Electronic apparatus having camera sensing circuit and object sensing circuit used for switching between two different operation modes and related computer-readable medium

1. An electronic apparatus, comprising:

a circuit system, arranged for controlling an operation of the electronic apparatus;

a camera sensing circuit, coupled to the circuit system, the camera sensing circuit arranged for sensing at least a portion of a portrait of a user; and

an object sensing circuit, coupled to the circuit system, the object sensing circuit arranged for sensing object(s) around the electronic apparatus, wherein an operation of the object sensing circuit is different from an operation of the camera sensing circuit;

wherein the camera sensing circuit is used for determining whether to notify the circuit system to switch from a first operation mode to a second operation mode, and the object sensing circuit is used for determining whether to notify the circuit system to switch from the second operation mode to the first operation mode; the camera sensing circuit is coupled between the circuit system and the object sensing circuit; when the object sensing circuit determines that a distance between the object and the electronic apparatus is changed by sensing an object distance, the object sensing circuit notifies the circuit system through the camera sensing circuit for switching the circuit system from the second operation mode to the first operation mode.

2. The electronic apparatus of claim 1 , wherein the first operation mode is a normal mode, and the second operation mode is a power saving mode.

3. The electronic apparatus of claim 2 , wherein when the camera sensing circuit detects no portrait of the user or determines that the user is not operating the electronic apparatus, the camera sensing circuit notifies the circuit system for switching the circuit system into the power saving mode.

4. The electronic apparatus of claim 2 , wherein when the circuit system enters the power saving mode, the circuit system is configured to control the camera sensing circuit to enter the power saving mode from the normal mode.

5. The electronic apparatus of claim 4 , wherein when the object sensing circuit determines that a distance between the object and the electronic apparatus is changed, the object sensing circuit notifies the camera sensing circuit and the circuit system for making the camera sensing circuit and the circuit system switch from the power saving mode to the normal mode.

6. The electronic apparatus of claim 5 , wherein the object sensing circuit is a proximity sensor or a distance measure system.

7. The electronic apparatus of claim 4 , wherein when the object sensing circuit determines that a distance between the object and the electronic apparatus is changed by sensing ambient light, the object sensing circuit notifies the camera sensing circuit and the circuit system for switching the camera sensing circuit and the circuit system from the power saving mode to the normal mode.

8. The electronic apparatus of claim 7 , wherein the object sensing circuit is an ambient light sensor.

9. The electronic apparatus of claim 1 , wherein when the object sensing circuit is operating in the second operation mode and determines that the distance between the object and the electronic apparatus is changed, the object sensing circuit notifies the camera sensing circuit to switch from the second operation mode to the first operation mode for performing a portrait determination.

10. The electronic apparatus of claim 9 , wherein when the camera sensing circuit determines that the object change is related to the portrait, the camera sensing circuit notifies the circuit system to switch from the second operation mode to the first operation mode.

11. The electronic apparatus of claim 9 , wherein when the camera sensing circuit determines that the object change is not related to the portrait, the camera sensing circuit enters the second operation mode without notifying the circuit system of a result of the portrait determination, and the circuit system remains in the second operation mode.

12. A non-transitory computer-readable medium, coupled to an electronic apparatus having a circuit system, wherein the computer-readable medium includes at least a program code stored therein, and following steps are performed when the program code is read and executed:

using an image sensing technique to sense at least a portion of a portrait of a user to determine whether to notify the circuit system to switch from a first operation mode to a second operation mode;

using an object sensing technique to sense object(s) around the electronic apparatus to determine whether to notify the circuit system to switch from the second operation mode to the first operation mode; and

when the object sensing technique determines that a distance between the object and the electronic apparatus is changed by sensing an object distance, using the object sensing technique to notify the circuit system through the image sensing technique for switching the circuit system from the second operation mode to the first operation mode;

wherein the object sensing technique is different from the image sensing technique.

13. The computer-readable medium of claim 12 wherein the first operation mode is a normal mode, and the second operation mode is a power saving mode.

14. The computer-readable medium of claim 13 wherein the step of determining whether to notify the circuit system to exit the first operation mode and enter the second operation mode comprises:

when the image sensing technique detects no portrait of the user or determines that the user is not operating the electronic apparatus, notifying the circuit system to enter the power saving mode.

15. The computer-readable medium of claim 14 wherein the step of determining whether to notify the circuit system to switch from the second operation mode to the first operation mode comprises:

when the object sensing technique determines that the distance between the object and the electronic apparatus is changed by sensing the object distance, notifying the circuit system to exit the power saving mode and enter the normal mode.

16. The computer-readable medium of claim 14 wherein the step of determining whether to notify the circuit system to switch from the second operation mode to the first operation mode comprises:

when the object sensing technique determines that the distance between the object and the electronic apparatus is changed by sensing ambient light, notifying the circuit system to exit the power saving mode and enter the normal mode.

17. The computer-readable medium of claim 12 further comprising:

when the object sensing technique is in the second operation mode and determines that the distance between the object and the electronic apparatus is changed, enabling the image sensing technique to sense the portrait of the user for performing a portrait determination.

18. The computer-readable medium of claim 17 wherein performing the portrait determination comprises:

when the image sensing technique determines that the object change is related to the portrait, notifying the circuit system to switch from the second operation mode to the first operation mode.

19. The computer-readable medium of claim 17 , wherein performing the portrait determination comprises:

when the image sensing technique determines that the object change is not related to the portrait, not notifying the circuit system of a result of the portrait determination, and remaining the circuit system in the second operation mode.