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rodgrac774 : A 16 bit, is this data buss width, resolution or what? Give more data Type of focusing ( mechanical,etc. )

Temperature dynamic range of the infrared camera is 16 bits(which means 256 colors).

rodgrac774: I see, the display color range change in temperature per degree of variation within the selected range of coverage. That would be determined by the display ( 256 colors or whatever you choose ) used and the range( hotest to coldest expected of that scale ) and temperature scale ( Centigrade,Fahenheit,Rankine, or absolute) of choice. You would need also to select the color mix which the average human eye can respond to, with a desirable distinction between graduations chosen. I'm sure I have not covered one tenth of what is involved, but May be I have given you something to get started on.You will also need to understand the limits of the detector chosen and all the necessary support mechanism needed for that detector. As you may know this will require a lot of research.

rodgrac774

Temperature dynamic range of the infrared camera is 16 bits(which means 256 colors).

Actually 16 bits which is 2^16 gives you 65536 different levels, not just 256. In regards to your question, at different focal lengths you would see a different image scale, ie. at the shorter focal length you would see a wider field of view, while at the longer focal length you'd see a more magnified image, of a smaller region of the field of view. This is true whether you are looking in the infrared or in the visible part of the spectrum. There is no difference.

If you want to examine different parts of the spectrum itself, ie. different wavelengths within the infrared region you would have to use a different filter. A spectroscope would also give you information about different regions of the IR spectrum.

Can you describe what your interests are with infrared imaging?

Thanks for the clear explanation.

Actually, I'm a payload subsystem member of a student satellite team.Infrared imaging is our main payload. I'm are trying to find a good application of the image data we receive.It is a nano-satellite with a weight of roughly 3 kgs.The altitude of the orbit is roughly 800 Kms. Ocean imaging using an IR camera is what I was thinking of. It would be helpful if I would get some more applications with an IR imaging camera. I doubt that when we focus the camera on the ocean surface by increasing the focal length as mentioned, the clouds will interfere in the image. Can this happen? 

rodgrac774

Ocean imaging using an IR camera is what I was thinking of. It would be helpful if I would get some more applications with an IR imaging camera. I doubt that when we focus the camera on the ocean surface by increasing the focal length as mentioned, the clouds will interfere in the image. Can this happen? 

Possibly. But IR can penetrate through clouds, as is evidenced by the fact that planet Venus can be imaged in the IR even on a cloudy day. However I suspect there would be more scatter, and some attenuation.

Thermal imaging of cloud patterns themselves would be useful, such as observing tropical storms which helps to predict the direction they are moving in.

With IR one can also "see" in the dark, when there is no light source other than thermal emission. That is how night vision cameras operate. There might be an application to study energy loss in technologically advanced societies, by measuring "waste heat". There could also be a security or "spying" application, if it's possible to see sources of heat at high resolution, and thereby look at activities taking place in remote areas. Military facilities, laboratories, nuclear facilities. But if the optical system is small then it's challenging to get enough resolution. You can't just keep increasing focal length forever, eventually the images will be blurry. Magnification would increase but the modulation transfer function is limited by other factors, such as the diameter of the lens.

If IR can pass through clouds then how can we monitor the clouds? Does that have something to do with the focus of the camera?

I even wonder  how would one decide the direction of the tropical storms by just receiving the temperature through the image?

It would be helpful if you would clarify this doubt:)

rodgrac774 : If you do comparison in different wave lengths( through filtering ) and use that information along with the visible light spectrum, you can determine a great deal of information. A great deal depends ont he data processing done by the comparator and the selected wave lengths, from which your data depends. Build your system with the inclusion of concepts of known special effects which can occur due to the objects or points of interest, which you wish to observe, these can help to designate shortcutts in processing.

rodgrac774

If IR can pass through clouds then how can we monitor the clouds? Does that have something to do with the focus of the camera?

I even wonder  how would one decide the direction of the tropical storms by just receiving the temperature through the image?

It would be helpful if you would clarify this doubt:)

I don't know for sure, because I'm not a meteorologist. I have done some IR imaging of planets and read literature on the value of collecting astronomical data in the IR region. I have studied earth weather maps a bit and have a general idea of what scientists are trying to understand.

