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Darth Eggplant
08-24-2003, 12:24 AM
umm i know that images such as jpg's get made up as pixels and as dpi values, dots per inch, I have heard of something called vector graphics. Now with pixel's if you reduce or enlarge too much you get image fuzzy's; but I heard vectors are computer mathematical and so can go up in size or down without any image distortion. my quandry then....
i have a jpg, it is good quality but small, I want to turn it into a desktop size, resizing it up makes it look wonky. Now is there some way to convert my jpg to a vector? because if my image was a vector i could blow it up real good. then i want to reconvert it back into a jpg.

is this impossible? please post or PM me if you have or know about this kind of thing.

coupes.
08-24-2003, 01:43 AM
Well it IS possible to 'turn' a pixel image to a vertor one but there is NO way you'll acheive what you are talking about. Let me explain...

some software (flash is one of them) can 'vectorize' an image, but what it really does is it takes areas of about the same color (you can set the threshold) and makes a vector shape out of it. Now this shape will always look the same even if you zoom in 1500% (it'll only be bigger :rolleyes: ). This means the result looks like a bunch of color patches with no gradient colors, so you will get the best results with cartoon or simple images. Even if you max out all the setting to acheive the most accurate result, the best you could get would be every pixel is changed to a little vector square of the same color, so if you were to enlarge it you would get bigger squares, much like you would get bigger pixels with a matric picture.

I hope you all got that... (I'll post an example of what I just explained if you want)

So the best way to improve your picture would be to touch it up once it's been enlarged so it looks better, or of course trying to find a bigger better version of this pic, if you found it on the net, of course. If it's a scan, then try rescanning it with a higher resolution.

StormHammer
08-24-2003, 02:33 AM
The other way to do it is to physically 'trace' it yourself, or use something like the 'autotrace' function in applications like CorelDRAW. Autotrace usually works best for very simple images, though. In the past when I've wanted to 'blow up' a small line drawing/cartoon etc, I've just manually traced the necessary outlines, and then blown up the vector version.

So if you've got the time and patience (and a suitable application) you can achieve some good results. Of course, it totally depends on the complexity of the image. If it's like a miniature photo with lots of detail, then you may have a problem. :/

Eldritch
08-24-2003, 03:51 AM
I'm not sure where you heard that you can change the resolution of vector images without ANY distortion, but that's incorrect.

There are basically 2 types of images - Vector (which use mathematical formulas to redraw the image on screen), and Raster (which is drawn pixel by pixel). When you enlarge a Raster image you get an effect called pixelation. Since Vector images don't store specific pixel info, they are more easily scaleable, but there is a limit to how far you can scale it before you get distortion.

To answer your question though... .jpg files ARE vector images, so you don't need to convert it (an example of a Raster image would be a .bmp file, in case you were wondering).

Like CoupeS said, if it's a scan, you can try rescanning it at higher rez (though you should know all scans start as raster images). The best solution if it's not a scan would just be to find a larger version of the picture.

coupes.
08-24-2003, 03:53 AM
Of course you can always trace you pic but you can't really acheive a realistic look (for organic things at least), It'll always look somewhat cartoony, and it will take a lot of time, like Stromy said. I use Adobe Illustrator, it's my favorite vector software, but close second would have to be Macromedia FreeHand. They are both professionnal softwares and are really easy to use.

edit: Eldritch, I just saw your post... and jpegs ARE NOT vector files, I don't know where you heared that but it's not true.

Eldritch
08-24-2003, 04:26 AM
Strictly speaking, JPEG refers only to a family of compression algorithms; it does *not* refer to a specific image file format. However, the JPEG committee was prevented from defining a file format by turf wars within the international standards organizations.

So even though it can't technically be considered vector, it uses the same style compression formulas as other accepted vector formats.

JPEGs certainly aren't raster images... just because it doesn't have the title doesn't mean it's not storing image data the same way vectors do.

coupes.
08-24-2003, 05:00 AM
Ok... sure jpeg is a compression technology, you got that right, but there IS a jpeg/jpg/jpe (call it what you want) file format, you are basically saying that jpeg files don't exist :confused: . And jpegs certainly aren't vetor. Just because they use similar compression technologies that some vector images use doesn't make them vector images.

And I don't get how vector images can get distorted as the software rendering them, calculates the vectors so they are always the same.

