Image Analysis with CASA - ESO

More documents

Recommendations

Info

CASA> imgstat = imstat() imgstat is now defined as a Python dictionary, containing all keys listed on the right. Access: imgstat['KEY'][AXIS] CASA>rms=(imgstat['rms'][0]) print '>> rms: '+str(rms) peak=(imgstat['max'][0]) print '>> Peak: '+str(peak) print '>> Dynamic range: '+str(peak/rms) KEYS blc absolute PIXEL coordinate of the bottom left corner of the bounding box surrounding the selected region blcf Same as blc, but uses WORLD coordinates instead of pixels trc the absolute PIXEL coordinate of the top right corner of the bounding box surrounding the selected region trcf Same as trc, but uses WORLD coordinates instead of pixels flux the integrated flux density if the beam is defined and the if brightness units are $Jy/beam$ npts the number of unmasked points used max the maximum pixel value min minimum pixel value maxpos absolute PIXEL coordinate of maximum pixel value maxposf Same as maxpos, but uses WORLD coordinates instead of pixels minpos absolute pixel coordinate of minimum pixel value minposf Same as minpos, but uses WORLD coordinates instead of pixels sum the sum of the pixel values: $\sum I_i$ sumsq the sum of the squares of the pixel values: $\sum I_i^2$ mean the mean of pixel values: $ar{I} = \sum I_i / n$ sigma the standard deviation about the mean: $\sigma^2 = (\sum I_i ar{I})^2 / (n1)$ rms the root mean square: $\sqrt {\sum I_i^2 / n}$ median the median pixel value (if robust=T) medabsdevmed the median of the absolute deviations from the median (if robust=T) quartile the interquartile range (if robust=T). Find the points which are 25% largest and 75% largest (the median is 50% largest), find their difference and divide that difference by 2. 14
Mathematical operations on images immath – perform mathematical operations on or between images Examples: Divide an image by another, with a threshold on one image: CASA>immath( imagename = ['img1.image','img2.image'] exp = 'IM0/IM1[IM1>0.007]', outfile = 'div.image') Select a single plane of a cube and subtract and subtract it from all planes: CASA>immath( imagename = 'cube.image', exp = 'IM0', chans = '77', outfile = 'chan77.image') CASA>immath( imagename = ['cube.image','chan77.image'] exp = 'IM0IM1', outfile = 'cubeminuschan77.image') 15
Page 1 and 2: Image Analysis with CASA Sebastien
Page 3 and 4: View images Extract information fro
Page 5 and 6: Working with images: General tasks
Page 7 and 8: Viewer CASA> viewer and then use th
Page 9 and 10: Header hdkey for reference beammaj
Page 11 and 12: Defining box / region - Command lin
Page 13: Image Statistics imstat : calculate
Page 17 and 18: Smooth images imsmooth - Image conv
Page 19 and 20: If only 1 Gaussian component (defau
Page 21 and 22: Working with spectral data cube
Page 23 and 24: Extract a spectrum - Script mode Us
Page 25 and 26: Moments Images Sometimes, informati
Page 27 and 28: Spectral Lines Search 1) Use SPLATA
Page 29 and 30: ToolKit For (very?) advanced users,

Image Analysis with CASA - ESO

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?