Rearward view assistance apparatus displaying cropped vehicle rearward image

A rearward view assistance apparatus in a vehicle includes an imaging device that acquires a vehicle rearward image by taking a rearview from the vehicle, a control circuit that sets a cropped image by cropping part of the vehicle rearward image in response to a state of a vehicle, and a display device that is provided in a passenger compartment and displays the cropped image. The control circuit preferably overlays a lower portion of the cropped image with a mask. The control circuit preferably displays an indication corresponding to a rear portion of the vehicle on the cropped image. The rearward view assistance apparatus is thus provided to view rearward from the vehicle even when passengers are present on the seats in the second and third rows.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on and incorporates herein by reference Japanese Patent Application No. 2011-680 filed on Jan. 5, 2011.

FIELD OF THE INVENTION

The present invention relates to a rearward view assistance apparatus.

BACKGROUND OF THE INVENTION

It is known to provide a technique to take images outside a vehicle by use of a vehicle camera and display the images on a monitor in the vehicle. Patent document 1 discloses a technique to take images of right and left views from a vehicle by use of vehicle cameras mounted to the right and left of the vehicle.

The technique of Patent document 1 is to view the right and left directions from the vehicle. In the past, an optical rearview mirror installed in a passenger compartment is used for a driver to view rearward from the vehicle. When passengers are present on the seats in the second and third rows, a view of the optical rearview mirror may be interrupted by the passengers to make the rearward viewing difficult.

SUMMARY OF THE INVENTION

The present invention is accomplished in view of the above point. It is an object of the present invention to provide a rearward view assistance apparatus in which a driver is capable of viewing rearward from a vehicle even when passengers are present on seats in the second and third rows of the vehicle.

To achieve the above object, according to an aspect of the present invention, a rearward view assistance apparatus is provided as follows. An imaging device is included to acquire a vehicle rearward image by taking a rearview from a vehicle. A control circuit is included to set a cropped image by cropping the vehicle rearward image in response to a state of the vehicle. A display device is included to be provided in a passenger compartment and displays the cropped image.

According to the rearward view assistance apparatus of the above aspect, a cropped image produced by cropping part of a vehicle rearward image taken by use of the imaging device is displayable on the display device. Therefore, rearward viewing is possible even when passengers are present on seats in the second and third rows.

In the rearward view assistance apparatus of the above aspect, a cropped image produced by cropping part of a vehicle rearward image is displayed on the display device, so that a driver is capable of view rearward easier than when the vehicle rearward image is displayed directly, i.e., without modification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are explained in reference to the appended drawings.

1. Structure of Rearward View Assistance Apparatus1

A structure of a rearward view assistance apparatus1is explained in reference toFIG. 1. The rearward view assistance apparatus1is a vehicular apparatus mounted to a vehicle3(also referred to as a subject vehicle3), and includes a camera (also referred to as an imaging device or means)5that takes or captures a rearview from the vehicle3, a display (also referred to as a display device or means)7that is provided in a passenger compartment of the vehicle3and displays the overall or part of an image taken or captured by the camera5, and an ECU (also referred to as a control circuit)9.

The ECU9supplies power and GND to the camera5and communicates with the camera5to control the camera5. The control of the camera5includes cropping part of a vehicle rearward image and setting the cropped image in response to a state of the vehicle3, as mentioned below. The ECU9acquires states of the vehicle3to execute the processing to be hereinafter described; the states of the vehicle3include a shift position, a speed, a state of a blinker (left turn, right turn, no signal), and an ON/OFF of a hazard light by using well-known sensors such as a shift position detection device, a vehicle speed detection device, a blinker state detection device, and a hazard detection device.

The camera5is attached to the back end of the vehicle3, and capable of acquiring or capturing images (hereinafter called vehicle rearward images) in the wide range shown by an angle X inFIG. 1. The camera5is capable of cropping part of a vehicle rearward image in response to a command from the ECU9. The camera5outputs an image signal of a vehicle rearward image or a cropped image to a display7. The cropped images include an image of a range centered directly behind the vehicle3shown by an angle Y inFIG. 1and an image of a leftward range from the vehicle3shown by an angle Z inFIG. 1. The cropped image is mentioned later in detail.

