Resolution Problem with still images

EhabMElkhooley wrote on 8/4/2003, 3:42 AM

Hi Guys, First of all I want to thank everyone here for these creative, productive & successive ideas.
I posted a topic about removing grains from video without losing too much details & the replies were very useful & the smoothhiq filter for virtualdub is really amazing.

My next project is to simulate a documentary about some monuments & so.
I've problems with resolution here's a describtion:-
I've a 1024x768 PSD image with 150 dpi & I want to simulate 4x zoom on it & also paning just if i were shooting it with a camcorder, but when i try to do so the video image is pixelated. Do you know any solution to this problem??? I tried to increase image size but still have the same problem....... thnx

Comments

Chienworks wrote on 8/4/2003, 6:44 AM

First of all, ignore dpi; it has no meaning in video. All that matters is the 1024x768. When you zoom in 4x on this you'll end up only using 256x192 pixels. When you enlarge this to fit the 720x480 frame it will look pixellated because the pixels are being enlarged over 2x.

When you say "increase image size", what did you do to accomplish this? If what you did was open the picture in an image editor and save it at a higher image size then you haven't changed anything because all you did was stretch the pixels there. You have to start with a larger image to begin with as your original image since once pixels are lost, they are gone for good and can't be recovered.

EhabMElkhooley wrote on 8/4/2003, 7:04 AM

Thnx Chienworks for your excellent diagnosis but dpi has much to do with image size not video. for example If you have 1024x768 @ 150dpi it means about 2134x1600 @ 72dpi--> - which is the default resolution - & you have the same image quality unchanged.
I think you now get it when i said "increase image size".........
So do you have a solution for my problem?
thnx again

TheHappyFriar wrote on 8/4/2003, 8:01 AM

yo're incorect in that 1024x768@ 150dpi = 2134x1600@72dpi. DPI is dots peR INCH. the 150/72 is pixels, and the 1024x768/2134x1700 are pixels. When you scan your image, it is a fixed INCH size. Lets say you have a 3/5 inch photo. If you scan it at 72dpi, the resolution on the image wil be low, say 1024x768. But, if you increase the dpi to 300, then the same 3x5 inch picture would have a resolution of oh, maybe 4266x3200 resolution.
But... Vegas vegas don't give a rats booty about DPI,only about resolution. So, scanyour images at a HIGH DPI (smaller the picture means you need a higher DPI to get a big resolution), then in Vegas you can pan/crop in more withthe pictures.

So, to sum it up:
1) Vegas don't care about DPI.
2) Higher DPI = higher resulotion. Vegas cares about higher resolution.
3) Higher DPI = higher detail.

farss wrote on 8/4/2003, 8:07 AM

If you cannot do anything to crank up the res of the original digital stills then you may get better results increasing the res in say Photoshop, it has some good algorithms for doing this sort of thing using bicubic transforms to create the extra pixels.

As has been said you cannot actually increase the resolution but you should be able to get rid of the square pixels which are so obvious to the eye by smoothing out the transition of one to the next.

BillyBoy wrote on 8/4/2003, 9:10 AM

I'm with farss... If you have Photoshop, it has an excellent algorithm for bicubic transformations, so resizing within reason almost always gives good results.

What's reasonable? I go as high as 50-60% increase.

Chienworks wrote on 8/4/2003, 10:55 AM

As TheHappyFriar said, in video, 1024x768 @ 150dpi = 1024x768 @ 72dpi = 1024x768 @ 600dpi = 1024x768 @ 36dpi = 1024x768 @ 7200dpi ... etc.

In other words, 1024x768 = 1024x768 no matter what dpi was used when scanning. That's the pixels you have to work with in your image and that's all there is to it.

BillyBoy wrote on 8/4/2003, 11:29 AM

We're talking apples and oranges. Photoshop's bicubic routine is BETTER (In my opinion) so regardless of DPI which I agree is a meaningless term in video if you start with a better QUALTITY source file, you will get a better end result.

EhabMElkhooley wrote on 8/6/2003, 2:31 AM

Thank u all for the valuable replies
First: Of course i know that dpi means nothing in video editing & I was talking generally cuz I also do some webdesign & GUI design.
Second: I always use Photoshop & it's bicubic resize is really amazing.
Third: I think that it's not a reasonable thing to zoom more than 2x cuz I tried to get a higher res using Photoshop & the problem still the same.
Fourth: A question: Are you all from planet earth??????? If you're so please explain being friendly, helpful, nice, cooperative......etc cuz I don't see much of these creatures around these days.
Thanks to all of you, any comments will be welcomed