Similar Pictures, explain concept of "100%"
Posted: 21 Oct 2023, 03:24
Similar Pictures, explain concept of "100%"?
And they should return the same results - from my reading (understanding, of which I may not, understand)?
Yet 100% aHash <> 100% SHA (necessarily).
In fact, a "similar" hash (aHash) may return 100% ("identical") on files that at least appear to not be 100% identical (that are not 100% identical).
Where MD5/SHA means that the picture "contents", the nuts & bolts of the picture - itself, & exclusive of "tags", or other "extraneous" data (like errant CR/LF after the data content of the picture) [& maybe ? even "compression options" used to compress the picture ?].
So maybe I'm understanding part of this process, but other parts, I'm not getting, yet?
Two pics, "clearly" not "identical" visually.
SHA1 confirms that, says, not identical.
Yet, aHash (default settings) says, "100%"?
.
So if I'm looking for "identical", "exactly the same pictures", I can choose to use either a "similar" hash method (like aHash) - set to 100%, OR, I could use MD5/SHA?"The comparison methods aHash, ... enables you to find similar or almost identical pictures by using a percent match lower than 100%.
If you want to find exactly the same pictures you have to use
a percent match of 100%
or the comparison methods MD5/SHA.
And they should return the same results - from my reading (understanding, of which I may not, understand)?
Yet 100% aHash <> 100% SHA (necessarily).
In fact, a "similar" hash (aHash) may return 100% ("identical") on files that at least appear to not be 100% identical (that are not 100% identical).
Where MD5/SHA means that the picture "contents", the nuts & bolts of the picture - itself, & exclusive of "tags", or other "extraneous" data (like errant CR/LF after the data content of the picture) [& maybe ? even "compression options" used to compress the picture ?].
So maybe I'm understanding part of this process, but other parts, I'm not getting, yet?
Two pics, "clearly" not "identical" visually.
SHA1 confirms that, says, not identical.
Yet, aHash (default settings) says, "100%"?
.