The display7displays vehicle rearward images or cropped images. When a region of a cropped image in a vehicle rearward image is small, the cropped image is enlarged to a constant display size in the display7. The display7can be provided to an instrument panel in a passenger compartment of the vehicle3, as shown inFIG. 2. The display7can be provided also to the other places (for example, a rearview mirror etc.) in the passenger compartment.

2. Types of Image Displayed on the Display7

Images displayed on the display7by the vehicle rearward view assistance apparatus1are as follows.

A rearward cropped image shows a laterally central, vertically upper region cropped from the vehicle rearward image. Therefore, the rearward cropped image shows a smaller region than the vehicle rearward image. The rearward cropped images have three types: a “rearward cropped image (vehicle is at low speed or rest)” inFIG. 3A; a “rearward cropped image (vehicle is at moderate speed)” inFIG. 3B; and a “rearward cropped image (vehicle is at high speed)” inFIG. 3C.

The “rearward cropped image (vehicle is at moderate speed)” shows a partial region of the “rearward cropped image (vehicle is at low speed or rest),” the partial region being smaller than the “rearward cropped image (vehicle is at low speed or rest).” The “rearward cropped image (vehicle is at high speed)” shows a partial region of the “rearward cropped image (vehicle is at moderate speed),” the partial region being smaller than the “rearward cropped image (vehicle is at moderate speed).” The lower portions of the “rearward cropped image (vehicle is at low speed or rest),” “rearward cropped image (vehicle is at moderate speed),” and “rearward cropped image (vehicle is at high speed)” are each overlaid with a mask11for image coverage. An outline13(also referred to as an indication) showing a shape of the rear portion of the vehicle3is displayed on the mask11.

(2) Left Rearward Cropped Image

A left rearward cropped image shows a laterally left, vertically upper region cropped from the vehicle rearward image. Therefore, the left rearward cropped image shows a smaller region than the vehicle rearward image. In the left rearward cropped image, the directly rearward direction of the vehicle3is set as a border to divide the rearward view into right and left. Therefore, a lateral half of a vehicle directly behind the vehicle3is displayed.

The left rearward cropped images have three types of image: a “left rearward cropped image (vehicle is at low speed or rest)” inFIG. 4A; a “left rearward cropped image (vehicle is at moderate speed)” inFIG. 4B; and a “left rearward cropped image (vehicle is at high speed)” inFIG. 4C.

The “left rearward cropped image (vehicle is at moderate speed)” shows a partial region of the “left rearward cropped image (vehicle is at low speed or rest),” the partial region being smaller than the “left rearward cropped image (vehicle is at low speed or rest).” The “left rearward cropped image (vehicle is at high speed)” shows a partial region of the “left rearward cropped image (vehicle is at moderate speed),” the partial region being smaller than the “left rearward cropped image (vehicle is at moderate speed).” The largeness of the region displayed by the “left rearward cropped image (vehicle is at low speed or rest)” is the same as that of the region displayed by the “rearward cropped image (vehicle is at low speed or rest).” The largeness of the region displayed by the “left rearward cropped image (vehicle is at moderate speed)” is the same as that of the region displayed by the “rearward cropped image (vehicle is at moderate speed).” The largeness of the region shown by the “left rearward cropped image (vehicle is at high speed)” is the same as that of the region shown by the “rearward cropped image (vehicle is at high speed).” The lower portions of the “left rearward cropped image (vehicle is at low speed or rest),” “left rearward cropped image (vehicle is at moderate speed),” and “left rearward cropped image (vehicle is at high speed)” are each overlaid with the mask11for image coverage. The outline13showing a shape of the rear portion of the vehicle3is displayed on the mask11.

Unless otherwise noted, the term “right and left” means the right and left viewed from a driver facing in the forward direction.

(3) Right Rearward Cropped Image

The right rearward cropped image shows a laterally right, vertically upper region cropped from the vehicle rearward image. Therefore, the right rearward cropped image shows a smaller region than that of the vehicle rearward image. In the right rearward cropped image, the directly rearward direction of the vehicle3is set as a border to divide the rearward view into right and left. Therefore, the right rearward cropped image shows a lateral half of a vehicle directly behind the vehicle3.

The right rearward cropped images have three types: a “right rearward cropped image (vehicle is at low speed or rest)” inFIG. 5A; a “right rearward cropped image (vehicle is at moderate speed)” inFIG. 5B; and a “right rearward cropped image (vehicle is at high speed)” inFIG. 5C.

