Dust Removal with Flatfield - Revision history

Erik Krause: avoided overlapping images with clr template

2007-12-03T21:22:02Z

avoided overlapping images with clr template

Klaus: working more on the text

2007-12-02T18:47:56Z

working more on the text

Klaus: text recycling - to be edited

2007-12-02T18:26:43Z

text recycling - to be edited

Klaus: first lines on flatfield

2007-12-02T18:11:58Z

first lines on flatfield

New page

Dust can get into camera optics. In panorama images created from such photos the repetitive pattern can be particulary irritating, as a dust speck or a dust speck pattern tends to show up multiple times.

One can prepare a flatfield for correction. While one may correct the input files prior to stitching precessing each with the ''gimp'' for example, a much smoother workflow results if the stitching software itself provides for the use of a flatfield.

Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal. -- [[User:Klaus|Klaus]] 19:11, 2 December 2007 (CET)

@@ Line 7: / Line 7: @@
 [[Image:Tuebingen Neckarfront small15 2006-06-11.jpg|thumb|600px|Image without dust specks]]
-Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal.
+Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal.{{clr}}
 == Example of flatfield performance ==

@@ Line 1: / Line 1: @@
 Dust can get into camera optics. In panorama images created from such photos the repetitive pattern can be particulary irritating, as a dust speck or a dust speck pattern tends to show up multiple times.
 One can prepare a flatfield for correction. While one may correct the input files prior to stitching precessing each with the ''gimp'' for example, a much smoother workflow results if the stitching software itself provides for the use of a flatfield.
-Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal. -- [[User:Klaus|Klaus]] 19:11, 2 December 2007 (CET)
+[[Image:Tuebingen Neckarfront small15 2006-06-11.jpg|thumb|600px|Image without dust specks]]
-<h1>Plea for Flatfield</h1>
+Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal.
-<p>
+== Example of flatfield performance ==
-<img width=640 height=480 alt="foto" src="flatfield3.jpg"><br>
-This is a photo with dust in the lense. Here it is rather visible,
+<gallery>
 as my camera sometimes had the habit of showing a focussed image
 of the dust specks as well. I have downscaled the images.
-<p>
 Shortly later the camera fell into that habit again, and I had a
 whiteboard nearby, so I set the lense aperture to the same value
 and took a photo of the featureless whiteboard.
 It is rather dark, but it shows the same dust specks
 as the photo I want to correct.
-<p>
-<img width=640 height=480 alt="foto" src="flatfield2.jpg"><br>
 After some brightness adjustment and blurring (details on request)
-with the gimp here is now the flatfield as used in the layer
+with the gimp the thrid images is now the flatfield as used in the layer
 with the mode set to "divide".
-<p>
+Rightmost the corrected photo. If one looks closely I did not get
-<img width=640 height=480 alt="foto" src="flatfield4.jpg"><br>
-<p>
-And here the corrected photo. If one looks closely I did not get
 the flatfield completely right in the upper half of the image,
-as the white is blown the dust specks in  the sky are under-corrected.
+as the white in the flatfield is blown the dust specks in the sky are under-corrected.
 See in particular the top left corner. with a little more time
 I probably could produce a better flatfield version. But the specks
 on the runway are pretty much gone.
-<p>
-I show this example with a view towards hugin, where recently a
+This example is shown with a view towards hugin, where in hugin 0.6beta
-flatfield image was available but the most recent beta release
+flatfield image was available but hugin 0.7beta5 does no longer have it in the GUI.
-does no longer have it in the GUI. In particular within a
+In particular within a panorama stitch the dust specks have the nasty habit of showing up
 panorama stitch the dust specks have the nasty habit of showing up
 several times and forming a repetitive pattern which your eye
 is faster to spot than a single spot positioned at random.
-<p>

← Older revision		Revision as of 18:26, 2 December 2007
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	Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal. -- [[User:Klaus\|Klaus]] 19:11, 2 December 2007 (CET)		Flatfields may also be used to correct [[vignetting]], or vignetting correction and dust removal combined. But even with hugin 0.7 using a parametrisation approach for vignetting, a suitably prepared flatfield is useful for dust removal. -- [[User:Klaus\|Klaus]] 19:11, 2 December 2007 (CET)
		+
		+	<h1>Plea for Flatfield</h1>
		+
		+	<p>
		+	<img width=640 height=480 alt="foto" src="flatfield3.jpg"><br>
		+	This is a photo with dust in the lense. Here it is rather visible,
		+	as my camera sometimes had the habit of showing a focussed image
		+	of the dust specks as well. I have downscaled the images.
		+	<p>
		+	Shortly later the camera fell into that habit again, and I had a
		+	whiteboard nearby, so I set the lense aperture to the same value
		+	and took a photo of the featureless whiteboard.
		+	<p>
		+	<img width=640 height=480 alt="foto" src="flatfield1.jpg"><br>
		+	It is rather dark, but it shows the same dust specks
		+	as the photo I want to correct.
		+	<p>
		+	<img width=640 height=480 alt="foto" src="flatfield2.jpg"><br>
		+	After some brightness adjustment and blurring (details on request)
		+	with the gimp here is now the flatfield as used in the layer
		+	with the mode set to "divide".
		+	<p>
		+	<img width=640 height=480 alt="foto" src="flatfield3.jpg"><br>
		+	Once again the uncorrected photo.
		+
		+	<p>
		+	<img width=640 height=480 alt="foto" src="flatfield4.jpg"><br>
		+	<p>
		+	And here the corrected photo. If one looks closely I did not get
		+	the flatfield completely right in the upper half of the image,
		+	as the white is blown the dust specks in the sky are under-corrected.
		+	See in particular the top left corner. with a little more time
		+	I probably could produce a better flatfield version. But the specks
		+	on the runway are pretty much gone.
		+	<p>
		+	I show this example with a view towards hugin, where recently a
		+	flatfield image was available but the most recent beta release
		+	does no longer have it in the GUI. In particular within a
		+	panorama stitch the dust specks have the nasty habit of showing up
		+	several times and forming a repetitive pattern which your eye
		+	is faster to spot than a single spot positioned at random.
		+	<p>