GB2459506A

GB2459506A - Surveillance Camera with Automatic Illumination

Info

Publication number: GB2459506A
Application number: GB0807585A
Authority: GB
Inventors: Wen-Hsiung Hsieh
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-26
Filing date: 2008-04-26
Publication date: 2009-10-28
Also published as: GB0807585D0

Abstract

A surveillance camera device has a camera 10 comprising an image sensor 11 and an image processing unit 12, a control unit 20 for getting illumination or brightness parameters from the image detected by the image sensor 11 and controlling a light source control unit 30 in response to these parameters, which in turn controls a light source 40, activating, de-activating or adjusting the light source 40. Thus optimum external lighting conditions are achieved and a clear image can be obtained. The image sensor 11 may be a CCD or CMOS sensor. The control unit 20 and the image processing unit 12 may be an integrated circuit which performs arithmetic and logic processing or digital processing. The control unit 20 may be installed inside or outside the camera. The light source 40 may be white light light emitting diodes (LEDs) or infra-red (IR) LEDs. A control signal to control the light source may be an electric pulse width modulation signal or an electric analogue or digital signal.

Description

SURVEILLANCE CAMERA DEVICE WITH A LIGHT SOURCE

BACKGROUND OF THE INVENTION

a) Field of the Invention

The present invention relates to a surveillance camera device with a light source, and more particularly to a surveillance camera device which is provided with a function of automatic light fill-in.

b) Description of the Prior Art

An ordinary surveillance camera will usually activate a night-vision function to fill in light automatically when light of external environment is insufficient, so as to capture clear images under a condition that illumination is not sufficient; whereas, a common night-vision camera is an infrared camera or a white-light camera.

A conventional infrared camera includes a circuit board, a center of which is provided with a lens containing an image sensor, with a periphery of the lens being surrounded by a plurality of infrared light emitting diodes, and below the lens being provided with a light-sensing element. When photographing, light intensity of external environment is detected by the light-sensing element that is located below the camera and aligns with a direction in taking images by the lens, and a signal of the light intensity is processed by a circuit of the circuit board to further control whether the infrared light emitting diodes are activated or not.

The conventional light-sensing element used for the infrared camera is a photoresistor or phototransistor which can only detect visible light. Therefore, when the light of the external environment is insufficient and thus the infrared light emitting diodes is activated to illuminate, as the infrared ray is non-visible light, it cannot be detected by this kind of photoresistor. Accordingly, the photoresistor will be able to accurately detect the light intensity of the external environment. However, if white-light light emitting diodes are used instead of infrared light emitting diodes, when the light-sensing element has detected that the light intensity of the external environment is insufficient; the white-light light emitting diodes will be activated to fill in the light. As the white light belongs to the visible light, it can be detected by the light-sensing element. Therefore, the light-sensing element detects that the external environment has the sufficient light intensity, to deactivate the white-light light emitting diodes, thereby easily resulting in incorrect determination. As the white-light light emitting diodes are deactivated, the light-sensing element detects that the light of the external environment is insufficient again, to activate the white-light light emitting diodes once more. Accordingly, the white-light light emitting diodes are activated and deactivated repeatedly, allowing the light intensity of the external environment unable to be determined accurately to control whether the light is filled in correctly, thereby prohibiting the lens from capturing clear images. Therefore, it will easily result in the incorrect determination when the conventional structure is applied to the infrared camera or the white-light camera, thereby affecting a quality of photographing and thus truly requiring improvement.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a surveillance camera device with a light source, which can accurately determine illumination of external environment to correctly control light fill-in, such that the camera can capture clear images when the illumination of the external environment is changed.

Accordingly, the present invention includes primarily a camera, a control unit which is connected to the camera, a light-source control unit which is connected to the control unit, and a light source. The camera includes an image sensor to capture external images, and an image processing unit to get and process image signals, that can provide parameters such as illumination of the external environment. The control unit gets parameter values, such as the illumination of images from the camera; and outputs a control signal to allow the light-source control unit to activate or deactivate the light source or to adjust the luminosity of fill-in light, such that the camera can capture clear images, when the control unit has determined that the illumination of the external environment is changed. By using the control unit to directly get the brightness of the images detected by the camera, the illumination of the external environment can be accurately determined to correctly control whether the light fill-in is needed, and the intensity of the fill-in light, thereby preventing from resulting in the incorrect determination, and allowing the clear images to be shot successfully.

Accordingly, the present invention can accurately determine the illumination of the external environment to decide whether the intensity of the light source or the fill-in light should be activated, thereby being able to be applied to the camera device which uses the white-light light emitting diodes or the infrared light emitting diodes as the light source, to save the photoresistor or other light-sensing element used by the conventional camera.

To enable a further understanding of the said objectives and the technological methods of the invention herein, the brief description of the drawings below is followed by the detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, it shows a preferred embodiment of the present invention which comprises primarily a camera 10, a control unit 20 which is connected to the camera 1 0, a light-source control unit 30 which is connected to the control unit 20, and a light source 40. The camera 10 includes an image sensor 11 and an image processing unit 12 which is connected to the image sensor 11.