The “right rearward cropped image (vehicle is at moderate speed)” shows a partial region of the “right rearward cropped image (vehicle is at low speed or rest),” the partial region being smaller than the “right rearward cropped image (vehicle is at low speed or rest).” The “right rearward cropped image (vehicle is at high speed)” shows a partial region of the “right rearward cropped image (vehicle is at moderate speed),” the partial region being smaller than the “right rearward cropped image (vehicle is at moderate speed).” The largeness of the region shown by the “right rearward cropped image (vehicle is at low speed or rest)” is the same as that of the region shown by the “rearward cropped image (vehicle is at low speed or rest)” and as that of the “left rearward cropped image (vehicle is at low speed or rest).” The largeness of the region shown by the “right rearward cropped image (vehicle is at moderate speed)” is the same as that of the region shown by the “rearward cropped image (vehicle is at moderate speed)” and as that of the “left rearward cropped image (vehicle is at moderate speed).” The largeness of the region shown by the “right rearward cropped image (vehicle is at high speed)” is the same as that of the region shown by the “rearward cropped image (vehicle is at high speed)” and as that of the “left rearward cropped image (vehicle is at high speed).” The lower portions of the “right rearward cropped image (vehicle is at low speed or rest),” “right rearward cropped image (vehicle is at moderate speed),” and “right rearward cropped image (vehicle is at high speed)” are each overlaid with the mask11for image coverage. The outline13showing a shape of the rear portion of the vehicle3is displayed on the mask11.

A left parallel-parking image is shown inFIG. 6A, and shows a laterally left region cropped from the vehicle rearward image. The left parallel-parking image contains the overall region of the “left rearward cropped image (vehicle is at low speed or rest)” and further its surrounding region. The left parallel-parking image shows a larger region than that of the “left rearward cropped image (vehicle is at low speed or rest).”

The lower portion of the left parallel-parking image is overlaid with the mask11. The outline13showing a shape of the rear portion of the vehicle3is displayed on the mask11.

(5) Rearward Monitor Image

A rearward monitor image is shown inFIG. 6Band shows a laterally central region cropped from the vehicle rearward image. The rearward monitor image contains the overall region of the “rearward cropped image (vehicle is at low speed or rest)” and further its surrounding region. The rearward monitor image shows a larger region than that of the “rearward cropped image (vehicle is at low speed or rest).”

A right parallel-parking image is shown inFIG. 6C, and shows a laterally right region cropped from the vehicle rearward image. The right parallel-parking image contains the overall region of the “right rearward cropped image (vehicle is at low speed or rest)” and further its surrounding region. The right parallel-parking image shows a larger region than that of the “right rearward cropped image (vehicle is at low speed or rest).”

The lower portion of the right parallel-parking image is overlaid with the mask11. The outline13showing a shape of the rear portion of the vehicle3is displayed on the mask11.

A rest/reverse image is shown inFIG. 7, and contains the overall region of the vehicle rearward image. The lateral center of the rest/reverse image corresponds to the directly rearward direction of the vehicle3. The rest/reverse image shows a larger region than each of the rearward cropped image, left rearward cropped image, right rearward cropped image, left parallel-parking image, rearward monitor image, and right parallel-parking image.

FIGS. 8A and 8Band8C show positional relationship among the rest/reverse image, “rearward cropped image (vehicle is at low speed or rest),” and “right rearward cropped image (vehicle is at low speed or rest).”FIG. 8Ashows the rest/reverse image. A region P in the rest/reverse image corresponds to the “rearward cropped image (vehicle is at low speed or rest)” ofFIG. 8B. A region Q in the rest/reverse image corresponds to the “right rearward cropped image (vehicle is at low speed or rest)” ofFIG. 8C.

3. Processing Executed by the Rearward View Assistance Apparatus1

The processing executed by the rearward view assistance apparatus1, i.e., by the ECU9is explained in reference to the flowcharts ofFIGS. 9 to 17.

Each or any combination of sections explained in the above can be achieved as (i) a software section in combination with a hardware device (e.g., computer) or (ii) a hardware section, including or not including a function of a related device; furthermore, the hardware section may be constructed inside of a microcomputer.

