Detection method, detection device, and lidar

A detection device comprising:

• an encoder disc configured to be mounted at and rotate together with a rotation object, wherein:
• the encoder disc includes N detection target portions arranged along a circumferential direction of the encoder disc, N being an integer greater than 2;
• the N detection target portions include N−K first detection target portions and K second detection target portions, K being an integer greater than or equal to 1 and smaller than N;
• along the circumferential direction of the encoder disc, a width of one of the N−K first detection target portions is different from a width of one of the K second detection target portions;
• a detection member configured to detect the first detection target portions and the second detection target portions;
• and
• a processor configured to in rotation of the encoder disc:
• obtain first count data when one detection target portion of the N detection target portions is detected and second count data between two neighboring detection target portions of the N detection target portions;
• and
• determine a rotation parameter of the rotation object according to the first count data and the second count data, the rotation parameter including a rotation angle and a rotation speed.

A LIDAR comprising:

• an optical element;
• a driver for driving the optical element to rotate;
• and
• a detection device configured to detect a rotation parameter of the optical element and including:
• an encoder disc configured to be mounted at and rotate together with the optical element, wherein:
• the encoder disc includes N detection target portions arranged along a circumferential direction of the encoder disc, N being an integer greater than 2;
• the N detection target portions includes N−K first detection target portions and K second detection target portions, K being an integer greater than or equal to 1 and smaller than N;
• along the circumferential direction of the encoder disc, a width of one of the N−K first detection target portions is different from a width of one of the K second detection target portions;
• a detection member configured to detect the first detection target portions and the second detection target portions;
• and
• a processor configured to in rotation of the encoder disc:
• obtain first count data when one detection target portion of the N detection target portions is detected and second count data between two neighboring detection target portions of the N detection target portions;
• and
• determine the rotation parameter of the optical element according to the first count data and the second count data, the rotation parameter including a rotation angle and a rotation speed.