Collimated meaningsynonym

The second filter transmits all of the incident radiation within a 10 nm narrow passband and blocks to a level of OD6 within the remaining 990 nm. Please note that the OD level is the same as for the first filter! Only the passband is ten times more narrow. In this case the SNR calculation yields 40 dB, which seems to indicate that the filter is not as good as the first one. But this is not the case! The blocking performance is the same but the narrower band lets pass 10 times less light. This effect should be considered when specifying optical filters.

LinkedIn and 3rd parties use essential and non-essential cookies to provide, secure, analyze and improve our Services, and to show you relevant ads (including professional and job ads) on and off LinkedIn. Learn more in our Cookie Policy.

Collimatedbeam

Optical density is a quantitative measure expressed as a logarithmic ratio between the radiation falling upon a material and the radiation transmitted through a material (Source: http://en.wikipedia.org/wiki/Optical_density). In the case of filters, optical density is a quantity that is dependent on wavelength (see typical transmission and blocking curves).

Collimation synonyms

An optical density of six (or OD6) for example describes that at a given wavelength a filter transmits only one millionth of the incident radiation. Please note that optical density is always  calculated from the transmittance value on a scale from 0 to 1, not from the %-value that is listed for correspondence in the table above.

Thanks Oliver. Another use of OD is to quantify immunohistochemisry: http://mdc.custhelp.com/app/answers/detail/a_id/18800 Acquire Background Reference Image by blocking light to the camera. Acquire White Reference Image: Use a slide that does not have sample or dirt on it. Adjust the exposure so that no pixels saturate. Create the Shading Reference Image: Use the Arithmetic dialog (subtraction mode) to do Shading = White Reference – Background Reference. Acquire Specimen image. Be sure the camera does not clip or saturate. If the camera does, add neutral density filters or decrease exposure time, and re-acquire the white reference image. If you are acquiring multiple images you may want to acquire them to a single stack, rather than separate image windows. Save the image(s) to disk before experimenting with shading correction for the first time. Not mentioned in the tech note is that MetaMorph users can activate the "ODscaled" dropin from MMAdmin. This enables calculating optical density for each pixel in an image. It is crucial that the microscope be optimized to not have glare -- set the condenser numerical aperture diaphragm correctly (and consistently for the entire data set. More MetaMorph software notes can be found by googling: MetaMorph Software Technical Notes

VP @ Standard BioTools | Pro-bono Editorial Board Member | Hyperion strategic development, collaborations, and partnerships

Let us look at two bandpass filters in order to exemplify how optical density and SNR are related. The first filter transmits all of the incident radiation (T=1) within a 100 nm wide passband and blocks to a level of OD6 within the remaining 900 nm. As the name suggests SNR is the ratio of the (desired) signal to the (undesired) noise. For comparison with the filter's OD, we calculate SNR for a detector (with constant spectral sensitivity) that is illuminated through the filter with a broad-band light source (of constant spectral intensity) by calculating the integral below the red curve. SNR is often given in decibel, in this example the sensor has an SNR of 50 dB.

Collimation definition in radiography

Select Accept to consent or Reject to decline non-essential cookies for this use. You can update your choices at any time in your settings.

If you like the post you can download a PDF version from http://de.slideshare.net/OliverPust/what-is-optical-density. Feedback is always welcome!

In our daily work as filter manufacturer we often talk to customers with an electrical engineering or imaging background. In these and other fields SNR is an important quantity to describe system or detector performance. Filters on the other hand are described by transmission and rejection performance at specific wavelengths over a wider wavelength range. Transmission is often given on a scale from 0 to 1 (preferably) or on a %-scale. Rejection is often described as optical density.

With the collimator, the coincidence rate drops by a factor of 10, but now exceeds the predicted accidental rate for both orientations.

Collimated meaningin Physics

These are hooked up to a collimator that they made out of a large cardboard tube with a hole at the end, which narrows the sound waves to a smaller area.

Using a remote, you can control the strength and direction of the water stream with the precision of an angular-distance collimator on an artillery gun.

After all these years I had no idea SNR for filters was calculated that way. Seems kind of silly. I don't understand why signal intensity is somehow related to filter bandwidth. Max intensity is max intensity regardless of how broad or narrow the filter is!