A stabilization technique of wobbly images taken by the inclined centrifuge microscope

The authors have observed behavior of HL60 cells on endothelial cells cultured on a flat glass plate for the understanding of fundamental mechanism of the immune response of neutrophils using the inclined centrifuge microscope. The inclined centrifuge microscope applies a centrifugal force to the HL60 cells using a centrifuge and records motion of the cells on the plate as successive stroboscopic images synchronized with rotation of the rotor of the centrifuge. The successive images were wobbly by flatter of the rotor or vibration of the motor of the centrifuge. To stabilize the images, they drew cross lines on the glass plate, and adjusted the images by fixing the position of the crossing point of the lines. However, it was difficult to extract the lines accurately, because the lines were not clear on the low-contrast images. Therefore, in this research, the authors introduced the Hough transformation to extract the lines. Moreover, adherent cells on the plate were also used to compensate remaining shaking of the images. Consequently, the displacements of the images were decreased to almost within±1 pixel.