Patent Description:
Vehicle lamps play an important role in safe driving at night or inside tunnels. If, with the priority on the visibility of the driver, vehicle lamps brightly illuminate a wide range in the space ahead of the vehicle, this creates a problem of causing glare to the driver of a preceding vehicle or an oncoming vehicle ahead of the host vehicle.

Adaptive driving beam (ADB) control has been proposed in recent years, and this ADB control dynamically and adaptively controls a light distribution pattern of a high beam based on the condition surrounding the vehicle (see, for example, patent document <NUM>). The ADB control, by use of a camera, detects the presence of a target that is located ahead of the host vehicle and that should be shaded against high luminance light. Then, the ADB control reduces or eliminates the light for the region corresponding to this target to be shaded against the light.

<CIT> discloses another vehicle detection method and device.

The ADB control described above can improve the visibility of the driver of the host vehicle while preventing glare caused to front vehicles, such as a preceding vehicle and an oncoming vehicle. The improved visibility allows the driver to recognize obstacles and so on ahead of the vehicle more reliably, and this in turn improves the safety in driving. Meanwhile, there exists a constant demand for further improving the visibility of drivers for further improvement in safety. In implementing the ADB control, grasping the position of a front vehicle is important.

The present invention has been made in view of such circumstances, and one object of the present invention is to provide a technique for improving the visibility of a driver. Another object of the present invention is to provide a novel technique for detecting the position of a vehicle.

An aspect not belonging to the present invention provides a light distribution controlling device. This device includes a vehicle detector, a region determiner, and pattern determiner. The vehicle detector detects a front vehicle through an image analysis on an image obtained from an imaging device that captures an image of a region ahead of a vehicle. The region determiner sets a processing region by adding a predetermined margin in a widthwise direction of the vehicle to a presence region of the front vehicle. The pattern determiner, in parallel with the detection of the front vehicle by the vehicle detector, sets a light blocking portion based on a pixel value of a pair of luminous points included in the processing region and appearing side by side in the widthwise direction of the vehicle in the image obtained from the imaging device and determines a light distribution pattern that includes the light blocking portion.

Another aspect not belonging to the present invention provides a vehicle lamp system. This system includes an imaging device, a light distribution variable lamp, the light distribution controlling device according to the above aspect, and a lamp controlling device. The imaging device captures an image of a region ahead of a vehicle. The light distribution variable lamp can illuminate the region ahead of the vehicle with a visible light beam of a variable intensity distribution. The lamp controlling device controls the light distribution variable lamp so as to form the light distribution pattern.

Another aspect not belonging to the present invention provides a light distribution controlling method. This controlling method includes: detecting a front vehicle through an image analysis on an image obtained from an imaging device that captures an image of a region ahead of a vehicle; setting a processing region by adding a predetermined margin in a widthwise direction of the vehicle to a presence region of the front vehicle; and in parallel with the detecting of the front vehicle, setting a light blocking portion based on a pixel value of a pair of luminous points included in the processing region and appearing side by side in the widthwise direction of the vehicle in the image obtained from the imaging device and determining a light distribution pattern that includes the light blocking portion.

To address the problem described above an aspect of the present invention provides a vehicle position detecting device as outlined in claim <NUM>. This device generates a lateral dilated region by performing a first dilation process and a first erosion process on an image that is based on an imaging device by use of a first structuring element of a predetermined shape elongated in a widthwise direction of a vehicle, and detects a position of a front vehicle based on the lateral dilated region. The lateral dilated region is a region in which a pair of luminous points included in the image and appearing side by side in the widthwise direction of the vehicle are connected to each other. The imaging device captures an image of a region ahead of the vehicle.

Yet another aspect of the present invention provides a vehicle lamp system as outlined in claim <NUM>. This system includes an imaging device, a light distribution variable lamp, a light distribution controlling device, and a lamp controlling device. The imaging device captures an image of a region ahead of a vehicle. The light distribution variable lamp can illuminate the region ahead of the vehicle with a visible light beam of a variable intensity distribution. The light distribution controlling device includes the vehicle position detecting device according to the above aspect and a pattern determiner that determines a light distribution pattern including a light blocking portion based on a detection result of the vehicle position detecting device. The lamp controlling device controls the light distribution variable lamp so as to form the light distribution pattern.

Yet another aspect of the present invention provides a vehicle position detecting method as outlined in claim <NUM>. This controlling method includes: generating a lateral dilated region by performing a first dilation process and a first erosion process on an image that is based on an imaging device by use of a first structuring element of a predetermined shape elongated in a widthwise direction of a vehicle, the lateral dilated region being a region in which a pair of luminous points included in the image and appearing side by side in the widthwise direction of the vehicle are connected to each other, the imaging device capturing an image of a region ahead of the vehicle; and detecting a position of a front vehicle based on the lateral dilated region.

The present invention can improve the visibility of a driver. Furthermore, the present invention can provide a novel technique for detecting the position of a vehicle.

Hereinafter, the present invention will be described based on some exemplary embodiments and with reference to the drawings. The embodiments are illustrative in nature and are not intended to limit the invention. Not all the features and combinations thereof described according to the embodiments are necessarily essential to the invention. Identical or equivalent constituent elements, members, and processes illustrated in the drawings are given identical reference characters, and duplicate description thereof will be omitted, as appropriate. The scales and the shapes of the components illustrated in the drawings are set merely for convenience in order to facilitate an understanding of the description and are not to be interpreted as limiting the invention, unless specifically indicated otherwise. When terms such as "first" and "second" are used in the present specification or in the claims, these terms do not indicate the order or the levels of importance in any way and are merely used to distinguish between a given configuration and another configuration, unless specifically indicated otherwise. The part of a member that is not important in describing the embodiments are omitted from the drawings.

<FIG> is a block diagram of a vehicle lamp system according to Embodiment <NUM>, which does not form part of the present invention. <FIG> depicts some of the constituent elements of a vehicle lamp system <NUM> in the form of functional blocks. These functional blocks are implemented, in terms of their hardware configuration, by elements and/or circuits, such as a CPU or a memory of a computer, or implemented, in terms of their software configuration, by a computer program or the like. It is to be appreciated by a person skilled in the art that these functional blocks can be implemented in a variety of forms through combinations of hardware and software.

The vehicle lamp system <NUM> includes a light distribution variable lamp <NUM>, an imaging device <NUM>, a light distribution controlling device <NUM>, and a lamp controlling device <NUM>. These members may be embedded within a single chassis, or some of these members may be provided outside a chassis, that is, provided in the vehicle.

The light distribution variable lamp <NUM> is a white light source that can illuminate a region ahead of the vehicle with a visible light beam L1 of a variable intensity distribution. The light distribution variable lamp <NUM> receives data indicating a light distribution pattern PTN from the lamp controlling device <NUM>, emits a visible light beam L1 having an intensity distribution corresponding to the light distribution pattern PTN, and forms the light distribution pattern PTN in the space ahead of the vehicle. There is no particular limitation on the configuration of the light distribution variable lamp <NUM>, and the light distribution variable lamp <NUM> may include, for example, a semiconductor light source, such as a laser diode (LD) or a light emitting diode (LED), and a lighting circuit that drives the semiconductor light source to turn it on.

In order to form an illuminance distribution corresponding to a given light distribution pattern PTN, the light distribution variable lamp <NUM> may include, for example, a pattern forming device of a matrix type, such as a digital mirror device (DMD) or a liquid crystal device, or a pattern forming device of a scan optics type that scans the space ahead of the host vehicle with light from a light source. The resolving power (the resolution) of the light distribution variable lamp <NUM> is, for example, from <NUM>,<NUM> pixels to <NUM>,<NUM> pixels. The time required for the light distribution variable lamp <NUM> to form a single light distribution pattern PTN is, for example, from <NUM> to <NUM>.

The imaging device <NUM> has a sensitivity to a visible light range and captures an image of a region ahead of the vehicle. The imaging device <NUM> according to the present embodiment includes a high-speed camera <NUM> and a low-speed camera <NUM>. The high-speed camera <NUM> has a relatively high frame rate, and its frame rate is, for example, from <NUM> fps to <NUM>,<NUM> fps (from <NUM> to <NUM> per frame). Meanwhile, the low-speed camera <NUM> has a frame rate lower than the frame rate of the high-speed camera <NUM>, and the frame rate of the low-speed camera <NUM> is, for example, from <NUM> fps to <NUM> fps (from about <NUM> to <NUM> per frame).

