Search found 50 matches
- 2016-01-17T11:33:25-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
Maybe such a bisection / binary search method should be implemented in ImageMagick (similarly to Excel solver) to help maximize certain image properties. For example to find a gamma value against maximizing the black-white pixel transitions (edges) on the thresholded image, or simply find the thresh...
- 2016-01-16T17:03:41-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
JB in facebook colours:
- 2016-01-16T11:47:20-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
Yes, in fact I need a cumulative histogram, but I had no clue that ImageMagick can provide it.
- 2016-01-16T10:41:37-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
"stabilized version": determined golden-ratio graylevel is averaged with graylevel got from the previous frame:
- 2016-01-16T09:21:55-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
Yes, because I applied a slow motion effect too, to double the number of frames. Maybe when converting to gray colorspace for making such a B/W animation one should discard the chroma information of the image completely, am I right?
- 2016-01-16T09:00:34-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
First result clip:
- 2016-01-16T07:08:19-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
And how can I get the histogram data from a jpg image grayscale equivalent without really converting it to a temporary image? I mean something like: convert input.jpg -colorspace gray -info:histogram BTW one can get good results by setting the ratio of black and white pixels to the golden ratio 1/1....
- 2016-01-16T06:54:32-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
Thx, it works, resulting image is very similar:
- 2016-01-16T05:56:12-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
I see, the problem is that I have little knowledge in image processing and ImageMagick, but I can easily code in Ruby. For example for this image (after converting to gray colorspace) I get the following histogram: Histogram: 1: ( 1, 1, 1) #010101 gray(1) 18: ( 2, 2, 2) #020202 gray(2) 88: ( 3, 3, 3...
- 2016-01-16T05:08:32-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
Re: How to threshold an image to get about same amount of black and white?
Thx, but this doesn't work with jpg image. My input image currently is: http://i.imgur.com/7cXqWHe.jpg And I am using a Ruby script and a simple binary search algorithm ( https://en.wikipedia.org/wiki/Bisection_method )to find a gamma value, which can be pre-applied to the input image to achieve my ...
- 2016-01-16T03:50:54-07:00
- Forum: Users
- Topic: How to threshold an image to get about same amount of black and white?
- Replies: 26
- Views: 20455
How to threshold an image to get about same amount of black and white?
I would like to assemble an ImageMagick command line which convert an image to pure black and white colors by simply thresholding it: convert rose: -colorspace gray -ordered-dither threshold -colors 2 output.gif After issuing: identify -verbose output.gif Histogram: 2640: ( 0, 0, 0) #000000 gray(0) ...
- 2014-12-14T18:07:58-07:00
- Forum: Users
- Topic: Image compressibility metric?
- Replies: 8
- Views: 7816
Re: Image compressibility metric?
In fact I would mean the detailness or "business" of an image, but I assumed in the past that it is in connection with the compressibility, so I used the quality 2 jpeg file size as a metric for the image quality. Now I will try to use the entropy instead of. How can I get a measurement / ...
- 2014-12-14T17:36:33-07:00
- Forum: Users
- Topic: Image compressibility metric?
- Replies: 8
- Views: 7816
Re: Image compressibility metric?
Thx, it works, and quick enough.
- 2014-12-14T14:22:55-07:00
- Forum: Users
- Topic: Image compressibility metric?
- Replies: 8
- Views: 7816
Re: Image compressibility metric?
Sad to hear, I never used an API. Is it possible to use it with Ruby?
- 2014-12-14T13:18:35-07:00
- Forum: Users
- Topic: Image compressibility metric?
- Replies: 8
- Views: 7816
Re: Image compressibility metric?
Thx, compiling.
Is it possible to calculate only the entropy with the "identify" command? For speed reasons.
Is it possible to calculate only the entropy with the "identify" command? For speed reasons.