Providing test patterns for sensor calibration

1. A method for testing an optical sensor of a device using a reflector having a light-blocking layer and a reflective layer, comprising:

capturing, by the optical sensor, a dark flat frame corresponding to the reflector being disposed over a display of the device with the light-blocking layer of the reflector facing downwards towards the display and the reflective layer of the reflector facing upwards away from the display;

capturing, by the optical sensor, a bright flat frame corresponding to the reflector being disposed over the display with the reflective layer of the reflector facing downwards towards the display and the light-blocking layer of the reflector facing upwards away from the display;

capturing, by the optical sensor, a test pattern frame corresponding to the reflector being disposed over the display with the reflective layer of the reflector facing downwards towards the display and the light-blocking layer of the reflector facing upwards away from the display, and further corresponding to a test pattern being displayed on the display and being reflected by the reflective layer of the reflector; and

calibrating, by a processing system, the optical sensor using the captured dark flat frame, the captured bright flat frame, and the captured test pattern frame.

2. The method according to claim 1 , wherein the reflector further comprises a spacer disposed on an opposite side of the reflective layer relative to the light blocking layer.

3. The method according to claim 1 , further comprising:

determining, by a processing system, whether to generate a failure report based at least in part on the captured dark flat frame, the captured bright flat frame, and the captured test pattern frame.

4. The method according to claim 1 , further comprising:

capturing, by the sensor, a dark test pattern frame corresponding to the reflector being disposed over the display with the light-blocking layer of the reflector facing downwards towards the display and the reflective layer of the reflector facing upwards away from the display, and further corresponding to a test pattern being displayed on the display and being reflected by the reflective layer of the reflector.

5. The method according to claim 1 , wherein the reflector is separated from the display by an air gap during capturing of the dark flat frame, the bright flat frame, and the test pattern frame.

6. The method according to claim 1 , wherein the optical sensor is an under-display optical fingerprint sensor or an optical fingerprint sensor integrated within the display.

7. The method according to claim 1 , wherein the test pattern comprises periodically varying dark and light regions.

8. The method according to claim 1 , wherein the test pattern corresponds to a USAF (United States Air Force) 1951 resolution target, a Syce resolution target, an NTSC (National Television System Committee) test screen, or a PAL (Phase Alternating Line) test screen.

9. The method according to claim 1 , wherein the reflective layer comprises a neutral density filter, a specular reflector, or a diffuse reflector.

10. The method according to claim 1 , wherein the reflective layer is 60-100% reflective.

11. A system for testing an optical sensor of a device, comprising:

the device, wherein the device comprises:

a display; and

the optical sensor; and

a reflector having a light-blocking layer and a reflective layer, wherein the reflector is switchable between a first configuration in which the reflector is disposed over the display of the device with the light-blocking layer of the reflector facing downwards towards the display and the reflective layer of the reflector facing upwards away from the display and a second configuration in which the reflector is disposed over the display with the reflective layer of the reflector facing downwards towards the display and the light-blocking layer of the reflector facing upwards away from the display;

wherein the optical sensor is configured to capture a dark flat frame corresponding to the reflector in the first configuration, a bright flat frame corresponding to the reflector in the second configuration, and a test pattern frame corresponding to a test pattern being displayed on the display and being reflected by the reflector in the second configuration; and

wherein the system further comprises a processing system configured to calibrate the optical sensor using the captured dark flat frame, the captured bright flat frame, and the captured test pattern frame.

12. The system according to claim 11 , wherein the test pattern comprises periodically varying dark and light regions.

13. The system according to claim 11 , wherein the display is configured to display multiple test patterns, including one or more of the following: a USAF (United States Air Force) 1951 resolution target, a Syce resolution target, an NTSC (National Television System Committee) test screen, or a PAL (Phase Alternating Line) test screen.

14. The system according to claim 11 , wherein the optical sensor is an under-display optical fingerprint sensor or an optical fingerprint sensor integrated within the display.

15. The system according to claim 11 , wherein the reflector comprises a spacer, configured to separate a reflective layer of the reflector from a surface of the display.

16. The system according to claim 11 , further comprising:

a holding apparatus, configured to hold the reflector over the display such that the reflector is separated from a surface of the display by an air gap.

17. A method for testing an optical sensor of a device using a reflector having a light-blocking layer and a reflective layer, comprising:

capturing, by the optical sensor, a dark flat frame corresponding to the reflector being disposed over a display of the device with the light-blocking layer of the reflector facing downwards towards the display and the reflective layer of the reflector facing upwards away from the display;

capturing, by the optical sensor, a bright flat frame corresponding to the reflector being disposed over the display with the reflective layer of the reflector facing downwards towards the display and the light-blocking layer of the reflector facing upwards away from the display;

capturing, by the optical sensor, a test pattern frame corresponding to the reflector being disposed over the display with the reflective layer of the reflector facing downwards towards the display and the light-blocking layer of the reflector facing upwards away from the display, and further corresponding to a transparent material having a test pattern being illuminated by the display and the illuminated test pattern being reflected by the reflective layer of the reflector towards the optical sensor; and

calibrating, by a processing system, the optical sensor using the captured dark flat frame, the captured bright flat frame, and the captured test pattern frame.

18. The method according to claim 17 , further comprising:

removing the transparent material having the test pattern after capturing the test pattern frame.

19. The method according to claim 17 , wherein the transparent material having the test pattern is a patterned, clear film disposed on the display.

20. The method according to claim 17 , wherein the optical sensor is an under-display optical fingerprint sensor or an optical fingerprint sensor integrated within the display.