The high-speed camera <NUM> has a relatively low resolution, and its resolution is, for example, from <NUM>,<NUM> pixels to less than <NUM>,<NUM>,<NUM> pixels. Meanwhile, the low-speed camera <NUM> has a relatively high resolution, and its resolution is, for example, no lower than <NUM>,<NUM>,<NUM> pixels. Accordingly, an image IMG1 that the high-speed camera <NUM> generates is of relatively low definition, whereas an image IMG2 that the low-speed camera <NUM> generates is of relatively high definition. In other words, an image IMG1 is of lower definition than an image IMG2, whereas an image IMG2 is of higher definition than an image IMG1. The resolution of the high-speed camera <NUM> and the resolution of the low-speed camera <NUM> are not limited to the numerical values mentioned above and can each be set to any value within a range of technological consistency.

The high-speed camera <NUM> and the low-speed camera <NUM> each capture an image of reflected light L2 of a visible light beam L1 reflected by an object located ahead of the vehicle. It suffices that the high-speed camera <NUM> and the low-speed camera <NUM> each have a sensitivity to a wavelength range of at least a visible light beam L1. Preferably, the high-speed camera <NUM> and the low-speed camera <NUM> are provided such that their respective angles of view coincide with each other.

The light distribution controlling device <NUM> executes ADB control of dynamically and adaptively controlling a light distribution pattern PTN to be supplied to the light distribution variable lamp <NUM> based on an image obtained from the imaging device <NUM>. A light distribution pattern PTN can be regarded as a two-dimensional illuminance distribution of an illumination pattern <NUM> that the light distribution variable lamp <NUM> forms on a virtual vertical screen <NUM> located ahead of the host vehicle. The light distribution controlling device <NUM> can be formed by a digital processor. The light distribution controlling device <NUM> may be formed, for example but not limited to, by a combination of a microcomputer including a central processing unit (CPU) and a software program or by a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

The light distribution controlling device <NUM> includes a vehicle detector <NUM>, a region determiner <NUM>, and a pattern determiner <NUM>. These components each operate as an integrated circuit constituting the component executes a program stored in a memory. <FIG> is an illustration for describing an operation of the light distribution controlling device <NUM>. The upper section illustrates results output from the vehicle detector <NUM>, the middle section illustrates results output from the region determiner <NUM>, and the lower section illustrates results output from the pattern determiner <NUM>. The four images arrayed sideways in each section are results output from the corresponding component at respective times t<NUM> to t<NUM>.

The vehicle detector <NUM> detects a front vehicle <NUM> through an image analysis on an image obtained from the imaging device <NUM>. The vehicle detector <NUM> according to the present embodiment detects a front vehicle <NUM> based on a high-definition image IMG2 obtained from the low-speed camera <NUM>. A front vehicle <NUM> includes a preceding vehicle and an oncoming vehicle. A front vehicle <NUM> includes a pair <NUM> of luminous points corresponding to its lamps. A pair <NUM> of luminous points corresponds to headlamps if the front vehicle <NUM> is an oncoming vehicle or corresponds to rear lamps if the front vehicle <NUM> is a preceding vehicle. A rear lamp includes a stop lamp and a tail lamp. A pair <NUM> of luminous points include a left luminous point 102a and a right luminous point 102b.

The vehicle detector <NUM> executes a high-precision image analysis by use of a known method including, for example, algorithm recognition or deep learning and outputs a result of the analysis at low speed. For example, the vehicle detector <NUM> can output a result of detecting a front vehicle <NUM> every <NUM>. In the example illustrated in <FIG>, the vehicle detector <NUM> outputs a detection result at time t<NUM> and at time t<NUM>.

The vehicle detector <NUM> generates, as the result of detecting a front vehicle <NUM>, angle information of a presence region <NUM> of the front vehicle <NUM> relative to the host vehicle. This angle information includes an angle θL to the left end of the front vehicle <NUM> and an angle θR to the right end of the front vehicle <NUM>. The left-end angle θL and the right-end angle θR are mapped to the angle of view of the low-speed camera <NUM> and match the positions of, respectively, the left end and the right end of the front vehicle <NUM> in an image IMG2. The vehicle detector <NUM> transmits a signal indicating this detection result to the region determiner <NUM>.

The region determiner <NUM> sets a processing region <NUM> by adding a predetermined margin M in the widthwise direction (the right-left direction) of the vehicle to the presence region <NUM> of the front vehicle <NUM>. The region determiner <NUM> adds a left margin ML to the left-end angle θL and a right margin MR to the right-end angle θR. Accordingly, the processing region <NUM> is wider in the widthwise direction of the vehicle than the presence region <NUM> of the front vehicle <NUM> by the left margin ML and right margin MR. The region determiner <NUM> generates angle information of a processing region <NUM> as information that indicates the result of determining the processing region <NUM> and transmits a signal that indicates this determination result to the pattern determiner <NUM>.

The only process that the region determiner <NUM> executes is adding a margin M to a presence region <NUM> set by the vehicle detector <NUM>. Therefore, the processing speed of the region determiner <NUM> is higher than the processing speed of the vehicle detector <NUM>, and the region determiner <NUM> can, for example, output a result of determining a processing region <NUM> from every <NUM> to every <NUM>. In the example illustrated in <FIG>, the region determiner <NUM> outputs a determination result at each of time t<NUM> to time t<NUM>.

The pattern determiner <NUM> determines a light distribution pattern PTN in which light is blocked at a portion corresponding to a front vehicle <NUM>, based on an image obtained from the imaging device <NUM>. The pattern determiner <NUM> according to the present embodiment determines a light distribution pattern PTN based on an image IMG1 obtained from the high-speed camera <NUM>. "Light being blocked at a certain portion" includes a case where the brightness (the illuminance) of that portion is lowered as well as a case where the brightness (the illuminance) of that portion is brought absolutely to zero.

In parallel with the process where the vehicle detector <NUM> detects a front vehicle <NUM>, the pattern determiner <NUM> sets a light blocking portion <NUM> based on the pixel value of a pair <NUM> of luminous points included in a processing region <NUM> in an image IMG1 and located side by side in the widthwise direction of the vehicle. <FIG> are illustrations for describing an operation of the pattern determiner <NUM>.

As illustrated in <FIG>, first, the pattern determiner <NUM> maps angle information of a processing region <NUM> received from the region determiner <NUM> onto an image IMG1 and thus sets the processing region <NUM> on the image IMG1. Then, the pattern determiner <NUM> extracts a pixel pair <NUM> corresponding to a pair <NUM> of luminous points based on the pixel value of each pixel, or specifically, the brightness value or the color value of each pixel in the processing region <NUM> on the image IMG1. The pixel pair <NUM> includes a left luminous point pixel 26a that overlaps a left luminous point 102a and a right luminous point pixel 26b that overlaps a right luminous point 102b.

Next, as illustrated in <FIG>, the pattern determiner <NUM> sets, as an upper left dilating group 30a, the left luminous point pixel 26a and a predetermined number of upper left pixels 28a that are arrayed in the upward direction from the left luminous point pixel 26a in the image IMG1. Moreover, the pattern determiner <NUM> sets, as an upper right dilating group 30b, the right luminous point pixel 26b and a predetermined number of upper right pixels 28b that are arrayed in the upward direction from the right luminous point pixel 26b in the image IMG1.

The pattern determiner <NUM> according to the present embodiment, by use of a first structuring element <NUM> of a predetermined shape elongated in the up-down direction, maps a pixel at the upper end of the first structuring element <NUM> to a pixel 32a of interest and thus performs a dilation process on the processing region <NUM> in the image IMG1. Thus, in the image IMG1, the pixel value of the upper left pixels 28a is changed to the pixel value of the left luminous point pixel 26a, and the pixel value of the upper right pixels 28b is changed to the pixel value of the right luminous point pixel 26b. As a result, an upward dilated pattern image IMG1a that includes the upper left dilating group 30a and the upper right dilating group 30b is created.

Next, as illustrated in <FIG>, the pattern determiner <NUM> sets, as a right dilating group <NUM>, the upper left dilating group 30a and a predetermined number of right column pixels <NUM> that are arrayed in the right direction from the upper left dilating group 30a in the upward dilated pattern image IMG1a. The pattern determiner <NUM> according to the present embodiment, by use of a second structuring element <NUM> of a predetermined shape elongated in the widthwise direction of the vehicle, maps a pixel at the right end of the second structuring element <NUM> to a pixel 38a of interest and thus performs a dilation process on the processing region <NUM> in the upward dilated pattern image IMG1a. The second structuring element <NUM> has a length that can at least connect the upper left dilating group 30a and the upper right dilating group 30b through the dilation process. Thus, the pixel value of the right column pixels <NUM> is changed to the pixel value of the upper left dilating group 30a in the upward dilated pattern image IMG1a. As a result, a right dilated pattern image IMG1b that includes the right dilating group <NUM> is created.

