>Hi Wes.</p>
<p>So, if I use the function "getpixel" I'll get an absolute value (not related to 0028|1050 and 0028|1051).</p>
<p>Could you confirm it?</p>
<p>br</p>
<p>roberto</p>
<p>Il giorno 02/gen/2012 19.13, "Wes Turner" <<a href="mailto:wes.turner@kitware.com" target="_blank">wes.turner@kitware.com</a>> ha scritto:</p><div><div></div><div class="h5"><br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Roberto,<div><br></div><div>I believe <span style="background-color:rgb(255,255,255);font-family:arial,sans-serif;font-size:13px">0028|1050 and 0028|1051 are display only parameters and only impact how bright a given pixel value appears. I do not believe that they actually specify modifications to the pixel values. They are not binding on the viewer and almost any software for viewing DICOM images will allow you to interactively change the actual display settings used, but again, that does not translate into an actual change in the pixel value, only how bright a given value appears.</span><span style="background-color:rgb(255,255,255);font-family:arial,sans-serif;font-size:13px"> </span></div>
<div><span style="background-color:rgb(255,255,255);font-family:arial,sans-serif;font-size:13px"><br></span></div><div><font face="arial, sans-serif">- Wes</font></div><div><br><div class="gmail_quote">On Fri, Dec 30, 2011 at 12:51 PM, Martijn Steenwijk <span dir="ltr"><<a href="mailto:martijnsteenwijk@gmail.com" target="_blank">martijnsteenwijk@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Roberto,<br>
<br>
Can you supply some information about the scanner manufacturer and<br>
sequences? Were both slices acquired in the same series?<br>
<br>
Best,<br>
Martijn<br>
<br>
-----Oorspronkelijk bericht-----<br>
Van: <a href="mailto:insight-users-bounces@itk.org" target="_blank">insight-users-bounces@itk.org</a> [mailto:<a href="mailto:insight-users-bounces@itk.org" target="_blank">insight-users-bounces@itk.org</a>]<br>
Namens Fleysher, Lazar<br>
Verzonden: vrijdag 30 december 2011 15:53<br>
Aan: Roberto Laurita<br>
CC: <a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a><br>
Onderwerp: Re: [Insight-users] DICOM WINDOW CENTER AND WIDTH<br>
<div><div></div><div><br>
Dear Roberto<br>
<br>
I am not familiar with the meaning of "window center" and "window width" so<br>
cannot help you there, but as I mentined earlier, when two different<br>
acquisitions are made, you have to worry about other things.<br>
You really have to know what your particular system does. there are other<br>
factors involved which may not be even stored in DICOM... :( These factors<br>
are receiver gain, some other scale factors which manufacturer decided to<br>
put in .... yes yes... You have to force the system to operate under<br>
identical conditions in two cases. Probably you did that, but I thought I<br>
would mention it anyway.<br>
<br>
Lazar<br>
________________________________<br>
From: Roberto Laurita [<a href="mailto:roberto.laurita@gmail.com" target="_blank">roberto.laurita@gmail.com</a>]<br>
Sent: Thursday, December 29, 2011 07:30<br>
To: Fleysher, Lazar<br>
Cc: <a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a><br>
Subject: Re: [Insight-users] DICOM WINDOW CENTER AND WIDTH<br>
<br>
Hi Lazar,<br>
<br>
thank you for the answer.<br>
<br>
It's better to supply more details. I have 1 slice acquired 2 times with a<br>
different TR. So I have 2 dicom files.<br>
Reading the headers of these 2 files I found different values of "window<br>
center" and "window width". The MRI scanner provided 2 couples of values for<br>
rendering reason.<br>
<br>
I'd like to know if it's possible to set "window center" and "window width"<br>
in the second file the same values of the first one. I need to compare the<br>
intensities (with different TR) of the same pixel<br>
<br>
I thought about manual rescaling, but ...... if there is a better way ......<br>
<br>
Thanks again<br>
<br>
Ciao<br>
<br>
Roberto<br>
<br>
<br>
2011/12/29 Fleysher, Lazar<br>
<<a href="mailto:lazar.fleysher@mountsinai.org" target="_blank">lazar.fleysher@mountsinai.org</a><mailto:<a href="mailto:lazar.fleysher@mountsinai.org" target="_blank">lazar.fleysher@mountsinai.org</a>>><br>
Hello Roberto<br>
<br>
If I understood you correctly, you are asking how to convert from pixel<br>
intensity to image intensity.<br>
This is done, as far as I know like this:<br>
<br>
ImageValue = slope * storedValue + intercept.<br>
<br>
However, you should be aware that this is not the whole story. Some other<br>
hardware-related<br>
parameters might be at play which might contribute to scaling. It depends on<br>
how the data was acquired...<br>
<br>
Lazar<br>
________________________________________<br>
From: <a href="mailto:insight-users-bounces@itk.org" target="_blank">insight-users-bounces@itk.org</a><mailto:<a href="mailto:insight-users-bounces@itk.org" target="_blank">insight-users-bounces@itk.org</a>><br>
[<a href="mailto:insight-users-bounces@itk.org" target="_blank">insight-users-bounces@itk.org</a><mailto:<a href="mailto:insight-users-bounces@itk.org" target="_blank">insight-users-bounces@itk.org</a>>] on<br>
behalf of roberto.laurita<br>
[<a href="mailto:roberto.laurita@gmail.com" target="_blank">roberto.laurita@gmail.com</a><mailto:<a href="mailto:roberto.laurita@gmail.com" target="_blank">roberto.laurita@gmail.com</a>>]<br>
Sent: Wednesday, December 28, 2011 17:57<br>
To: <a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a><mailto:<a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a>><br>
Subject: [Insight-users] DICOM WINDOW CENTER AND WIDTH<br>
<br>
Hi all,<br>
<br>
I hope someone will help me. My deal is to import and compare 2 slices<br>
(.dcm).<br>
<br>
In Dicom header there are 2 parameters 0028|1050 and 0028|1051 which work<br>
like contrast and brightness. I need to modify these parameters. Doing this,<br>
pixel intensity should be modified.<br>
<br>
Using ITK examples I'm able to do everything (read dicom header, and read<br>
pixels) but the change above.<br>
<br>
To compare pixel intensities of 2 slice windows center and width must be the<br>
same. A normalization is required.<br>
<br>
Could you suggest me how to change windows center and width ?<br>
<br>
Thanks<br>
<br>
BR<br>
<br>
Roberto<br>
<br>
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</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>Wesley D. Turner, Ph.D.<br>Kitware, Inc.<br>Technical Leader<br>28 Corporate Drive<br>Clifton Park, NY 12065-8662<br>Phone: <a href="tel:518-881-4920" value="+15188814920" target="_blank">518-881-4920</a><br>
</div>
</blockquote></div></div><p></p>
</blockquote></div><br><br clear="all"><div><br></div>-- <br>Wesley D. Turner, Ph.D.<br>Kitware, Inc.<br>Technical Leader<br>28 Corporate Drive<br>Clifton Park, NY 12065-8662<br>Phone: 518-881-4920<br>
</div>