Legacy ImageMagick Discussions Archive

"identify" is a 'simplified' command for quick use, and when it comes down to it is equivalent to convert image options info: Basically you can do a lot more with "convert" (or in IMv7 "magick"), for example process the image in some way before getting information about...

The -channel values refer to the channels for colorspaces RGBA or CMYKA. Thus 'A' in the original example refers to the alpha channel (which is probably pure white or opaque) and not the 'A' channel of "LAB". To get the 'A' channel of 'LAB' you would need to use name for the second RGB cha...

I can see that the stddev of saturation basically halved in the two images with red mid-tones. There were also a reduction in both color images showing that they had overall more red colors than blue-green colors. Judging by the sudden jump in 'color counts' (N) in the 'lq' I can see you did apply t...

Beware of the standard deviation of the hue, as this wraps around at 360 degrees. Yes, but these image colorizations are often centered around a particular degree distant from 0° and 360°, in addition (I think) the exclusion of the first and last hue values from the histogram should attenuate this ...

Hmm yes you are right. it is essentially a greyscale image with color highlight. or perhaps with a parabolic curve so mid-greys -> some highlight color. So colors would generally all lie in a plane (or curved path), rather than as a line. The same sort of vector test (planar rather than linear) woul...

Image 3 can only be separated by doing a test that looks to see if the color form a line in 3D colorspace. That is a color gradient. I have done this though it is tricky. I talk about it in.. http://www.imagemagick.org/Usage/compare/#type_linear The script was written in perl, and uses the perl Math...

The break up method is interesting. You are basically looking for the average saturation of a area that is appreciable to the 50x50 tile. In other words you want a largish spot of color and not just a single pixel of color. Hmmm, How about this. Take your image and resize it to 1:50 of the original ...

Examples of using Flood Fill (both Draw and Operator)
http://www.imagemagick.org/Usage/color_ ... dfill_draw

One of the things mentioned was about "linear scale". Thanks for all the options. I'm trying to classify scanned manga/comics images on grayscale and color. The grayscale can be "linear scale" from yellowed/not balanced scans. This is not pure grayscale, but a image in which the ...

To extend look at IM Examples, Thumbnails, Square Padding or Cropping
http://www.imagemagick.org/Usage/thumbnails/#square

Of course as you have a specific size (or sizes) you have other options
http://www.imagemagick.org/Usage/thumbn ... it_summery

Hmm seems to work well convert -size 8x8 pattern:CrossHatch30 -magnify -magnify -magnify show: compare to direct scaling... convert -size 8x8 pattern:CrossHatch30 -scale 800% show: A little wonky near the edges, but then that should be expected, unless more appropriate -virtual-pixel tile is used fo...

Unless someone volunteers to add it to the library, no.

The reason green screen is used in move making is they can only take one image for sequences involving live actors. The perfect solution requires 2 images with different backgrounds, which is impossible in real time. Some 'space opera' movies (starwars some to mind) use two separate shots with diffe...

But if your software can't generate transparency (alpha mask), all is not lost in getting a perfect transparency. Generate the same image on 2 complementary colored backgrounds. For example black-white, green-purple, blue-yellow. Black-white is the easiest as the mathematics simplifies, thus avoidin...

You will need to becareful with video as the image quality (on individual frames) is typically quite low. That is why snibgo used a very high threshold for the difference comparison. Also remember that outdoor cameras tend to have very wide ranging global changes. For example a cloud does past, and ...