Moreover, as illustrated in <FIG>, the pattern determiner <NUM> sets, as a left dilating group <NUM>, the upper right dilating group 30b and a predetermined number of left column pixels <NUM> that are arrayed in the left direction from the upper right dilating group 30b in the upward dilated pattern image IMG1a. The pattern determiner <NUM> according to the present embodiment, by use of a third structuring element <NUM> of a predetermined shape elongated in the widthwise direction of the vehicle, maps a pixel at the left end of the third structuring element <NUM> to a pixel 44a of interest and thus performs a dilation process on the processing region <NUM> in the upward dilated pattern image IMG1a. The third structuring element <NUM> has a length that can at least connect the upper left dilating group 30a and the upper right dilating group 30b through the dilation process. Thus, the pixel value of the left column pixels <NUM> is changed to the pixel value of the upper right dilating group 30b in the upward dilated pattern image IMG1a. As a result, a left dilated pattern image IMG1c that includes the left dilating group <NUM> is created.

Then, as illustrated in <FIG>, the pattern determiner <NUM> incorporates a pixel region <NUM> where the right dilating group <NUM> and the left dilating group <NUM> overlap each other into a light blocking portion <NUM>. The pattern determiner <NUM> according to the present embodiment combines the right dilated pattern image IMG1b and the left dilated pattern image IMG1c, that is, performs an AND operation on the right dilated pattern image IMG1b and the left dilated pattern image IMG1c. Thus, the pattern determiner <NUM> identifies the pixel region <NUM> where the right dilating group <NUM> and the left dilating group <NUM> overlap each other and sets the light blocking portion <NUM> such that the light blocking portion <NUM> includes this pixel region <NUM> (see <FIG>).

Then, the pattern determiner <NUM> determines a light distribution pattern PTN that includes the light blocking portion <NUM>. For example, the pattern determiner <NUM> sets a predetermined first illuminance to a region excluding the light blocking portion <NUM> and sets a second illuminance lower than the first illuminance to the light blocking portion <NUM>. As described above, the second illuminance may be zero or an illuminance that is higher than zero but lower than the first illuminance. The pattern determiner <NUM> transmits data indicating this light distribution pattern PTN to the lamp controlling device <NUM>.

The target of the process performed by the pattern determiner <NUM> is limited to a processing region <NUM> in an image IMG1. The pattern determiner <NUM> determines a light blocking portion <NUM> based on the pixel values (the brightness values, the color values, or the like) of the image IMG1. Specifically, the pattern determiner <NUM> determines a light blocking portion <NUM> by performing the dilation processes described above on an image IMG1 to convert the pixel value of each pixel. Accordingly, the process executed by the pattern determiner <NUM> is completed in a shorter period than a high-level image analysis executed by the vehicle detector <NUM>. Therefore, the processing speed of the pattern determiner <NUM> is higher than the processing speed of the vehicle detector <NUM>, and the pattern determiner <NUM> can, for example, output a result of determining a light distribution pattern PTN from every <NUM> to every <NUM>. In the example illustrated in <FIG>, the pattern determiner <NUM> outputs a determination result at each of time t<NUM> to time t<NUM>.

It is to be noted that the order of the process of creating a right dilated pattern image IMG1b illustrated in <FIG> and the process of creating a left dilated pattern image IMG1c illustrated in <FIG> is flexible, and these processes can be performed in parallel. Moreover, <FIG> illustrate the first structuring element <NUM> to the third structuring element <NUM> schematically, and the number of pixels forming each of the first structuring element <NUM> to the third structuring element <NUM> is not limited to what is depicted in the drawings. A presence region <NUM> and a processing region <NUM> may be defined in terms of not only the angular range in the widthwise direction of the vehicle but also the angular range in the up-down direction.

The lamp controlling device <NUM> controls the light distribution variable lamp <NUM> so that the light distribution variable lamp <NUM> emits a visible light beam L1 having an intensity distribution corresponding to a light distribution pattern PTN set by the pattern determiner <NUM>. For example, in a case where the light distribution variable lamp <NUM> includes a DMD, the lamp controlling device <NUM> controls the on and off of the light source and the on/off switching of each mirror element forming the DMD. The lamp controlling device <NUM> can transmit a driving signal to the light distribution variable lamp <NUM>, for example, every <NUM> to <NUM>.

This control makes it possible to form a light distribution pattern PTN having a light blocking portion <NUM> that overlaps a front vehicle <NUM> and to increase the visibility of the driver of the host vehicle without causing glare to the driver of the front vehicle <NUM>. As described above, the pattern determiner <NUM> has a higher processing speed than the vehicle detector <NUM> and can determine a light blocking portion <NUM> and a light distribution pattern PTN at a frequency higher than the frequency at which the vehicle detector <NUM> outputs a detection result. Accordingly, this configuration allows a light blocking portion <NUM> to follow the movement of a front vehicle <NUM> with higher accuracy than a configuration where a light blocking portion <NUM> is set directly based on a detection result of the vehicle detector <NUM>.

Moreover, as described above, the vehicle detector <NUM> has a relatively lower processing speed (i.e., a lower processing speed than the region determiner <NUM>) and outputs a detection result at time t<NUM> and at time t<NUM> in the example illustrated in <FIG>. Therefore, the presence region <NUM> set by the vehicle detector <NUM> partially fails to cover the front vehicle <NUM> at time t<NUM> and at time t<NUM>. Meanwhile, the region determiner <NUM> has a relatively higher processing speed (i.e., a higher processing speed than the vehicle detector <NUM>) and determines a processing region <NUM> at a frequency higher than the frequency at which the vehicle detector <NUM> outputs a detection result. Therefore, at time t<NUM> and at time t<NUM>, the region determiner <NUM> sets the processing region <NUM> relative to the presence region <NUM> output from the vehicle detector <NUM> at time t<NUM>. In other words, at a predetermined timing (times t<NUM>, t<NUM>), the region determiner <NUM> repeatedly sets a processing region <NUM> with respect to the same detection result (a presence region <NUM>) obtained from the vehicle detector <NUM>.

As the number of times the region determiner <NUM> sets a processing region <NUM> with respect to the same presence region <NUM> increases, the region determiner <NUM> gradually increases the size of the margin M. This causes the size of the processing region <NUM> to increase gradually. This configuration can reduce the likelihood that a front vehicle <NUM> goes outside a processing region <NUM> even when the front vehicle <NUM> has gone outside its presence region <NUM>. Accordingly, the front vehicle <NUM> can be shaded more reliably. Moreover, setting a smaller margin M at an early stage of setting a processing region <NUM> makes it possible to set the processing speed of the pattern determiner <NUM> higher. Herein, the region determiner <NUM> restores the margin M to its initial value upon receiving a new detection result from the vehicle detector <NUM>.

The pattern determiner <NUM> may identify whether a pair <NUM> of luminous points included in a processing region <NUM> is headlamps of an oncoming vehicle or rear lamps of a preceding vehicle. For example, the pattern determiner <NUM> performs a gray scale conversion process on a processing region <NUM>. Then, the pattern determiner <NUM> binarizes the brightness value of each pixel and thereby extracts headlamps. In addition, the pattern determiner <NUM> performs an HSV conversion process on a processing region <NUM>. Then, the pattern determiner <NUM> binarizes the color value of each pixel and thereby extracts rear lamps. Thereafter, the pattern determiner <NUM> performs an OR operation on the image obtained as a result of extracting the headlamps and the image obtained as a result of extracting the rear lamps. Thus, the pattern determiner <NUM> generates an image that includes a pixel pair <NUM> corresponding to the headlamps and a pixel pair <NUM> corresponding to the rear lamps and, based on these images, obtains an upward dilated pattern image IMG1a that includes an upper left dilating group 30a and an upper right dilating group 30b.

In one example, in a case where a light blocking portion <NUM> is set for a pixel pair <NUM> corresponding to the headlamps of an oncoming vehicle, the pattern determiner <NUM> sets a pixel region <NUM> where a right dilating group <NUM> and a left dilating group <NUM> overlap each other as the light blocking portion <NUM>. Meanwhile, in a case where a light blocking portion <NUM> is set for a pixel pair <NUM> corresponding to the rear lamps of a preceding vehicle, the pattern determiner <NUM> sets a region obtained by adding a predetermined margin to each of the right and left of a pixel region <NUM> as the light blocking portion <NUM>. This predetermined margin corresponds to a region that overlaps each sideview mirror of the preceding vehicle. This configuration can further suppress glare caused to the driver of the preceding vehicle.

<FIG> are each a flowchart illustrating an example of ADB control executed by the light distribution controlling device <NUM> according to Embodiment <NUM>. This flow is executed repeatedly at predetermined timings, for example, when the light distribution controlling device <NUM> is instructed to execute the ADB control via a light switch (not illustrated) and when the ignition is on, and the flow is terminated when the instruction to execute the ADB control is canceled (or upon the light distribution controlling device <NUM> instructed to stop the ADB control) or when the ignition is turned off. The flow illustrated in <FIG> and the flow illustrated in <FIG> are executed in parallel.

