JP2010219864A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an appropriate exposure after a moving body has come out of a frame. <P>SOLUTION: An imaging apparatus 2 includes: an imaging part 10; and a photometry area-setting part 41 which detects a moving body in an image taken with the imaging part 10 and determines whether a moving body has been detected or not. If a moving body is detected, a photometry area is set in the area of the detected moving body, but if a predetermined time period has passed without detecting a moving body, a preset initial area is set to be a photometry area. The imaging apparatus also includes an automatic exposure control part 42 which control exposure at the imaging part 10 according to brightness information of the photometry area set by the photometry area-setting part 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus that captures an image.

  2. Description of the Related Art Conventionally, a technique is known in which a person is imaged in a digital camera, a photometric area is set from the captured image, and automatic exposure control of an imaging unit is performed according to luminance information of the set photometric area.

  In addition, the moving body of the captured image is detected, and it is determined whether or not the luminance value of the detected moving body area is greater than a certain value and the area of the moving body area is included in a certain value. An imaging device that performs exposure control according to luminance information of a photometric area when the area of the moving object is included in a certain value when the luminance value is greater than or equal to a certain value is known. (For example, refer to Patent Document 1). With this photographing apparatus, it is possible to perform exposure control with appropriate luminance contrast according to luminance information of an area of a moving object such as a person.

JP-A-5-183801

  However, in the configuration in which the conventional automatic exposure control is performed, when a moving object is not detected, the photometric area of the previous frame is continuously set as the photometric area. For this reason, when the moving object stops at the edge of the screen, the photometric area is fixed at the edge of the screen. For this reason, for example, when the luminance difference between the moving object and the background is large in the fixed photometry area due to backlight, when the moving object is out of frame, the exposure is excessively over the background image after the next frame. There was a fear.

  An object of the present invention is to obtain an appropriate exposure for imaging after a moving object is out of frame.

In order to solve the above problem, an imaging apparatus according to claim 1 is provided.
An imaging unit that captures an image;
A moving object is detected from the image captured by the imaging unit, and it is determined whether or not a moving object is detected. When a moving object is detected, a photometric area is set in the area of the detected moving object, and the moving object is detected. A metering area setting unit for setting a preset initial area as a metering area when a predetermined time has passed without
An automatic exposure control unit that performs exposure control on the imaging unit in accordance with luminance information of the photometric area set by the photometric area setting unit.

The invention according to claim 2 is the imaging apparatus according to claim 1,
When the moving object is detected, the photometric area setting unit detects the face of the subject person from the moving object area, and sets the photometric area in the detected face area.

The invention according to claim 3 is the imaging apparatus according to claim 2,
The face detection is face detection using skin color or face detection by pattern matching.

The invention according to claim 4 is the imaging device according to any one of claims 1 to 3,
The initial area is a selection area among all the areas of the image, the center area, or a plurality of divided areas into which the image is divided.

  According to the present invention, it is possible to obtain an exposure suitable for imaging after the moving object is out of frame.

It is a figure which shows a vending machine provided with the imaging device of embodiment which concerns on this invention. It is a block diagram which shows the function structure of an imaging device. It is a flowchart which shows an automatic exposure control process. It is a figure which shows all the areas in an image. It is a figure which shows the center area in an image. It is a figure which shows the division area in an image.

  Embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the illustrated example.

  First, with reference to FIG. 1, a mode in which the imaging apparatus of the present embodiment is used will be described. FIG. 1 shows a vending machine 1 including an imaging device 2 according to the present embodiment.

  As shown in FIG. 1, the imaging device 2 of the present embodiment is fixed to a vending machine 1. The vending machine 1 is assumed to be a vending machine that sells cigarettes as a product that requires checking the age of the adult. As a product for which the age verification of the adult is necessary, alcohol or the like may be used. The vending machine 1 images the person 3 who is the customer of the product with the imaging device 2, analyzes the captured image data to perform age authentication of the person 3, and if the product is authenticated as an adult, Sell.

  It is assumed that the vending machine 1 is installed outdoors. For this reason, it is assumed that the person 3 may be imaged with different brightness by the imaging device 2 depending on the position of the sun 4 in time zones such as daytime and nighttime.

