FLIM Mean Lifetime
Calculate a count-weighted mean fluorescence lifetime from a supplied histogram.
Description
A histogram-weighted fluorescence lifetime averages supplied time coordinates with photon counts as weights.
A histogram-weighted fluorescence lifetime averages supplied time coordinates with photon counts as weights. It is a moment estimate rather than an exponential fit.1
Calculate a count-weighted mean fluorescence lifetime from a supplied histogram.
When to use FLIM Mean Lifetime
Use this tool to calculate a count-weighted mean fluorescence lifetime from a supplied histogram.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use FLIM Mean Lifetime and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter timeBinsNanoseconds, photonCounts using the field table and calculation rules, then run the tool.
- Read meanLifetimeNanoseconds, totalPhotonCount. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| timeBinsNanoseconds | Lifetime time bins (ns) | list of number | Required |
| photonCounts | Photon counts | list of number | Required |
Enter nonempty aligned finite time bins and nonnegative counts with positive total. Return mean ns and total count. Fractional counts and signed or unsorted times are accepted.
mean=Σtime_i×count_i/Σcount_i Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| meanLifetimeNanoseconds | Count-weighted mean lifetime (ns) | number; minimum: 0 |
| totalPhotonCount | Total photon count | number; minimum: 0 |
{
"input": {
"timeBinsNanoseconds": [
1,
2,
3
],
"photonCounts": [
0,
2,
2
]
},
"output": {
"meanLifetimeNanoseconds": 2.5,
"totalPhotonCount": 4
}
}Limitations and assumptions
No background, instrument response, time-zero or bin-width correction is applied.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Transient-Absorption Lifetime Fit: Fit a positive transient-absorption trace to a single exponential using log-linear regression. For a complementary task, use Fluorescence Upconversion: Gaussian-deconvolve gate width from a fluorescence-upconversion cross-correlation.
References
-
FLIM Mean Lifetime — tool.io
Similar or alternative tools
- Transient-Absorption Lifetime Fit
Fit a positive transient-absorption trace to a single exponential using log-linear regression.
- Fluorescence Upconversion
Gaussian-deconvolve gate width from a fluorescence-upconversion cross-correlation.