Brett's Pick this week isPIVLab, byWilliam Thielicke.

Contents

A Particle Velocimetry Suite of Tools!

Many years and as a postdoc at the National Institutes of Health, I was working on a problem with a colleague characterizing the (spiral) shape of the cochlea. Armed with my knowledge of the Image Processing Toolbox, I pretty quickly calculatededgesIn an image of the structure, and then calledbwtraceboundaryTo direct a path along the edge.

My colleague's eyes glazed over as she informed me that I had just recreated a significant part of its ehrs dissertation - one that took its ehrs. A very long time to implement.

The FormyThe dissertation, I implemented the from scratch a particle image velocimetry (PIV) -based approach to measuring retinal blood flow by tracking fluorescent particles in the ocular circulation. "Coming up with the PIV algorithm constituted a significant portion of my effort. Today, I feel a bit like my colleague did, & the at William 's PIVLab!With a very nicely implemented, MATLAB - built app, William facilitated nearly everything I men to do to track those particles. But his code is light - years nicer and faster - than mine was. (This goes back 25 years!)

With PIVLab, can on simple load the images in my video sequence, set the parameters, and start tracking:

In the way, I haven 't (yet!)Had been able to recreate the with PIVLab the results from my dissertation. But one thing is sure - this order have had a very useful starting point, and it he have saved me countless weekes of effort!(The flexibility and customizability of MATLAB code - o that on The File Exchange - is truly top service it so useful.)

A video tutorial!

I love that William took the trouble of recording a twelve - minute video to get you started using his tool.

The tool is richly featured, and includes many marketers visualizations and processing functions provides for & The at particle flows:

One the suggestion

I had to convert my video files to sequences of images to get them to work in PIVLab. It 's not about to make your app support 金宝appvideo files - using VideoReader, for instance!But creating an image sequence from a video is a minor task, too:

Vid = VideoReader (' C: \ Sample Data \ ONH_PIV_10. Avi ");Frame = readFrame (vid);Imgh = imshow (frame);The index = 1;While hasFrame (vid) imwrite (frame, [' C: \ Sample Data \ ONHFramewise \ ', 'Frame_, sprintf (' %' 03 I 'index),' tif ']);The index = index + 1;Set (imgh, 'the cdata, frame) frame = readFrame (vid);Drawnow end

It 's worth noting that William is among the top 100 most - downloaded the authors on the File Exchange - largely on the strength of PIVLab. It is the current (the last update was January 2019);It has 80 user reviews hovering, on average, around 5/5 of the stars;And has had downloaded thousands of times. This file is long overdue for a Pick - of - the - Week recognition!William, I appreciate the effort it took to create this fine tool. And I greatly appreciate your sharing it with the MATLAB community!

As always, I welcome yourThoughts and comments.

Get the MATLAB code

Published with MATLAB ® R2018b