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community home > Free Pattern Wizard > Updates > v2.9.0 Added "Stray pixel cleanup" to reduce unwanted stitches
v2.9.0 Added "Stray pixel cleanup" to reduce unwanted stitches
3262 views   0 replies   Latest reply: February 25, 2014 at 6:43:27 PM

Member since:
Jul 1, 2009
Posts: 1085
Stitchboard Support message #1
v2.9.0 Added "Stray pixel cleanup" to reduce unwanted stitches
February 25, 2014 at 6:43:27 PM
Even I've been waiting for this and it's been much needed.

Here's the deal... When you upload a compressed image or ask the patternWizard to enlarge or reduce your image, you'll often get stray pixels in the new image.  The technical term for this is "compression artifacts".  Unfortunately, this will carry through to your chart and you'll have stray stitches.

Until I implement a new edit mode, the new "Stray pixel cleanup" option in section 8 will help.  The upside is that it will greatly reduce stray stitches.  The downside is that it might also add some additional black or white to the image but usually only in the "heavy" setting.

Not getting too technical, and for those very familiar with a graphics editor like Photoshop, this functions similar to sliding one side or the other up or down in an image histogram.  It minimizes the effects on mid-tones and alters either whites or blacks.  So if your image is on a white background, it will turn most, if not all stray background "junk" white.

It's not perfect and sometimes you actually want stray background stitches (like stars on a black background).  It theory, if the stars are bright enough in your image, they'll probably not be affected with this new function.  I haven't tried it.

Anyway, here's an example.  First, a note.  The following examples are not great due to the fact that they're actually saved here in the Community as compressed .jpg images so the Community software re-introduces some stray compression noise.  So here I am talking about how the new feature clears up compression noise and my examples actually have a bit added back in!  So you will see a bit of "noise" in the following images (mainly in the blue backgrounds) that are not really there.  Just follow me through the examples and ignore the non-white "junk" that you see in the blue backgrounds.

The first image below is the original image with no loss.  For illustration purposes, I filled the background with blue so you can better see the stray pixels.  You can see there are no stray pixels in the background of the original image.

The second is the same image compressed in the jpg format.  It shows the stray background "junk" that was created during compression (shows up here in white around the wizard). 

The third, fourth, and fifth are what the new "Stray pixel cleanup" function did with the .jpeg image depending on  the setting of "light", "medium" and "heavy".
The first image above was run with a "light" setting and removed much of the stray "junk". The second image shows what the medium setting did.  Almost all of the "junk" is gone.  And in the heavy setting, it's clean again.  Note that the image gets slightly lighter depending on the setting and you can compensate for this by slightly changing the brightness and contrast if you want.  As I mentioned before, this is not a perfect solution.  You can see in the "heavy" setting, there's a bit of white introduced in the wizard's face.

To better illustrate stray pixels in a chart, here are portions of a chart showing the compressed image, and the same image run through the "Stray pixel cleanup" in a "medium" fix setting.


If you look closely at the left image you'll see some shades of gray, purple, and whatever in the white area.  This was cleaned up in the second image using the "Stray pixel cleanup"

As always, experiment!  But at least this is a "cleanup" helper until I implement the actual chart editor.  Yes, yes, it's coming eventually...

Have fun!

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