  Next, the internal configuration of the imaging apparatus 2 will be described with reference to FIG. FIG. 2 shows a functional configuration of the imaging apparatus 2. The imaging device 2 includes an imaging unit 10, a signal processing unit 20, an image memory 30, and a control unit 40.

  The imaging unit 10 is a digital movie camera that images a subject. The imaging unit 10 includes an optical system, an imaging device, an A / D (Analog to Digital) conversion unit, and the like. The optical system includes various lenses, a diaphragm mechanism, and the like. The image sensor is an image sensor such as a CCD (Charge Coupled Device), CMOS, etc., and photoelectrically converts the optical signal of the subject image formed by the optical system into an analog electrical signal and outputs it as an analog image signal. It is assumed that the exposure of the imaging unit 10 can be adjusted by adjusting the aperture value of the aperture mechanism, the exposure time (shutter speed) of the image sensor, and the sensitivity. The A / D converter converts an analog image signal input from the image sensor into digital image data (RGB data) and outputs the digital image data. RGB data is image data represented by red, blue, and green component signals. The imaging unit 10 generates and outputs image data for each frame of a moving image. The imaging speed of the imaging unit 10 is, for example, 30 fps.

  The signal processing unit 20 is a signal processing circuit for various signal processing such as interpolation processing, color processing (color difference conversion processing for converting RGB data into YUV data), luminance signal processing (edge enhancement processing, gamma correction processing), and the like. The signal processing unit 20 performs various types of signal processing on the image data (RGB data) input from the imaging unit 10 and converts the image data into YUV data. The YUV data is image data represented by a luminance signal Y, a blue component color difference signal U (Cb), and a red component color difference signal V (Cr). The signal processing unit 20 stores the converted YUV data in the image memory 30 and outputs it to the authentication unit (not shown). The authentication unit performs image analysis on the image data input from the signal processing unit 20 and performs age authentication of the subject person.

  Further, when photometric area information (photometric area coordinate information) is input from the control unit 40, the signal processing unit 20 stores the coordinate information in a register (not shown), and stores image data corresponding to the coordinate information. It has a function of reading out from the image memory 30 and calculating luminance information (average luminance value) of the photometric area in the image of the read out image data according to the input photometric area information and outputting it to the control unit 40. To do.

  The image memory 30 is composed of a RAM (Random Access Memory), and temporarily stores image data (YUV data) for each frame output from the signal processing unit 20.

  The control unit 40 controls each unit of the imaging device 2. The control unit 40 includes a CPU (Central Processing Unit), a RAM, and a ROM (Read Only Memory). In the control unit 40, a designated program among the programs stored in the ROM is expanded in the RAM, and various processes are executed in cooperation with the expanded program and the CPU. It is assumed that an automatic exposure control program is stored in the ROM. The control unit 40 includes a photometric area setting unit 41 and an automatic exposure control unit 42 as functional units according to the automatic exposure control program.

  The photometric area setting unit 41 detects a moving object from the image captured by the imaging unit 10, determines whether or not the moving object has been detected, and if a moving object is detected, sets the photometric area within the area of the detected moving object. When a predetermined time has elapsed without detecting a moving object, a preset initial area is set as a photometric area. The automatic exposure control unit 42 performs exposure control on the imaging unit 10 according to the luminance information of the photometric area set by the photometric area setting unit 41.

  Next, the operation of the imaging device 2 will be described with reference to FIGS. FIG. 3 shows the flow of the automatic exposure control process. FIG. 4 shows the central area 101 in the image F. FIG. 5 shows the entire area 102 in the image F. FIG. 6 shows a divided area 103 in the image F.

  In the imaging apparatus 2, for example, the automatic exposure control process based on the automatic exposure control program is executed by the control unit 40, triggered by the power-on input. In addition, the image data (YUV data) of each frame generated by imaging the subject by the imaging unit 10 and the signal processing unit 20 with the power-on as a trigger is stored in the image memory 30 in the imaging order, and Output to the authentication unit.

  As shown in FIG. 3, first, the photometric area setting unit 41 sets the photometric area to a preset initial area (step S1). The initial area may be, for example, a selection area in the central area 101 located at the center of the image F shown in FIG. 4, the entire area 102 of the image F shown in FIG. 5, or a plurality of divided areas 103 obtained by dividing the image F. Other areas may be used. In step S1, since the image data is not read out, when the photometric area is selected as the selection area of the divided area 103, the area is not actually selected, and the photometric area is set as the selected area of the divided area 103. Is set.