The image sensor 11 can be a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor), to capture external images and to transmit image signals to the image processing unit 12.

The image processing unit 12 is an integrated circuit which operates arithmetic and logic processing or digital signal processing or both, which can be a MCU (Microcontroller Unit), a DSP (Digital Signal Processor), a FPGA (Field-Programmable Gate Array), or a CPLD (Complex Programmable Logic Device). The image processing unit 12 gets and processes the image signals; as well as outputs parameters, such as illumination of the images of lighting area or its related parameters such as AGC (Automatic Gain Control) or AEC (Automatic Exposure Control) values, to the control unit 20.

The control unit 20 is connected to the image processing unit 1 2 of the camera 1 0, to get control reference values from the image processing unit 12, such as the illumination of the images or its related parameters such as AGO (Automatic Gain Control) or AEC (Automatic Exposure Control) values. When the control unit 20 has determined that the illumination of the external environment is changed, a lighting control signal will be outputted to the light-source control unit 30 which will activate or deactivate the light source, or adjust a degree of fill-in of the light source 40, depending on the lighting control signal. The light source can be a plurality of white-light light emitting diodes or a plurality of infrared light emitting diodes.

The control unit 20 is an integrated circuit which operates arithmetic and logic processing or digital signal processing, which can be an MCU (Microcontroller Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), or a CPLD (Complex Programmable Logic Device) which outputs a corresponding lighting control signal in responding to the illumination of the external environment, to control the activation or deactivation of the light source, or the lighting degree of the fill-in light, for providing the correct light fill-in. The lighting control signal can be an electric PWM (Pulse Width Modulation) signal, or an electric analog signal or an electric digital signal.

The control unit 20 can be installed inside or outside the camera 1 0. Furthermore, the image sensor 11 and the image processing unit 12 can be configured into a sole integrated circuit. The image processing unit 12 and the control unit 20 can be configured into a sole integrated circuit. The image sensor 11 and the image processing unit 12 and the control unit 20 can be configured into a sole integrated circuit, also.

As the present invention uses the image sensor to access the parameters, such as the illumination of the external environment; and then uses the control unit to directly access the illumination of the images or its related parameters to determine the lighting degree of the fill-in light. Therefore, the illumination of the external environment can be accurately determined to provide the correct fill-in light, allowing the camera to automatically choose whether the light fill-in is needed or the lighting degree of the fill-in light needs to be adjusted, to shoot the clear images, under the condition that the light of the external environment is changed.

The light-source control unit 30 is an electronic circuit that applies power from a source of electric power to the light source 40, and maintains the light output intensity of the light source 40 based on the control signal from the control unit 20.

It is of course to be understood that the embodiments described herein is merely illustrative of the principles of the invention and that a wide variety of modifications thereto may be effected by persons skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

What is claimed is: 1. A surveillance camera device with a light source, comprising: a camera, which includes an image sensor and an image processing unit being connected to the image sensor, for capturing and processing images; a control unit, which is connected to the camera to get illumination of images; a light-source control unit, which is connected to the control unit; and a light source, which is connected to the light-source control unit; the control unit getting the illumination of the images detected by the camera or its related parameters, and then outputting a control signal to the light-source control unit to determine whether to activate the light source or to adjust the illumination of the light source, enabling the clear images to be captured when the light of the external environment is changed.
2. The camera device according to claim 1, wherein the control unit is connected to the image processing unit to get the illumination of the images and related parameters detected by the camera.
3. The camera device according to claim 1, wherein the control unit is installed inside or outside the camera.
4. The camera according to claim 1, wherein the image sensor is a COD image sensor.
5. The camera according to claim 1, wherein the image sensor is a CMOS image sensor.
6. The camera according to claim 1, wherein the image processing unit is an integrated circuit which operates arithmetic and logic processing or digital signal processing or both.
7. The camera according to claim 1, wherein the control unit is an integrated circuit which operates arithmetic and logic processing or digital signal processing or both.
8. The camera device according to claim 1, wherein the image processing unit and the image sensor is configured into a sole integrated circuit.
9. The camera device according to claim 1, wherein the control unit, the image processing unit is configured into a sole integrated circuit.
1 0. The camera device according to claim 1, wherein the control unit, the image processing unit and the image sensor is configured into a sole integrated circuit.
11. The camera device according to claim 1, wherein the light-source control unit is an electronic circuit that applies power from a source of electric power to the light source, and maintains the light output intensity of the light source or turns on or turns off the light source based on the control signal from the control unit.
12. The camera device according to claim 1, wherein the light source is white-light light emitting diodes.
13. The camera device according to claim 1, wherein the light source is infrared light emitting diodes.
14. The camera device according to claim 1, wherein the control signal outputted by the control unit is a lighting control signal, to control a lighting degree of the light source, in responding to the illumination of the environment.
15. The camera device according to claim 14, wherein the lighting control signal is an electric pulse width modulation signal.
1 6. The camera device according to claim 14, wherein the lighting control signal is an electric analog signal.
17. The camera device according to claim 14, wherein the lighting control signal is an electric digital signal.