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Displaying photos on display with non-square pixels

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Anonymous
September 24, 2005 4:01:43 PM

Archived from groups: rec.photo.digital (More info?)

I know this has come up before here and I've read the posts but haven't
found a solution to my problem.

I want to display my pictures on a 1280x768 pixel screen with phyical
dimensions of of 16:9. The pixels are not square. This means if I make
a perfect square, say 100 x 100 pixels, it appears to be 6.67% wider
than it is taller on my screen. So, in my case, the TV really does add
20 pounds.

I found a post about HardView picture viewer that claims to be able to
stretch images for display automatically and therefore get arround the
problem. Unfortunately, I can't download it, I can only presume that
MrMills is no longer developign the viewer. Is there a viewer that can
take care of this for me.

I'd prefer not to have to batch resize my photos to compensate as they
would then all have the wrong aspect ratio for displaying on anything
else.

Any help would be greatly appreciated.

Cheer,
Phill
September 24, 2005 8:49:53 PM

Archived from groups: rec.photo.digital (More info?)

Phill wrote:
> I know this has come up before here and I've read the posts but haven't
> found a solution to my problem.
>
> I want to display my pictures on a 1280x768 pixel screen with phyical
> dimensions of of 16:9. The pixels are not square. This means if I make
> a perfect square, say 100 x 100 pixels, it appears to be 6.67% wider
> than it is taller on my screen. So, in my case, the TV really does add
> 20 pounds.
>
> I found a post about HardView picture viewer that claims to be able to
> stretch images for display automatically and therefore get arround the
> problem. Unfortunately, I can't download it, I can only presume that
> MrMills is no longer developign the viewer. Is there a viewer that can
> take care of this for me.
>
> I'd prefer not to have to batch resize my photos to compensate as they
> would then all have the wrong aspect ratio for displaying on anything
> else.
>
> Any help would be greatly appreciated.
>
> Cheer,
> Phill
>
An image 1280 pixels wide would have to be 720 pixels high to have a 16:9 aspect ratio.
If you force the image to have an aspect ratio of 16:9, there has to be some distortion.
If you want the picture to fill the screen undistorted, you need to crop the picture to
the 16:9 aspect ratio. B.t.w., there is no such thing as a non-square pixel.
Anonymous
September 25, 2005 10:17:09 AM

Archived from groups: rec.photo.digital (More info?)

David J Taylor wrote:
> Marvin wrote:
> []
> > B.t.w., there is no such thing as a non-square pixel.
>
> Actually, a pixel can be any size of shape you want. It is only by choice
> that most pixels are nominally rectangular, of equal horizontal and
> vertical size, and presented on a rectilinear grid. Some Fuji cameras
> have a grid at 45 degrees to the horizon. HDTV uses non-square pixels.

And at least according to dpreview's review of Canon EOS 5D, Nikon D1X
used a CCD with rectangular pixels half as wide as they were high.

Jan Böhme
Related resources
Anonymous
September 25, 2005 10:30:49 AM

Archived from groups: rec.photo.digital (More info?)

I was afraid of starting this old debate about pixel shapes. I have a
Pioneer PDP-503CMX. Honestly, it has rectangular pixels, they are
0.858x0.808 mm in shape.

http://www.panwebi.com/plasma/default.asp?pc=pdp503cmx

^Scroll down to pixel pitch

It's native resolution is not in the same ratio as it's physical
dimensions so if you display a perfect circle it looks oval on the
monitor . There are a few plasma TVs on the market which are like this
and if you connect them to a PC and give them something to display at
their native resolution it looks great but it's distorted. If I'd have
done the maths before buying it, I'd have bought the Panasonic.

For watching movies, I use zoomplayer, which has a setting to adjust
the aspect ratio of the image to compensate for non-square pixels. I
just need an image viewer with a similar function.

I don't fancy downloading and installing every freeware and shareware
viewer I can find until I find one that does it. Since you guys have
probably got or have used a rang of viewers, could you just check to
see if your viewer can do this and if so I'd love to hear from you.

Cheers,
Phill
Anonymous
September 25, 2005 12:20:27 PM

Archived from groups: rec.photo.digital (More info?)

Marvin wrote:
[]
> B.t.w., there is no such thing as a non-square pixel.

Actually, a pixel can be any size of shape you want. It is only by choice
that most pixels are nominally rectangular, of equal horizontal and
vertical size, and presented on a rectilinear grid. Some Fuji cameras
have a grid at 45 degrees to the horizon. HDTV uses non-square pixels.

