Legacy ImageMagick Discussions Archive

ImageMagick is great at image processing. It has many options when writing JPEGs . If your command is the last step of a longer process, fmw42's advice is perfect. But if you are only modifying jpeg attributes such as the coding, a jpeg specific tool, such as jpegtran , will work faster and with zer...

Welcome. Also see http://imagemagick.org/script/compare.php Is AE the metric you want? Are only regions of your image changing? Is the image format lossless? Is a slightly brightened image 100% different? AE = absolute error count, number of different pixels (-fuzz effected) Or do you have your meth...

Welcome. Morphology is a neighborhood operator. http://www.imagemagick.org/Usage/morphology/ Can you provide an example image and give any constraints that may help? "binary black-and-white image" helps clarify. Does perimeter mean that you always have a single, solid, black shape on a whi...

etb972 wrote:the problem is that my image is not croped.. and has not the good size !

I'm not clear on your meaning. Do you know about the viewport setting of -distort ?

fx expects expression in double quotes, while the examples use single quotes. My platform is Windows, which is the reason for the above. I don't think IM or fx care, but it does want one parameter. Windows breaks at spaces unless inside double quotes. Most examples need to be converted for Windows....

-fx "u+v.p{w/2,h/2}-v" That puts a lot of weight on an individual pixel. Make sure the center one is a good one. It might help to blur ColorVign.tif slightly. HDRI is best. An alternative is to de-contrast using +level, do your correction, then re-contrast. -auto-level is ideal , but play...

joew wrote:Printing from gimp is exactly what I want to avoid.

My mistake. I don't print using Gimp because it frequently gets the position wrong, but maybe this is an incompatibility with my very old printer. How are you printing?

u and v are the two images (pixels/colors) being compared. .r, .g, .b are the three channels. Red, green, blue for RGB. Or, somewhat confusingly, Lightness, a, b for Lab. Or hue, saturation, value for HSV. Etc. I found lab is more precise than RGB. Lab matches human perception better. But which colo...

IM does have -fuzz, but it is only one method of calculating such things and may not be what you want. It will be affected by your -colorspace.

Source code is available:
http://www.imagemagick.org/script/install-source.php

You can print from Gimp and still let your printer driver handle the colorspace and sampling conversions.

You know your image's size in pixels, and you know what you want it printed in inches. Divide and set density (pixels per inch).

You want all lines and shapes thinned? Morphology is one option.
http://www.imagemagick.org/Usage/morphology/

The aliasing of your lines may add a step of complexity.

I would let your printer do the sRGB to CMYK conversion unless you have a reason for doing otherwise. I would also let your printer do the -resample/-resize unless you have a reason. Use -density to set the print size.

I second the suggestion to read up on colorspaces. This is a huge topic we couldn't do justice to here. There are no simple answers, so be prepared to commit some time and learn a lot. I realized that it is something completely different to calculate colors on real world painting than we do in IT wo...

I figured, I should use the "-colorspace XXX" options instead of directly fiddling with gamma. Can anybody confirm this assumption? I would use -colorspace RGB and -colorspace sRGB above, especially since the sRGB gamma isn't quite 2.2 (or even constant). However, the improvement will be ...

"Best I can suggest is do it twice, once with -trim and once with -shave. Then chose the larger of the two output images." But GreenKoopa's solution will produce the same result. I'm not sure that they are always the same. Each of the four sides may be trimmed more or less than the shave....