As illustrated in <FIG>, the light distribution controlling device <NUM> determines whether the light distribution controlling device <NUM> has received a new image IMG2 from the low-speed camera <NUM> (S101). If the light distribution controlling device <NUM> has received a new image IMG2 (Y at S101), the light distribution controlling device <NUM> detects a front vehicle <NUM> based on the received image IMG2 and updates a presence region <NUM> (S102). Then, the light distribution controlling device <NUM> updates a processing region <NUM> based on the obtained presence region <NUM> (S103) and terminates this routine. If the light distribution controlling device <NUM> has not received a new image IMG2 from the low-speed camera <NUM> (N at S101), the light distribution controlling device <NUM> updates a processing region <NUM> based on an already acquired presence region <NUM> (S103).

Meanwhile, as illustrated in <FIG>, the light distribution controlling device <NUM> determines whether the light distribution controlling device <NUM> has received a new image IMG1 from the high-speed camera <NUM> (S201). If the light distribution controlling device <NUM> has not received a new image IMG1 (N at S201), the light distribution controlling device <NUM> terminates this routine. If the light distribution controlling device <NUM> has received a new image IMG1 (Y at S201), the light distribution controlling device <NUM> sets the processing region <NUM> updated at step S103 in the image IMG1 (S202). Then, the light distribution controlling device <NUM> extracts luminous points in the processing region <NUM>, that is, extracts a pixel pair <NUM> (S203). Then, the light distribution controlling device <NUM> determines a light blocking portion <NUM> through a dilation process (S204). Then, the light distribution controlling device <NUM> transmits data indicating a new light distribution pattern PTN to the lamp controlling device <NUM> to update the light distribution pattern PTN (S205) and terminates this routine.

As described above, the light distribution controlling device <NUM> according to the present embodiment includes the vehicle detector <NUM>, the region determiner <NUM>, and the pattern determiner <NUM>. The vehicle detector <NUM> detects a front vehicle through an image analysis on an image obtained from the imaging device <NUM> that captures an image of a region ahead of the vehicle. The region determiner <NUM> sets a processing region <NUM> by adding a predetermined margin M in the widthwise direction of the vehicle to a presence region <NUM> of a front vehicle <NUM>. The pattern determiner <NUM>, in parallel with the detection of the front vehicle <NUM> by the vehicle detector <NUM>, sets a light blocking portion <NUM> based on the pixel value of a pair <NUM> of luminous points included in the processing region <NUM> and appearing side by side in the widthwise direction of the vehicle in the image obtained from the imaging device <NUM> and determines a light distribution pattern PTN that includes the light blocking portion <NUM>.

The pattern determiner <NUM> determines the light blocking portion <NUM> based on the pixel values of the image. Therefore, the pattern determiner <NUM> can execute the process at a higher speed than the vehicle detector <NUM> that executes the image analysis. Moreover, the image region on which the pattern determiner <NUM> executes the process is limited to the processing region <NUM>. In addition, the pattern determiner <NUM> executes the process in parallel with the process by the vehicle detector <NUM>. Therefore, the light distribution controlling device <NUM> according to the present embodiment can update the light distribution pattern PTN at a high frequency. This configuration allows the light blocking portion <NUM> to follow the movement of the front vehicle <NUM> with high accuracy.

In conventional ADB control in which a front vehicle is detected through an image analysis and a light blocking portion is determined based directly on the result of the image analysis, the light blocking portion is given a margin in consideration of a mismatch between the light blocking portion and the front vehicle caused by a delay in the process of determining the light blocking portion. In contrast, according to the present embodiment, the light blocking portion <NUM> can be matched to the front vehicle <NUM> with high accuracy, and this can help reduce the margin that is given to the light blocking portion. Accordingly, the visibility of the driver can be improved.

Moreover, in the image obtained from the imaging device <NUM>, the pattern determiner <NUM> according to the present embodiment sets, as an upper left dilating group 30a, a left luminous point pixel 26a that overlaps a left luminous point 102a in the pair <NUM> of luminous points and a predetermined number of upper left pixels 28a that are arrayed in the upward direction from the left luminous point pixel 26a and sets, as an upper right dilating group 30b, a right luminous point pixel 26b that overlaps a right luminous point 102b and a predetermined number of upper right pixels 28b that are arrayed in the upward direction from the right luminous point pixel 26b. In addition, the pattern determiner <NUM> sets, as a right dilating group <NUM>, the upper left dilating group 30a and a predetermined number of right column pixels <NUM> that are arrayed in the right direction from the upper left dilating group 30a and sets, as a left dilating group <NUM>, the upper right dilating group 30b and a predetermined number of left column pixels <NUM> that are arrayed in the left direction from the upper right dilating group 30b. Furthermore, the pattern determiner <NUM> incorporates a pixel region <NUM> where the right dilating group <NUM> and the left dilating group <NUM> overlap each other into the light blocking portion <NUM>. This configuration can further increase the processing speed of the light distribution controlling device <NUM>.

Furthermore, in the image obtained from the imaging device <NUM>, the pattern determiner <NUM> changes the pixel value of the upper left pixels 28a to the pixel value of the left luminous point pixel 26a and changes the pixel value of the upper right pixels 28b to the pixel value of the right luminous point pixel 26b. Thus, the pattern determiner <NUM> creates an upward dilated pattern image IMG1a that includes the upper left dilating group 30a and the upper right dilating group 30b. Moreover, in the upward dilated pattern image IMG1a, the pattern determiner <NUM> changes the pixel value of the right column pixels <NUM> to the pixel value of the upper left dilating group 30a. Thus, the pattern determiner <NUM> creates a right dilated pattern image IMG1b that includes the right dilating group <NUM>. In addition, in the upward dilated pattern image IMG1a, the pattern determiner <NUM> changes the pixel value of the left column pixels <NUM> to the pixel value of the upper right dilating group 30b. Thus, the pattern determiner <NUM> creates a left dilated pattern image IMG1c that includes the left dilating group <NUM>. Furthermore, the pattern determiner <NUM> sets the light blocking portion <NUM> by combining the right dilated pattern image IMG1b and the left dilated pattern image IMG1c. This configuration can further increase the processing speed of the light distribution controlling device <NUM>.

Meanwhile, the region determiner <NUM> repeatedly sets the processing region <NUM> relative to the same detection result obtained from the vehicle detector <NUM> and gradually increases the size of the margin M as the number of times the processing region <NUM> is set increases. This configuration makes it possible to shade the presence region <NUM> of the front vehicle <NUM> more reliably.

The imaging device <NUM> includes the high-speed camera <NUM> and the low-speed camera <NUM> that has a frame rate lower than the frame rate of the high-speed camera <NUM>. The vehicle detector <NUM> detects the front vehicle <NUM> based on an image IMG2 obtained from the low-speed camera <NUM>, and the pattern determiner <NUM> determines the light distribution pattern PTN based on an image IMG1 obtained from the high-speed camera <NUM>. This configuration makes it possible to execute the ADB control with higher accuracy. Assigning a camera to each of the vehicle detector <NUM> and the pattern determiner <NUM> makes it possible to adopt cameras specialized for the performance required for the respective processes. Typically, a camera having performance required for both the process of the vehicle detector <NUM> and the process of the pattern determiner <NUM> is expensive. As such, according to the present embodiment, the cost of the imaging device <NUM> can be reduced, and in turn the cost of the vehicle lamp system <NUM> can be reduced.

Thus far, Embodiment <NUM> according to the present invention has been described in detail. Embodiment <NUM> described above merely illustrates a specific example for implementing the present invention. The content of Embodiment <NUM> does not limit the technical scope of the present invention, and a number of design changes, including modification, addition, and deletion of a constituent element, can be made within the scope that does not depart from the sprit of the invention defined by the claims. A new embodiment resulting from adding a design change has advantageous effects of the embodiment combined as well as advantageous effects of the variation. With regard to Embodiment <NUM> described above, the expressions "according to the present embodiment," "in the present embodiment," and so on are added for emphasis to the content that can be subjected to such a design change as described above, but such a design change is also permitted on the content without these expressions. A desired combination of the constituent elements described above is also valid as an aspect of the present invention. Hatching added along a section in the drawings does not limit the material of such with hatching.

A single camera may fill both the function of the high-speed camera <NUM> and the function of the low-speed camera <NUM>. For example, the low-speed camera <NUM> may be omitted if the high-speed camera <NUM> and the low-speed camera <NUM> have an equivalent resolution or if, while the high-speed camera <NUM> has a low resolution, the vehicle detector <NUM> is equipped with an algorithm that allows the vehicle detector <NUM> to detect a vehicle at a sufficient level with this low resolution. This configuration makes it possible to reduce the size of the vehicle lamp system <NUM>.

