DRR generator angle question

[Daisy S]

Dear All,

I have CT volume with size of 256*256*256. When I use DRR rotational mode by 45 degree, for the synthesis X-Ray image at 45 degree angle, I notice the size of image is still 256*256 which it should be (256*square 2)*(256*square 2).

Does anyone know the software use which strategy, crop or resize to this size?

Thank you so much!

Best,

Daisy

[Daisy S]

Sorry, one sentence type mistake "(256* square root of 2) * (256* square root of 2)"

[Daisy S]

And could some one point the resize code to me? Thank you so much!

[Sharp, Gregory C.]

Hi Daisy,

 

My first thought is for you to run two times, once with starting angle 0 at 256x256, then a second time with starting angle 45 at the larger size.

 

But if you need other angles, that will be tedious, and I suggest to crop them programmatically using Octave or python.

 

Greg

 

From: plast...@googlegroups.com <plast...@googlegroups.com> On Behalf Of Daisy S
Sent: Tuesday, October 25, 2022 10:08 PM
To: Plastimatch <plast...@googlegroups.com>
Subject: [Plastimatch] Re: DRR generator angle question

 

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[Daisy S]

Thank you Greg!

My question would also be for drr: for different -r option in command line -- resolution of output Xray image, the different resolution settings would only lead to different size of same body part Xray image right?

On Wed, Oct 26, 2022 at 11:41 AM Daisy S <daisy....@gmail.com> wrote:

Thank yo Greg!

My question would also be for drr: for different -r option in command line -- resolution of output Xray image, the different resolution settings would only lead to different size of same body part Xray image right?

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[Daisy S]

Thank yo Greg!

My question would also be for drr: for different -r option in command line -- resolution of output Xray image, the different resolution settings would only lead to different size of same body part Xray image right?

On Wednesday, October 26, 2022 at 11:21:40 AM UTC-5 Sharp, Gregory C. wrote:

[Sharp, Gregory C.]

Hi Daisy,

 

The drr options are terrible, by the way.  I should make them easier to use.

 

The -r option is incorrectly documented in the help.  It is the detector resolution in pixels, not in mm!  You'll want to increase this by sqrt(2).  But you'll need to round the result to get an integer.

 

You also need to set the -z option.  Your detector size in mm should be scaled up the same way, rounding the result to get the same pixel size.

 

I think those are the only things you will need to change.

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