Re: [Boost-users] [GIL] gray pixel iterator in generic algorithm

Subject: Re: [Boost-users] [GIL] gray pixel iterator in generic algorithm
From: Curtis Gehman (curtis2006_at_[hidden])
Date: 2011-03-02 12:40:38

Dr. Lupton,

Sorry for the slow response.  I simply defined the following:

typedef boost::gil::pixel<float, boost::gil::gray_layout_t> gray_float_pixel_t;
typedef boost::gil::image<gray_float_pixel_t, false> gray_float_image_t;
typedef gray_float_image_t::view_t gray_float_view_t;
typedef gray_float_image_t::const_view_t gray_float_const_view_t;

As Dr. Bourdev advised, I do not use with these typedefs any of the color conversion operations offered by GIL.  Apparently those rely on the scaling properties of the float wrapper type.

So far, all I have done with these typedefs is ...

   1. construct views using interleaved_view and pixel data pointed to by [const] float*, as illustrated near the beginning of the GIL tutorial
   2. create x- and y- iterators for the views to apply row- and column-oriented algorithms

I implemented reasonably fast gray morphology operations for rectangular structure elements.  I wouldn't mind offering this code for contribution to some open source project; but this work is for my corporate employer, from whom I would need to get legal permission.

Cheers.

On Feb 18, 2011, at 12:27 PM, Robert Lupton the Good <rhl_at_[hidden]> wrote:

> > With this, the unit test for my gray opening function with an unscaled float image now compiles and works fine.
>
> Does this mean that you have some clean way to handle gil images that don't automatically scale into [0,1]? If so, can we have it pushed into the next boost release?
>
> I have a clunky version of this that I'm not proud of, but I certainly need. I'm an astronomer, and the values in my images (unsigned short, int, float) are directly related to the number of photons detected so scaling is a real problem.
>
> R
>
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