Automatic light supplementing circuit of USB camera

Abstract

The utility model discloses a USB camera automatic light supplement circuit, which comprises an MCU controller U12, a 4P socket J3, a photosensitive device U15 and a matching resistor R38, the VDD end of the MCU controller U12 is connected with the camera power supply end VDD33RGB through a resistor R41, the matching resistor R38 is connected between the first end of the photosensitive device U15 and the camera power supply end VDD33RGB, and the second end of the photosensitive device U15 is connected with the camera power supply end VDD33RGB. The second end of the photosensitive device U15 is grounded, the first end of the photosensitive device U15 is further connected to an IO port of the MCU controller U12, and the URX pin of the MCU controller U12 is connected to the signal output end of the 4P socket J3. The face recognition device can automatically sense the brightness of a shooting environment, and can effectively improve the face recognition accuracy.

Description

Technical Field

[0001] The utility model relates to a USB camera, in particular to an automatic light supplement circuit for a USB camera. Background Art

[0002] In the existing field of face recognition, when using a camera to take pictures of a face, situations such as insufficient light and alternating light and darkness often occur. Such unsatisfactory lighting conditions will lead to a decrease in the recognition rate due to the too-dark image during the face recognition process. However, the binocular cameras on the market cannot provide the perception change of dark light, let alone control the on / off of the fill light under alternating light and dark conditions. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide an automatic light supplement circuit for a USB camera that can automatically sense the brightness and darkness of the shooting environment and improve the accuracy of face recognition in view of the deficiencies of the prior art.

[0004] To solve the above technical problem, the utility model adopts the following technical solutions.

[0005] An automatic light supplement circuit for a USB camera includes an MCU controller U12, a 4P socket J3, a photosensitive device U15 and the matching resistor R38. The VDD terminal of the MCU controller U12 is connected to the camera power supply terminal VDD33_RGB through a resistor R41. The matching resistor R38 is connected between the first terminal of the photosensitive device U15 and the camera power supply terminal VDD33_RGB. The second terminal of the photosensitive device U15 is grounded. The first terminal of the photosensitive device U15 is also connected to an IO port of the MCU controller U12. The URX pin of the MCU controller U12 is connected to the signal output terminal on the 4P socket J3.

[0006] Preferably, the MCU controller U12 is an SN8F5701SG single-chip microcomputer.

[0007] Preferably, the photosensitive device U15 is a photoresistor.

[0008] Preferably, the resistance value of the resistor R41 is 0Ω, and the resistance value of the matching resistor R38 is 4.7kΩ.

[0009] Preferably, a capacitor C81 is connected in parallel with the photosensitive device U15.

[0010] Preferably, the USB camera includes a main control module U6, and the INT0 terminal of the MCU controller U12 is connected to the GPIO terminal of the main control module U6.

[0011] Preferably, a voltage threshold is preset in the MCU controller U12. When the voltage at the first end of the photosensitive device U15 is greater than the voltage threshold, the URX pin of the MCU controller U12 outputs a high level.

[0012] Preferably, the MCU controller U12 is configured to compare the voltage at the first end of the photosensitive device U15 with the voltage threshold after the URX pin outputs a high level and a delay of 6 seconds.

[0013] In the automatic fill light circuit of the USB camera disclosed by the present utility model, when the camera is plugged into the USB interface, the camera is turned on and enters the working state. At the same time, the MCU controller U12 is powered by the camera power supply terminal VDD33_RGB. The MCU controller U12 starts to work, and the voltage at the first end of the photosensitive device U15 changes with the intensity of the light. When the ambient light is dim and the voltage at the first end of the photosensitive device U15 is greater than the preset voltage threshold in the MCU controller U12, the URX pin of the MCU controller U12 outputs a high level, and the main control of the camera controls the fill light to turn on. On the contrary, if it is during the day or in an environment with high ambient light, the voltage at the first end of the photosensitive device U15 is less than the preset voltage threshold in the MCU controller U12, the URX pin of the MCU controller U12 outputs a low level, and the main control of the camera controls the fill light to turn off. Based on the above principle, the present utility model can automatically sense the brightness of the shooting environment and effectively improve the accuracy of face recognition. Description of the Drawings

[0014] Figure 1 is the schematic diagram of the automatic fill light circuit of the USB camera;

[0015] Figure 2 is the schematic diagram of the main control module. Detailed Embodiment

[0016] The present utility model will be described in more detail below with reference to the drawings and embodiments.

[0017] The present utility model discloses an automatic fill light circuit for a USB camera. Please refer to Figure 1, which includes an MCU controller U12, a 4P socket J3, a photosensitive device U15 and the matching resistor R38. The VDD terminal of the MCU controller U12 is connected to the camera power supply terminal VDD33_RGB through a resistor R41. The matching resistor R38 is connected between the first terminal of the photosensitive device U15 and the camera power supply terminal VDD33_RGB. The second terminal of the photosensitive device U15 is grounded. The first terminal of the photosensitive device U15 is also connected to an IO port of the MCU controller U12. The URX pin of the MCU controller U12 is connected to the signal output terminal on the 4P socket J3.

