Automated analysis device, and liquid surface detection method

An automated analysis device comprising:

• a rack conveyance path that transfers a sample tube rack storing a sample tube containing a sample;
• a camera provided on a side of the rack conveyance path;
• a control unit that controls the rack conveyance path and the camera,
• wherein the control unit is configured to:
• stop transfer of the sample tube rack transferred by the rack conveyance path;
• image the sample tube stored in the sample tube rack in which the transfer is stopped a plurality of times with the camera while a liquid surface of the sample continues to swing, and acquire a plurality of captured images of the sample tube while the liquid surface of the sample continues to swing;
• create a difference image of a plurality of the captured images;
• and
• set a region having a largest area among regions having a temporal change in the difference image as a position of the liquid surface of the sample.

A liquid surface detection method, comprising:

• a step of transferring a sample tube rack storing a sample tube containing a sample by a rack conveyance path;
• a step of stopping transfer of the sample tube rack transferred by the rack conveyance path;
• a step of capturing an image of the sample tube stored in the sample tube rack in which transfer is stopped a plurality of times with a camera while a liquid surface of the sample continues to swing, and acquiring a plurality of captured images of the sample tube while the liquid surface of the sample continues to swing;
• a step of creating a difference image of a plurality of the captured images;
• and
• a step of setting a region having a largest area among regions having a temporal change in the difference image as a position of the liquid surface of the sample.