imread directely into Roi?

[gabor]

I have 2 images: A,B of same size w,h
I want to compose them into a wide image AB of size (w+w,h)
I use the following code:

AB=cv.Mat(cv.Size2i(2*w, h),cv.CV_8UC3)
#copy left part
roi=cv.Rect(0,0,w,h)
img=AB(roi)
tmp=imread("A",1)
tmp.copyTo(img)
#copy right part
roi=cv.Rect(w,0,w,h)
img=AB(roi)
tmp=imread("B",1)
tmp.copyTo(img)
#dispose tmp

I cannot write it like -

roi=cv.Rect(0,0,w,h)
img=AB(roi)
img=imread("A",1)

because 'assigning' in Python is just aliasing.

How can I save this unnecessary copying of array (which means writing
everything twice)?
Thanks

[Minh-Tri Pham]

Hi gabor,

Have you tried 'tmp.assignTo(img)'?

Cheers,
Minh-Tri

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Dr. Minh-Tri Pham
Research Fellow, University of Surrey, UK
Email: t.p...@surrey.ac.uk or pmt...@gmail.com
Mob: +44 (0) 778 774 1089 | Tel: +44 (0) 148 368 4711

[info gabor]

Thanks, Minh-Tri.

I tried 'tmp.assignTo(img)' - but it didn't work.

I need a way to read directly into an existing Mat, defined as roi of another Mat. I think it should be defined somehow as a destination to imread.

T%hanks again,

Gabor

 

On Sat, Jul 10, 2010 at 1:59 AM, Minh-Tri Pham <pmt...@gmail.com> wrote:

Hi gabor,

Have you tried 'tmp.assignTo(img)'?

Cheers,

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[Minh-Tri Pham]

IIRC, the ROI concept is no longer supported in OpenCV's C++ interface. How
about doing it in the 'numpy' way? E.g.

import numpy as np
C = asMat(np.concatenate([A[:], B[:]]))

Minh-Tri

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