[OoklaTheMok]

I'm just posting this as a curiosity...basically, I have various scanned 1200 dpi bitmap images that have lots of white specks in the solid black areas that I want to get rid of easily without affecting fine detail anywhere else.

Specifically, I'd love to get rid of all white one-pixel specks in black areas (all 8 adjacent pixels being black). Bigger specks would be nice too, but I'd be happy with one-pixel specks going away.

I DON'T want it to affect one-pixel black specks in white areas.

Any ideas?

[FauxCaster]

There are several things you can try (always save a copy).

*Dust & Scratches filter

*Small-radius Gaussian blur, then one or more of the following: sharpen, levels, unsharp mask etc. Basically gaussian blur will dull edges and fill in small holes; use another filter to tighten up the edges. There are plenty that *might* work.

*A dirty trick, depending entirely on the scan. Select color range: black; then expand selection 1 pixel, then contract selection 1 pixel. All of the one-pixel holes will now be left out. Then fill in the selection with black on a new layer and toggle on and off to see if its working. If some parts worked better than others, just erase it from the layer.

[chris v]

^^ What he said.

[OoklaTheMok]

Thanks for the suggestions.

Unfortunately, all of those throw out the baby with the bathwater. The most promising seemed to be the expand/contract selection one, but even expanding by one and then contracting by 10 still does too much damage...I'd have to spend more time using the history brush than it would take me to just paint out the black areas by hand.

It seems to me it ought to be easy to WRITE a filter to do what I want. It would only take 12 steps...

1. Is current pixel black? If so, go to step 11
2. is pixel west of current pixel white? if so, go to step 11
3. is pixel east of current pixel white? if so, go to step 11
4. is pixel northwest of current pixel white? if so, go to step 11
4. is pixel north of current pixel white? if so, go to step 11
6. is pixel northeast of current pixel white? if so, go to step 11
7. is pixel southwest of current pixel white? if so, go to step 11
8. is pixel south of current pixel white? if so, go to step 11
9. is pixel southeast of current pixel white? if so, go to step 11
10. set current pixel to black
11. move to next pixel
12. go to step 1

or...

Code:
for pixels() {
if (currpixel != 0) {
   if (neighbor(W) != 1 {
      if (neighbor(E) != 1 {
         if (neighbor(NW) != 1 {
            if (neighbor(N) != 1 {
               if (neighbor(NE) != 1 {
                  if (neighbor(SW) != 1 {
                     if (neighbor(S) != 1 {
                        if (neighbor(SE) != 1 {
                           setCurrPixel(0)
                        }
                     }
                 }
             }
         }
     }
}
currpixel++;
}

That's all I want...

Anyone know how to write filters?