<FIG> is a block diagram of a vehicle lamp system according to Embodiment <NUM>, which forms part of the present invention. <FIG> depicts some of the constituent elements of a vehicle lamp system <NUM> in the form of functional blocks. These functional blocks are implemented, in terms of their hardware configuration, by elements and/or circuits, such as a CPU or a memory of a computer, or implemented, in terms of their software configuration, by a computer program or the like. It is to be appreciated by a person skilled in the art that these functional blocks can be implemented in a variety of forms through combinations of hardware and software.

The vehicle lamp system <NUM> includes a light distribution variable lamp <NUM>, an imaging device <NUM>, a light distribution controlling device <NUM>, and a lamp controlling device <NUM>. These members may be embedded within a single chassis, or some of the members may be provided outside a chassis, that is, provided in the vehicle.

In order to form an illuminance distribution corresponding to a given light distribution pattern PTN, the light distribution variable lamp <NUM> may include, for example, a pattern forming device of a matrix type, such as a digital mirror device (DMD) or a liquid crystal device, or a pattern forming device of a scan optics type that scans a space ahead of the host vehicle with light from a light source. The resolving power (the resolution) of the light distribution variable lamp <NUM> is, for example, from <NUM>,<NUM> pixels to <NUM>,<NUM> pixels.

The imaging device <NUM> has a sensitivity to a visible light range and captures an image of a region ahead of the vehicle. The imaging device <NUM> captures an image of reflected light L2 of a visible light beam L1 reflected by an object located ahead of the vehicle. It suffices that the imaging device <NUM> have a sensitivity to a wavelength range of at least a visible light beam L1.

The light distribution controlling device <NUM> executes ADB control of dynamically and adaptively controlling a light distribution pattern PTN to be supplied to the light distribution variable lamp <NUM> based on an image IMG obtained from the imaging device <NUM>. A light distribution pattern PTN can be regarded as a two-dimensional illuminance distribution of an illumination pattern <NUM> that the light distribution variable lamp <NUM> forms on a virtual vertical screen <NUM> located ahead of the host vehicle. The light distribution controlling device <NUM> can be formed by a digital processor. The light distribution controlling device <NUM> may be formed, for example but not limited to, by a combination of a microcomputer including a CPU and a software program or by a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

The light distribution controlling device <NUM> includes a vehicle position detecting device <NUM> and a pattern determiner <NUM>. These components each operate as an integrated circuit constituting the component executes a program stored in a memory. <FIG> is an illustration for describing a flow of control executed by the light distribution controlling device <NUM>. <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG> each illustrate a structuring element used or an image generated in the control executed by the light distribution controlling device <NUM>.

The vehicle position detecting device <NUM> detects the position of a front vehicle, including an oncoming vehicle or a preceding vehicle, by performing predetermined image processing on an image that is based on the imaging device <NUM>. An image that is based on the imaging device <NUM> includes not only an image IMG obtained directly from the imaging device <NUM> but also an image obtained by subjecting the image IMG to predetermined image processing, that is, an image derived from the directly obtained image IMG.

First, the vehicle position detecting device <NUM> acquires an image IMG (a camera image) from the imaging device <NUM> (S1101). As illustrated in <FIG>, the image IMG obtained from the imaging device <NUM> includes luminous points corresponding to rear lamps RL of preceding vehicles (hereinafter, also referred to simply as rear lamps RL) and luminous points corresponding to headlamps HL of oncoming vehicles (hereinafter, also referred to simply as headlamps HL). A rear lamp RL includes a stop lamp and a tail lamp.

The vehicle position detecting device <NUM> performs an HSV conversion process on the image IMG and performs a binarization process on an HSV image by use of a predetermined threshold value for the rear lamps RL (S1102). Thus, a rear lamp image IMGa where the rear lamps RL have been extracted is obtained, as illustrated in <FIG>. In the rear lamp image IMGa, pixels corresponding to the rear lamps RL have a high pixel value, and the remaining pixels have a low pixel value.

In addition, the vehicle position detecting device <NUM> performs an HSV conversion process on the image IMG and performs a binarization process on an HSV image by use of a predetermined threshold value for the headlamps HL (S1103). Thus, a headlamp image IMGb where the headlamps HL have been extracted is obtained, as illustrated in <FIG>. In the headlamp image IMGb, pixels corresponding to the headlamps HL have a high pixel value, and the remaining pixels have a low pixel value.

Herein, the order of the process of extracting the rear lamps RL (step S1102) and the process of extracting the headlamps HL (step S1103) is flexible, and these processes can be performed in parallel. In addition, there is no particular limitation on the method used in each extracting process, and a known method can be employed.

The vehicle position detecting device <NUM> performs a second erosion process a predetermined number of times on the image that is based on the imaging device <NUM>, or specifically, on the rear lamp image IMGa by use of a second structuring element <NUM> of a predetermined shape illustrated in <FIG> (S1104). <FIG> indicates that the second erosion process is performed three times on the rear lamp image IMGa, but this is not a limiting example, and this number can be set as desired.

The second structuring element <NUM> according to the present embodiment is cross-shaped. The vehicle position detecting device <NUM> performs the second erosion process on the rear lamp image IMGa with the center pixel of the second structuring element <NUM> mapped to a pixel 1014a of interest. <FIG> schematically illustrates the second structuring element <NUM>, and the number of pixels forming the respective portions that extend upward, downward, rightward, and leftward from the center pixel of the second structuring element <NUM> is not limited to what is depicted in the drawing.

In the second erosion process, if the pixels that overlap the second structuring element <NUM> include a pixel of a low pixel value, the pixel value of the pixel 1014a of interest is changed to this low pixel value. Therefore, the luminous points are deleted successively from a smaller luminous point as the number of times the second erosion process is performed increases. Normally, the size of a headlamp HL or a rear lamp RL of a front vehicle appears greater as the front vehicle is located closer to the host vehicle. Therefore, the headlamps HL or the rear lamps RL are deleted successively from those of the front vehicle located farther from the host vehicle as the number of times the second erosion process is performed increases.

The vehicle position detecting device <NUM> generates a first image that includes a pair of rear lamps RL located at a predetermined first distance and a pair of rear lamps RL located at a second distance farther than the first distance with the number of times the second erosion process is performed on the rear lamp image IMGa set to a relatively low number. In addition, the vehicle position detecting device <NUM> generates a second image that includes the pair of rear lamps RL located at the first distance and in which the pair of rear lamps RL located at the second distance has been deleted with the number of times the second erosion process is performed set to a relatively high number. In other words, the number of times the second erosion process is performed in generating a first image is lower than the number of times the second erosion process is performed in generating a second image, and the number of times the second erosion process is performed in generating a second image is higher than the number of times the second erosion process is performed in generating a first image.

<FIG> shows a rear lamp image IMGa0 obtained when the second erosion process has been performed zero times. <FIG> shows a rear lamp image IMGa1 obtained when the second erosion process has been performed once. <FIG> shows a rear lamp image IMGa3 obtained when the second erosion process has been performed three times. Herein, the vehicle position detecting device <NUM> also generates a rear lamp image IMGa by performing the second erosion process two times, but the illustration thereof is omitted.

The rear lamp image IMGa0 includes a pair RL1 of rear lamps RL located at a predetermined first distance and pairs RL2 of rear lamps RL located at a second distance farther than the first distance. Meanwhile, the rear lamp image IMGa1 includes the pair RL1 of rear lamps RL located at the first distance, but the pairs RL2 of rear lamps RL located at the second distance have been deleted in the rear lamp image IMGa1. Therefore, the rear lamp image IMGa0 corresponds to a first image, and the rear lamp image IMGa1 corresponds to a second image. Herein, the rear lamp images IMGa0 and IMGa1 each include a pair RL3 of rear lamps RL located closer than the pair RL1 of rear lamps RL.

The rear lamp image IMGa1 includes the pair RL3 of rear lamps RL located at a predetermined first distance and the pair RL1 of rear lamps RL located at a second distance farther than the first distance. Meanwhile, the rear lamp image IMGa3 includes the pair RL3 of rear lamps RL located at the first distance, but the pair RL1 of rear lamps RL located at the second distance has been deleted in the rear lamp image IMGa3. Therefore, the rear lamp image IMGa1 corresponds to a first image, and the rear lamp image IMGa3 corresponds to a second image.

The vehicle position detecting device <NUM> executes a similar process on the headlamp image IMGb as well. In other words, the vehicle position detecting device <NUM> performs the second erosion process a predetermined number of times on the headlamp image IMGb by use of the second structuring element <NUM> illustrated in <FIG> (S1105). <FIG> indicates that the second erosion process is performed five times on the headlamp image IMGb, but this is not a limiting example, and this number can be set as desired.

