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Took the Plunge - GoldStar OS-7020 Oscilloscope

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Brumby:
It's amazing how you can ask for suggestions and get ignored - but put something out there that isn't up to some people's expectations and watch all the experts chime in.

Yes, I know there was colour.  Yes, I know there was some text visible through the back of the page.  Yes, I could have reduced it to greyscale - but my efforts took long enough as it was, scanning each page separately, keeping things as square as possible and as clear as possible, stitching together pages that had to be done in two passes because they were too big for the scanner.

Considering that this was my first foray into PDF wrangling, the result seems useful enough.  I've already admitted it isn't optimal.


Here's the original scan that came straight off the scanner...
https://www.dropbox.com/sh/dqj8qe9jvfodvfz/AACdycgDv4HgFte3aI7KPHLra?dl=0&preview=Goldstar_OS7020_ServMan_OriginalScan.PDF
(There are a couple of pages that were double scanned.)

Knock yourself out.

Edit: Bit of a rant there.... sorry.

AVGresponding:
Haha no worries.

I know the basics regarding lossy and lossless compression; I recently completed an HNC with the OU that included these topics.

I just wasn't aware of the quality of the source material you were working with, that's quite an effort you put in there!

rsjsouza:
Whales, your posts above are pretty well written indeed, thanks for taking the time.

One question I have: does the process of removing the background shade performs yet another decompression/recompression? I suspect not, but wanted to ask.

As for the utilities, I usually use IrfanView and Foxit for this handling. They tend to do quite a reasonable job, but I will check these tools as well.

In my opinion, however, Brumby's grayscale version looks much more appealing to my eyes than your two versions above.

When I got my Keithley 191, its online manual at Tektronix was scanned in BW with very poor detailing overall, with blocky graphics (due to the threshold in BW conversion) and other issues. I got a physical copy, scanned it in uncompressed 300dpi TIFF (schematics and mechanicals at 600dpi) and worked around to compress it to a more reasonable size. Sure, the file size is much larger than theirs (26MB) but disk space is cheap, internet connections are improving and there are no continuous upgrades, thus making it a one time process.

One thing I may do to this and another manual I posted there is the removal of the shading of the other pages - a brightness setting on the scanner would have minimized/solved this.

Brumby:

--- Quote from: rsjsouza on February 03, 2020, 11:43:19 am ---.... was scanned in BW with very poor detailing overall, with blocky graphics (due to the threshold in BW conversion) and other issues.

--- End quote ---

This is why I avoid threshhold processing for text.  The intermediate intensity pixels add clarity when viewed by our eyes, which - in conjunction with the human brain - have developed algorithms to see things much more clearly.

Reducing the ghosting from the back of the pages would have been useful - so would converting from a colour palette to greyscale.

rsjsouza:

--- Quote from: Brumby on February 03, 2020, 12:33:04 pm ---
--- Quote from: rsjsouza on February 03, 2020, 11:43:19 am ---.... was scanned in BW with very poor detailing overall, with blocky graphics (due to the threshold in BW conversion) and other issues.

--- End quote ---

This is why I avoid threshhold processing for text.  The intermediate intensity pixels add clarity when viewed by our eyes, which - in conjunction with the human brain - have developed algorithms to see things much more clearly.

Reducing the ghosting from the back of the pages would have been useful - so would converting from a colour palette to greyscale.

--- End quote ---
Yes, that is the effect also brought by some of these subpixel rasterizing methods. Interesting that Microsoft's ClearType uses RGB, not only greyscale, but I imagine that greyscale is already good enough for these manuals.

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