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General Philatelic/Gen. Discussion : Using Scanner to measure Hight and width?

 

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RobertMG
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11 Nov 2015
03:22:33pm
Howdy Everyone!
Has anyone ever tried using they're scanner for measuring hight and width in mm? or any programs that might do something similar? I was toying around with mine but not sure how reliable/accurate something like this could be. Any Thoughts?

Gracias!
RobertImage Not Found

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simothecat

11 Nov 2015
05:11:35pm
re: Using Scanner to measure Hight and width?

You can do this, but it is not clear what accuracy you will get.

A while back I tried scanning an accurate ruler (Fischer Scientific) at 1200 dpi. It turned out that on the left side, one inch was 1201 pixels, while on the right side it was 1206 pixels. This doesn't seem bad, but realize that this is not accurate to a tenth of a millimetre (5 pixels). When I rotated the ruler 180°, I got the same result, so this difference was in my scanner.

At 600 dpi, a tenth of a mm is only about 2 pixels, so I would be doubtful about the accuracy your program is showing.

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ThomasGalloway
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11 Nov 2015
06:41:40pm
re: Using Scanner to measure Hight and width?

I have been using Photofiltre (free software) for years now. They have an add-on that does measurements. Here is a screenshot of me measuring the head on a U429 to help determine the die type:

Image Not Found



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keesindy
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12 Nov 2015
01:11:03am
re: Using Scanner to measure Hight and width?

I've never tried to measure with the scanner software. I never thought about it, but the comments in this thread raise a question in my mind. Isn't it likely the accuracy of such measurements will vary from one scanner to another? Or at least from one brand to another?

Wouldn't higher end scanners be more likely to be designed to eliminate any distortions? I've never seen any analysis or comparison of scanners with this issue in mind, but hadn't given it much thought.

What scanner is each of you using?

I've done measurements in Photoshop after scanning, particularly the Die 88 (and 89?) cut squares being discussed in a couple of other threads. However, because of the inking/printing issues with postal stationery, I chose to do comparisons rather than measurements. Here are two images templates I created several years ago to compare Die 88 (and 89?) variations. Although they're comparisons rather than actual measurements, I think they share some of the same potential problems as measurement since my scans have been created on two different scanners! They are two generations of the same Epson scanner, models 4870 and v700. However, I am now wondering what difference, if any, that might make.

The first image below was designed in Photoshop to show a side-by-side comparison of shield shape differences while the second was designed to overlay a cut square (or section thereof) over the template images to reveal head shape differences. I found this more useful than direct measurements, but I realize this model may not always replace the need to measure.

Image Not Found

Image Not Found

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ThomasGalloway
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12 Nov 2015
09:01:24am
re: Using Scanner to measure Hight and width?

"Isn't it likely the accuracy of such measurements will vary from one scanner to another?"

Yes. And this brings up another feature of Photofiltre that is useful.

Image Not Found

My Peak (model) 1975 scale loupe has a removable reticle which I find useful in calibrating my scanner. My current scanner (Canon LiDE 210) has no error in maintaining linear measurements of its scans. But my previous scanner was off a bit. The field in the Photofiltre measuring tool (see previous demo image up thread) labelled "coefficient" allows you to tell the tool to apply a factor in making measurements. All my scans form that previous scanner required a coefficient of 1.02 to render accurate linear measurements.

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keesindy
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12 Nov 2015
06:17:45pm
re: Using Scanner to measure Hight and width?

Nice! I saw that coefficient value in your previous post and wondered what that represented. Given Epson's reputation for scanner technology over several years, I would hope that both of mine have been accurate. I should check it out.

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RobertMG

11 Nov 2015
03:22:33pm

Howdy Everyone!
Has anyone ever tried using they're scanner for measuring hight and width in mm? or any programs that might do something similar? I was toying around with mine but not sure how reliable/accurate something like this could be. Any Thoughts?

Gracias!
RobertImage Not Found

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likes this post.
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simothecat

11 Nov 2015
05:11:35pm

re: Using Scanner to measure Hight and width?

You can do this, but it is not clear what accuracy you will get.

A while back I tried scanning an accurate ruler (Fischer Scientific) at 1200 dpi. It turned out that on the left side, one inch was 1201 pixels, while on the right side it was 1206 pixels. This doesn't seem bad, but realize that this is not accurate to a tenth of a millimetre (5 pixels). When I rotated the ruler 180°, I got the same result, so this difference was in my scanner.

At 600 dpi, a tenth of a mm is only about 2 pixels, so I would be doubtful about the accuracy your program is showing.

Like
Login to Like
this post
Members Picture
ThomasGalloway

11 Nov 2015
06:41:40pm

re: Using Scanner to measure Hight and width?

I have been using Photofiltre (free software) for years now. They have an add-on that does measurements. Here is a screenshot of me measuring the head on a U429 to help determine the die type:

Image Not Found



Like
Login to Like
this post
Members Picture
keesindy

12 Nov 2015
01:11:03am

re: Using Scanner to measure Hight and width?

I've never tried to measure with the scanner software. I never thought about it, but the comments in this thread raise a question in my mind. Isn't it likely the accuracy of such measurements will vary from one scanner to another? Or at least from one brand to another?

Wouldn't higher end scanners be more likely to be designed to eliminate any distortions? I've never seen any analysis or comparison of scanners with this issue in mind, but hadn't given it much thought.

What scanner is each of you using?

I've done measurements in Photoshop after scanning, particularly the Die 88 (and 89?) cut squares being discussed in a couple of other threads. However, because of the inking/printing issues with postal stationery, I chose to do comparisons rather than measurements. Here are two images templates I created several years ago to compare Die 88 (and 89?) variations. Although they're comparisons rather than actual measurements, I think they share some of the same potential problems as measurement since my scans have been created on two different scanners! They are two generations of the same Epson scanner, models 4870 and v700. However, I am now wondering what difference, if any, that might make.

The first image below was designed in Photoshop to show a side-by-side comparison of shield shape differences while the second was designed to overlay a cut square (or section thereof) over the template images to reveal head shape differences. I found this more useful than direct measurements, but I realize this model may not always replace the need to measure.

Image Not Found

Image Not Found

Like
Login to Like
this post

"I no longer collect, but will never abandon the hobby"
Members Picture
ThomasGalloway

12 Nov 2015
09:01:24am

re: Using Scanner to measure Hight and width?

"Isn't it likely the accuracy of such measurements will vary from one scanner to another?"

Yes. And this brings up another feature of Photofiltre that is useful.

Image Not Found

My Peak (model) 1975 scale loupe has a removable reticle which I find useful in calibrating my scanner. My current scanner (Canon LiDE 210) has no error in maintaining linear measurements of its scans. But my previous scanner was off a bit. The field in the Photofiltre measuring tool (see previous demo image up thread) labelled "coefficient" allows you to tell the tool to apply a factor in making measurements. All my scans form that previous scanner required a coefficient of 1.02 to render accurate linear measurements.

Like
Login to Like
this post
Members Picture
keesindy

12 Nov 2015
06:17:45pm

re: Using Scanner to measure Hight and width?

Nice! I saw that coefficient value in your previous post and wondered what that represented. Given Epson's reputation for scanner technology over several years, I would hope that both of mine have been accurate. I should check it out.

Like
Login to Like
this post

"I no longer collect, but will never abandon the hobby"
        

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