G****n
发帖数: 32 | 1 For two running cars, I can say one car is faster than another one by saying
"speed" is higher. When I have two images, just from my eye, I can clearly
see which one is more clear, which one is not. From a more professional way,
what term or specification will you use to indicate clear / not clear?
thanks. | s******s
发帖数: 13035 | 2 more sharp? color difference between 2 pixels are larger?
saying
clearly
way,
【在 G****n 的大作中提到】
: For two running cars, I can say one car is faster than another one by saying
: "speed" is higher. When I have two images, just from my eye, I can clearly
: see which one is more clear, which one is not. From a more professional way,
: what term or specification will you use to indicate clear / not clear?
: thanks.
| v****x
发帖数: 980 | 3 In a local window, such as 5x5 window, calculate the variance of graylevel
for 9 pixels.then, sum or average all the variances, so called average local variance.
saying
clearly
way,
【在 G****n 的大作中提到】
: For two running cars, I can say one car is faster than another one by saying
: "speed" is higher. When I have two images, just from my eye, I can clearly
: see which one is more clear, which one is not. From a more professional way,
: what term or specification will you use to indicate clear / not clear?
: thanks.
| n*******e
发帖数: 2213 | 4 image contrast is used to do the comparison you want.
saying
clearly
way,
【在 G****n 的大作中提到】
: For two running cars, I can say one car is faster than another one by saying
: "speed" is higher. When I have two images, just from my eye, I can clearly
: see which one is more clear, which one is not. From a more professional way,
: what term or specification will you use to indicate clear / not clear?
: thanks.
| G****n
发帖数: 32 | 5 Yes, the bad one is almost buried in noise, while the good one show some
clearer lines.
【在 s******s 的大作中提到】
: more sharp? color difference between 2 pixels are larger?
:
: saying
: clearly
: way,
| G****n
发帖数: 32 | 6 Can you please say more details? Do you mean I select a 5x5 window, then
calculate variance of first 3x3 pixels? then calculate all next? If that is
right, then I should get 9 variances from this 5x5 window. then average
these 9 values into one to compare?
Do you have any link for this method?
Thanks for help.
local variance.
【在 v****x 的大作中提到】
: In a local window, such as 5x5 window, calculate the variance of graylevel
: for 9 pixels.then, sum or average all the variances, so called average local variance.
:
: saying
: clearly
: way,
| v****x
发帖数: 980 | 7 sorry. it should be 25 pixels if you use 5*5 window, 9 pixels for 3x3
windows.
just calculate the variance of the graylevel for the 25 pixels and put this
variance in the center pixel. For any pixel, do the same calculation except
for edge pixels.
Then, just average all these variance. | G****n
发帖数: 32 | 8 Thanks. Now it is clear. Some more questions:
1. Is this (local variance) a typical assessment method for image comparison?
2. Are there softwares can do such job?
Thanks a lot.
this
except
【在 v****x 的大作中提到】
: sorry. it should be 25 pixels if you use 5*5 window, 9 pixels for 3x3
: windows.
: just calculate the variance of the graylevel for the 25 pixels and put this
: variance in the center pixel. For any pixel, do the same calculation except
: for edge pixels.
: Then, just average all these variance.
| r**********e
发帖数: 133 | 9 What's the intuition?
local variance.
【在 v****x 的大作中提到】
: In a local window, such as 5x5 window, calculate the variance of graylevel
: for 9 pixels.then, sum or average all the variances, so called average local variance.
:
: saying
: clearly
: way,
|
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