Add "Clip Low Pixels" to GESD.

[rockenrog]

Hi!
I have had black spots showing up in the registered/debayered Ha subs after run WBPP 2.3.2. My data is dithered. Adding some pedestal helped, but re-running WBPP multiple time to test pedestals is time consuming.

The cause of the black dots is another issue I am investigating, but I found GESD in Image Integration is not rejecting these and some black spots are still showing up in the integrated image. I looked back and found that some at hot pixel locations, but others also showing up. This was not the typical narrowband being 'too close to zero' problem, because my 'average minimum' is .07, and 'average max' in the master dark was .056.

Windsorized Sigma Clipping gave superior results because I could set Clip Low Pixels to any value I want. .06 worked great for my data set, with .5% to 1% low rejections. Carefully comparing, even at 3:1zoom, the GESD to Windsorized rejection showed no visible difference excepting the black dots went away.

Suggestion: Add "Clip Low Pixels" to GESD.
Thks,
Roger

 

[Juan Conejero]

The GESD pixel rejection algorithm rejects high and low pixels automatically. The problem you are experiencing is very easy to solve: set the ESD low relaxation parameter to 1.0 (the default value is 1.5; read the parameter's tool tip for more information). You'll find this parameter on the Pixel Rejection (2) section of the ImageIntegration tool.

Never use the WBPP script to generate your final integrated image, but the ImageIntegration tool manually with the registered images (and their corresponding .xdrz files if appropriate) that WBPP produces. WBPP has a warning message box that says this.

 

[rockenrog]

Thanks for your reply. I will re-integrate with the ESD low at 1.0 and see the result. If good, then I will report back here and advise no need for my Clip Low Pixels request.
I have never found the ESD tool tip words very understandable, but with enough experience I will learn how to control it better.
I agree and never integrate within WBPP.
Roger

 

[rockenrog]

I re-integrated my subs with ESD Low at 1.0. It was better but still had some black spots. I discovered there is a Clip Low Pixels for ESD, and I tried several values until I got rid of the black spots. Rejection was under 1%.

So I withdraw this wish list request!

 

[dhickey]

The GESD pixel rejection algorithm rejects high and low pixels automatically. The problem you are experiencing is very easy to solve: set the ESD low relaxation parameter to 1.0 (the default value is 1.5; read the parameter's tool tip for more information). You'll find this parameter on the Pixel Rejection (2) section of the ImageIntegration tool.

Never use the WBPP script to generate your final integrated image, but the ImageIntegration tool manually with the registered images (and their corresponding .xdrz files if appropriate) that WBPP produces. WBPP has a warning message box that says this.

I ran across this while searching for a solution to the "black dots" as well. In PixInsight 1.8.9 (Windows 10), I don't see the ESD Low Relaxation parameter. I tried looking at release notes for the last couple versions but didn't see anything stating it had been changed (although I might have missed it). What am I missing?

Dave