The vehicle position detecting device <NUM> generates a first image that includes a pair of headlamps HL located at a predetermined first distance and a pair of headlamps HL located at a second distance farther than the first distance with the number of times the second erosion process is performed on the headlamp image IMGb set to a relatively low number. In addition, the vehicle position detecting device <NUM> generates a second image that includes the pair of headlamps HL located at the first distance and in which the pair of headlamps HL located at the second distance has been deleted with the number of times the second erosion process is performed set to a relatively high number. In other words, the number of times the second erosion process is performed in generating a first image is lower than the number of times the second erosion process is performed in generating a second image, and the number of times the second erosion process is performed in generating a second image is higher than the number of times the second erosion process is performed in generating a first image.

<FIG> shows a headlamp image IMGb0 obtained when the second erosion process has been performed zero times. <FIG> shows a headlamp image IMGb1 obtained when the second erosion process has been performed once. <FIG> shows a headlamp image IMGb5 obtained when the second erosion process has been performed five times. Herein, the vehicle position detecting device <NUM> also generates headlamp images IMGb by performing the second erosion process two to four times, but the illustration thereof is omitted.

The headlamp image IMGb0 includes a pair HL1 of headlamps HL located at a predetermined first distance and pairs HL2 of headlamps HL located at a second distance farther than the first distance. Meanwhile, the headlamp image IMGb1 includes the pair HL1 of headlamps HL located at the first distance, but the pairs HL2 of headlamps HL located at the second distance have been deleted in the headlamp image IMGb1. Therefore, the headlamp image IMGb0 corresponds to a first image, and the headlamp image IMGb1 corresponds to a second image. Herein, the head lamp images IMGb0 and IMGb1 each include a pair HL3 of headlamps HL located closer than the pair HL1 of headlamps HL.

The headlamp image IMGb1 includes the pair HL3 of headlamps HL located at a predetermined first distance and the pair HL1 of headlamps HL located at a second distance farther than the first distance. Meanwhile, the headlamp image IMGb5 includes the pair HL3 of headlamps HL located at the first distance, but the pair HL1 of headlamps HL located at the second distance has been deleted in the headlamp image IMGb5. Therefore, the headlamp image IMGb1 corresponds to a first image, and the headlamp image IMGb5 corresponds to a second image.

Herein, the order of the second erosion process performed on the rear lamp image IMGa (step S1104) and the second erosion process performed on the headlamp image IMGb (step S1105) is flexible, and these processes can be performed in parallel.

The vehicle position detecting device <NUM> performs a first dilation process and a first erosion process on images that are based on the imaging device <NUM>, or specifically, on the rear lamp images IMGa0 to IMGa3 by use of respective first structuring elements <NUM> of a predetermined shape illustrated in <FIG> (S1106).

The first structuring elements <NUM> according to the present embodiment each have a shape elongated in the widthwise direction of the vehicle (the lateral direction). The vehicle position detecting device <NUM> performs the first erosion process after performing the first dilation process on the rear lamp images IMGa0 to IMGa3 with the center pixels of the respective first structuring elements <NUM> each mapped to a pixel 1016a of interest. <FIG> schematically illustrate the first structuring elements <NUM>, and the number of pixels forming the respective portions that extend rightward and leftward from the center pixel of each first structuring element <NUM> is not limited to what is depicted in the drawing.

In the first dilation process, if the pixels that overlap the first structuring element <NUM> includes a pixel of a high pixel value, the pixel value of the pixel 1016a of interest is changed to this high pixel value. Meanwhile, in the first erosion process, if the pixels that overlap the first structuring element <NUM> include a pixel of a low pixel value, the pixel value of the pixel 1016a of interest is changed to this low pixel value. Thus, a lateral dilated region <NUM> where a pair of rear lamps RL included in the rear lamp image IMGa0, IMGa1, or IMGa3 and appearing side by side in the widthwise direction of the vehicle is connected to each other is generated.

The vehicle position detecting device <NUM> performs the first dilation process and the first erosion process on a first image by use of a first structuring element <NUM> that is relatively shorter in the widthwise direction of the vehicle and performs the first dilation process and the first erosion process on a second image by use of a first structuring element <NUM> that is relatively longer in the widthwise direction of the vehicle. In other words, the first structuring element <NUM> used on the first image is shorter in the widthwise direction of the vehicle than the first structuring element <NUM> used on the second image, and the first structuring element <NUM> used on the second image is longer in the widthwise direction of the vehicle than the first structuring element <NUM> used on the first image. To rephrase, the vehicle position detecting device <NUM> performs the first dilation process and the first erosion process by use of the first structuring element <NUM> that is shorter in the widthwise direction of the vehicle on the image that has been subjected to the second erosion process a smaller number of times.

<FIG> shows a first structuring element 1016b used in the first dilation process and the first erosion process performed on the rear lamp image IMGa0. <FIG> shows a first structuring element 1016c used in the first dilation process and the first erosion process performed on the rear lamp image IMGa1. <FIG> shows a first structuring element 1016d used in the first dilation process and the first erosion process performed on the rear lamp image IMGa3.

Normally, the distance in a pair of rear lamps RL increases gradually as the vehicle becomes closer to the host vehicle. Therefore, the first dilation process in which the first structuring element <NUM> that is shorter in the widthwise direction of the vehicle is used can connect a pair of rear lamps RL that is far from the vehicle but cannot connect a pair of rear lamps RL that is close to the host vehicle. Accordingly, performing the first dilation process by use of the first structuring elements <NUM> of different lengths makes it possible to select a pair for which a lateral dilated region <NUM> is generated in accordance with the distance from the host vehicle.

The first structuring element 1016b used on the rear lamp image IMGa0, or a first image, is shorter in the right-left direction than the first structuring element 1016c used on the rear lamp image IMGa1, or a second image. The rear lamp image IMGa0 is an image that has been subjected to the second dilation process zero times and includes not only the pairs RL1 and RL3 of rear lamps RL close to the host vehicle but also the pair RL2 of rear lamps RL far from the host vehicle. Accordingly, performing the first dilation process on the rear lamp image IMGa0 by use of the first structuring element 1016b yields a lateral dilated region <NUM> where the rear lamps RL in each pair RL2 are connected to each other, but keeps the rear lamps RL in each of the pairs RL1 and RL3 separated from each other, as illustrated in <FIG>.

Meanwhile, the first structuring element 1016c used on the rear lamp image IMGa1, or a second image, is longer in the right-left direction than the first structuring element 1016b. Therefore, performing the first dilation process on the rear lamp image IMGa1 by use of the first structuring element 1016c yields a lateral dilated region <NUM> where the rear lamps RL in the pair RL1 close to the host vehicle are connected to each other, as illustrated in <FIG>. Here, the rear lamps RL in the pair RL3 that is closer to the host vehicle than the rear lamps RL in the pair RL1 remain separated from each other.

The first structuring element 1016c used on the rear lamp image IMGa1, or a first image, is shorter in the right-left direction than the first structuring element 1016d used on the rear lamp image IMGa3, or a second image. Accordingly, performing the first dilation process on the rear lamp image IMGa1 by use of the first structuring element 1016c yields a lateral dilated region <NUM> where the rear lamps RL in the pair RL1 are connected to each other, but keeps the rear lamps RL in the pair RL3 separated from each other, as illustrated in <FIG>.

Meanwhile, the first structuring element 1016d used on the rear lamp image IMGa3, or a second image, is longer in the right-left direction than the first structuring element 1016c. Therefore, performing the first dilation process on the rear lamp image IMGa3 by use of the first structuring element 1016d yields a lateral dilated region <NUM> where the rear lamps RL in the pair RL3 close to the host vehicle are connected to each other, as illustrated in <FIG>.

The length of each first structuring element <NUM> can be set as appropriate in accordance with the distance in the pair of luminous points from which a lateral dilated region <NUM> is generated. Moreover, the correspondence relationship between the number of times the second erosion process is performed and the length of the first structuring element <NUM> can be set as appropriate. For example, the length of each first structuring element <NUM> used on the corresponding one of the rear lamp images IMGa0 to IMGa3 is set in accordance with the least spaced part pair of luminous points among pairs of luminous points that remain after the second erosion process has been performed each number of times.

The rear lamp image IMGa1 does not include the pair RL2 of rear lamps RL as the rear lamp image IMGa1 has been subjected to the second erosion process. This can prevent a lateral dilated region <NUM> derived from the pair RL2 of rear lamps RL from being generated through the first dilation process where the first structuring element 1016c is used. In a similar manner, the rear lamp image IMGa3 does not include the pairs RL1 and RL2 of rear lamps RL as the rear lamp image IMGa3 has been subjected to the second erosion process. This can prevent a lateral dilated region <NUM> derived from the pair RL1 or RL2 of rear lamps RL from being generated through the first dilation process where the first structuring element 1016d is used.

