Search found 7 matches

by darksndr
2019-05-03T13:39:10-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

I think you can use the same trick as I did: get the histogram for the LAB colorspace and then check the L values of each row:

Code: Select all

convert fname.ext -colorspace LAB -format %c histogram:info:-
by darksndr
2017-04-07T07:15:59-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

This should work: 1. Open up a command prompt: Windows Menu > Run > type "cmd" and hit ENTER 2. type: cd "c:\path\to\your\images folder" 3. type ruby file_that_iterates_among_images.rb if it doesn't then ask for help to some IT friend near you, to run this you must have some basic knowledge of the d...
by darksndr
2017-04-07T00:24:47-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

darksndr, I want to use your script to check my images for greyscale color, but I do not know how to use this ruby script in Windows 7, I do not understand anything about it. What do I need to do? Please describe the instructions step by step how to use this. After I installed the Ruby installer fo...
by darksndr
2016-07-12T08:21:37-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

But it can still easily fail with regard to the red hue. I would probably do it twice, ... When testing I would separate them into three groups... Also take your test images and save and reload them using the JPEG format, with a very very low quality setting... ...remove not only the pure black and...
by darksndr
2016-07-11T10:30:35-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

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 ...
by darksndr
2016-07-11T05:54:42-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

Hi all, I took some time to think about a solution for my needs based on your suggestions. I ended up with this solution: 1. compute the mean saturation percentage (1-100%) 2. compute the standard deviation of the unique hues (without considering their absolute frequency) 3. if sat_mean >= 30, then ...
by darksndr
2016-06-30T13:57:05-07:00
Forum: Users
Topic: How to check image color or back and white
Replies: 45
Views: 91706

Re: How to check image color or back and white

Due to HSL being a double hexcone model [...] In its place, use HCL, HCLp, HSI or HSB above. These are all single hexcone type models and should work fine in the above equation. Thank you fmw42, so if I use this command I can safely distinguish a color image from a grayscale's one: convert image -c...