stsdas.toolbox.imgtools

Tasks for performing operations on images and masks.

Notes

For questions or comments please see our github page. We encourage and appreciate user feedback.

Most of these notebooks rely on basic knowledge of the Astropy FITS I/O module. If you are unfamiliar with this module please see the Astropy FITS I/O user documentation before using this documentation.

The various image tasks found in the stsdas.toolbox.imgtools package have been replaced in the Numpy and Astropy libraries.

Contents:

addmasks

Please review the Notes section above before running any examples in this notebook

Addmasks is used to combine several masks or bad pixel lists. We can do this using the numpy bitwise tasks: bitwise_or, bitwise_and, and invert, along with a slew of other numpy bit functions. Below we show examples of bitwise_and and bitwise_or.

# Standard Imports
import numpy as np

a = np.array([1,4,10])
b = np.array([1,0,8])

# OR
print(np.bitwise_or(a,b))

# AND
print(np.bitwise_and(a,b))

[ 1  4 10]
[1 0 8]

iminsert

Please review the Notes section above before running any examples in this notebook

Iminsert is used to insert a small image into a larger image. This is easy to do with the Numpy array indexing after you’ve read in your images with Astropy.io.fits. Below we’ll show a quick array example.

# Standard Imports
import numpy as np

# generate test arrays
my_array = np.random.rand(7,5)
ones = np.array(([1,1],[1,1]))

# replace middle 3x3 square with ones
my_array[2:4,2:4] = ones

# Print result
print(my_array)

[[ 0.06888833  0.15088263  0.00241     0.09282496  0.07325408]
 [ 0.78665832  0.3402431   0.5265134   0.46253075  0.54305974]
 [ 0.63473001  0.92986634  1.          1.          0.0904689 ]
 [ 0.2887482   0.50178461  1.          1.          0.78550679]
 [ 0.07945175  0.12885675  0.06588469  0.63534732  0.62024358]
 [ 0.53344071  0.2852475   0.03736071  0.30043438  0.97523821]
 [ 0.10331126  0.52996828  0.51318396  0.47988347  0.7098808 ]]

improject

Please review the Notes section above before running any examples in this notebook

Improject is used to sum or average an image along one axis. This can be accomplised using the numpy.average or the numpy.sum functions and choosing which dimensions you wish to collapse. Below we show an example using numpy.average.

# Standard Imports
import numpy as np

# build random test array
my_array = np.random.rand(5,4,3)

# reduce third dimension down
new_array = np.average(my_array, axis=2)
print(new_array.shape)
print(new_array)

# reduce second dimension down
new_array_2 = np.average(my_array, axis=1)
print(new_array_2.shape)
print(new_array_2)

(5, 4)
[[ 0.60660306  0.55628564  0.79297796  0.73016308]
 [ 0.48911929  0.36071454  0.6167648   0.4261005 ]
 [ 0.47187441  0.21748297  0.92223167  0.64068855]
 [ 0.14900289  0.70091688  0.51759779  0.29799824]
 [ 0.85235487  0.79360714  0.60374945  0.40032384]]
(5, 3)
[[ 0.70389997  0.59038403  0.72023831]
 [ 0.4937127   0.44684555  0.47896609]
 [ 0.43435416  0.5368765   0.71797754]
 [ 0.45942245  0.4114324   0.37828199]
 [ 0.64567646  0.51639255  0.82545747]]

mkgauss

Please review the Notes section above before running any examples in this notebook

The mkgauss funtionality has been replicated in the Photutils package with photutils.datasets.make_random_gaussians_table and photutils.datasets.make_gaussian_sources_image.

pixlocate

Please review the Notes section above before running any examples in this notebook

Pixlocate is used to print positions matching a certain value condition. This is replicated with the numpy.where function. Please see the documentation for more details and examples.

rd2xy-xy2rd

Please review the Notes section above before running any examples in this notebook

Rd2xy and xy2rd are used to translate RA/Dec to the pixel coordinate and vice-versa. This capability is well covered in the astropy.wcs package. Please see the documentation for more details on usage.

Not Replacing

  • boxinterp - Fill areas with smoothed values from surrounding area. See images.imfit notebook.
  • countfiles - Count how many files are in the input file template. Deprecated.
  • gcombine - Combine a set of GEIS images into one image. Deprecated, for FITS see stsdas.toolbox.imgtools.mstools.mscombine
  • gcopy - Generic multi-group copy utility. GEIS, deprecated.
  • gstatistics - Compute and print image pixel statistics for all groups. GEIS, deprecated. For FITS see images.imutil.imstatistics
  • imcalc - Perform general arithmetic operations on images. See images.imtuil.imarith.
  • imfill - Set fill value in image according to a mask. See images.imutil.imreplace.
  • listarea - Print an area of an image. See numpy basics documentation.
  • moveheader - Combine the header and pixels from two images. GEIS, deprecated.
  • pickfile - Get the file name picked from the input file template. Deprecated.
  • pixedit - Screen editor for image pixels. See images.tv.imedit
  • rbinary - Create an image from a binary file. Deprecated.
  • stack - Stack images to form a new image with one more dimension. See images.imutil.imstack
  • xyztable - Interpolate table values, writing results to a table. See images.imfit.imsurfit and tables.ttools.tcopy-tdump
  • xyztoim - Interpolate table values, writing results to an image. See images.imfit.imsurfit, Astropy Tables documentation, and tables.ttools.tcopy-tdump.