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Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

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Page 1: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

http://www.euhou.net

http://www.euhou.net

Page 2: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJ

Page 3: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Pedagogical resources :

SalsaJ software

Didactical software for image and data handling Such A Lovely Software for Astronomy, in Java

Multi-platform (Windows, Linux, Mac)

Java, modularity; easily extensible to implement new fonctionnalities

Adaptation in different languages; recently in arabic; chinese in progress

Free of charge (download from the EU-HOU web site); open-source

Up to date sources (derived from the free medical research tool ImageJ

developed at NIH); adapted to astronomy (FITS format; photometry…);

friendly tool for classrooms

Developed by F-HOU ; SalsaJ v2.0 to be released by the end of 2007

Page 4: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJ: a multilingual interface

Page 5: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Digital Images

Page 6: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Digital Images

Page 7: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Digital Images

A digital image is a set of values gathered in a 2D (or 3D) arrayEach element is a pixel (picture element)Each pixel has a corresponding physical size Each pixel can have one or more values

1 value = “black&white” images 3 values = true-color RGB images

Page 8: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Digital Images

Black and white images are actually gray-level imagesEach pixel has one value corresponding to a particular shade of gray

0 for black and max for white max depends on the dynamics of the image

8-bits : 255 16-bits : 65 535 32-bits : real values

Page 9: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

• Example : – Black : (0,0,0) White : (255,255,255)– Red : (255,0,0) Green : (0,255,0)– Blue : (0,0,255) Cyan : (0,255,255)– Magenta : (255,0,255)– Yellow : (255,255,0)– Orange : (255,190,93) – Gray : (128,128,128)

Digital Images

Page 10: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJSalsaJ

Open

Page 11: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJSalsaJ

Brightness/Contrast

Page 12: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Measurements

In pixels

Page 13: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Scale

Page 14: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

In km

Page 15: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,
Page 16: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

doublet du sodium

Page 17: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Image obtained with Mars Global Surveyor (NASA/JPL/Malin Space Sciences Systems)

Pixel size=1500/(80-7)=20.54m/pixel

Crater size ~ (177-52)x20.54~2567.5m

SalsaJ

Page 18: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

Stellar objects = point sources

Convolved by the Point Spread Function (PSF) of the

« instrument » (atmosphere + optics)

PSF ~ bell-like shape function ~ Gaussian + tails

Characterised by its Full Width Half Maximum (FWHM) in arcsec (cf

pixel size)

Good sampling: FWHM ~2-3 pixel size

1/2

1/2FWHM

SalsaJ

Page 19: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

r1

r3

Fstar= Sum of intensity (pixels with r<r1) –Sky*N1

N1 = Number of pixels in the radius r1

Sky = Sum of intensity (pixels with r2<r <r3) / N23

N23 = Number of pixels in the corona r2 < r < r3

Use:

Instrumental value

proportional to the stellar

object flux (luminosity)

r2

SalsaJ : photometry

Page 20: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJ

Page 21: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJ

Cepheids in the SMC distances

Page 22: Http://. SalsaJ Pedagogical resources : SalsaJ software Didactical software for image and data handling Such A Lovely Software for Astronomy,

SalsaJ

Perspectives:

- Addition of other astronomical functionalities

(astrometry, PSF photometry, etc.)- Optimisation of the tool with intensive testing in schools- Extension to biological imaging and developments of more synergy with ImageJ (sustainability of the software).- Translation in other languages