Astra Image Help

[gbeal]

Hi Team,
could use a little help please.
I have downloaded the evaluation copy of the 2.5Max version of Astra Image. It seems somewhat daunting, but primarily I want to use it to combine the RGB images that the DMK is spitting at me.
Talking of spitting, I processed some very rough RGB's from the other night, and saved them as BMP's from Registax. When I open these in Astra Image and try to RGB combine them it says that they need to be grayscale? Go figure. I mean the images are taken with a mono camera, what else can I do??
Gary

[[1ponders] (Paul)]

When you processed them in Reg did you have the colour box ticked on the align page? Anywayyyyyy. Under the Process menu in Astra Image you will see a "covert to greyscale" selection at the bottom of the menu. Convert each of your RGB images to greyscale and then try it. Just remember for each image you convert, go into the Edit menu and change it's Image title to something like "Image name blue greyscale". After each processing action I change the new images title so I can keep track of where I am

[gbeal]

Thanks Paul, I thought it was merely old age creeping in, and very well it could be.
No when I Registax them they are mono, and without the colour box ticked.
I might go stack them again and see what gives.
This RGB stuff is a great reason to own a ToUcam.

[[1ponders] (Paul)]

Maybe saving them in Registax automatically saves the bmps as colour.

When you convert to greyscale you will notice the images have increased contrast and brightness. That is normal.

[davidpretorius]

yup an automatic histostretch gets performed in astra image when you split or convert to greyscale

[iceman (Mike)]

I get the same when I save as TIFFs from Registax.. even though they're supposed to be mono, it still saves them as a colour image.

Maybe if you save it as a FIT separate? I dunno, haven't tried it.

[gbeal]

Thanks again team.
I managed to convert them as you suggested Paul, and yes they would LR as well as Combine. It was a mis-aligned stack/combine though. Not sure how to align them yet. I can understand how to with stellar images, but planetary haven't got minute detail to align on.
I'll get there, but it is a steep curve.

[[1ponders] (Paul)]

There are probably a couple of ways to do it Gary. If you have ImagesPlus then run the three rgb images through the planetary alignment function first before opening them into astraimage. Altenatively you could try running them through ppm center. Or you could try using the xy adjustment in the RGB combine dialogue box in Astra Image. That would probably be the hardest. I'd suggest the ImagesPlus option, then the xy for finishing off.

You might even try a rough alignment and crop in PS and see how that works. Whichever way you will probably need to do some tweeking with the xy adjustment in AI anyway you go

[Hitchhiker]

Now that I know more about bitmap file formats than I ever wanted to know(!), I think I understand why these packages will not handle bitmap files even if they are not 'colour', unless converted to grayscale. In fact, all bitmap file formats are in colour - even an 8 bit format is a colour image (which was a real surprise to me!).

An 8 bit format bitmap uses numbers from 0 to 255 to define colour - those numbers, though, refer back to a lookup table that contains R, G & B values eg 128,128,128 for a mid gray colour. So even if your image is all grays, it is potentially a colour image because each pixel has R, G and B colour information in a lookup table.

A 24 bit bitmap file has the RGB information encoded for each pixel (no lookup table).

When AstraImage (and AIP4WIN performs the same way) converts to grayscale, I think it is internally translating the RGB values (even though they are grays) into a gray scale where 0 equals black and 255 equals white so that the deconvolution (or other process) can take place more easily (AIP4WIN can deconvolve a colour image - though maybe it splits it internally )

[[1ponders] (Paul)]

I knew that

Thanks Adam

[gbeal]

Whatever the reason, what Paul suggested worked.
I re-did them as greyscales, and combined them.
I needed to align them (severely) with the X&Y bit as well.
The colour is/was awful.
I may return to the ToUcam!!!

[[1ponders] (Paul)]

After you aligned them, did you try adjusting the red, green and blue relative intensity? The lower you go with an intensity the stronger the colour becomes. After each adjustment remember to update. Small changes in relative intensity make big changes in the image. I've don't think I've gone below .9 for read and above 1.05 for blue. I try not to muck around with the green too much. After the comination is finished I'll often drop the gamma back to around 0.7

[iceman (Mike)]

Send me the avi's, Gary!