  Then, the photometric area setting unit 41 determines whether or not a plurality of image data including the latest one frame of image data that has not been read is stored in the image memory 30 (step S2). If a plurality of image data including the latest one frame of image data that has not been read is not stored (step S2; NO), the process proceeds to step S2.

  When a plurality of image data including the latest one frame of image data that has not been read is stored (step S2; YES), the photometry area setting unit 41 causes the image data for the latest two frames from the image memory 30. Is read (step S3). Step S2 is a step of reading out image data of a plurality of frames used for the moving object detection process, and image data of three frames or more may be read out.

  Then, the photometric area setting unit 41 performs moving object detection based on the image of the image data read in step S3 (step S4). In step S4, an area in which the luminance value changes between a plurality of images in a plurality of frames of image data is detected as a moving object. The moving object detection in step S3 is performed by a known moving object detection technique. As the moving object, a person who is a customer of the vending machine 1 is assumed. The height of the person differs depending on the person, and when the person poses for authentication in front of the lens of the imaging unit 10, the person (face) may not be located at the same position in the image. For this reason, detecting a moving object in an image is effective in detecting a human face described later.

  Then, the photometric area setting unit 41 determines whether or not a moving object is detected in step S4 (step S5). When a moving body is detected (step S5; YES), the timer count value is cleared (step S6). The timer count value is a count value that is counted up for each frame of image data (moving object detection process). That is, the count value is based on the frame imaging time interval in the imaging unit 10.

  Then, the moving body portion detected in step S4 is determined (set) as a moving body area in the image of the latest one frame of image data read in step S2 (step S7).

  Then, the photometric area setting unit 41 performs face detection processing on the moving object area determined in step S7 (step S8). For the face detection process in step S8, a known face detection technique for detecting a face area from an image (moving body area) is used. As a face detection method, for example, there is a method of specifying an eye, nose and mouth in an image by pattern matching and detecting a face area including the specified eye, nose and mouth. Moreover, as a face detection method, it is good also as a method etc. which detect the face containing a person's skin color area using the skin color information in an image. Skin color means, for example, that the blue color difference signal Cb and the red color difference signal Cr are 90 <Cb <122 (setting range 0 to 255), 132 <Cr <160 (setting range 0 to 255) (gray: Cb = Cr = 128).

  Then, the face area detected in step S8 is set as the (current) photometry area by the photometry area setting unit 41 (step S9). Then, luminance information of the photometric area, which is the average luminance value of the photometric area set in step S9, S13, or S14, is calculated, and automatic exposure control is performed on the imaging unit 10 according to the calculated luminance information of the photometric rear. (Step S10), the process proceeds to Step S2. In step S10, for example, the coordinate information of the photometric area set in step S9, S13, or S14 and the latest one frame of image data stored in the image memory 30 are sent to the signal processing unit 20 ( Note that the transmitted image data may be the image data used in the process of step S8, or the latest image data imaged and generated by the imaging unit 10). The signal processing unit 20 calculates luminance information of the photometric area according to the input coordinate information of the photometric area, and outputs it to the automatic exposure control unit 42. In step S10, the automatic exposure control unit 42 adjusts the aperture value of the aperture mechanism, the exposure time of the image sensor, and the sensitivity to appropriate values according to the luminance information of the photometry area. The imaging unit 10 is controlled to an appropriate exposure.

  If no moving object is detected (step S5; NO), the timer count value is incremented by one (step S11). Then, the time count value is referred to and it is determined whether or not the time is over (step S12). For example, when the time count value corresponds to 2 to 3 minutes or more, it is determined that the time is over. Two to three minutes is a threshold of time estimated to be required for one customer to purchase a product with the vending machine 1. However, the time count value at which the time is over is not limited to this time threshold value.

  When the time is not over (step S12; NO), the photometry area setting unit 41 sets the previous photometry area as the current photometry area (step S13), and the process proceeds to step S10. That is, in step S13, there is no change in the photometric area.

