Liveness test method and liveness test apparatus

1. A liveness test method, comprising:

determining a presence of a subject using a radar sensor;

performing a first liveness test on the subject based on radar data obtained by the radar sensor, in response to the subject being present;

determining that a result of the first liveness test satisfies a first condition;

acquiring image data of the subject using an image sensor, in response to the result of the first liveness test satisfying the first condition;

performing a second liveness test on the subject based on the image data; and

determining that a result of the second liveness test satisfies a second condition;

performing a third liveness test on the subject based on the radar data and the image data, in response to the result of the second liveness test satisfying the second condition.

2. The liveness test method of claim 1 , wherein the determining comprises determining whether there is a human face based on the radar data.

3. The liveness test method of claim 2 , wherein the radar data is obtained using a portion of antennas in the radar sensor.

4. The liveness test method of claim 1 , wherein the determining comprises:

extracting an intensity feature of each distance from reception signals of the radar data; and

determining the presence of the subject based on the intensity feature.

5. The liveness test method of claim 1 , wherein the performing of the first liveness test comprises:

extracting a feature from the radar data; and

determining a result of the first liveness test on the subject based on the extracted feature.

6. The liveness test method of claim 5 , wherein the extracting comprises extracting, from the radar data, any one or any combination of a distance to the subject, a size of the subject, a direction in which the subject is positioned, and a shape of the subject.

7. The liveness test method of claim 1 , wherein the result of the first liveness test is determined to be a score indicating a likelihood of the subject corresponding to an animate object, and

the first condition corresponds to a condition that the score is greater than a threshold value.

8. The liveness test method of claim 1 , wherein the acquiring comprises:

activating the image sensor, in response to the result of the first liveness test satisfying the first condition; and

acquiring the image data from the activated image sensor.

9. The liveness test method of claim 1 , wherein the performing of the second liveness test comprises:

detecting a face region of the subject in the image data; and

performing the second liveness test based on the face region.

10. The liveness test method of claim 1 , wherein the performing of the second liveness test comprises:

detecting a region of interest in the image data;

extracting pixel value information from the region of interest;

obtaining a score based on inputting the pixel value information into a liveness test model; and

determining the subject to be an animate object, in response to the score being greater than a threshold.

11. The liveness test method of claim 1 , wherein the result of the second liveness test is determined to be a score indicating how likely the subject is to correspond to an animate object, and

the second condition corresponds to a condition that the score is greater than a threshold value.

12. The liveness test method of claim 1 , wherein the performing of the third liveness test comprises:

extracting a first feature based on pixel values of pixels included in a face region in the image data;

extracting a second feature from the radar data; and

determining a result of the third liveness test based on the first feature and the second feature.

13. The liveness test method of claim 1 , wherein the determining comprises:

continuously obtaining the radar data from the radar sensor; and

determining whether the subject is present based on the obtained radar data.

14. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the liveness test method of claim 1 .

15. A liveness test apparatus, comprising:

a radar sensor;

an image sensor; and

a processor configured to:

determine a presence of a subject using the radar sensor,

perform a first liveness test on the subject based on radar data obtained by the radar sensor, in response to the subject being present,

determine that a result of the first liveness test satisfies a first condition,

acquire image data of the subject using the image sensor, in response to the result of the first liveness test satisfying the first condition,

perform, based on the image data, a second liveness test on the subject,

determine that a result of the second liveness test satisfies a second condition, and

perform a third liveness test on the subject based on the radar data and the image data, in response to the result of the second liveness test satisfying the second condition.

16. The liveness test apparatus of claim 15 , wherein the processor is further configured to activate the image sensor, in response to the result of the first liveness test satisfying the first condition, and to acquire the image data from the activated image sensor.

17. The liveness test apparatus of claim 15 , wherein the processor is further configured to extract an intensity feature of each distance from reception signal of the radar data and determine the presence of the subject based on the intensity feature.

18. The liveness test apparatus of claim 15 , wherein the processor is further configured to perform the first liveness test by extracting a feature from the radar data and determining a result of the first liveness test on the subject based on the extracted feature.

19. The liveness test apparatus of claim 15 , wherein the processor is further configured to perform the second liveness test by detecting a region of interest in the image data, extracting pixel value information from the region of interest, obtaining a score based on inputting the pixel value information into a liveness test model, and determining the subject to be an animate object, in response to the score being greater than a threshold.

20. The liveness test apparatus of claim 15 , wherein the processor is further configured to perform the third liveness test by extracting a first feature based on pixel values of pixels included in a face region in the image data, extracting a second feature from the radar data, and determining a result of the third liveness test based on the first feature and the second feature.