Eldritch
08-24-2003, 05:22 AM
"Vector graphics is the creation of digital images through a sequence of commands or mathematical statements that place lines and shapes in a given two-dimensional or three-dimensional space. In physics, a vector is a representation of both a quantity and a direction at the same time. In vector graphics, the file that results from a graphic artist's work is created and saved as a sequence of vector statements. For example, instead of containing a bit in the file for each bit of a line drawing, a vector graphic file describes a series of points to be connected. One result is a much smaller file.

At some point, a vector image is converted into a raster image, which maps bits directly to a display space (and is sometimes called a bitmap). The vector image can be converted to a raster image file prior to its display so that it can be ported between systems.

A vector file is sometimes called a geometric file. Most images created with tools such as Adobe Illustrator and CorelDraw are in the form of vector image files. Vector image files are easier to modify than raster image files (which can, however, sometimes be reconverted to vector files for further refinement)."

From C. Wayne Brown and Barry J. Shepherd, authors of Graphics File Formats Reference and Guide.

Originally posted by .:CoupeS:.
get how vector images can get distorted as the software rendering them, calculates the vectors so they are always the same.
If you have a low rez image, there's not as much detail in a 320x240 picture as there is in one that's drawn at 800x600 or higher (for desktop resolution). So if you're enlarging it with something like Photoshop or Illustrator (Illustrator is mainly for raster images, btw), there's only so much picture information contained in it that can be enlarged before it gets distorted.

EDIT:
The problem is that MOST programs cannot save Vector info in a JPG file, so it is commonly thought that JPG is not a vector format. JPG is capable of doing so, but most programs rasterize the image before using standard JPG compression formulas. This is why most people think JPG is not a vector format.

BCanr2d2
08-24-2003, 06:57 AM
Is Fractal imaging the thing you are after?

Emon
08-24-2003, 07:35 AM
I'm almost positive JPEG does not do vectors. Show me a program that can do this.

coupes.
08-25-2003, 01:00 AM
Originally posted by Eldritch
"Vector graphics is the creation of digital images through a sequence of commands or mathematical statements that place lines and shapes in a given two-dimensional or three-dimensional space. In physics, a vector is a representation of both a quantity and a direction at the same time. In vector graphics, the file that results from a graphic artist's work is created and saved as a sequence of vector statements. For example, instead of containing a bit in the file for each bit of a line drawing, a vector graphic file describes a series of points to be connected. One result is a much smaller file.

At some point, a vector image is converted into a raster image, which maps bits directly to a display space (and is sometimes called a bitmap). The vector image can be converted to a raster image file prior to its display so that it can be ported between systems.

A vector file is sometimes called a geometric file. Most images created with tools such as Adobe Illustrator and CorelDraw are in the form of vector image files. Vector image files are easier to modify than raster image files (which can, however, sometimes be reconverted to vector files for further refinement)."

From C. Wayne Brown and Barry J. Shepherd, authors of Graphics File Formats Reference and Guide.


If you have a low rez image, there's not as much detail in a 320x240 picture as there is in one that's drawn at 800x600 or higher (for desktop resolution). So if you're enlarging it with something like Photoshop or Illustrator (Illustrator is mainly for raster images, btw), there's only so much picture information contained in it that can be enlarged before it gets distorted.

EDIT:
The problem is that MOST programs cannot save Vector info in a JPG file, so it is commonly thought that JPG is not a vector format. JPG is capable of doing so, but most programs rasterize the image before using standard JPG compression formulas. This is why most people think JPG is not a vector format.
I know what vector graphics are...:rolleyes:

If you read correctly what you posted it says pretty much what I'm saying. Vector files can be converted to any resolution raster image and saved to any raster image formats and sub-formats.

And I don't see how Illustrator (a vector graphics software) can be mainly used for raster images, that's not making any sense. And I have yet to see a vector graphics program use the jpeg compression to save a vector file, it is reserved to raster images.

Darth Eggplant
08-25-2003, 02:22 AM
:D wow no posts and then a plethora of help. thanks one and all but being a neo ludite, trace image the old fashion way I understood. i will trace and then blow up like a coloring book and do what i need doing, thankfully my subject matter is cartoony already so i do not need to worry about that. again thanks for all the technical info and assistance.:D