When the first dilation process is performed on the pair RL2 of rear lamps RL by use of the first structuring element 1016c or the first structuring element 1016d that are each relatively longer, the lateral dilated region <NUM> obtained through this first dilation process may be longer in the widthwise direction of the vehicle than a lateral dilated region <NUM> obtained by use of the first structuring element 1016b that is relatively shorter.

For example, if the process of extracting each lamp described above is not performed, that is, if the first dilation process is performed on the image IMG illustrated in <FIG> that includes the headlamps HL and the rear lamps RL, using the first structuring element 1016c or the first structuring element 1016d that are each relatively longer may yield a single lateral dilated region <NUM> generated from the pair RL2 of rear lamps RL and the pair HL2 of headlamps HL that appear side by side in the right-left direction.

Alternatively, when, for example, the host vehicle is traveling on a road with multiple lanes in each direction, all the luminous points in the image IMG illustrated in <FIG> can be rear lamps RL. In this case, even if the process of extracting the rear lamps RL described above has been performed, that is, even if the first dilation process has been performed on the rear lamp image IMGa, using the first structuring element 1016c or the first structuring element 1016d that is relative longer may yield a single lateral dilated region <NUM> generated from two pairs RL2 of rear lamps RL appearing side by side in the right-left direction.

In these cases, even though two vehicles are actually traveling side by side ahead of the host vehicle, the vehicle position detection that is based on the lateral dilated region <NUM> may determine that there is only one vehicle. In this respect, when the first structuring elements <NUM> of different lengths are used in accordance with the distance in each pair of luminous points, the lateral dilated region <NUM> corresponding to each front vehicle can be generated more reliably. This configuration makes it possible to detect the position of a vehicle with higher accuracy.

The vehicle position detecting device <NUM> executes a similar process on the headlamp image IMGb as well. In other words, the vehicle position detecting device <NUM> performs the first dilation process and the first erosion process on the headlamp images IMGb0 to IMGb5 by use of respective first structuring elements <NUM> of a predetermined shape elongated in the widthwise direction of the vehicle schematically illustrated in <FIG> (S1107). The vehicle position detecting device <NUM> performs the first erosion process after performing the first dilation process on the headlamp images IMGb0 to IMGb5 with the center pixels of the respective first structuring elements <NUM> each mapped to a pixel 1016a of interest. The first dilation process and the first erosion process yield each lateral dilated region <NUM> where the pair of headlamps HL included in the headlamp image IMGb and appearing side by side in the widthwise direction of the vehicle are connected to each other.

The vehicle position detecting device <NUM> performs the first dilation process and the first erosion process on a first image by use of a first structuring element <NUM> that is relatively shorter in the widthwise direction of the vehicle and performs the first dilation process and the first erosion process on a second image by use of a first structuring element <NUM> that is relatively longer in the widthwise direction of the vehicle. In other words, the first structuring element <NUM> used on the first image is shorter in the widthwise direction of the vehicle than the first structuring element <NUM> used on the second image, and the first structuring element <NUM> used on the second image is longer in the widthwise direction of the vehicle than the first structuring element <NUM> used on the first image.

<FIG> shows a first structuring element 1016e used in the first dilation process and the first erosion process performed on the headlamp image IMGb0. <FIG> shows a first structuring element 1016f used in the first dilation process and the first erosion process performed on the headlamp image IMGb1. <FIG> shows a first structuring element <NUM> used in the first dilation process and the first erosion process performed on the headlamp image IMGb5.

The first structuring element 1016e used on the headlamp image IMGb0, or a first image, is shorter in the right-left direction than the first structuring element 1016f used on the headlamp image IMGb1, or a second image. Accordingly, performing the first dilation process on the headlamp image IMGb0 by use of the first structuring element 1016e yields a lateral dilated region <NUM> where the headlamps HL in the pair HL2 are connected to each other, but keeps the headlamps HL in each of the pairs HL1 and HL3 separated from each other, as illustrated in <FIG>.

Meanwhile, the first structuring element 1016f used on the headlamp image IMGb1, or a second image, is longer in the right-left direction than the first structuring element 1016e. Therefore, performing the first dilation process on the headlamp image IMGb1 by use of the first structuring element 1016f yields a lateral dilated region <NUM> where the headlamps HL in the pair HL1 close to the host vehicle are connected to each other, as illustrated in <FIG>. The headlamps HL in the pair HL3 that are closer to the host vehicle than the headlamps HL in the pair HL1 remain separated from each other.

The first structuring element 1016f used on the headlamp image IMGb1, or a first image, is shorter in the right-left direction than the first structuring element <NUM> used on the headlamp image IMGb5, or a second image. Accordingly, performing the first dilation process on the headlamp image IMGb1 by use of the first structuring element 1016f yields a lateral dilated region <NUM> where the headlamps HL in the pair HL1 are connected to each other, but keeps the headlamps HL in the pair HL3 separated from each other, as illustrated in <FIG>.

Meanwhile, the first structuring element <NUM> used on the headlamp image IMGb5, or a second image, is longer in the right-left direction than the first structuring element 1016f. Therefore, performing the first dilation process on the headlamp image IMGb5 by use of the first structuring element <NUM> yields a lateral dilated region <NUM> where the headlamps HL in the pair HL3 close to the host vehicle are connected to each other, as illustrated in <FIG>.

The headlamp image IMGb1 does not include the pair HL2 of headlamps HL as the headlamp image IMGb1 has been subjected to the second erosion process. This can prevent the lateral dilated region <NUM> derived from the pair HL2 of headlamps HL from being generated through the first dilation process where the first structuring element 1016f is used. In a similar manner, the headlamp image IMGb5 does not include the pairs HL1 and HL2 of headlamps HL as the headlamp image IMGb5 has been subjected to the second erosion process. This can prevent the lateral dilated region <NUM> derived from the pair HL1 or HL2 of headlamps HL from being generated through the first dilation process where the first structuring element <NUM> is used. This configuration makes it possible to detect the position of a vehicle with higher accuracy.

The order of the first dilation process and first erosion process performed on the rear lamp image IMGa (step S1106) and the first dilation process and first erosion process performed on the headlamp image IMGb (step S1107) is flexible, and these processes can be performed in parallel.

The vehicle position detecting device <NUM> generates a rear lamp lateral dilated image including the lateral dilated regions <NUM> that are based on the respective pairs of rear lamps RL by combining the rear lamp images IMGa0 to IMGa3, that is, by performing an OR operation on the rear lamp images IMGa (S1108). In addition, the vehicle position detecting device <NUM> generates a headlamp lateral dilated image including the lateral dilated regions <NUM> that are based on the respective pairs of headlamps HL by combining the headlamp images IMGb0 to IMGb5, that is, by performing an OR operation on the headlamp images IMGb (S1109). Herein, the order of the process of combining the rear lamp images IMGa (step S1108) and the process of combining the headlamp images IMGb (step S1109) is flexible, and these processes can be performed in parallel.

Then, the vehicle position detecting device <NUM> generates a collective lateral dilated image IMGc illustrated in <FIG> by combining the rear lamp lateral dilated image and the headlamp lateral dilated image, that is, by performing an OR operation on these two images (S1110). The vehicle position detecting device <NUM> can detect the position of each front vehicle based on the lateral dilated regions <NUM> included in the collective lateral dilated image IMGc. For example, the vehicle position detecting device <NUM> detects the position of each lateral dilated region <NUM> itself in the collective lateral dilated image IMGc as the position of each front vehicle in the region ahead of the host vehicle.

The vehicle position detecting device <NUM> transmits the collective lateral dilated image IMGc to the pattern determiner <NUM> as information indicating the detection result. Herein, the vehicle position detecting device <NUM> may extract, for example, angle information indicating the position of each front vehicle from the collective lateral dilated image IMGc and transmit the extracted result to the pattern determiner <NUM>. Moreover, the vehicle position detecting device <NUM> may transmit the information indicating the detection result to, for example but not limited to, an ECU that controls automatic driving.

The pattern determiner <NUM> determines a light distribution pattern PTN in which light is blocked at a portion corresponding to a front vehicle based on the result detected by the vehicle position detecting device <NUM>. "Light being blocked at a certain portion" includes a case where the brightness (the illuminance) of that portion is lowered as well as a case where the brightness (the illuminance) of that portion is brought absolutely to zero.

The pattern determiner <NUM> according to the present embodiment generates an inverted image IMGd illustrated in <FIG> by inverting the image including the generated lateral dilated regions <NUM>, that is, by inverting the pixel value of each pixel in the collective lateral dilated image IMGc (S1111). In the inverted image IMGd, the lateral dilated regions <NUM> have a low pixel value, and the region excluding the lateral dilated regions <NUM> has a high pixel value.

