Event-based spatial transformation

Patent metadata

Field	Value
Publication number	US-9846677-B2
Application number	US-201514855351-A
Country	US
Kind code	B2
Filing date	Sep 15, 2015
Priority date	Sep 16, 2014
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A method for computing a spatial Fourier transform for an event-based system includes receiving an asynchronous event output stream including one or more events from a sensor. The method further includes computing a discrete Fourier transform (DFT) matrix based on dimensions of the sensor. The method also includes computing an output based on the DFT matrix and applying the output to an event processor.

First claim

What is claimed is:

1. A method for computing a spatial Fourier transform for an event-based system, comprising:
receiving an asynchronous event output stream comprising an event from an event-based sensor, the event comprising an address;
generating a discrete Fourier transform (DFT) matrix, the event-based sensor and the DFT matrix having same dimensions;
generating an outer product of a first vector and a second vector obtained from a row and column of the DFT matrix corresponding to coordinates of the address;
generating an output based on the outer product;
applying the output to an event processor; and
classifying the event-based on the output.

2. The method of claim 1 , in which generating the output comprises:
initializing the output;
selecting the first vector corresponding to the row of the DFT matrix based at least in part on an x-coordinate of the address;
selecting the second vector corresponding to the column of the DFT matrix based at least in part on a Y-coordinate of the address;
updating the output based on the outer product; and
decaying the output.

3. The method of claim 1 , in which:
the event further comprises a polarity, and
the address comprises horizontal coordinates and vertical coordinates.

4. The method of claim 1 , in which the event processor is a feature extractor.

5. An apparatus for computing a spatial Fourier transform for an event-based system, comprising:
a memory unit; and
at least one processor coupled to the memory unit, the at least one processor configured:
to receive an asynchronous event output stream comprising an event from an event-based sensor, the event comprising an address;
to generate a discrete Fourier transform (DFT) matrix, the event-based sensor and the DFT matrix having same dimensions;
to generate an outer product of a first vector and a second vector obtained from a row and column of the DFT matrix corresponding to coordinates of the address;
to generate an output based on the outer product;
to apply the output to an event processor; and
to classify the event-based on the output.

6. The apparatus of claim 5 , in which the at least one processor is further configured:
to initialize the output;
to select the first vector corresponding to the row of the DFT matrix based at least in part on an x-coordinate of the address;
to select the second vector corresponding to the column of the DFT matrix based at least in part on a Y-coordinate of the address;
to update the output based on the outer product; and
to decay the output.

7. The apparatus of claim 5 , in which:
the event further comprises a polarity, and
the address comprises horizontal coordinates and vertical coordinates.

8. The apparatus of claim 5 , in which the event processor is a feature extractor.

9. A non-transitory computer-readable medium having program code recorded thereon for computing a spatial Fourier transform for an event-based system, the program code being executed by a processor and comprising:
program code to receive an asynchronous event output stream comprising an event from an event-based sensor, the event comprising an address and a time stamp;
program code to generate a discrete Fourier transform (DFT) matrix, the event-based sensor and the DFT matrix having same dimensions;
program code to generate an outer product of a first vector and a second vector obtained from a row and column of the DFT matrix corresponding to coordinates of the address;
program code to generate an output based on the outer product;
program code to apply the output to an event processor; and
program code classify the event-based on the output.

10. The computer-readable medium of claim 9 , in which the program code to generate the output comprises:
program code to initialize the output;
program code to select the first vector corresponding to the row of the DFT matrix based at least in part on an x-coordinate of the address;
program code to select the second vector corresponding to the column of the DFT matrix based at least in part on a Y-coordinate of the address;
program code to update the output based on the outer product; and
program code to decay the output.

11. The computer-readable medium of claim 9 , in which:
the event further comprises a polarity, and
the address comprises horizontal coordinates and vertical coordinates.

12. The computer-readable medium of claim 9 , in which the event processor is a feature extractor.

Assignees

• Qualcomm Inc

Inventors

• Wang Xin
• Rastogi Manu
• Rangan Venkat
• Constable William Howard

Classifications

• G06V10/10

  Image acquisition (document image scanning and transmission H04N1/00; control of digital cameras H04N23/60) · CPC title

• G06V10/431

  Frequency domain transformation; Autocorrelation · CPC title

• G06K9/522

  Physics · mapped topic

• G06F17/141 Primary

  Discrete Fourier transforms · CPC title

• G06K9/20

  Physics · mapped topic