First question

[DaveS]

Hi Guys

Ok here's my first question

I open an image (FITS), I select the STF function, click on 'auto' and I now have a viewable image to work with. So far so good  

Select 'histogram transformation' and the relevant 'window' opens. However, the histogarm of the 'active' image does not appear, and as such adjusting the curve or the slider has no effect on the image. 'Clicked' 'reset', 'track view' and also tried 'real time preview, but still no histogram  

I'm clearly not 'seeing the wood for the trees' here, so apologies for that, but thought it quicker to ask than to continue 'poking and hoping'.

I'll also ask a pre-emptive question, as without a histogram I can't yet see for myself. The question is, can I put 'anchor points' on the curve, as I do in PS ?.

Thanks in advance.

Dave

[Redshift]

Dave,

Just below the Histogram display is a drop down menu where you have to select the name of the active image. Then it should work for you.

Regards
Dave

[Harry page]

Hi

Don't forget to disable the stf before you start stretching a image 

If you have a image open , clicking on track view the active image will appear  don't forget a unstretched histogram is tiny

Yes when you use curves you can anchor points  , but you will not use curves as much in pixinsight try a straight histogram stretch


Harry

[Carlos Milovic]

Hi Dave

PixInsight is based on a object oriented paradigm. This means, in practice, that process windows do not belong to the images. They have theyr own lives. You have to create some links between the processes and the images, to allow them to interact. In fact, you may open the histogram windows, play with the parameters, create a new icon, etc. without a single image opened. The same is true for every non dynamic process (the dynamic processes create a link with the images when they are launched, so you need at least one opened). Another example of this object oriented design is in the use of the "drag and drop objects", i.e. the blue triangles at the bottom left of the process windows. If you click over it, and drag the triangle, a new instance of the current process will be created. You may drop it over a image, to apply the process, drop it to the workspace and then create a new process icon, or over image-container icons to perform batch processing. Furthemore, some processes interact through these icons, like the ProcessContainer.
There is a lot new in the interface. Believe me that is not hard at all to use. You just need time to get familiar with it. Then it just becomes natural, and does make a lot of sense

[DaveS]

Ok Dave, and Harry.

I needed to 'double click' on the image name in the drop down menu to activate, and now have a very 'cramped' histogram in the top box.

I can stretch the diplayed histogram by increasing the numbers in the second numeric box in from the right hand side.

However, neither the sliders or the curve have any effect on the image?

Dave

[DaveS]

Hi Carlos

My last 'post' and yours crossed in 'cyber-space'  , so I now need to read and digest what you have said.

Thanks

Dave

[Carlos Milovic]

Nor the sliders, the numeric edits or anything you do at any process window will modify the image contents (the STF is a special process... it changes how the pixels are visualizated, not theyr values. It is just an aid for propper visualization of the data, without actually modifying its contents). To try the parameters you have two standard ways:
- Use the RealTimePreview window. This will open a new window, with a copy of the current focused image. It is a 16bits approximation. Many processes may comunicate with this window, and give you an idea of the final result based on this approximation, at real time. Please note that if you apply the process to a image the results may vary. As I said, this is a copy of the image, resampled and with only 16bits. This will be specially true with very agressive midtones adjustments, or with some processes that depends on scale information (some convolutions, wavelets, etc). So, aways check the results.
- Use a Preview image (or many). This are something like "childrens" of the main image. You create selections over it (New Preview mode or button) and these previews will call the original data without modifying the main image. They are fast, accurate, but not real time based. There is a lot to learn about them... I suggest you to read the documentation of the PixInsight LE release on this subject, which is pretty much the same as in the current version.:
http://pixinsight.com/doc/legacy/LE/index.html
specifically this:
http://pixinsight.com/doc/legacy/LE/08_previews/working_with_previews.html

[DaveS]

Understood Carlos 

I'll go and download/print those documents as you suggest.

I'm just finding it a little strange, learning to 'drive' a new piece of software without a 'user manual' at my side  .

Once I have an understanding of how PI's GUI functions, I'm sure I can move forward with it.

Thanks for your help.

Dave

[Carlos Milovic]

It may be far less than optimal, but LE's documentation could give you a solid foundation, somewhere to start with. Right now there are lots of new features, and others are obsolete, but the idea behing the GUI is the same. I hope it helps meanwhile...

[Harry page]

Hi Dave

you are going to have to watch a couple of my video's 

once you have altered the histogram you have to apply the change to the image by clicking on the small square or dragging the triangle to image and releasing, it will soon become second nature

Harry