Legacy ImageMagick Discussions Archive

hi there, thank you so much for your energy and for sharing your thoughts! i was looking for gray images, one per channel, technically in the RGB colorspace. but i will look at your suggestion and think about my direction further. thanks again!

- J

I'd like to output separate channel images in RGB format, but can't seem to get what I need: convert input.ext -separate channel_%d.jpg i've tried putting -colorspace RGB after -separate without luck. I understand the separate argument wisely outputs grayscale images; I want to make them RGB and mai...

Is the JPEG quality reported by identify based on statistics of the quantization tables, or a metadata report? How reliable is it?

Thanks so much!
J

I've just spent the last week studying perceptual hashes and CBIR and such, and have to commend you on your choice of algorithms. Using invariant moments was very wise, in my semi-educated opinion! I'm eager to test this and explore more; please let me know when you release an actual hash creation p...

I wish I could be of more help. I've done research on this but am not a statistics-savvy person enough to know how to resolve the matter.

Regarding skewness, I have researched the matter and discovered that ImageMagick is reporting the values correctly. False alarm there, so sorry!

J

Thanks for including me, but unfortunately I'm a beginner in many regards and can't help much other than testing, sharing resources, and trying to become more helpful by studying. (I manage and design the development of software but don't code myself often.) It's great to hear that this is on your m...

it would be a great convenience in terms of synchronization for coding, as well as visibly possibly more pleasing, if the order of the -unique-colors operation convert colorbar.gif -unique-colors -depth 8 txt:- was the same as the order in which you receive: convert colorbar.gif -define histogram:un...

I may be mistaken, but i am seeing the skewness measure out of line with the distribution, as if it's opposite (negative switch to positive values). I believe skewness is supposed to be a negative value for skewed left distributions, and positive skewed right, but it seems ImageMagick is returning t...

Spectral hashing algorithm:

http://www.cs.huji.ac.il/~yweiss/SpectralHashing/

http://people.csail.mit.edu/torralba/pu ... ashing.pdf

I would bet real cash that you are all very ahead of me on this matter, but I thought in the spirit of collaboration I would share what resources I've come across: http://hackerlabs.org/blog/2012/07/30/organizing-photos-with-duplicate-and-similarity-checking/ http://www.hackerfactor.com/blog/?/archi...

This is stellar work! You are royalty! I've been studying perceptual hashes and similarity algorithms lately, and this is a fascinating approach. A question - I see this is a metric, and you can compare, and see moments, but I don't see any literal hash generation that is exposed to the user. Ideall...

thanks as always, fred! the first definition has the normal distribution as 3 though, and the second one subtracts 3 to make it 0. so, i believe ImageMagick is using the second definition, yes?

J

is the kurtosis formula in use by identify using 0 or 3 as the normal distribution value?

http://itl.nist.gov/div898/handbook/eda ... eda35b.htm

thank you so much for your attention!!

J

thank you so much!!! : )

J

when i run this
i get a value of
18232.1

but when i run
i see in overall image statistics a standard deviation of 70.9422 (0.278205)

how can i get the value shown in the verbose output?

thanks so much!!

J