Skip to content

Latest commit

 

History

History
112 lines (81 loc) · 4 KB

sampinfo.rst

File metadata and controls

112 lines (81 loc) · 4 KB
Raw

sampinfo

Sampinfo prints information about a WFC3/IR MultiAccum image, including exposure time information for the individual samples (readouts). The global information listed (and the names of the header keywords from which it is retrieved) includes:

  • the total number of image extensions in the file (NEXTEND)
  • the name of the MultiAccum exposure sample sequence (SAMP_SEQ)
  • the total number of samples, including the "zeroth" read (NSAMP)
  • the total exposure time of the observation (EXPTIME).

Information that is listed for each sample is the IMSET number (EXTVER), the sample number (SAMPNUM), the sample time, which is the total accumulated exposure time for a sample (SAMPTIME), and the delta time, which is the additional exposure time accumulated since the previous sample (DELTATIM).

Note that the samples of a MultiAccum exposure are stored in the FITS file in reverse time order. The initial, or "zeroth" read, appears last in the FITS file, with IMSET=NSAMP, SAMPNUM=0, SAMPTIME=0, and DELTATIM=0. The final read of the exposure appears first in the file and has IMSET=1, SAMPNUM=NSAMP-1 (SAMPNUM is zero-indexed), and SAMPTIME=EXPTIME.

Options

This version will accept a single image name or a python list of images. The list of images should be a python style list, such as:

>>> ["image1.fits","image2.fits"]

add_keys=list(): You can also supply a supplimental list of keywords to print for each sample, if the key isn't found in the sample the global header will be checked.If a key is not found the "NA" string will be printed. Additionally you can ask for the median or mean of the datavalues for each sample using the appropriate switch.

median=False: Set to True in order to report the median pixel value for each sample

mean=False: Set to True in order to report the mean pixel value for each sample (as measured with np.min and np.max)

Usage

Typical:

>>> python >>> from wfc3tools import sampinfo >>> sampinfo(imagename)

Where imagename can be a single filename or a python list() of names

To get the median value for each sample:

>>> sampinfo.sampinfo(imagename, median=True)

To print additional keys for information:

>>> sampinfo.sampinfo(imagename,add_keys=["DETECTOR"])

To get the average balue for each sample:

>>> sampinfo.sampinfo(imagename, mean=True)

Example Output

Default output:

In [3]: wfc3tools.sampinfo('ibcf02faq_raw.fits')
IMAGE           NEXTEND SAMP_SEQ    NSAMP   EXPTIME
ibcf02faq_raw.fits  80  STEP50      16  499.234009

IMSET   SAMPNUM SAMPTIME    DELTATIM
1   15  499.234009  50.000412
2   14  449.233582  50.000412
3   13  399.233154  50.000412
4   12  349.232727  50.000412
5   11  299.2323    50.000412
6   10  249.231873  50.000412
7   9   199.231461  50.000412
8   8   149.231049  50.000412
9   7   99.230637   50.000412
10  6   49.230225   25.000511
11  5   24.229715   12.500551
12  4   11.729164   2.932291
13  3   8.796873    2.932291
14  2   5.864582    2.932291
15  1   2.932291    2.932291
16  0   0.0 0.0

with median=True:

In [4]: wfc3tools.sampinfo('ibcf02faq_raw.fits',median=True)
IMAGE           NEXTEND SAMP_SEQ    NSAMP   EXPTIME
ibcf02faq_raw.fits  80  STEP50      16  499.234009

IMSET   SAMPNUM SAMPTIME    DELTATIM
1   15  499.234009  50.000412   MedPixel: 11384.0
2   14  449.233582  50.000412   MedPixel: 11360.0
3   13  399.233154  50.000412   MedPixel: 11335.0
4   12  349.232727  50.000412   MedPixel: 11309.0
5   11  299.2323    50.000412   MedPixel: 11283.0
6   10  249.231873  50.000412   MedPixel: 11256.0
7   9   199.231461  50.000412   MedPixel: 11228.0
8   8   149.231049  50.000412   MedPixel: 11198.0
9   7   99.230637   50.000412   MedPixel: 11166.0
10  6   49.230225   25.000511   MedPixel: 11131.0
11  5   24.229715   12.500551   MedPixel: 11111.0
12  4   11.729164   2.932291    MedPixel: 11099.0
13  3   8.796873    2.932291    MedPixel: 11097.0
14  2   5.864582    2.932291    MedPixel: 11093.0
15  1   2.932291    2.932291    MedPixel: 11090.0
16  0   0.0 0.0 MedPixel: 11087.0