LSST Applications
21.0.0-172-gfb10e10a+18fedfabac,22.0.0+297cba6710,22.0.0+80564b0ff1,22.0.0+8d77f4f51a,22.0.0+a28f4c53b1,22.0.0+dcf3732eb2,22.0.1-1-g7d6de66+2a20fdde0d,22.0.1-1-g8e32f31+297cba6710,22.0.1-1-geca5380+7fa3b7d9b6,22.0.1-12-g44dc1dc+2a20fdde0d,22.0.1-15-g6a90155+515f58c32b,22.0.1-16-g9282f48+790f5f2caa,22.0.1-2-g92698f7+dcf3732eb2,22.0.1-2-ga9b0f51+7fa3b7d9b6,22.0.1-2-gd1925c9+bf4f0e694f,22.0.1-24-g1ad7a390+a9625a72a8,22.0.1-25-g5bf6245+3ad8ecd50b,22.0.1-25-gb120d7b+8b5510f75f,22.0.1-27-g97737f7+2a20fdde0d,22.0.1-32-gf62ce7b1+aa4237961e,22.0.1-4-g0b3f228+2a20fdde0d,22.0.1-4-g243d05b+871c1b8305,22.0.1-4-g3a563be+32dcf1063f,22.0.1-4-g44f2e3d+9e4ab0f4fa,22.0.1-42-gca6935d93+ba5e5ca3eb,22.0.1-5-g15c806e+85460ae5f3,22.0.1-5-g58711c4+611d128589,22.0.1-5-g75bb458+99c117b92f,22.0.1-6-g1c63a23+7fa3b7d9b6,22.0.1-6-g50866e6+84ff5a128b,22.0.1-6-g8d3140d+720564cf76,22.0.1-6-gd805d02+cc5644f571,22.0.1-8-ge5750ce+85460ae5f3,master-g6e05de7fdc+babf819c66,master-g99da0e417a+8d77f4f51a,w.2021.48
LSST Data Management Base Package
|
All of these algorithms require the inclusion of lsst/afw/image/ImageAlgorithm.h
, and are in namespace lsst::afw::image
.
afw
supports for_each_pixel
as a way to process each pixel in an Image, in a similar way to the STL's for_each
. The name doesn't follow the LSST C++ guidelines, but in this case I felt that conformity to the spirit of the STL was more important. There are variants of for_each_pixel
corresponding to setting a pixel to a function, setting it to a function of an Image, and setting it to a function of its value and a second Image's pixel value. The selection of which of these operations is desired is done by requiring the functor to inherit from a class such as pixelOp0
or pixelOp1XY
, each of which is a std::function
with a virtual operator()
added.
for_each_pixel(Image<LhsT> &lhs, pixelOp0<LhsT> const& func)
Set each pixel in lhs
to the value of func.
for_each_pixel(Image<LhsT> &lhs, pixelOp1<LhsT> const& func)
Set each pixel in lhs
to the value of func(lhs)
.
for_each_pixel(Image<LhsT> &lhs, pixelOp1XY<LhsT> const& func)
Set each pixel in lhs
to the value of func(x, y, lhs)
.
for_each_pixel(Image<LhsT> &lhs, Image<RhsT> const& rhs, pixelOp1<RhsT> const& func)
Set each pixel in lhs
to the value of func(lhs)
.
for_each_pixel(Image<LhsT> &lhs, Image<RhsT> const& rhs, pixelOp2<Lhs, RhsT> const& func)
Set each pixel in lhs
to the value of func(lhs, rhs)
.
for_each_pixel(Image<LhsT> &lhs, Image<RhsT> const& rhs, pixelOp2XY<Lhs, RhsT> const& func)
Set each pixel in lhs
to the value of func(x, y, lhs, rhs)
.
This code is in forEachPixel.cc.
Include needed header file, and define a namespace alias
Here's the simplest possible functor, simply setting each pixel to 0. Note that operator()
is declared const, as we pass these functors by (const
) reference. If this surprises you, take a look at Meyers, Effective STL, Item 38.
This one's a bit more interesting. We save a value in the constructor, and use it to set each pixel. It's analogous to std::fill
, but if I called it fill
then following a using namespace std;
the compiler would complain about ambiguity; it's simpler just to use a different name.
Here are examples of pixelOp1
and pixelOp2
.
A functor designed to add a Gaussian to an image
Declare a couple of Images to play with
Apply erase
to each pixel in img1
, setVal
to each pixel in img2
, set img1 = img2 + 1
, and finally img1 /= img1
Add a Gaussian to the image, centered at (xc, yc)
and with central intensity 1000.