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:
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.
>>> ["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)
>>> python
>>> from wfc3tools import sampinfo
>>> sampinfo.sampinfo(imagename)
Where imagename can be a single filename or a python list() of names
>>> sampinfo.sampinfo(imagename, median=True)
>>> sampinfo.sampinfo(imagename,add_keys=["DETECTOR"])
>>> sampinfo.sampinfo(imagename, mean=True)
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