Resolution of Image View of PNG file

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 From:  bemfarmer
6276.1 
Attached are 3 views of a pixel image.
Image one is a sample of a small portion of a PDF, from a scan at 400 dpi. It is a pixel image in AdobeReader11-0-5.
In order to add the image to MoI, the PDF was exported by the GIMP image program to a PNG, using 400 pixels/inch., which is the third view, in WindowsPhotoViewer.
The middle view is the image after the same PNG is added to MoI. With a little magnification, this third view does not show up as clearly.
Is there some way to improve the "resolution" of the Image View in MoI?
What is the "resolution" in MoI? Is there some other explaination for the way the Image View shows up, like "dithering" or "anti-aliasing," or something?
- Thank you, Brian

The goal is to "trace" the pixel view of the model, into MoI NURBS curves.
Image Attachments:
Size: 62.2 KB, Downloaded: 19 times, Dimensions: 687x480px
Size: 256.8 KB, Downloaded: 16 times, Dimensions: 932x628px
Size: 38.3 KB, Downloaded: 14 times, Dimensions: 1024x681px
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 From:  Frenchy Pilou (PILOU)
6276.2 In reply to 6276.1 
Why not use http://www.autotracer.org/ with the better image you have?
or if you don't want go to the Net use the free Expression 3 (old creature house) who has a tracer inside! :)
http://www.microsoft.com/en-us/download/details.aspx?id=31249

So you can have real curves inside moi ;)

As you can see you have interest to have the more clean start image possible!
Here with any regulate!
I have just enlight in yellow some curves but all is real curves directly inside MOi! (here from EPS format from autotracer with regulates by default!

EDITED: 13 Nov 2013 by PILOU

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 From:  Michael Gibson
6276.3 In reply to 6276.1 
Hi Brian, the image will be rendered as a texture map in MoI, and texture magnification or minification filtering will be applied in order to stretch the image up or down. This is done by the video card using a method called "bilinear interpolation".

The easiest way to get a clearer image should be to have a higher resolution image - if you have more pixels in the image it will not be so grainy as that.

What is the overall pixel resolution (just in direct pixel count, not any "dots per inch" measurement) of the image that you're using?

- Michael
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 From:  Michael Gibson
6276.4 In reply to 6276.1 
Hi Brian, is the first image that you attached the image you're using?

That image is only 687 by 480 pixels in size, which is pretty low resolution, with an image of a low pixel density like that each pixel will end up being kind of large on the MoI viewport and the bilinear blending effect will be exaggerated.

Are you cropping out a small area of the scan to get this particular image? If you want it to be clearer it just has to be higher resolution, if there are more pixels in the image the individual pixels will not stretch out to as large of an area in the MoI viewport.

It can be problematic to have images that are excessively large as well but you would probably want to shoot for something more in the 1500 or 2000 pixels in width and height to get a better viewport display of it.

- Michael
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 From:  bemfarmer
6276.5 
The posted images are just very small snips of the overall scan of the purchased plans, in order to show the relative level of "blurriness" or "clarity" of the 3 different display methods of the original PDF, and PNG exported from the PDF. The middle one is the MoI Image version of the PNG.

The purchased plans allow models to be created, but the plans cannot be disseminated. They were hand drafted a few decades ago, to 1:8 scale, and one Black and White "blueprint" page measures about 25" X 36." The pdf is described as 400 dpi, and looks fairly clear. The png from the pdf, is 3,542 kbytes, and looks fairly clear also. The MoI version is still very useable, but I thought I would check on how it is displayed, as the way the curve pixels are displayed seems very "different" from the other two views.

I'll try the tracing method later today. Edit: The file is too big for autotracer.

Here is a small snip of the MoI top view of a test DXF created from the PNG by the free version of the program PDFtoDWGConverter. This display shows up very clearly in MoI, although the converted curves are not how they should be, which is no fault of MoI. (I understand that this view is of a ("vector trace"?) DXF, not a PNG).

Thank you
- Brian




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 From:  Frenchy Pilou (PILOU)
6276.6 In reply to 6276.5 
Miro before painting! :)

---
Pilou
Is beautiful that please without concept!
My Gallery
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 From:  bemfarmer
6276.7 In reply to 6276.3 
Michael, thank you for the information. Did a little google research. A couple of explanations:

Circa 2005: http://www.chadvernon.com/blog/resources/managed-directx-2/texture-compression-filters-and-transformations/

Up to date: http://msdn.microsoft.com/en-us/library/bb206250.aspx
It seems that turning off "bilinear interpolation" would require changing the MoI program as to how it uses Direct3D9 ( or DirectX?),
and maybe the result would be very poor anyway?

Read that NVIDIA video cards do not allow disabling of bilinear filters.

So I'll probably proceed using the filtered PDF textures, and guess at where to place the MoI Nurbs curves. The difference in location
is, (at a rough guess), say maybe 1/100 of an inch, and the plans are not perfect anyway. The Nurbs curves will be nice and crisp.

- Brian
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 From:  Michael Gibson
6276.8 In reply to 6276.7 
Hi Brian,

> It seems that turning off "bilinear interpolation" would require changing the MoI program as to
> how it uses Direct3D9 ( or DirectX?),
> and maybe the result would be very poor anyway?

Yeah that's correct - currently MoI turns on bilinear interpolation when it sets up things for Direct3D and there isn't any method set up right now to turn it off.

When turned off you end up with "nearest neighbor" filtering which tends to be very heavily blocky and jaggedy. Things that look blurry to you right now instead be big jagged stair steps.

The main thing you need to do to get a better quality screen image is to get a higher resolution image to work with, the image that you're working with at the start of this thread here is too low in pixel count to get a good display, you basically need more pixel dots in order for the pixel structure of the image to not be so visible on the display.

If you have a really large plan then you may need to work on it in some separate pieces so that you can have a higher resolution (with a higher pixel count, again something like 2000x2000 instead of 600 pixels across like your image above) scan of each piece.

- Michael
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