[0018] In the above circuit, when the camera is plugged into the USB interface, the camera is turned on and enters the working state. At the same time, the MCU controller U12 is powered by the camera power supply terminal VDD33_RGB. The MCU controller U12 starts to work. The voltage at the first terminal of the photosensitive device U15 changes with the intensity of the light. When the ambient light is dim, when the voltage at the first terminal of the photosensitive device U15 is greater than the preset voltage threshold in the MCU controller U12, the URX pin of the MCU controller U12 outputs a high level, and the main control of the camera controls the fill light to turn on. On the contrary, if in the daytime or in an environment with high ambient light, the voltage at the first terminal of the photosensitive device U15 is less than the preset voltage threshold in the MCU controller U12, the URX pin of the MCU controller U12 outputs a low level, and the main control of the camera controls the fill light to turn off. Based on the above principle, the present utility model can automatically sense the brightness of the shooting environment and can effectively improve the accuracy of face recognition.

[0019] In this embodiment, the MCU controller U12 is preferably a single-chip microcomputer. Specifically, the MCU controller U12 is an SN8F5701SG single-chip microcomputer.

[0020] As a preferred method, the photosensitive device U15 is a photoresistor. Please refer to Figure 1 , in this embodiment, the photosensitive device U15 and the matching resistor R38 are connected in series and then connected between the camera power supply terminal VDD33_RGB and the ground. When the photosensitive device U15 senses that the light becomes dim, its resistance value increases. After being divided by the matching resistor R38, the voltage at the first terminal of the photosensitive device U15 also increases. Thus, the MCU controller U12 collects the voltage change of the photosensitive device U15 and uses this to characterize the brightness change of the ambient light.

[0021] In this embodiment, the resistance value of the resistor R41 is 0Ω, and the resistance value of the matching resistor R38 is 4.7kΩ. Further, a capacitor C81 is connected in parallel with the photosensitive device U15.

[0022] As a preferred method, please refer to Figure 2 , the USB camera includes a main control module U6, and the INT0 terminal of the MCU controller U12 is connected to the GPIO terminal of the main control module U6. Among them, the main control module U6 serves as the DSP main control of the camera, and it can transmit control instructions to the MCU controller U12 through the GPIO terminal (pin 40).

[0023] Regarding the specific comparison method, in this embodiment, a voltage threshold is preset in the MCU controller U12. When the voltage at the first end of the photosensitive device U15 is greater than the voltage threshold, the URX pin of the MCU controller U12 outputs a high level.

[0024] Further, the MCU controller U12 is configured to compare the voltage at the first end of the photosensitive device U15 with the voltage threshold after the URX pin outputs a high level and a delay of 6 seconds. During the specific working process, when the camera is inserted into the USB interface, the camera is turned on and the MCU controller starts to work. The photoresistor changes with the intensity of the light, and the resistance change causes the input voltage to change. The MCU controller internally sets a voltage threshold (2.8V). If the voltage is lower than the threshold, it is determined that there is no need to supplement light during the day; if it exceeds the threshold, it is determined that it is night and light supplementation is required. The MCU controller U12 internally sets a 6-second delay to avoid the supplementary light being repeatedly turned on and off due to too rapid light changes.

[0025] The above are only preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, or improvements made within the technical scope of the present invention shall be included within the scope protected by the present invention.

Claims

1. An automatic light compensation circuit for a USB camera, characterized in that, It includes an MCU controller U12, a 4P socket J3, a photosensitive device U15 and a matching resistor R38. The VDD terminal of the MCU controller U12 is connected to the camera power supply terminal VDD33_RGB through a resistor R41. The matching resistor R38 is connected between the first terminal of the photosensitive device U15 and the camera power supply terminal VDD33_RGB. The second terminal of the photosensitive device U15 is grounded. The first terminal of the photosensitive device U15 is also connected to an IO port of the MCU controller U12. The URX pin of the MCU controller U12 is connected to the signal output terminal on the 4P socket J3.

2. The automatic light compensation circuit for a USB camera according to claim 1, wherein The MCU controller U12 is an SN8F5701SG single-chip microcomputer.

3. The automatic light compensation circuit for a USB camera according to claim 1, characterized in that, The photosensitive device U15 is a photoresistor.

4. The automatic light compensation circuit for a USB camera according to claim 1, characterized in that The resistance value of the resistor R41 is 0Ω, and the resistance value of the matching resistor R38 is 4.7kΩ.

5. The automatic light compensation circuit for a USB camera according to claim 1, characterized in that, A capacitor C81 is connected in parallel with the photosensitive device U15.

6. The automatic light compensation circuit for a USB camera according to claim 1, wherein, The USB camera includes a main control module U6. The INT0 terminal of the MCU controller U12 is connected to the GPIO terminal of the main control module U6.

7. The automatic light compensation circuit for a USB camera according to claim 1, characterized in that, A voltage threshold is preset in the MCU controller U12. When the voltage at the first terminal of the photosensitive device U15 is greater than the voltage threshold, the URX pin of the MCU controller U12 outputs a high level.

8. The automatic light compensation circuit for a USB camera according to claim 7, wherein The MCU controller U12 is used to compare the voltage at the first terminal of the photosensitive device U15 with the voltage threshold after the URX pin outputs a high level and a delay of 6 seconds.

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