Manual available?

XnConvert Multi Platform - Windows, MacOSX, Linux

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jimandy
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Manual available?

Post by jimandy »

I am new to this forum having just discovered this program. Have used Lemke's Graphic Converter but find this has features his apparently does not.
Is there a manual or guide somewhere? I don't understand some of the terms used, such as the numeric choices in action "filter size".

I need to convert images of poorly handwritten documents (pencil writing) into non-greyscale (1 bit) values but don't understand to how to set or change the threshold.

Thanks for this product. The price is great but I will donate!
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XnTriq
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Re: Manual available?

Post by XnTriq »

Welcome to the forum, jimandy (-:

Which edition are you referring to? XnView Classic (Windows only) or XnViewMP (multi-platform)?
jimandy wrote:I need to convert images of poorly handwritten documents (pencil writing) into non-greyscale (1 bit) values but don't understand to how to set or change the threshold.
Could you post a sample?
jimandy
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Re: Manual available?

Post by jimandy »

I guess MP as I am running it on a Mac.

In the "filters" section under "average" there are options in a drop down menu for 3x3, 5x5, etc. Whit is this averaging?
Is there some place I can find a description about the various actions?
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XnTriq
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Re: Manual available?

Post by XnTriq »

jimandy wrote:In the "filters" section under "average" there are options in a drop down menu for 3x3, 5x5, etc. Whit is this averaging?
Is there some place I can find a description about the various actions?
Does this answer your question:
Hypermedia Image Processing Reference ([url=http://homepages.inf.ed.ac.uk/rbf/HIPR2/mean.htm]Mean Filter[/url] » How It Works) wrote:The idea of mean filtering is simply to replace each pixel value in an image with the mean (‘average’) value of its neighbors, including itself. This has the effect of eliminating pixel values which are unrepresentative of their surroundings. Mean filtering is usually thought of as a convolution filter. Like other convolutions it is based around a kernel, which represents the shape and size of the neighborhood to be sampled when calculating the mean. Often a 3×3 square kernel is used, as shown in Figure 1, although larger kernels (e.g. 5×5 squares) can be used for more severe smoothing. (Note that a small kernel can be applied more than once in order to produce a similar but not identical effect as a single pass with a large kernel.)
Wikipedia: Box blur
jimandy
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Re: Manual available?

Post by jimandy »

Thanks, it does answer the question about the "average" option. But that is just one of the many actions that can be added. I understand several actions such as "resize" and "rotate" but my post also asked if there is a manual or reference document that explains the other actions available.

In a different image convert that I use I could select "threshold" and adjust to a value at which a light grey went white and a darker grey went black, useful for bringing out detail in faded typed or pencil written documents. So far I can not find such a method in any of the actions available in Xn. The closest option is to convert color depth to "binary" but there is no way to adjust the threshold.
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XnTriq
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Re: Manual available?

Post by XnTriq »

jimandy wrote:I understand several actions such as "resize" and "rotate" but my post also asked if there is a manual or reference document that explains the other actions available.
There's a help topic about filters (in the user guide for XnView Classic on the offical XnView Wiki), but it's not very detailed.
jimandy wrote:In a different image convert that I use I could select "threshold" and adjust to a value at which a light grey went white and a darker grey went black, useful for bringing out detail in faded typed or pencil written documents. So far I can not find such a method in any of the actions available in Xn. The closest option is to convert color depth to "binary" but there is no way to adjust the threshold.
I've had good results with Mehdi's Fine Threshold. Unfortunately, only the Windows edition of XnViewMP can make use of Photoshop-compatible plug-in filters.
jimandy wrote:I need to convert images of poorly handwritten documents (pencil writing) into non-greyscale (1 bit) values but don't understand to how to set or change the threshold.
Could you upload an example of the images that need to be converted?
jimandy
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Re: Manual available?

Post by jimandy »

I am new to this forum but good at following instructions. How do I upload. Do I need to leave the forum and go to an upload page on the site?
cday
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Re: Manual available?

Post by cday »

jimandy wrote:I am new to this forum but good at following instructions. How do I upload...
Instructions for uploading a file as an attachment to a forum post are provided in this post:

http://newsgroup.xnview.com/viewtopic.p ... 28#p120077

If the extension of the file to be uploaded isn't one supported by the forum settings, the file (or files) can normally be uploaded if placed in a ZIP or RAR archive. The current attachment size limit is 1MB.

Files can alternatively be uploaded to a file hosting service and a link provided in the post, which enables files larger than 1MB to be made available for download if required.
jimandy
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Re: Manual available?

Post by jimandy »

Here are two images from a scan. (Before.tiff is the original scan) Using another conversion program the "Before" was converted with an adjustable threshold setting to arrive at the high contract version "after".
The program also gave an option to save as a low res gif. What was before a 258 KB file became, after processing, a 4 KB file with the pencil handwriting more legible.
The program I used will do batch processing but does not include the threshold setting an an action. I have tried in XN convert to posterize and to change depth to 4 bit greyscale which helps.
I tried using binary depth but that doesn't produce the desired result.
Attachments
Using another conversion program
Using another conversion program
After_low.gif (3.68 KiB) Viewed 4472 times
Before.tiff
An original scanned document
(250 KiB) Downloaded 97 times
cday
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Re: Manual available?

