Histogram and median filters...AGAIN
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Previously I applied a filter to a histogram and attained a slope. I am still waiting for some insight into what the slope might mean in a previous question that I asked. Now I do the same thing (I strongly believe) and now I am getting a horizontal line straight across, can someone tell me what I've possibly done wrong? Or if there's something I'm missing? Thanks, Neo
2 commentaires
per isakson
le 31 Déc 2014
Modifié(e) : per isakson
le 31 Déc 2014
You should at least provide a link to the previous question. Don't expect us to search.
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Image Analyst
le 1 Jan 2015
Running a median filter on a histogram can smooth out spurious noise spikes and let you get a smoother histogram that's easier to find thresholds on.
The slope might indicates how the number of gray levels changes. If it changes a lot (high slope) then it could indicate that that is a good place for a threshold. Of course a flat slope could also indicate that, like where you threshold in the valley centered between two humps.
You really need to provide some context to get a good answer.
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Image Analyst
le 2 Jan 2015
Statistically it's unlikely that every single possible gray level would have the exact same number of pixels. If you roll a die 24 times, you're not going to get every value of 1-6 exactly 4 times are you? So that natural statistical variation (call it noise if you want) is real and the histogram accurately portrays it (in this case though there are cases where it won't be accurate if you have more bins than pixels you're displaying it on and your bar width is not 1.0).
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