Then, the pattern determiner <NUM> performs a third erosion process on the inverted image IMGd by use of a third structuring element <NUM> of a predetermined shape illustrated in <FIG> (S1112). The third structuring element <NUM> according to the present embodiment has a shape elongated in the up-down direction. The vehicle position detecting device <NUM> performs the third erosion process on the inverted image IMGd with a pixel at the upper end of the third structuring element <NUM> mapped to a pixel 1020a of interest. <FIG> schematically illustrates the third structuring element <NUM>, and the number of pixels forming the portion that extends downward from the pixel at the upper end of the third structuring element <NUM> is not limited to what is depicted in the drawing.

In the third erosion process, if the pixels that overlap the third structuring element <NUM> include a pixel of a low pixel value, the pixel value of the pixel 1020a of interest is changed to this low pixel value. This causes the region with a high pixel value located on the upper side of the inverted lateral dilated regions <NUM> to be eroded in the upward direction, and a light distribution pattern image IMGe illustrated in <FIG> is generated. The light distribution pattern image IMGe includes an upper eroded region <NUM> that extends upward from the lateral dilated regions <NUM>.

The pattern determiner <NUM> determines a light distribution pattern PTN that includes a light blocking portion based on the light distribution pattern image IMGe (S1113). In determining the light distribution pattern PTN, the pattern determiner <NUM> incorporates the upper eroded region <NUM> into the light blocking portion. For example, the pattern determiner <NUM> sets the shape itself of the pixel group of a low pixel value in the light distribution pattern image IMGe as the light blocking portion and sets the shape itself of the pixel group of a high pixel value as the shape of the light distribution pattern PTN. Moreover, the pattern determiner <NUM> sets a predetermined first illuminance to a region excluding the light blocking portion and sets a second illuminance lower than the first illuminance to the light blocking portion. As described above, the second illuminance may be zero or an illuminance that is higher than zero but lower than the first illuminance.

The pattern determiner <NUM> transmits data indicating this light distribution pattern PTN to the lamp controlling device <NUM>. The lamp controlling device <NUM> controls the light distribution variable lamp <NUM> so that the light distribution variable lamp <NUM> emits a visible light beam L1 having an intensity distribution corresponding to the light distribution pattern PTN set by the pattern determiner <NUM>. For example, in a case where the light distribution variable lamp <NUM> includes a DMD, the lamp controlling device <NUM> controls the on and off of the light source and the on/off switching of each mirror element forming the DMD. This control makes it possible to form the light distribution pattern PTN having the light blocking portion that overlaps the front vehicles and to increase the visibility of the driver of the host vehicle without causing glare to the driver of the front vehicles.

Herein, the pattern determiner <NUM> may generate an inverted image IMGd and perform image processing involving the third structuring element <NUM> in reverse order. In other words, the pattern determiner <NUM> performs the third dilation process on the collective lateral dilated image IMGc by use of the third structuring element <NUM> and then generates an upper dilated region that extends upward from the lateral dilated regions <NUM>. Thereafter, the pattern determiner <NUM> generates an inverted image IMGd by inverting the pixel value of each pixel in the image in which the upper dilated region has been generated and incorporates the upper dilated region in this inverted image IMGd into the light blocking portion.

As described above, the vehicle position detecting device <NUM> according to the present embodiment generates a lateral dilated region <NUM> by performing the first dilation process and the first erosion process on the image that is based on the imaging device <NUM> by use of the first structuring element <NUM> of a predetermined shape elongated in the widthwise direction of the vehicle, and detects the position of a front vehicle based on the lateral dilated region <NUM>. The lateral dilated region <NUM> is a region in which a pair of luminous points included in an image and appearing side by side in the widthwise direction of the vehicle is connected to each other, and the imaging device <NUM> captures an image of a region ahead of the vehicle. This configuration can provide a novel detection method with which the position of a front vehicle can be detected in a simpler way as compared to a case where, for example, a front vehicle is detected by executing an image analysis, including algorithm recognition or deep learning, on an image IMG obtained from the imaging device <NUM>.

The vehicle position detecting device <NUM> generates a first image that includes a pair of luminous points located at a predetermined first distance and a pair of luminous points located at a second distance farther than the first distance with the number of times the second erosion process is performed on an image that is based on the imaging device <NUM> by use of the second structuring element <NUM> of a predetermined shape set to a relatively low number, and generates a second image that includes the pair of luminous points located at the first distance and in which the pair of luminous points located at the second distance has been deleted with the number of times the second erosion process is performed on the image that is based on the imaging device <NUM> set to a relatively high number. Then, the vehicle position detecting device <NUM> performs the first dilation process and the first erosion process on the first image by use of the first structuring element <NUM> that is relatively shorter in the widthwise direction of the vehicle and performs the first dilation process and the first erosion process on the second image by use of the first structuring element <NUM> that is relatively longer in the widthwise direction of the vehicle. In other words, the vehicle position detecting device <NUM> generates the first image by performing the second erosion process on the image a predetermined number of times and generates the second image by performing the second erosion process on the image a greater number of times than the number of times the second erosion process is performed to generate the first image. Then, the vehicle position detecting device <NUM> performs the first dilation process and the first erosion process on the first image by use of the first structuring element <NUM> of a predetermined length in the widthwise direction of the vehicle and performs the first dilation process and the first erosion process on the second image by use of the first structuring element <NUM> that is longer in the widthwise direction of the vehicle than the first structuring element <NUM> used on the first image.

In other words, the vehicle position detecting device <NUM> distinguishes the luminous points of each front vehicle based on the distance by varying the number of times the second erosion process is performed and performs the first dilation process and the first erosion process by use of a first structuring element <NUM> of a size that varies for each distinguished pair of luminous points. This configuration makes it possible to detect the position of a front vehicle with higher accuracy.

The vehicle lamp system <NUM> according to the present embodiment includes the imaging device <NUM>, the light distribution variable lamp <NUM>, the light distribution controlling device <NUM>, and the lamp controlling device <NUM>. The imaging device <NUM> captures an image of a region ahead of the vehicle. The light distribution variable lamp <NUM> can illuminate the region ahead of the vehicle with a visible light beam L1 of a variable intensity distribution. The light distribution controlling device <NUM> includes the vehicle position detecting device <NUM> and the pattern determiner <NUM> that determines a light distribution pattern PTN including a light blocking portion based on a detection result of the vehicle position detecting device <NUM>. The lamp controlling device <NUM> controls the light distribution variable lamp <NUM> so as to form the light distribution pattern PTN. This configuration can improve the visibility of the driver of the host vehicle while preventing glare caused to the driver of a front vehicle.

The pattern determiner <NUM> generates an inverted image IMGd by inverting the pixel value of each pixel in an image in which a lateral dilated region <NUM> has been generated, generates an upper eroded region <NUM> that extends upward from the lateral dilated region <NUM> by performing the third erosion process by use of the third structuring element <NUM> of a predetermined shape elongated in the up-down direction, and incorporates the upper eroded region <NUM> into the light blocking portion. This configuration can prevent glare caused to the driver of a front vehicle more reliably.

The present invention can be used for a light distribution controlling device, a vehicle position detecting device, a vehicle lamp system, a light distribution controlling method, and a vehicle position detecting method.

Claim 1:
A vehicle position detecting device (<NUM>), wherein
the vehicle position detecting device (<NUM>)
generates a lateral dilated region (<NUM>) by performing a first dilation process and a first erosion process on an image that is based on an imaging device (<NUM>) by use of a first structuring element (<NUM>) of a predetermined shape elongated in a widthwise direction of a vehicle, the lateral dilated region (<NUM>) being a region in which a pair of luminous points included in the image and appearing side by side in the widthwise direction of the vehicle are connected to each other, the imaging device (<NUM>) capturing an image of a region ahead of the vehicle, and
detects a position of the lateral dilated region (<NUM>) as a position of a front vehicle,_
characterized in that the vehicle position detecting device (<NUM>)
generates a first image (IMGa0, IMGa1, IMGb0, IMGb1) that includes a pair of luminous points not connected to each other located at a predetermined first distance and a pair of luminous points connected to each other located at a second distance farther than the first distance, with the number of times a second erosion process is performed on the image that is based on the imaging device (<NUM>) by use of a second structuring element (<NUM>) of a predetermined shape set to a relatively low number,
generates a second image (IMGa, IMGa3, IMGb3, IMGb5) that includes the pair of luminous points located at the first distance being connected to each other and in which the pair of luminous points located at the second distance has been deleted, with the number of times the second erosion process is performed on the image that is based on the imaging device (<NUM>) set to a relatively high number, and
performs the first dilation process and the first erosion process on the first image by use of the first structuring element (<NUM>) that is relatively shorter in the widthwise direction of the vehicle and performs the first dilation process and the first erosion process on the second image by use of the first structuring element (<NUM>) that is relatively longer in the widthwise direction of the vehicle.