HistogramTransformation documentation

[Juan Conejero]

Hi all,

The reference documentation for the HistrogramTransformation tool is now finished:

http://pixinsight.com/doc/tools/HistogramTransformation/HistogramTransformation.html

Please let me know if you find any error, as well as something unclear or requiring more elaboration (within the reasonable limits of a manual; remember that this is not a collection of tutorials).

Edited: The PIDoc source file for this document (and also for all documents now finished) is here:

http://pixinsight.com/download/pidoc/examples/

The documentation system's style sheet has also been slightly updated:

http://pixinsight.com/doc/pidoc/css/

Hope you find everything useful.

[Jack Harvey]

Good work keep on keeping on.  This is one of the most complete discussions of histograms and the tool I have read. Great job

[Juan Conejero]

Thanks Jack

[Harry page]

Hi

Keep going chum . I know its hard work 

But you will get your reward

Harry

[DarrenS]

Excellent Juan 

Darren

[ManoloL]

Hola Juan:
Veo que el documento ha sido compilado con la versión 1.1.0 del compilador.
¿donde se puede descargar esta nueva versión del compilador?

Saludos.
Manolo L

Editado:
Ya lo he encontrado en
http://pixinsight.com/download/pidoc/compiler/

Saludos.

[Niall Saunders]

Hi Juan,

I am struggling to make sense of the following

Histogram Readout Modes

The PixInsight Core application generates pixel readouts when you click on an image in readout mode, which is the default working mode for all images (you know the readout mode is active because the image cursor is a simple crosshair). Pixel readouts are sampled pixel values at the current cursor coordinates, and their generation is controlled through a set of readout options that you can define with the ReadoutOptions tool. Pixel readouts are broadcasted to all process interfaces that can receive them; HistogramTransformation is one of those tools.

Basically, if I use this then I seem to 'lose' the upper histogram display altogether. I think I am doing something wrong. Intuitively, I expected that wherever I might have the cursor 'pointing' on a selected image, the ADU value at that point would be used to set the appropriate slider on the Histo winodow.

So, for example, if I was 'pointing' at a location on an image that returned and ADU value of 0.25, and I had the little 'grey' box selected on the Histo GUI, and I clicked the mouse, then the MTF slider would change to 0.25.

Is this what is supposed to happen? Because it doesn't

Have I just 'missed the point'

[Carlos Milovic]

Yes it does If you are working on a RGB image, and click on the "Midtones readout mode" at the HT window, the MTF values will be uploaded with the current pixel ones, at each RGB channel, not the composite. The same happens with black and white points, and the propper readout mode.

[Jordi Gallego]

Great work Juan, very complete and good information

[Niall Saunders]

Yes it does If you are working on a RGB image, and click on the "Midtones readout mode" at the HT window, the MTF values will be uploaded with the current pixel ones, at each RGB channel, not the composite. The same happens with black and white points, and the propper readout mode.

It seems to be functional on an RGB image (a useful facility, which I need to start using!!) - but I definitely seem to have a 'problem' if I try using these buttons when working on a Greyscale image. For example, clicking ANYWHERE on a well-formed image had the effect of setting the MTF slider value (and hence position) to '0.00000' - and the upper Histo display effectively 'disappears'.

Can anybody verify this? If so, we can take it to the 'Bugs' section.

[Juan Conejero]

Hi Niall,

Add one more to your personal bugs account. The histogram readout modes don't work correctly for grayscale images. The good news is that I've found the bug and it is very simple; it is in fact fixed right now.

By the way, this bug is grand reserve. It has been quietly awaiting you to discover it for years, at least from 2006

Thanks for catching it!

[Niall Saunders]

By the way, this bug is grand reserve. It has been quietly awaiting you to discover it for years, at least from 2006
Thanks for catching it!

In fairness Juan, it wasn't 'me' that cuaght this bug - it was 'you', or at least the excellent new documentation from you. Up until then I probably 'experimented' with the buttons, but could not figure out what they were 'supposed' to do, so stopped 'playing' with them.

I did prove their operation in an RGB environement, and can certainly see how they will be useful in the future. In fact, this very question was raised elsewhere on the Forum a few days ago - in connection with 'locking' a highlighted image point onto the Curves process.

As I see it the Curves process is not yet 'as' compatible with the Histo window for 'receiving broadcast information' - perhaps it is time to upgrade the Curbes interface (and, the STF is another process that would benefit as well, it being a 'sister' process to the HistoTransform).

In any case, I'm always happy to have helped.