JP2011042179A - Projector control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector control device which can obtain the image of an imaging target correctly even for an object having a reflecting surface in the front surface of the imaging target such as a person who wears glasses. <P>SOLUTION: An imaging region surface (a part in the angle α<SB>C</SB>of view of a camera 1 within P<SB>1</SB>) is determined in an imaging object position of the imaging object 4, and a lighting projector is disposed outside of a square pole having this region surface as its vertical section (within a region indicated by the thick arrows in the figure if on the same horizontal cross section as the square pole) and closer to the camera 1 than the imaging region surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projector control device that irradiates imaging light to an imaging target of an imaging device, for example, a projector control device for an imaging device that acquires a face image for driver's face recognition in a vehicle.

The driver's face image is acquired by the camera as a method to detect the driver's arousal level or side-view driving, etc., and the information obtained by detecting the face direction, line-of-sight direction, blink state, etc. by image processing Devices that make a determination based on this are known. In this type of apparatus, in order to acquire a stable driver image regardless of whether it is daytime or nighttime or the weather, a projector that irradiates the driver with near infrared light is provided. The technique described in Patent Document 1 is a technique related to such a projector, and detects the distance from the projector to the face from images acquired by the main camera and the sub camera, and adjusts the amount of light emitted by the projector according to the distance. Is.
JP-A-2005-323180

  As this type of imaging apparatus, as shown in FIG. 11, an apparatus is widely used in which the camera 1 and the projectors 33 and 34 are set and arranged toward the driver's face 4. However, in such an imaging apparatus, when the driver wears spectacles, when the light emitted from the projectors 33 and 34 is reflected by the lens surface of the spectacles, the reflected light directly enters the camera 1. The image around the driver's eyes cannot be acquired well, and the gaze direction and blinking cannot be detected.

  Therefore, the present invention provides a projector control apparatus that can correctly acquire an image of an imaging target even for an object having a reflective surface in front of the imaging target, such as a person wearing glasses. Let it be an issue.

  In order to solve the above problems, a projector control device according to the present invention is a projector control device that irradiates imaging light to an imaging target of an imaging device, and has an imaging range surface at an imaging target position of the imaging device. It is determined, and the outside of the rectangular column having the same range plane as a vertical cross section is set as the illumination position by the projector.

  This imaging device is an imaging device for recognizing a driver's face mounted on a vehicle, and an imaging range surface at an imaging target position may be set based on a passenger compartment shape. For example, the imaging range plane is set based on a position range in which the driver's face in the standard physique range is expected to be located from the passenger compartment shape.

  The face position may be acquired from the driver's face image acquired by the imaging device, and the illumination amount of the projector may be controlled based on the face position. For example, an illumination amount map corresponding to the face position may be determined in advance, and illumination may be performed according to the map.

  By setting the illumination position in the above range, the optical axis of the camera and the light irradiation direction can be given an angle. As a result, the reflected light from the imaging target surface is prevented from directly entering the camera, Reflection of light in an image acquired as a captured image is suppressed, and an image having a desired luminance can be obtained. For example, in the case of a driver's face recognition imaging device, even if the driver is wearing spectacles, the eyeglasses will not appear in the state of shining with irradiation light, and the gaze direction, blinking state, etc. will be detected appropriately It becomes possible to do.

  By setting the imaging range plane based on the vehicle shape, it is possible to install and fix the projector at an appropriate illumination position at the time of manufacture, eliminating the need for adjustment during imaging and improving convenience.

  According to the prior art, not only the distance to the camera but also the face position varies depending on the physique and driving posture of the driver, so that the appropriate position as shown in FIGS. 12 and 13 depends on the positional relationship between the face and the camera. In the case of the face position 4C, even if the irradiation light amount is good, the face position is shifted 4L, 4R, 4u, but the light amount is insufficient, whereas in the case of the face position 4d, the light amount is excessive. An image suitable for processing may not be acquired. By controlling the amount of illumination based on the face position, it is possible to illuminate with an appropriate amount of light even under conditions where the amount of light is insufficient or excessive in FIGS. be able to.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a block diagram showing a configuration of an imaging apparatus including a projector control apparatus according to the present invention. This imaging device is mounted on a vehicle for driver's face recognition, and acquires a driver's face image. This imaging device includes an imaging camera 1, a projector control device 2, and an illumination A31 and an illumination B32 that are projectors. The projector control device 2 includes a face position detection unit 21, an illumination control unit 22, and a control map 23 for illumination control. The camera 1 is disposed, for example, on a steering column or in an instrument panel, and continuously acquires a driver's face image at, for example, a TV frame rate. The face position detection unit 21 and the illumination control unit 22 are configured by a CPU, a ROM, a RAM, and the like. The face position detection unit 21 and the illumination control unit 22 may be independent in hardware, but share a part or all of them, and in software It may be realized. Or you may comprise as a part of image recognition apparatus. The control map 23 is a storage device that stores information for lighting control, and a magnetic disk, a nonvolatile semiconductor memory, a ROM, or the like can be used. The lighting A31 and the lighting B32 irradiate the driver with light (near infrared light) from positions different from each other on the axis of the driver and the camera 1 as will be described in detail later, respectively. Is.

