Rapid measurement of morphological features of Spirulina microalgae filaments using microscopy and image processing algorithms

Rapid measurement of morphological features of Spirulina microalgae filaments was achieved using image processing algorithms based on microscopy images of Spirulina filaments. Determination of the mid-line and vertices of Spirulina enable a condensed description of Spirulina filament. The mid-line of filament was represented by the skeleton of filament with the elimination of the side branches on the skeleton. The vertices of filament were determined based on discrete contour evolution algorithm. On the basis of this condensed description, morphological features can be rapidly and accurately measured, which include length, diameter of helix, width of filament and degree of spiralisation. The errors between manually obtained and automatic calculated values were 4.8% for length measurement, 4.7% for degree of spiralisation measurement, 5.6% for diameter of the helix measurement, and 6.2% for width of filament measurement, respectively. The overall results show that the proposed algorithms can rapidly and accurately measure the morphological features of Spirulina filaments.