Thank you for being a valued part of the CNET community. As of December 1, 2020, the forums are in read-only format. In early 2021, CNET Forums will no longer be available. We are grateful for the participation and advice you have provided to one another over the years.

Thanks,

CNET Support

General discussion

What is interpolated?

Oct 20, 2004 12:54AM PDT

i recently bought a camera. it stated in its specifications that it has 4 megapixel interpolated. may i ask what does that means?

thanks.

Discussion is locked

- Collapse -
Re: What is interpolated?
Oct 20, 2004 1:27AM PDT

The dictionary says:

To introduce something extraneous between other things.
To alter by the insertion of new matter.

...

Suppose you have a photo that is 800x600 pixels.
You decide to make it bigger (1024x76Cool.
Computer software will let you do that.
Just where did the software get those extra pixels?
The software will apply an algorithm (usually Bicubic) that generates extra pixels based upon adjacent pixels.

A photo that was taken at 1024x768 will be more accurate than a photo that was taken at 800x600 and then interpolated to 1024x768.

If your camera documentation says interpolated to 4 megapixel, it is likely a 2 megapixel camera which is using Bicubic to produce the extra 2 megapixels.

e.g. 1600x1200 interpolated to 2272x1704.


.....

- Collapse -
Re: What is interpolated?
Oct 23, 2004 3:25PM PDT

Basicly it's a way for a camera manufacturer to claim that their camera takes pictures with X number of pixels, when it can't actually "see" that number. Just because the picture has more pixels, doesn't make it better compared to a camera that can actually see that number of pixels.

- Collapse -
How can you make shure what the camera can see?
Apr 12, 2005 7:29PM PDT

What is the terminology that I should look for for seen megapixles? thanks joe

- Collapse -
Interpolation
Apr 13, 2005 12:38AM PDT

Almost all of these deceptively advertised cameras are found on eBay or any auction site.

They usually include the specifications, which may or may not say "interpolated" in the Image Resolution part of the specifications.

Almost all seem to take pleasure in stating that the Image Sensor is the OmniVision 3610 1/2 inch CMOS.

This is a dead giveaway, as that sensor is 3 megapixels and it is the actual maximum sensors in the camera.

I just looked at an advertisement for a 10meg camera and it has that OmniVision sensor. So it is a 3 megapixel camera.

Another clue is......no one builds a small camera sensor above 7 megapixels.

There are 8 megapixel sensors in larger expensive cameras.....you will not find one in a $500 (or under) camera. All of these 8 megapixel sensors are made by Sony.

If anyone falsely advertises a camera, you should not buy from them.


...
..
.

- Collapse -
Interpolation is guessing what a value is when you don't
Oct 20, 2004 10:35AM PDT

know. The guess is based on knowing other values on each side of the desired point. In this case, the camera doesn't actually 'see' four megapixels. It's guessing what the missing pixels are to come up with a picture. It usually doesn't work very well.

- Collapse -
Re: What is interpolated?
Oct 21, 2004 3:41PM PDT

I could be mistaken here, but the last time I saw "interpolated" on a digicam, it was a 6-Mpixel model. It meant that the actual native resolution was lower (in the camera I saw, about 3 Mpixels) than the "interpolated" number. The extra pixels were derived with a mathematical formula, basically spreading out the pixels and calculating what's supposed to be in-between. I don't know about you, but that sounds to me like a cheat to boost the pixel count... I can't imagine such a camera would be the equal of a non-interpolated version. When you see "interpolated," think "interpreting what's inbetween instead of actually capturing it in the first place..."

- Collapse -
Re: What is interpolated?
Oct 22, 2004 3:44AM PDT

Actually, the word "interpolated" is incorrect with regard to increasing the actual Megapixels to a greater Megapixel count. "Extrapolate" is the corrrect word, meaning to go beyond the known data. Interpolating makes use of two data points that are greater and lower then the desired answer.

- Collapse -
I don't think so. You are suggesting that they are
Oct 22, 2004 7:40AM PDT

going from, for sake of illustration, a 1" by 1" sensor to values for a 2" by 2" sensor. They would be doing that based on projections from within the 1" by 1" sensor. I doubt that they are doing that. What they are doing is doubling the number of points observed by the 1" x 1" sensor. That is, they are estimating a value between two real points. That is interpolation.

- Collapse -
Re: I don't think so. You are suggesting that they are
Oct 23, 2004 1:51AM PDT

That is, they are estimating a value between two real points. That is interpolation. I find interpolation on the minolta 323 goes from 3 m to 6 but I find it changes the ISO and I get grainer pictures. I cannot use optical zoom while using the interpolation. In the end I get the best picture with optical zoom. I thought this might be good when I don't quite have enough optical zoom fro some wild life.

Now the same question with a fugi 7000 has a totaly different answer.

- Collapse -
Re: What is interpolated?
Oct 23, 2004 2:34PM PDT

Photo enlargement of digital pictures is done through a process called interpolation: the computation of pixel color values between the pixels that already exist. A pixel is the smallest element of an image or picture on a computer screen - usually it is a single-colored dot. You can read more about photo enlargement and interpolation here: http://photoenlargement.imagener.com

- Collapse -
Re: What is interpolated?
Oct 26, 2004 10:31AM PDT

i asked the same qustion...got the answer looking it up on the Web..type in (interpolated ?) and the definition will be there...in short its a 2meg..with a electronic magnification ..results is distorted image at higher resolutions its a 2 meg camera by any means and nothing else...call it a slight of hand...

- Collapse -
Is there a link to a side by side graphic sample comparison
Feb 8, 2005 4:19PM PST

Is there a link to a side by side graphic sample comparison between say, 3.2 non-int. and 6.1 int.?

- Collapse -
You can make your own
Feb 8, 2005 11:20PM PST

If you have software that can resize photos.

If you don't you can download Irfanview for free.

http://www.irfanview.com

Use the software to open a 3 meg photo (2048 x 1536).

With the software do a resize/resample to 6 meg size (2816 x 2112).

The results will actually be pretty good.
But when you look at both at 100 percent expansion, you will see the original is better.

...
..
.

- Collapse -
Thanks
Feb 8, 2005 11:59PM PST

Good idea!

- Collapse -
This site shows just that and more
Feb 9, 2005 12:46AM PST