  An image continuously acquired by the camera 1 is converted into digital data of a predetermined format by an AD converter arranged inside the camera 1 or between the camera 1 and the projector control device 2 (not shown), and is a face position detection unit. 21 is input. The face position detection unit 21 extracts a face image from the input image by image extraction, and obtains the face position (step S1). Next, the illumination control unit 22 collates the obtained face position information with the illumination control map stored in the control map 23 (step S2), and reads light amount information for the face position information. Next, each of the illumination A31 and the illumination B32 is controlled so that the light amount corresponds to the read light amount information (step S3).

  Specific arrangement positions of the illumination A31 and the illumination B32 will be described with reference to FIGS. FIG. 3 is a view of the relationship between the camera 1 and the face 4 to be imaged from above, and FIG. 4 is a view of this from the side (left side as viewed from the driver).

Here, if the horizontal angle of view of the camera 1 is α _C and the vertical angle of view is β _C , the region sandwiched between the lines L _CL and L _CR in the horizontal direction, and the lines L _cd and L _{cu in the} vertical direction. The area between the two is a range where the camera 1 captures an image. A vertical plane P ₁ including the center position of 95% of the eyeball position is determined from the region where the driver's face 4 can be located based on the shape of the vehicle at the time of design. Here, the face center position when the eye is positioned on the plane P1 will be located on the line L ₁ in FIG. Here, the width of the average face 4 is 2 W _a , and the width of the region where the face 4 can be located is 2 W _b . Through the intersection of the plane _{P 1} and _{L CL} 3, the plane _{P 1 L} perpendicular line _L, and similarly as the intersection of the plane _{P 1} and _{L CR,} when a line perpendicular to _{L R} in the plane _{P 1} , when positioned at a height range including the area to be imaged by the camera 1 and the illumination A31, B32 in the plane _{P 1,} these illumination 31 and 32 are both top viewed from line _L L, from _{L R} It is arranged on the outer side closer to the camera 1 than the plane P1 (region indicated by a thick arrow in the figure).

On the other hand, in FIG. 4, the line passing through the intersection of the planes P ₁ and L _cu and passing through the line perpendicular to the plane P ₁ is represented by L _u , and the line passing through the intersection of the planes P ₁ and L _cd and perpendicular to the plane P ₁ is represented by L _d. when, if placed in a lateral width range including the area to be imaged by the camera 1 and the illumination A31, B32 in the plane _{P 1,} these illumination 31 and 32, the line _L u, plane outside the _{L d} It is arranged on the side closer to the camera ₁ than P ₁ (region indicated by a thick arrow in the figure).

In other words, placing the illumination A31, B32 to the camera 1 side from the region outside the square pillar which the rectangular region is a vertical cross-section which is captured by the camera 1 of the plane P _1. At this time, it is more preferable that the illumination A31 and the illumination B32 are arranged so as to illuminate the driver's face 4 from different directions. A specific arrangement example is shown in FIG. For example, as shown in FIG. 5 (a), illuminations 31 and 32 are arranged on the lower left and right with respect to the face 4, or with respect to the face 4 as shown in FIG. 5 (b). It is good to arrange the lights 31 and 32 respectively. As the arrangement position in the vehicle, as shown in FIG. 5C, the position A in the instrument panel 62 between the driver's seat and the passenger seat, the lower position B of the front pillar 61 or the upper position D, It may be arranged by selecting from the position C above the room mirror 60. Here, although the example arrange | positioned in two places was shown, illumination may be one place or may be arrange | positioned in three or more places. When it arrange | positions at three or more places, it is good to arrange | position each illumination so that the driver | operator's face 4 may be illuminated from at least two different directions. By irradiating light from a plurality of different directions, it is possible to irradiate illumination light evenly over the entire face 4 and to perform uniform illumination even when the position of the face 4 is different.

  Next, FIG. 6 and FIG. 7 show the results of comparing face images obtained by the camera 1 between the case of using a projector (illumination) arranged based on the above method and the case of using the same arrangement as the apparatus shown in FIG. It explains using. FIG. 6 is a diagram for explaining the positional relationship between the illumination arrangement and the face in the comparison, and FIG. 7 is a diagram comparing the acquired images obtained by the respective illumination arrangements shown in FIG.

  In the conventional arrangement shown in FIG. 6 (b), when the driver wears glasses 41 on the face 4, the illumination light from the illuminations 31 and 32 is reflected at a position overlapping the eyeball position on the surface of the glasses 41. Since the light enters the camera 1 between the illuminations 31 and 32, the glasses 41 shine in the acquired image, and the image around the eyeball cannot be acquired well (see FIG. 7B). Gaze direction and blink cannot be determined accurately.

