schlierenvelocimetr​y

Velocimetry of constant frame rate schlieren videos using temporal cross correlation techniques

Calculates velocity field of high speed schlieren images with constant frame-rate. Analysis is based on temporal cross correlation of the fluctuating intensities of each pixel. Each pixel is correlated with all others within the frame, destination pixel is that which has the highest correlation magnitude at a single-frame offset. Video of interest must be in monochrome .avi format

[U,V]=schlierenvelocimetry(filename) returns X and Y pixel shifts as 2D arrays of the same dimension as the pixel space of the provided video. Pixel shifts are calculated using 'xcorr' for the first 1000 frames of the avi file. filename variable is a string.

[U,V]=schlierenvelocimery(filename,fps,res) returns X an Y component velocities a 2D arrays of the same dimension as the pixel space of the provided video. Velocities are converted from the pixel shits based on provided spatial and temporal resolutions. fps is measures in frames per second, spatial resolution is measured in pixels/meter

[U,V]=schlierenvelocimetry(filename,...,Fstart,Fend) returns pixel shifts in X and Y directions calculated on the avi file between the integer frame number input provided.

[U,V]=schlierenvelocimetry(filename,fps,res,Fstart,Fend) returns velocities in X and Y directions calculated on the avi file between the integer frame number input provided.

[U,V,Metadata]=schlerenvelocimetry(filename,...) Returns as above, as well as calculation and video metadata; 'filename', 'fps','res','fstart','fend'. All recorded in a cell array for ease of analysis data management.