Dear  Sumaiya,

First , you will have to decide which frequency SAR data you will need after you review your needs. For example, RADARSAT (Canadian Space Agency) data are in C-band, JERS-1 and ALOS 1/2 SAR data are L-band and TerraSAR-X data are X-band. Depending on your application requirements, you can decide which SAR data you will need for your project or research task over the area of interest. After this step, if you are an academic or a student, your team can approach the space agency responsible for the chosen SAR system and submit a research proposal with your specific data requirements.

However, if you just want to learn and/or test the change detection application technique using a set of SAR data, you can ask around for the availability of an old data set(s). There are also many airborne SAR data sets available, depending on where you are located.

Dear Sumaiya,

As Dr. Moon says above, the SAR wavelength - as well as the temporal frequency of your time series - you would be interested in depends on your application. In case you are looking at changes in vegetation cover, a longer wavelength like L-band (23.5 cm) would probably be preferred. And in case of you are interested in detecting changes in e.g. forest cover over several years, you can try using a time series of annual data from ALOS-1. The Japanese space agency (JAXA) provide global ALOS-1 mosaics from 2007, 2008, 2009 and 2010 for free download at http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/fnf_index.htm (following user registration at http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/data/index.htm. The mosaics are geo-corrected and provided in geographical coordinates (lat/long) projection at a pixel spacing of 25m.

Good luck - Ake Rosenqvist

Dear All,  

First, Thank you all for your Valuable information.

As Dr. Moon said, initially i would like to learn change detection application techniques using old data sets. For that data sets only, i am trying to get, but i could not. 

Then i am planning to work on flood detection . I guess C or X band images would be used since water has lower reflectance energy  and  higher dielectric constant. 

Thanks & Regards.

Hi again Sumaiya,

For flood detection, L-band would probably be recommended as the longer wavelength provides better contrast between water and land.  Cross polarisation preferred but like pol normally works too.  If using the shorter C- or X-band wavelengths, you would probably need cross-polarisation in order to avoid ambiguous bright signals in water due to rain or winds in the like-pol.

Ake R.

Hi Ake Sir,

May i get SAR Image Change Detection data set from your end. I have been trying to get through many sources. But it is very difficult to get data sets. Hope to get reply from you.

Regards,

Sumaiya.

Hi again Sumaiya,

ALOS and ALOS-2 (L-band) PALSAR data are unfortunately not free and you would need to purchase it from a commercial provider (such as e.g. RESTEC Japan). As I mentioned in my post to you above however, the Japanese space agency (JAXA) provide global ALOS-1 mosaics from 2007, 2008, 2009 and 2010 for free download at http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/fnf_index.htm (following user registration at http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/data/index.htm. The mosaics are geo-corrected and provided in geographical coordinates (lat/long) projection at a pixel spacing of 25m.

C-band SAR data from Sentinel-1 are available from the European Spece Agency (ESA) for free at https://scihub.esa.int/

Good luck again - Ake Rosenqvist

Hi again Sumaiya,

ALOS and ALOS-2 (L-band) PALSAR data are unfortunately not free and you would need to purchase it from a commercial provider (such as e.g. RESTEC Japan). As I mentioned in my post to you above however, the Japanese space agency (JAXA) provide global ALOS-1 mosaics from 2007, 2008, 2009 and 2010 for free download at http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/fnf_index.htm (following user registration at http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/data/index.htm. The mosaics are geo-corrected and provided in geographical coordinates (lat/long) projection at a pixel spacing of 25m.

C-band SAR data from Sentinel-1 are available from the European Spece Agency (ESA) for free at https://scihub.esa.int/

Good luck again - Ake Rosenqvist

Thank You Sir!

Try this website

https://vertex.daac.asf.alaska.edu/

https://landsatlook.usgs.gov/viewer.html

hi sumaiya madam

iam also working on change detection in SAR images i visited above links and got the data but the data is in tiff format and not in jpeg and i tried to convert it into jpeg but the image is showing only black color and if i view tiff image then also it is showing only black color

i did like this i took the images from the ieee papers of change detection in sar images and using them for my implementation.

so madam if you found the dataset please tell me the link or how to get data in jpeg format or how to see data in an image format

Hi

Please from where I can get SAR images for ships or airplane for object detection purpose ?

Regards