For one thing, clouds are not totally transparent to IR, and it most likely depends on the specific wavelength you are measuring. As I stated there would likely be attenuation, that means some remnant of the visible image can still be seen.

Take a look at these images from NASA satellite-

http://weather.msfc.nasa.gov/GOES/

You will be able to compare the visible and IR images, which should give you some idea of what kind of data is potentially available from your satellite.

Predicting tropical storm intensity/ direction is already a well established technique, I believe they measure sea water temperatures to predict whether the hurricane will grow or fade in intensity. Some scientific literature exists, eg. http://www.ssec.wisc.edu/media/newsletter/fall2011/trackinghurricanes.pdf found via google search.

Primordial

rodgrac774 : If you do comparison in different wave lengths( through filtering ) and use that information along with the visible light spectrum, you can determine a great deal of information.

Yes that makes a lot of sense,Primordial. Compare the known to the unknown.

TeleNoob : He has a challenge, with a 3Kg payload. He will need to reach for the latest technology in almost all parts of this project. I know we have made some big steps to keep down wight, but I think he may need a little more. I hope you can help him, I know I can't.

Hi,

I am pleased to say that your information helped a lot in fixing the payload.

We have finally decided on four applications using the IR camera:

1.Cloud monitoring

2.Ocean surface imaging

3.Observe urban heat islands.

4.Snow cover and polar caps monitoring(depends on orbit inclination)

We had decided on the QUARK model IR camera manufactured by FLIR company.Most of the features look good.But, the range of detection is very less.Actually, the camera would be clicking the image from roughly 800 Kms. Here is the link leading to the datasheet of this camera:

http://www.flir.com/cvs/cores/view/?id=51266&collectionid=549&col=51276

Can you kindly go briefly through the features and conclude whether it could be implemented for the above applications in the satellite.(especially the range of detection looks bad).

It would be great if you would mention some companies better than this in IR space imaging.Because this company doesn't manufacture space graded cameras.

Awaiting for your reply,

Thank you.

I cannot tell you if it's suitable or not, I don't have enough criteria or the expertise to determine that. My background is in particle accelerators. But I can give you some observations:

- The camera has an operating temperature range down to -50 Deg. C. Will this be a problem?

- By "Range of Detection" I think you're talking about the resolution, ie. ability to resolve to a certain level of detail. This is the image scale. If the satellite is at 800 km, then a quick calculation using trigonometry shows that the Earth at 13000 km diameter will occupy about 166 degrees in the field of view. The datasheet  for the camera shows the field of view in degrees for the two models, with different combinations of lenses. A calculation gives an image scale of about 4-5 km/pixel, regardless of camera/ lens combination.

This is done simply by dividing the field of view of camera by the FOV for the whole Earth. In each case for the cameras about 1/4 to 1/5. Multiply this by the diameter of Earth, 13,000. This gives you the field of view in km. Now divide by the number of pixels, and you get the resolution of one pixel.

Note the difference in resolution between these two models with their lenses provided is minimal. Although the 640 camera has more pixels, it also has a larger sensor size so there is not much gained in terms of resolution (because the larger sensor effectively lowers the field of view) so the image scale in terms of km/ pixel is about the same.

If this is correct (and again I am not an expert, your team should review/ calculate all of these factors) it means you cannot resolve smaller than 5km, or by nyquist theorem actually 10 km. This could have implications for some of the project objectives.

Hi,

Actually we had calculated all the factors while selecting the cameras. Now, the problem is with the range of detection which is not the resolution, but the maximum distance between the camera and the focused object beyond which the camera can't detect(If the range of detection of a camera is 1km, it cannot detect  the object or it doesn't detect the characteristics related to the object like temperature beyond 1Km). As you had mentioned that you had done IR imaging of planets, by your experience can you please tell whether range of detection is the one mentioned above. As the satellite will be above 800Kms, range of detection will matter a lot. The FLIR quark 640 camera datasheet mentions that the range of detection of the camera with 19mm lens is only 640m if the object is man. So, can you please give your opinion on this?