Few questions (Night Lights of Town)

[fmw42]

I am going to do mask from the roads and streets.

Can you write syntax how to make multiple fills? As I would want to select more colors and to fill them white to create binary mask.

The only way I know, is

convert image \
-fuzz XX% -fill white -opaque "color1" \
-fuzz YY% -fill white -opaque "color2" \
...
result

You can specify one -fuzz value and it will be used for all fills.


You may want to convert your image to some other colorspace such as HSL, HSB, YUV, etc and separate channels and then look to see if any one channel can be thresholded to give what you need.

[VanGog]

Thanks.
I have no experience with channels in IM so I would like not to do it more complicated then necessary until there is some very serious reason to do so.

Edit:
Main image to this topic:
http://upload.wikimedia.org/wikipedia/c ... 007%29.jpg

[VanGog]

While I worked on masks for shadows removal from aerial photo, I have found by incident how to create "snow like" effect of night city. It looks quite amazing. If I would apply this effect on more masks (or better to say: join the masks together as one mask and then apply), then I should get look like from January-March, when the town can be partially under snow.



What I did is that I took the mask of shadows of group "Very dark green grass":

Code: Select all

	H	S	Brightness
min:	0	16	16
max:	96	30	24

And I applied the masks with Soft light blending in Photoshop. So the areas which are dark in the mask look like in the dark, but the white looks like snow. I have applied two masks at Soft light blending 100% visibility.