Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye. The fundamental difference between radiometry and photometry is that radiometry gives the entire optical radiation spectrum, while photometry is limited to the visible spectrum. Radiometry is distinct from quantum techniques such as photon counting.
The use of radiometers to determine the temperature of objects and gasses by measuring radiation flux is called pyrometry. Handheld pyrometer devices are often marketed as infrared thermometers.
Radiometry is important in astronomy, especially radio astronomy, and plays a significant role in Earth remote sensing. The measurement techniques categorized as radiometry in optics are called photometry in some astronomical applications, contrary to the optics usage of the term.
Spectroradiometry is the measurement of absolute radiometric quantities in narrow bands of wavelength.
Consider the infrared led TSAL7600 which has the following properties:
$$ \Phi = 35 mW $$
$$ I_e = 25 mW/sr $$
The half angle is ## 30^\circ ## and:
$$ I_r(\theta) = cos^{4.818}(\theta) $$
is a good approximation for the relative radiant intensity.
However, finding the actual radiant...
This course is teaching a lot of stuff I'm interested in, which is radiometry and sensing. I don't want to email the instructor as I am not a student at this school, so it would just seem like I'm some nosey nobody. Does anybody have any idea of what they are using, or something similar to what...
I'm currently a sophomore physics major in undergraduate. I'm doing physics because I want my undergrad education to be really general. I want a goof foundation. What I'm really interested in is radiometry, which I believe is like optics but for all wavelengths, not just visible ones. I want to...
I am interested in evaluating light intensity variation in a digital image. A colleague wants to apply an inverse square law correction to account for distance variation. I am trying to justify that in this case, the inverse square law does not apply.
Treating each pixel as a detector, it has...
What are the math concepts I have to learn for Radiometry, Photometry and Thermodynamics (all Calculus-based) as applied in building science (engineering, architecture, etc.).
I'm almost done with Multivariable Calculus and I'm aware that MV Calculus is necessary, but what specific calculus...
Learning Radiometry, Photometry, Optics, Thermodynamics, Fluid Mechanics(Statics & Dynamics) with great resources.
I'm looking for resources for understanding the topics above. I prefer video tutorials as opposed to books but I couldn't find any video resources on Photometry and Radiometry (I...
Hey folks, I'm having a little bit of trouble shaking the rust off of my radiometry.
I'm projecting a circular beam of some known divergence and power onto a surface angled relative to the center of the beam. Say holding a flashlight, with a cone of half angle θ, at my waist some height h off...
I'm stuck on this idea. How are initial radioactive isotope quantities assumed in radiometric dating? There are current abundances for all isotopes, but wouldn't these abundances have been different in the past (much higher)? I honestly can't grasp how radioactive isotopes with short half lives...
I have an Antenna that receives signal coming from a wide band of distances, 10-2000 meters from a 10mW transmitter. I am working with 868 MHz band. What is the cheapest method ( or cheapest circuit ) to amplify this signal with an Automatic Gain Control LNA so that the received signal stays...
Hi all,
I have to estimate a photocurrent produced in the following simulation setup.
Photodiode (detector) and LED (spaced 2cm) lie on one axis, oriented toward a wall (radiometer film) which is parallel to the axis and at a distance of about 10cm from the axis. How much photocurrent would an...
I want to send radio waves through distances of 0 to 10 miles, maybe even hundreds of miles eventually. What book should I buy to educate myself?
I am not really interested in doing complicated things with electricity unless it translates directly into something which will improve the...
Hi,
I have an experiment set up to get two beam interference fringes. I would like to know how I could measure the actual amplitude of the irradiance from the experiment. I have with me a power meter and a CMOS camera. How can I go about this? Thank you
I'm looking for a good text or online source that can take me through radiometry at an undergraduate level. I'm interested in drill type problems that can help me sort out the different quantities intensity, irradiance, exitance, radiance and their spectral counterparts. Also, solid angle vs...
Homework Statement
If the light source in figure 12.1 (see figure below) of the Warren Smith text is replaced
by a 100W light bulb, and the lens aperture is 20cm, what would the 1cm detector at
point E record? Assume all other values are the same, and the light bulb is not
Lambertian...
Homework Statement
According to some pages on web, differential formula for calculating radiance L is :
L = d2P / ( dA*cos(a)*dw)
L : radiance
P : power flux
A*cos(a) : projected area
w : solid angle
Please tell me why does power P has derivaties two times d2P ?
Homework...
The exercise i have is as follows:
A flat plate (measuring 0.5 meter by 0.5 meter) is placed on the highest mountain in the landscape, exactly horizontal. It is a cloudy day, such that the sky has a uniform radiance of 1000 W/ m^2 sr.
The plate has a uniform Lambertian reflectance p=0.4...
Hello,
assuming the definition of radiance in http://web.cs.wpi.edu/~emmanuel/courses/cs563/write_ups/chuckm/chuckm_BRDFs_overview.html" , I want to compute the radiance at the point P=(0,0,0) lying on the xy-plane, given a point-source of light at (0,0,1).
The angle \theta in this scenario...
Can a thermal imaging camera detect a body that is cooler than the detector? Or does the temperature of the detector put an absolute floor on the temperatures of objects that can be detected?
How do radiometers detect radiating bodies that are lower temperature than the radiometer? Or does...