Photomerge: Greater than the Sum of the Parts

X
Posted By
xDsrtRat
Dec 31, 2004
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245
Replies
5
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I was archiving some record album covers and I noticed an odd phenomenon. The album cover does not fit the bed of my scanner, so I was using two passes of the scanner, with a good deal of overlap, and using Photomerge to join the two images. Photomerge did a very nice job, but here’s where I noticed the oddity.

I’m scanning about 80% of the cover on each pass, so there’s quite a lot of duplicate data. Image1 was perhaps 18K in size and Image2 was about 15K. The total of the two images was about 33K. After I saved the Photomerged image the file size was somewhere about 55K. Where did the overhead come from?

Logically, I’d expect the final image to be way less than the sum of the two images and I think the duplicate data is being thrown away. Yes, I expect a file size bigger than the lager of the two files since some information is being added. Having the file size bigger than the sum of the two was unexpected.

The physical look of the merge was very nice, by the way. Since it is the image I’m interested in, not the file size, I’m not going to loose any sleep over this. I was just wondering if anyone else has noticed this.

Happy New Year to All!


________________________________
Iraq is a Farsi phrase meaning Viet Nam

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C
Corey
Dec 31, 2004
"xDsrtRat" wrote in message
I was archiving some record album covers and I noticed an odd phenomenon. The album cover does not fit the bed of my scanner, so I was using two passes of the scanner, with a good deal of overlap, and using Photomerge
to
join the two images. Photomerge did a very nice job, but here’s where I noticed the oddity.

I’m scanning about 80% of the cover on each pass, so there’s quite a lot
of
duplicate data. Image1 was perhaps 18K in size and Image2 was about 15K.
The
total of the two images was about 33K. After I saved the Photomerged image the file size was somewhere about 55K. Where did the overhead come from?
Logically, I’d expect the final image to be way less than the sum of the
two
images and I think the duplicate data is being thrown away. Yes, I expect
a
file size bigger than the lager of the two files since some information is being added. Having the file size bigger than the sum of the two was unexpected.

The physical look of the merge was very nice, by the way. Since it is the image I’m interested in, not the file size, I’m not going to loose any
sleep
over this. I was just wondering if anyone else has noticed this.
Happy New Year to All!

My first question is why are the initial scans so tiny? These are vinyl album covers–12 inches by 12 inches, correct? At what resolution are you scanning them to be so small? What type of file were saving the Photomerged version as?

Peadge 🙂
X
xDsrtRat
Dec 31, 2004

________________________________
Iraq is a Farsi phrase meaning Viet Nam
"Peadge" wrote in message
"xDsrtRat" wrote in message
I was archiving some record album covers and I noticed an odd
phenomenon.
The album cover does not fit the bed of my scanner, so I was using two passes of the scanner, with a good deal of overlap, and using Photomerge
to
join the two images. Photomerge did a very nice job, but here’s where I noticed the oddity.

I’m scanning about 80% of the cover on each pass, so there’s quite a lot
of
duplicate data. Image1 was perhaps 18K in size and Image2 was about 15K.
The
total of the two images was about 33K. After I saved the Photomerged
image
the file size was somewhere about 55K. Where did the overhead come from?
Logically, I’d expect the final image to be way less than the sum of the
two
images and I think the duplicate data is being thrown away. Yes, I
expect
a
file size bigger than the lager of the two files since some information
is
being added. Having the file size bigger than the sum of the two was unexpected.

The physical look of the merge was very nice, by the way. Since it is
the
image I’m interested in, not the file size, I’m not going to loose any
sleep
over this. I was just wondering if anyone else has noticed this.
Happy New Year to All!

My first question is why are the initial scans so tiny? These are vinyl album covers–12 inches by 12 inches, correct? At what resolution are you scanning them to be so small? What type of file were saving the
Photomerged
version as?

Peadge 🙂
My bad . . . That should have been Megs, not Kb. (Bashful blush!) The files are saved as a PSD and the original scan was at 300 DPI.
C
Corey
Jan 1, 2005
"xDsrtRat" wrote in message
Iraq is a Farsi phrase meaning Viet Nam
"Peadge" wrote in message
My first question is why are the initial scans so tiny? These are vinyl album covers–12 inches by 12 inches, correct? At what resolution are
you
scanning them to be so small? What type of file were saving the
Photomerged
version as?

Peadge 🙂
My bad . . . That should have been Megs, not Kb. (Bashful blush!) The files are saved as a PSD and the original scan was at 300 DPI.

Oh man! And I was hoping a new type of scanner came out that saved great copies at a small file size. I’ve never used Photomerge. Does it merge the two scans into one layer or does it create two layers that line up correctly? It is a strange thing.

Peadge 🙂
X
xDsrtRat
Jan 1, 2005
"Peadge" wrote in message
"xDsrtRat" wrote in message
Iraq is a Farsi phrase meaning Viet Nam
"Peadge" wrote in message
My first question is why are the initial scans so tiny? These are
vinyl
album covers–12 inches by 12 inches, correct? At what resolution are
you
scanning them to be so small? What type of file were saving the
Photomerged
version as?

Peadge 🙂
My bad . . . That should have been Megs, not Kb. (Bashful blush!) The files are saved as a PSD and the original scan was at 300 DPI.

Oh man! And I was hoping a new type of scanner came out that saved great copies at a small file size. I’ve never used Photomerge. Does it merge
the
two scans into one layer or does it create two layers that line up correctly? It is a strange thing.

Peadge 🙂
Near as I can tell, it’s operating on the same layer as no new layers are shown in the final output . . . unless it creates a new layer then automatically flattens the final. You can also use three photos to do a panorama view. Beats trying to do it by hand! If you’re critical, you may want to do a little touch-up along the join line, but it is usually quite seamless.
C
Corey
Jan 3, 2005
"xDsrtRat" wrote in message

Oh man! And I was hoping a new type of scanner came out that saved
great
copies at a small file size. I’ve never used Photomerge. Does it merge
the
two scans into one layer or does it create two layers that line up correctly? It is a strange thing.

Peadge 🙂
Near as I can tell, it’s operating on the same layer as no new layers are shown in the final output . . . unless it creates a new layer then automatically flattens the final. You can also use three photos to do a panorama view. Beats trying to do it by hand! If you’re critical, you may want to do a little touch-up along the join line, but it is usually quite seamless.

I did a similar thing at school with a "stitching" program of some sort on a Mac. It was a 360 degree panorama. When put on a website, placing your cursor to one side and holding would pan in that direction. Pretty cool.

Peadge 🙂

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