  When the time is over (step S12; YES), the photometry area setting unit 41 sets the initial area as the (current) photometry area (step S14), and the process proceeds to step S10. In step S14, the initial area may be a selected area in the central area 101 shown in FIG. 4, the entire area 102 shown in FIG. 5, or the divided area 103, as in step S1, or may be another area. When the initial area is set as the selection area of the divided area 103 in step S14, for example, luminance information (average luminance value) of all the divided areas 103 in the image of the latest one frame of image data being read is calculated, When the backlight is determined and the backlight is not backlit, the central divided area 103 in the image is set as the initial area. When the backlight is backlit, the darkest divided area 103 among all the divided areas 103 in the image is set as the initial area. Is done.

  As described above, according to the present embodiment, the photometric area setting unit 41 detects a moving object from the image of the image data captured by the imaging unit 10, determines whether or not a moving object is detected, and detects the moving object. In addition, a photometric area is set in the area of the detected moving object, and when a predetermined time has passed without detecting the moving object, a preset initial area is set as the photometric area, and the automatic exposure control unit 42 Exposure control according to the luminance information of the photometric area set by the photometric area setting unit 41 is performed on the imaging unit 10.

  For this reason, it is possible to obtain an appropriate exposure for imaging after the moving object is out of the frame. For example, when a person image of a customer is taken in the daytime by the image pickup apparatus 2 and another person of a customer is picked up at night after the photographed customer's frame is out, the photometry area returns to the initial area. Therefore, the exposure of the captured image of the frame before the detection of the moving object of the person does not fly, the detection of the moving object of the person can be performed properly, and an appropriate exposure for imaging can be obtained. In addition, it is possible to prevent a delay in the automatic exposure control reaction caused by a captured image of a frame before detection of a human moving object.

  Furthermore, even when the moving object (person) is out of the frame, in the configuration in which the captured image data is recorded for the purpose of monitoring or the like, it is possible to capture the exposure suitable for the purpose of monitoring or the like without the image skipping. The captured image data with appropriate exposure can be recorded.

  Further, when a moving object is detected, the photometric area setting unit 41 detects the face of the subject person from the moving object area, and sets the photometric area within the detected face area. For this reason, it is possible to obtain an exposure appropriate for imaging a human face.

  The face detection by the photometric area setting unit 41 is face detection using the skin color of the image or face detection by pattern matching. For this reason, face detection can be performed appropriately.

  In addition, the initial area is a selection area among all areas of the image, the center area, or a plurality of divided areas into which the image is divided. For this reason, after a moving body goes out of a frame, exposure suitable for the imaging according to the initial area can be obtained.

  The description in the above embodiment is an example of a suitable imaging apparatus according to the present invention, and the present invention is not limited to this.

  For example, in the above embodiment, the imaging device 2 is provided in the vending machine 1, but the present invention is not limited to this. For example, the imaging device 2 may be provided in another device that involves human imaging, such as an ATM (Automated Teller Machine) such as a bank or a convenience store, or an authentication device for a visitor to a predetermined area.

  In the above embodiment, the photometry area setting unit 41 and the automatic exposure control unit 42 are configured to cause the signal processing unit 20 to calculate the luminance information of the specific area of the image of the image data. However, the present invention is not limited to this. It is not something. The photometric area setting unit 41 and the automatic exposure control unit 42 may be configured to calculate luminance information of a specific area of the image data image.

  Further, the detailed configuration and detailed operation of each part constituting the imaging device 2 in the above embodiment can be appropriately changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Vending machine 2 Imaging device 10 Imaging part 20 Signal processing part 30 Image memory 40 Control part 41 Photometry area setting part 42 Automatic exposure control part 3 Person 4 Sun

Claims (4)

An imaging unit that captures an image;
A moving object is detected from the image captured by the imaging unit, and it is determined whether or not a moving object is detected. When a moving object is detected, a photometric area is set in the area of the detected moving object, and the moving object is detected. A metering area setting unit for setting a preset initial area as a metering area when a predetermined time has passed without
An imaging apparatus comprising: an automatic exposure control unit that performs exposure control on the imaging unit in accordance with luminance information of the photometric area set by the photometric area setting unit.   The imaging device according to claim 1, wherein when a moving object is detected, the photometric area setting unit detects a face of a subject person from the area of the moving object, and sets a photometric area in the detected face area. .   The imaging apparatus according to claim 2, wherein the face detection is face detection using skin color or face detection by pattern matching.   The imaging apparatus according to any one of claims 1 to 3, wherein the initial area is an entire area of the image, a center area, or a selection area among a plurality of divided areas into which the image is divided.

Images