David
Anonymous
September 25, 2005 5:30:21 PM

Archived from groups: rec.photo.digital (More info?)

David J Taylor wrote:

>> B.t.w., there is no such thing as a non-square pixel.

> Actually, a pixel can be any size of shape you want. It is only by
> choice that most pixels are nominally rectangular, of equal
> horizontal and vertical size, and presented on a rectilinear grid.
> Some Fuji cameras have a grid at 45 degrees to the horizon. HDTV
> uses non-square pixels.

SDTV, too. (While there are no "pixels" in analog broadcasts, DVB, DVD,
SVCD, VCD, DV, Digital Betacam, and digital production facilities -
everything that is connected together using SDI - all use sampling
matrices with non-square pixel aspect ratios.)

--
znark
September 25, 2005 6:20:52 PM

Archived from groups: rec.photo.digital (More info?)

David J Taylor wrote:
> Marvin wrote:
> []
>
>>B.t.w., there is no such thing as a non-square pixel.
>
>
> Actually, a pixel can be any size of shape you want. It is only by choice
> that most pixels are nominally rectangular, of equal horizontal and
> vertical size, and presented on a rectilinear grid. Some Fuji cameras
> have a grid at 45 degrees to the horizon. HDTV uses non-square pixels.
>
> David
>
>
And somehow those pixels must be transformed to work with, for example, a monitor with
square pixels, or there will be distortion.
Anonymous
September 26, 2005 4:02:58 AM

Archived from groups: rec.photo.digital (More info?)

Marvin <physchem@cloud9.net> wrote:
>David J Taylor wrote:
>> Marvin wrote:

>>>B.t.w., there is no such thing as a non-square pixel.
>>
>> Actually, a pixel can be any size of shape you want. It is only by choice
>> that most pixels are nominally rectangular, of equal horizontal and
>> vertical size, and presented on a rectilinear grid. Some Fuji cameras
>> have a grid at 45 degrees to the horizon. HDTV uses non-square pixels.
>>
>And somehow those pixels must be transformed to work with, for example, a monitor with
>square pixels, or there will be distortion.

Of course, but programs like Photoshop allow for non-square pixel
aspect ratios.

--
Ray Fischer
rfischer@sonic.net
Anonymous
September 26, 2005 10:08:20 AM

Archived from groups: rec.photo.digital (More info?)

That's right, there is embeded information (EXIF, I believe it's
called), that allows an image viewer to account for the pixels in the
image not being square and even to have a default size to print out at.
Since most computer minitors have sqare pixels and the operating system
assumes you have square pixels on you display, that's usually
sufficient. This is a different problem to the one I have.

My problem is that the display device doesn't have square pixels. It's
not actually a problem with the imges, which is why I don't like the
idea of distorting the images to compensate or editing the EXIF
information to fool the image viewer into reshaping the image.

Perhaps I haven't made it clear that I'm trying to display the images
on a large screen, rather than preparing them for printing.
Anonymous
September 27, 2005 10:14:49 AM

Archived from groups: rec.photo.digital (More info?)

Thanks Dave, I'll drop the Irfan an email and see what he says.
Anonymous
September 27, 2005 10:24:49 AM

Archived from groups: rec.photo.digital (More info?)

"Phill" <phill_jones5@yahoo.com> writes:
>I know this has come up before here and I've read the posts but haven't
>found a solution to my problem.

>I want to display my pictures on a 1280x768 pixel screen with phyical
>dimensions of of 16:9. The pixels are not square. This means if I make
>a perfect square, say 100 x 100 pixels, it appears to be 6.67% wider
>than it is taller on my screen. So, in my case, the TV really does add
>20 pounds.

Unfortunately, almost all displays in the computer/digital photography
realm use square pixels, so most tools for viewing images support only
that. In the video world, where pixels are almost always non-square,
software that resamples as necessary is routine.

>I'd prefer not to have to batch resize my photos to compensate as they
>would then all have the wrong aspect ratio for displaying on anything
>else.

One suggestion: you might ask the author of Irfanview if he has
considered supporting non-square pixels. Irfanview already contains
quite high-quality resampling filters, and it can resample at different
ratios for horizontal and vertical so you can explicitly resize images
for correct display on your screen. Further, Irfanview can
automatically resize images to fit the screen as it's going through a
directory full of images.

Given all this supporting code already in place, I suspect it would
take only a few extra lines of code to support automatically resizing
for non-square pixels. Most of the work adding support for this would
probably be in adding a pixel aspect ratio option to the Properties
menu. From what others have said, the author of Irfanview has a good
record of incorporating user suggestions in new versions of the software.

Dave
!