Post by cday »

jimandy wrote:I need to convert images of poorly handwritten documents (pencil writing) into non-greyscale (1 bit) values but don't understand to how to set or change the threshold.
You might look at Image > Adjust > Levels... keyboard shortcut 'L' as one possible substitute for the lack of a binarisation threshold action. You would then have the option to convert the resulting image to binary using Image > Change color depth... if you wish, and to save the resulting file in whichever file format is optimum. Note that detailed 'save' settings are currently quite well-hidden in File > Format settings... .

The After_low.gif image you uploaded is in fact 4-bit grayscale, as I think you know. If file size is a consideration and your final image is binary, TIFF with CCITT G4 ('Fax') compression can produce quite small file sizes.

Edit:

Here's your startiing image with a 'levels' adjustment applied, with the resulting 8-bit grayscale image saved as a PNG with maximun compression. My version is slightly darker than yours -- a matter of the exact settings used -- and I haven't attempted to minimise the file size.

Your starting image doesn't convert well to binary, but in the rather unlikely event that file size is critical, there may be ways of using further processing to obtain a better result.
Attachments
After_cday_PNG.png
After_cday_PNG.png (6.88 KiB) Viewed 4456 times
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XnTriq
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Re: Manual available?

Post by XnTriq »

  1. Open Before.tiff.
  2. Go to Image » Map » Posterize and move the slider to 6.
    Confirm with OK.
  3. Go to Image » Adjust » Levels..., select Luminosity and move the the gray slider to the far right.
    Confirm with OK.
  4. Go to Image » Change color depth..., select Binary and None for Dithering.
    Confirm with OK.
  5. Go to File » Export... » PNG, change the Compression level to 9 and Filter to All.
  6. Save the file.
Attachments
p121961.png
p121961.png (4.5 KiB) Viewed 4451 times
cday
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Re: Manual available?

Post by cday »

Good result but if a 4.5KiB binary (black and white) file is too large...

Only 1.41KiB saved as a TIFF with CCITT G4 ('Fax') lossless compression: :D
p121961_TIFF_CCITT_G4.tif
(1.41 KiB) Downloaded 98 times
Edit:

On close inspection the grayscale versions are still better quality images, but possibly the above binarisation settings were not optimal...
jimandy
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Re: Manual available?

Post by jimandy »

Thanks, you are doing a great job of explaining but maybe I am using the wrong version of software.
Version 1.65-x64 (Aug20,2014) Libformat version 6.60)

When I add the Posterize action I do not get a slider but I get a drop down menu with choices of color (4, 8, 16, etc.)
No slider.

However, I played with the brightness and contrast settings as you suggested and got just what I want

adjust> (brightness at -82; contrast at 127)
Posterize (# of colors 4)
Color depth: Binary

(I still think a manual would be nice. I know a few things about imaging but you have a lot of terms in there for which I would appreciate some explanation)
I am so pleased with your support and the quality of this program I will send a donation via PayPal.
cday
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Re: Manual available?

Post by cday »

jimandy wrote:... maybe I am using the wrong version of software. Version 1.65-x64 (Aug20,2014) Libformat version 6.60)

When I add the Posterize action I do not get a slider but I get a drop down menu with choices of color (4, 8, 16, etc.)
No slider.
I think you are using XnConvert rather than XnViewMP, both are cross-platform and so can be run on a MAC, but there are some detail differences in the interface as you have discovered...
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XnTriq
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Re: Manual available?

Post by XnTriq »

[edit]

cday is right! You're running XnConvert, jimandy.
I've moved the topic to the correct section of the boards.

[/edit]

jimandy wrote:Thanks, you are doing a great job of explaining but maybe I am using the wrong version of software.
Version 1.65-x64 (Aug20,2014) Libformat version 6.60)

When I add the Posterize action I do not get a slider but I get a drop down menu with choices of color (4, 8, 16, etc.)
No slider.
XnViewMP and XnConvert are based on Qt, a “cross-platform application framework”. Simply put, the rationale behind this framework is that developers can make their applications run on more than one operating system without the need to do the programming for each OS seperately.
Unfortunately, I can't do tests on a Mac system. I was assuming that the dialogs are roughly the same on all platforms. Apparently that's not the case. Thanks for pointing this out to me.
jimandy wrote:(I still think a manual would be nice. I know a few things about imaging but you have a lot of terms in there for which I would appreciate some explanation)
There have been several initiatives by the user community to write a comprehensive manual, but since XnView, XnViewMP and XnConvert are so feature-rich and subject to constant improvement, it's hard to keep up with the changes.
Please refer to the forum for your questions. (I've picked up a lot by hanging out here for the past nine years.)
jimandy wrote:I am so pleased with your support and the quality of this program I will send a donation via PayPal.
Pierre will be pleased to hear that. :-)
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