how to calculate min and max of images

[Prashant-2-3]

Hello EveryOne,

          I am using imagej tools for opening my images.
for changing the image window width and center imagej provides setMinAndMax()
So according to that min and max window level is set.

But my purpose is to by changing the Window width and window center i have to set min and max
Example:-

Suppose
Min = -32733 , Max = 32883
then
WindowCenter = (Max + Min)/2  = (32883 -32733)/2 =   150/2 = 75
WindowWidth = (Max - Min) = 32
But How to calculate min and max from Window Width and window center.



With Warm Regards
--------------------------------------------------------------------

Prashant Chandrakar
Software Developer
MedSynaptic Pvt Ltd
9270710943
[hidden email]
"If the facts don't fit the theory, change the facts."

[Robert Dougherty]

Prashant,

If you are asking an algebra question, the answer is

Min = WindowCenter - WindowWidth/2;
Max = WindowCenter + WindowWidth/2;

You can derive this graphically or by solving the simultaneous equations you
gave.

(In the example, should it read (Max - Min) = 32883 - (-32733) = 65616 ?)

Bob

Robert P. Dougherty, Ph.D.
President, OptiNav, Inc.
Phone [phone]
Fax [phone]
www.optinav.com
 
> WindowCenter = (Max + Min)/2  = (32883 -32733)/2 =   150/2 = 75
> WindowWidth = (Max - Min) = 32
> But How to calculate min and max from Window Width and window center.
>
>

[Prashant-2-3]

Hi,
    Thanks for you reply,
Actually its very different for signed and unsigned images.
currently i derive a formula which is reverse of those formula which
calculates window width and window center from min and max.
i.e it calculate min and max from window width and center
see

   min - max = WW -------eq1
   (max + min)/2 = WC   ----- eq2

  So finally by solving these equations we get

 min = (2 * WC - WW)/2
max = WW + min

So if i want to adjust WW = 1880 and WC = 950
then by formula

min = (2 * 950 - 1880)/2  = 10
max =1880 + 10  = 1890

but image is not looking good respetive to my min and max.
Please tell are i am doing anything wrong?






----- Original Message -----
From: "Robert Dougherty" <[hidden email]>
To: <[hidden email]>
Sent: Monday, October 20, 2008 8:28 PM
Subject: Re: how to calculate min and max of images


Prashant,

If you are asking an algebra question, the answer is

Min = WindowCenter - WindowWidth/2;
Max = WindowCenter + WindowWidth/2;

You can derive this graphically or by solving the simultaneous equations you
gave.

(In the example, should it read (Max - Min) = 32883 - (-32733) = 65616 ?)

Bob

Robert P. Dougherty, Ph.D.
President, OptiNav, Inc.
Phone [phone]
Fax [phone]
www.optinav.com

> WindowCenter = (Max + Min)/2  = (32883 -32733)/2 =   150/2 = 75
> WindowWidth = (Max - Min) = 32
> But How to calculate min and max from Window Width and window center.
>
>

[Harry Parker]

Hi Prashant,

Can you be more specific about what you mean by, "not looking good"?

 
--
Harry Parker
Senior Imaging Systems Engineer
Digital Imaging Systems, Inc.



----- Original Message ----
From: prashant <[hidden email]>
To: [hidden email]
Sent: Tuesday, October 21, 2008 1:25:40 AM
Subject: Re: how to calculate min and max of images

Hi,
    Thanks for you reply,
Actually its very different for signed and unsigned images.
currently i derive a formula which is reverse of those formula which
calculates window width and window center from min and max.
i.e it calculate min and max from window width and center
see

   min - max = WW -------eq1
   (max + min)/2 = WC   ----- eq2

  So finally by solving these equations we get

min = (2 * WC - WW)/2
max = WW + min

So if i want to adjust WW = 1880 and WC = 950
then by formula

min = (2 * 950 - 1880)/2  = 10
max =1880 + 10  = 1890

but image is not looking good respetive to my min and max.
Please tell are i am doing anything wrong?






----- Original Message -----
From: "Robert Dougherty" <[hidden email]>
To: <[hidden email]>
Sent: Monday, October 20, 2008 8:28 PM
Subject: Re: how to calculate min and max of images


Prashant,

If you are asking an algebra question, the answer is

Min = WindowCenter - WindowWidth/2;
Max = WindowCenter + WindowWidth/2;

You can derive this graphically or by solving the simultaneous equations you
gave.

(In the example, should it read (Max - Min) = 32883 - (-32733) = 65616 ?)

Bob

Robert P. Dougherty, Ph.D.
President, OptiNav, Inc.
Phone [phone]
Fax [phone]
www.optinav.com

> WindowCenter = (Max + Min)/2  = (32883 -32733)/2 =   150/2 = 75
> WindowWidth = (Max - Min) = 32
> But How to calculate min and max from Window Width and window center.
>
>