Thread: Maximizing image size without perceived pixelation

Is there a way to maximize the size of a JPEG image for display without pixelation?
As I see it, the beginning of pixelation is when one image pixel maps to more than one rod in your eyeball.
I have been limiting the image size by using the screen resolution so that JPEG pixels do not map to more than one screen pixel. However, this does not take into account (1) the screen (or window) size in inches and (2) viewer distance from the screen. The latter could be entered by the user with a common default, but is there a way to access the former? (Preferably in Java, Perl, or C/C++) With this information one could map the image pixels to eyeball rods and limit the image size so it produces no more than one rod/pixel. Actual visual perception is probably more complex than this, so a corrective factor may be desired.

Originally Posted by helloworld922

In general it's not possible to determine the DPI of a screen because some screens don't have a fixed size, for example projectors. You could try ask the user to input in a display size manually.

Additionally, for a normal viewing distance many displays don't have enough pixel density to be indistinguishable to viewers. An average display may have something like 72-150 DPI, but if viewed from under 2 ft this may not enough for the average viewer to not recognize pixels. Drawing less than 1 image pixel per 1 screen pixel is likely just a waste as you can't resolve details that fine anyways, and the drawing engine will have to do some kind of averaging of image pixels.

Thank you. The scenario I have in mind is a large high-resolution monitor used for a TV and computer screen. Say it can be viewed from 2' to 12'. Pixelation at 2' might disappear at 12'. Currently my OS learns some things about my plug and play monitor when it is installed, such as what driver it needs. Perhaps it also knows (or will some day know) the size of the monitor, and Java code can tell us programmers what it is. In some cases, as you say, the size is variable and would have to be entered. In any case a configurable presentation with maximum/non-pixelation viewing of images for a specified distance from the screen would be beneficial. Until then, I guess I will continue to limit the maximize size of the images to 1 screen pixel/image pixel. Eventually, I would hope to have the information to configure better.