  On the other hand, in the illumination arrangement according to the present invention shown in FIG. 6A, when the driver wears the glasses 41 on the face 4, the illumination light from the illuminations 31 and 32 is reflected on the surface of the glasses 41. Even if it is reflected by the camera 1 and enters the camera 1, its reflection position is shifted from the position of the eyeball and does not overlap therewith, so even if the glasses 41 are shining in the acquired image, Can be successfully acquired (see FIG. 7A), and the line-of-sight direction and blink can be accurately determined.

  Next, a specific example of illumination amount control will be described. Here, an example will be described in which control is performed so that the luminance of the driver's face image in the image 50 shown in FIG. First, the vehicle interior is divided into zones as shown in FIG. Here, with respect to the vehicle, the Z-axis is parallel to the longitudinal axis direction of the vehicle, the Y-axis is parallel to the vertical axis direction of the vehicle, and the X-axis is parallel to the lateral axis direction of the vehicle. A three-dimensional coordinate system is set at a position that matches the head center coordinates. Although it is divided into 3 × 3 × 3 areas in the figure, the present invention is not limited to this, and each zone does not have to be of equal size. Here, when the head center coordinates exist at the center position of each zone, an illumination amount is set in advance so that the brightness of the face image satisfies the standard. As the reference, for example, in the example shown in FIG. 8, the face area 51 in the image is divided into predetermined areas (4 × 4 areas in the figure), and the maximum luminance or the average luminance in each area is the predetermined luminance. It satisfies the condition that is within the range. The number of divisions of the predetermined area is not limited to the above example, and is not limited to the case where the divided areas have the same size. Thus, the light quantity control information for each preset zone is stored in the control map 23 as a map in advance. As the light amount control, a method of changing the number of lighting lights or a method of controlling the light amount of the illumination itself by changing a current value or a voltage value can be used.

  The face position is detected by extracting a face area by image processing, obtaining a head rotation center with reference to face orientation information based on the recognition result (see FIG. 10), and another distance measuring means. Thus, a method of obtaining the head rotation center by obtaining the distance to the face can be used. By controlling the lighting based on the obtained face position, it is possible to acquire a face image having a desired brightness, and to accurately perform various determination processes based on face image recognition and recognition results. It becomes.

  The present invention is not limited to the above embodiments. For example, in addition to an imaging device mounted in a vehicle, an imaging device for facial image recognition for a security system, an object other than a face, an object that has a reflective surface and needs to acquire an image inside it The present invention can also be applied to an imaging apparatus that images an object.

  The projector control device for an imaging device according to the present invention can be used for an imaging device for face recognition, and is particularly suitable as a projector control device for an imaging device that acquires a driver image mounted on a vehicle.

It is a block diagram which shows the structure of the imaging device containing the projector control apparatus which concerns on this invention. It is a flowchart of the light projection control by the apparatus of FIG. It is the figure which looked at the positional relationship of the camera and imaging object in the apparatus of FIG. 1 from the top. It is the figure which looked at the positional relationship corresponding to FIG. 3 from the side. It is a figure which shows the example of arrangement | positioning of a projector. It is a figure which compares and compares the positional relationship of a conventional example, illumination arrangement | positioning, and a face etc. with respect to the illumination with respect to the driver | operator with glasses. It is a figure which compares and shows the acquired image by each illumination arrangement | positioning shown in FIG. It is a figure explaining the light quantity measurement on a face. It is a figure explaining the map for illumination control. It is a figure explaining face position detection. It is a figure which shows the structure of the imaging device which has the conventional projector. It is a figure which shows the example of illumination by the conventional projector. It is a figure which shows another example of illumination by the conventional projector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Camera, 2 ... Floodlight controller, 4 ... Face, 21 ... Face position detection part, 22 ... Illumination control part, 23 ... Control map, 31, 32, 33 ... Illumination (light projector), 41 ... Glasses, 50 ... Image, 51 ... Face area, 60 ... Room mirror, 61 ... Front pillar, 62 ... Instrumental panel

Claims (3)

A control device for a projector that irradiates imaging light to an imaging target of an imaging device,
A projector having a plurality of the projectors, determining an imaging range plane at an imaging target position of the imaging apparatus, and setting an outside of a quadrangular prism having the same plane as a vertical cross section as an illumination position by the projector Control device.   The imaging device is an imaging device for recognizing a driver's face mounted on a vehicle, and an imaging range surface at the imaging target position is set based on a passenger compartment shape. The projector control device described. The projector control device according to claim 2, wherein a face position is acquired from a driver's face image acquired by the imaging device, and an illumination amount of the projector is controlled based on the face position.