Method for downsampling a signal outputted by an asynchronous sensor
Disclosed is a method for processing asynchronous signals generated by a light sensor, the sensor having a matrix of pixels, the method including: —receiving the asynchronous signals, each signal being associated with a pixel in a group of pixels in the matrix, each signal including successive events issued by the associated pixel; —upon an occurrence of an event in one of the asynchronous signals, updating an integration value associated to the group by adding an additive value to the integration value; —if the integration value is greater than a predetermined threshold, generating an event in an outputted asynchronous signal.
1. A method for processing asynchronous signals generated by a light sensor, the sensor having a matrix of pixels, the method comprising:
receiving the asynchronous signals, each asynchronous signal being associated with a pixel in a group of pixels in the matrix, each signal comprising successive events issued by the associated pixel;
upon an occurrence of an event in one of the asynchronous signals, updating an integration value associated to said group by adding an additive value to the integration value;
if the integration value is greater than a predetermined threshold, generating an event in an outputted asynchronous signal.
2. A method according to claim 1 , wherein the method further comprises:
decreasing the integration value according to a time-dependent function.
3. A method according to claim 1 , wherein the additive value is selected from the group consisting of:
a predetermined value;
a value function of a predetermined value and a weighting parameter function of a position in the group of the pixel from which the occurred event is issued;
a value function of an information of gray level associated with the occurred event; and
a value function of a value function of an information of gray level associated with the occurred event and a weighting parameter function of a position in the group of the pixel from which the occurred event is issued.
4. A method according to claim 1 , wherein the method further comprises:
sending the outputted asynchronous signal to a pixel of a retina implant.
5. A method according to claim 1 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to 0.
6. A method according to claim 1 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to a value corresponding to the difference of the integration value and the predetermined threshold.
7. A method according to claim 1 , wherein the predetermined threshold is function of a number of pixels in the group of pixels.
8. A non-transitory computer readable storage medium, having stored thereon a computer program comprising program instructions, the computer program being loadable into a data-processing unit and adapted to cause the data-processing unit to carry out the steps of claim 1 when the computer program is run by the data-processing unit.
9. A retinal device, the device comprising:
a light sensor, the sensor having a matrix of pixels,
a circuit for:
receiving the asynchronous signals, each asynchronous signal being associated with a pixel in a group of pixels in the matrix, each signal comprising successive events issued by the associated pixel;
upon an occurrence of an event in one of the asynchronous signals, updating an integration value associated to said group by adding an additive value to the integration value;
if the integration value is greater than a predetermined threshold, generating an event in an outputted asynchronous signal.
10. A method according to claim 2 , wherein the additive value is selected from the group consisting of:
a predetermined value;
a value function of a predetermined value and a weighting parameter function of a position in the group of the pixel from which the occurred event is issued;
a value function of an information of gray level associated with the occurred event; and
a value function of a value function of an information of gray level associated with the occurred event and a weighting parameter function of a position in the group of the pixel from which the occurred event is issued.
11. A method according to claim 2 , wherein the method further comprises:
sending the outputted asynchronous signal to a pixel of a retina implant.
12. A method according to claim 3 , wherein the method further comprises:
sending the outputted asynchronous signal to a pixel of a retina implant.
13. A method according to claim 2 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to 0.
14. A method according to claim 3 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to 0.
15. A method according to claim 4 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to 0.
16. A method according to claim 2 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to a value corresponding to the difference of the integration value and the predetermined threshold.
17. A method according to claim 3 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to a value corresponding to the difference of the integration value and the predetermined threshold.
18. A method according to claim 4 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to a value corresponding to the difference of the integration value and the predetermined threshold.
19. A method according to claim 5 , wherein the method further comprises:
upon the generation of the event in the outputted signal, setting the integration value to a value corresponding to the difference of the integration value and the predetermined threshold.
20. A method according to claim 2 , wherein the predetermined threshold is function of a number of pixels in the group of pixels.