Help with a webcam, please

[RogerI...@aol.com]

I'm hoping someone might have experience with webcams and can interpret some specs for me.

 

I'm looking at the specifications for a webcam that I've got connected to my computer and being controlled by a program I wrote. The specs say:

 

Optical Resolution (True) 1280 x 960 1.2MP
Image Capture (4:3 SD) 320x240, 640x480 1.2 MP, 3.0 MP
Image Capture (16:9 W) 360p, 480p, 720p
Video Capture (4:3 SD) 320x240, 640x480, 800x600
Video Capture (16:9 W) 360p, 480p, 720p,

 

But no matter what I do I always get 640X480 images when I capture an image from it.

 

How can it have 1280 x 960 "True" Optical resolution but Image Capture at only 320x240 and 640x480?

 

How can I get the TRUE 1280 x 960 images from it?

 

I assume that ...

 

Image Capture (4:3 SD) 320x240, 640x480

 

is indicating an aspect ratio of 4 : 3, with images being 320x240 or 640x480 (although I still can't figure how to get anything other than 640X480).

 

But then with

 

Image Capture (16:9 W) 360p, 480p, 720p

 

I'm guessing it's a different aspect ratio (16:9 W), but what do the 360p, 480p, 720p values mean?

 

- Roger Garrett

[David Cornejo]

The non-"True" resolutions are just scaled up or down to the specified size.

Since the true resolution is 4:3, the 16:9 screen sizes are likely vertically cropped from the 4:3 picture and then scaled.  As for how to capture a given size, I think we need to know what make & model the web cam is.

Also, it's probably a bad idea to cross post - the honolulu-makers list has the reply-to set to the group so the maui-makers will never see the honolulu side.  If maui-makers is configured similarly, then we can't see them either.

dave c

[Jerry Isdale]

On Jul 10, 2012, at 12:43 PM, David Cornejo wrote:

Also, it's probably a bad idea to cross post - the honolulu-makers list has the reply-to set to the group so the maui-makers will never see the honolulu side.  If maui-makers is configured similarly, then we can't see them either.

and it really confuses the heck out of those of us on both lists.

Wheels up in 3hrs for HOPE#9 !!

Jerry Isdale

isd...@gmail.com

[Binary Buddha]

Jerry, I hope you feel my envy since you're going to HOPE.


It sounds like you're using one of the Microsoft LifeCam webcams with
the "truecolor" thing. If it is, then "true" is refering to the color
of picture; with the required microsoft driver.

360p, 480p, and 720p are references to the image quality; like 1080i
for HD video. The "i" and "p" are essentially the same. So, those
images are taken at "partial" HD quality. It's a different "way" of
gauging quality from the "old analog" SD to the new digital signal
means.

This is how MS defines HD;
http://www.microsoft.com/windows/windowsmedia/howto/articles/understandinghdformats.aspx.

"SD" stands for Standard Definition and is pretty much just that; it's
not HD (High Definition). The "W" stands for Wide; which is because
it's 16:9. SD is more "legacy" and is always going to be 4:3.

360p, 480p, and 780p are the amount of "horizontal scan"/"vertical
resolution" lines. 1080 is "Full HD". The "p" and "i" indicates the
type of scan; progressive or interlaced. For the common user, it
doesn't matter. It's a thing of clarity over speed.

All videos are essentially a bunch of pictures displayed one after
another called frames. So, when you think about resolution it's
actually just the resolution of a single frame in the video. You can
also isolate a single frame in a video and export/convert it to a
picture/image.

640x480 is the probably the nominal resolution for your SD sensor
setting. That's the "natural" setting of the sensor sensitivity with
having to play with the driver. Which is why they normally have third
party software to handle the camera; and the fondleing of it's driver.

--
=====
The.Bina...@gmail.com

Thebinarybuddha.com


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