Flow cell alignment methods and systems

摘要

Imagers and alignment methods for use by imagers imaging deoxyribonucleic acid (DNA) fragments on a flow cell are disclosed. The imagers capture intensity values at DNA fragment bead locations in tiles with each tile having a reference location in the flow cell. Flow cells may be aligned by obtaining a dark field image of each tile during a first imaging session, identifying dark field constellations of bead locations within two separate tiles during the first imaging session, identifying corresponding constellations during a second imaging session, altering the reference location of at least one tile during the second imaging session to correct for a linear offset in the corresponding constellations, and applying at least one correction factor for reading out intensity values from the imager for the bead locations in the flow cell to correct for an angular offset determined from offsets in the corresponding constellations.

主权项

1. An alignment method for use by an imager imaging deoxyribonucleic acid (DNA) fragments on a flow cell, the imager capturing intensity values at DNA fragment bead locations in tiles with each tile having a reference location in the flow cell, the method comprising:
during a first imaging session:
positioning the flow cell on an xy stage with the flow cell facing an imaging axis, the xy stage being movable along an x-axis and a y-axis, the x-axis being perpendicular to the y-axis, and the imaging axis being perpendicular to the x-axis and the y-axis,illuminating the flow cell from the side of the flow cell with a first light to cause the first light to strike the DNA fragment beads from above the xy stage and at an angle relative to the imaging axis, and reflect off the DNA fragment bead locations,operating the xy stage to reposition the flow cell to obtain a respective first image of each of a first tile and a second tile during a first imaging session, the respective first image comprising reflections of the first light, andidentifying a first reference constellation of bead locations within the first tile and a second reference constellation of bead locations within the second tile during the first imaging session; and during a second imaging session:
identifying a first pattern of light corresponding to the first reference constellation in the first tile, and a second pattern of light corresponding to the second reference constellation in the second tile,determining a first offset between the first reference constellation during the first imaging session and the first pattern of light during the second imaging session,determining a second offset between the second reference constellation during the first imaging session and the second pattern of light during the second imaging session,moving the xy stage to alter the reference location of at least one tile during the second imaging session to correct for the first offset, andapplying at least one correction factor for reading out intensity values from the imager for the bead locations in the flow cell to correct for an angular offset determined from the first offset and the second offset.