Speckle Decorrelation

Calculate frame-to-frame speckle correlation and decorrelation.

Description

Speckle-frame decorrelation uses centered Pearson correlation between aligned samples.

Speckle-frame decorrelation uses centered Pearson correlation between aligned samples. The reported decorrelation is one minus correlation.^[1]

Calculate frame-to-frame speckle correlation and decorrelation.

When to use Speckle Decorrelation

Use this tool to calculate frame-to-frame speckle correlation and decorrelation.

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 Speckle Decorrelation 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 firstSpeckleFrame, secondSpeckleFrame using the field table and calculation rules, then run the tool.
Read correlationCoefficient, decorrelation. 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
firstSpeckleFrame	First speckle frame	list of number	Required
secondSpeckleFrame	Second speckle frame	list of number	Required

Enter at least two aligned finite samples per frame with variation in both. Return correlation and decorrelation; signed samples are allowed.

r=Σab/sqrt(Σa²Σb²); decorrelation=1−r

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
correlationCoefficient	Pearson correlation	number; minimum: -1; maximum: 1
decorrelation	One minus correlation	number; minimum: 0; maximum: 2

json

{
  "input": {
    "firstSpeckleFrame": [
      0,
      1
    ],
    "secondSpeckleFrame": [
      0,
      1
    ]
  },
  "output": {
    "correlationCoefficient": 1,
    "decorrelation": 0
  }
}

Limitations and assumptions

No image alignment, noise correction or flow calibration is supplied. Anticorrelation can make decorrelation exceed one.

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 Speckle Contrast: Calculate population speckle contrast from an intensity region. For a complementary task, use Doppler-Flow Perfusion Index: Calculate a first-moment laser-Doppler perfusion index from a supplied spectrum.

References

Speckle Decorrelation — tool.io

Similar or alternative tools

Speckle Contrast
Calculate population speckle contrast from an intensity region.
Doppler-Flow Perfusion Index
Calculate a first-moment laser-Doppler perfusion index from a supplied spectrum.