| Re: coregistering images - help needed [message #93780 is a reply to message #93779] |
Fri, 14 October 2016 04:12  |
gunvicsin11
Messages: 93
Registered: November 2012
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On Friday, October 14, 2016 at 3:16:05 PM UTC+5:30, Markus Schmassmann wrote:
> On 10/14/2016 11:27 AM, Helder wrote:
>> On Friday, October 14, 2016 at 9:38:34 AM UTC+2, sid wrote:
>>> I have two images I have to align one image with respect to the other,
>>>
>>> I have two solar images size is 2048 by 2048. But the problem is in one image the data resolution is 1.0648 arcsec/pixel and other is 1.2 arcsec/pixel
>>>
>>> So due to this in xaxis the data coverage is 1700pixels(out of 2048 pixels) in imagea
>>>
>>> in imageb the data coverage is 1900 pixels(out of 2048 pixels)
>>>
>>> I want imageb with resolution and data coverage as imagea.
>>>
>>> please do help me out in this regard.
>>>
>>> Note: I have 500 images (like imageb) which i have to bring to imagea resolution.
>> If the objective is to register the two images, then I would:
>> 1) cut the images to the relevant part (imagea to 1700x1700 pixels^2 and similarly for imageb)
>> 2) use congrid() to fix the sizes of the two images. Make sure you use a good interpolation option
>> 3) register the images
>>
>> Notice that 1700/1900 is not the same as 1.0648/1.2. In other words, the cutting the images as mentioned, will result in different data resolutions.
>> Or, by enlarging imagea from 1700 to 1900 pixel, you will end up with a resolution of 1.0648*1900/1700=1.19 and not 1.2.
> if the metadata of your images contain the position of the solar center
> and the angle indicating where solar north is, use this data instead of
> trying to figure out yourselve.
>
> You might get slightly better results, if you use a single call to
> interpolate instead of using congrid and later rotate your image and
> shift it fraction of a pixel.
Thanks a lot for the replies. It was really very helpful.
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