Vision sensor, event signal processing method of the vision sensor, and imaging processing device including the vision sensor
A vision sensor is provided. The vision sensor includes: a pixel array including a plurality of pixels, each of the plurality of pixels being configured to generate an event signal based on an event in which intensity of incident light changes; and an event detection circuit including a state register including a first flip-flop and a second flip-flop. The event detection circuit is configured to: based on the event signal, store first data in the first flip-flop, the first data indicating whether flicker has occurred in each of the plurality of pixels, store second data in the second flip-flop, the second data indicating whether the event has occurred in each of the plurality of pixels, and based on a comparison of the first data and the second data, identify and delete a portion of the second data in which the flicker has occurred.
1 . A vision sensor comprising:
a pixel array comprising a plurality of pixels, each of the plurality of pixels being configured to generate an event signal based on an event in which intensity of incident light changes; and
an event detection circuit comprising a state register comprising a first flip-flop and a second flip-flop,
wherein the event detection circuit is configured to:
based on the event signal, store first data in the first flip-flop, the first data indicating whether flicker has occurred in each of the plurality of pixels,
store second data in the second flip-flop, the second data indicating whether the event has occurred in each of the plurality of pixels, and
based on a comparison of the first data and the second data, identify and delete a portion of the second data in which the flicker has occurred.
2 . The vision sensor of claim 1 , wherein the first flip-flop is configured to store, as the first data, information indicating, a first state corresponding to occurrence of the flicker in a corresponding pixel of the plurality of pixels or information indicating a second state corresponding to no occurrence of the flicker in the corresponding pixel.
3 . The vision sensor of claim 2 , wherein the event detection circuit is further configured to transmit, to the first flip-flop, a first reset signal for resetting the first data in each of a plurality of preset reset periods, and
wherein the first flip-flop is configured to, based on the first reset signal, reset the first data in a subsequent period following a period in which the first reset signal is received.
4 . The vision sensor of claim 3 , wherein the second flip-flop is configured to store, as the second data, information indicating a third state corresponding to occurrence of the event in the corresponding pixel and information indicating a fourth state corresponding to no occurrence of the event in the corresponding pixel.
5 . The vision sensor of claim 4 , wherein the event detection circuit is further configured to transmit, to the second flip-flop, a second reset signal for resetting the second data in each of the plurality of preset reset periods, and
wherein the second flip-flop is configured to, based on the first flip-flop being reset and the second reset signal being received, reset the second data in a period in which the second reset signal is received.
6 . The vision sensor of claim 1 , wherein the event detection circuit is further configured to identify a target event as the flicker based on the target event and another event occurring within a specific period of time.
7 . The vision sensor of claim 1 , wherein the first flip-flop comprises a 1-bit delayed flip-flop,
wherein the second flip-flop comprises a 1-bit flip-flop, and
wherein the event detection circuit is further configured to process the event signal by reading the event signal from the pixel array based on a synchronous method or an asynchronous method.
8 . An operating method of a vision sensor, the operating method comprising:
reading an event signal from a pixel array including a plurality of pixels configured to generate the event signal by detecting an event in which intensity of incident light changes;
based on the event signal, storing first data in a first flip-flop, the first data indicating whether flicker has occurred in each of the plurality of pixels;
storing second data in a second flip-flop, the second data indicating whether the event has occurred in each of the plurality of pixels; and
based on a comparison of the first data and the second data, identifying and deleting a portion of the second data in which the flicker has occurred.
9 . The operating method of claim 8 , further comprising storing, in the first flip-flop, as the first data, information indicating a first state corresponding to occurrence of the flicker in a corresponding pixel of the plurality of pixels or information indicating a second state corresponding to no occurrence of the flicker in the corresponding pixel.
10 . The operating method of claim 9 , further comprising resetting the first data in each of a plurality of preset reset periods,
wherein the resetting of the first data comprises:
generating a first reset signal in the each of the plurality of preset reset periods, and
resetting the first data in a reset period subsequent a time point in which the first reset signal is generated.
11 . The operating method of claim 10 , further comprising storing, as the second data, information indicating a third state corresponding to occurrence of the event in the corresponding pixel and information indicating a fourth state corresponding to no occurrence of the event in the corresponding pixel.
12 . The operating method of claim 11 , further comprising resetting the second data in the each of the plurality of preset reset periods,
wherein the resetting of the second data comprises:
generating a second reset signal in the each of the plurality of preset reset periods, and
based on the first flip-flop being reset and the second reset signal being generated, resetting the second data in a reset period in which the second reset signal is generated.
13 . The operating method of claim 11 , further comprising, based on a target event and another event occurring within a specific period of time, identifying the target event as the flicker.
14 . The operating method of claim 8 , wherein the first flip-flop includes a 1-bit delayed flip-flop,
wherein the second flip-flop includes a 1-bit flip-flop, and
wherein the vision sensor further includes a state register.
15 . A vision sensor comprising:
a pixel array comprising a plurality of pixels, each of the plurality of pixels being configured to generate an event signal based on an event in which intensity of incident light changes; and
an event detection circuit configured to read the event signal from the pixel array and process the event signal, the event detection circuit comprising a state register comprising a first flip-flop and a second flip-flop,
wherein the event detection circuit is configured to:
store, in the first flip-flop, first data to which a first state and a second state are mapped, the first state indicating flicker occurs in a corresponding pixel of the plurality of pixels, and the second state indicating no occurrence of the flicker in the corresponding pixel,
store, in the second flip-flop, second data to which a third state, a fourth state, and a fifth state are mapped, the third state indicating an on-event in the corresponding pixel, the fourth state indicating an off-event in the corresponding pixel, and the fifth state indicating no occurrence of the event in the corresponding pixel, and
based on a comparison of the first data and the second data, identify and delete a portion of the second data corresponding to the first state of the first data.
16 . The vision sensor of claim 15 , wherein the event detection circuit is further configured to, based on a previous event that is detected before a target event having a polarity that is different from a polarity of the target event, identify that the flicker has occurred.
17 . The vision sensor of claim 15 , wherein the event detection circuit is further configured to transmit, to the first flip-flop, a first reset signal for resetting the first data in each of a plurality of preset reset periods, and
wherein the first flip-flop is configured to, based on the first reset signal, reset the first data in a subsequent period following a period in which the first reset signal is received.
18 . The vision sensor of claim 17 , wherein the event detection circuit is further configured to transmit, to the second flip-flop, a second reset signal for resetting the second data in each of the plurality of preset reset periods, and
wherein the second flip-flop is configured to, based on the first flip-flop being reset and the second reset signal being received, reset the second data in a period in which the second reset signal is received.
19 . The vision sensor of claim 15 , wherein the first flip-flop comprises a 1-bit delayed flip-flop, and
wherein the second flip-flop comprises a 2-bit flip-flop.
20 . The vision sensor of claim 15 , wherein the event detection circuit is further configured to process the event signal by reading the event signal from the pixel array based on a synchronous method or an asynchronous method.