IR by Digital Camera

[Abeer_engjbr]

Hi,

I want to know why we can see IR through digital camera? I know that we can't see IR because it's not in the visible range.

Thank you.

 

[3v0]

The IR the camera can see is in the visual range of the image sensor. The image sensor is read by a micro computer/controller and stored in the camera memory.

As I understand it, you would see even more IR if the cameras did not use a IR filter between the lense and the sensor.

HTH

 

[Abeer_engjbr]

Do you mean that the IR invisible range is considered visible to the camera? Is that what you ment by visual range of the image sensor? and what do you mean by "stored in the camera memory"?

 

[blueroomelectronics]

It's an optical IR filter, some people even pull them out of their cameras to take IR photos.
**broken link removed**

 

[3v0]

Do you mean that the IR invisible range is considered visible to the camera? Is that what you ment by visual range of the image sensor?

Somewhat yes and Yes.

and what do you mean by "stored in the camera memory"?

You can think of a camera sensor as a special type of memory chip. Light striking the chip changes the value of each cell. A computer in the camera reads these cells to get the picture. The data/picture is then stored in the camera flash memory. This is a very simplistic version. If you want more details read Digital camera

 

[crutschow]

IR covers a considerable range of wavelengths. The typical silicon sensor, such as in a camera can see to about 0.9-1um wavelength. (0.7um is about the limit of the human eye). IR sensors designed for sensitive night vision typically operate in the long wavelenght 5um to 10um region (objects at room temperature radiate most strongly in the 10um region). To operate at these long wavelength regions with best sensitivity requires cooled detectors, but some of the new thermal type detectors have remarkeably good sensitivity operating uncooled at room temperature.

A natural IR detector example is a rattlesnake, which has two IR thermal sensors, one in each of the pits between its eyes and the nostril. Since a rattlesnake is cold-blooded the sensors are naturally somewhat cool as compared to any warm-blooded prey which improves sensitivity. Probably don't work so well on a hot day.