Furthermore, the software section may be included in a software program, which may be contained in a non-transitory computer-readable storage media as a program product.

(1) First, the main processing is explained in reference to the flowchart ofFIG. 9. The main processing is executed when an ignition of the vehicle3is turned ON.

At S10, an initial screen transition is performed. This initial screen transition is mentioned later.

At S20, it is determined whether a predetermined time has elapsed after the initial screen transition. When the predetermined time has elapsed, the process proceeds to S30, and when predetermined time has not yet elapsed, the process stays at S20.

At S30, a transition to a screen for vehicle rest is performed. In this transition, an image displayed until then transitions to the rest/reverse image (SeeFIG. 7).

At S40, shift position information on the vehicle3at this point (forward, rest, or reverse) is acquired.

At S50, blinker information on the vehicle3at this point (no signal, a right turn, or a left turn) is acquired.

At S60, hazard light information on the vehicle3at this point (ON/OFF of the hazard light) is acquired.

At S70, a vehicle speed of the vehicle3at this point is acquired.

At S80, it is determined whether the shift position information, blinker information, hazard light information, or vehicle speed acquired at the last S30to S70has changed from that acquired at S30to S70in the previous processing. When no information changes, the process proceeds to S90and the screen of the display7remains unchanged (the type of the displayed image is not changed). On the other hand, when the shift position information, blinker information, hazard information, or vehicle speed has changed, the process proceeds to S100, at which the screen transition is executed. This screen transition is mentioned later.

(2) Next, the initial screen transition processing is explained in reference to the flowchart ofFIG. 10.

At S110, a morphing speed is set as “low.” Here, the morphing means a gradual change from an image before transition to an image after transition. For example, at first a ratio of the image before transition is 100%, then a ratio of the image after transition increases gradually, and finally the ratio of the image after transition becomes 100%. The morphing speed is a transition speed in morphing. The morphing speed has three steps, low, medium, and high. As the morphing speed is higher, the morphing completes for a shorter time. The set morphing speed is used in subsequent morphing operations until the morphing speed is reset.

At S120, an image displayed on the display7at this point is morphed to the “left rearward cropped image (vehicle is at low speed or rest).”

At S130, the image displayed on the display7is morphed from the “left rearward cropped image (vehicle is at low speed or rest)” to the “right rearward cropped image (vehicle is at low speed or rest).”

At S140, the image displayed on the display7is morphed from the “right rearward cropped image (vehicle is at low speed or rest)” to the “rearward cropped image (vehicle is at low speed or rest).”

(3) Next, the screen transition processing is explained in reference to the flowchart ofFIG. 11.

At S210, a shift position of the vehicle3is determined on the basis of the shift position information acquired at the last S40. When the vehicle is at rest, the process proceeds to the transition to a screen for vehicle rest at S220to display the rest/reverse image on the display7. When the shift position is at reverse, the process proceeds to the transition to a screen for reverse at S230to display the rest/reverse image on the display7. When the shift position is at forward, the process proceeds to S240.

At S240, on the basis of the shift position information acquired at the previous S40(to the “last” S40by one main processing), the previous shift position in the vehicle3is determined. When the shift position is other than at reverse, the process proceeds to S250. When the shift position is at reverse, the process proceeds to S350.

At S250, a state of the blinker is determined on the basis of the blinker information acquired at the last S50. In case of a left turn, the process proceeds to S260. In case of no signal, the process proceeds to S270. In case of a right turn, the process proceeds to S280.

At S260, S270, and S280, on the basis of the hazard light information acquired at the last S60, a state of the hazard light is determined (ON or OFF).

When the hazard light is determined as OFF at S260, the process proceeds to the transition to the left rearward cropped screen in S290. When the hazard light is determined as ON at S260, the process proceeds to the transition to the left parallel-parking screen in S300. The transitions to the left rear cropped screen and to the left parallel-parking screen are mentioned later.

When the hazard light is determined as OFF at S270, the process proceeds to the transition to the rearward cropped screen in S300. When the hazard light is determined as ON at S270, the process proceeds to the transition to the rearward monitor screen in S320. The transitions to the rearward cropped screen and to the rearward monitor screen are mentioned later.

When the hazard light is determined as OFF at S280, the process proceeds to the transition to the right rearward cropped screen in S330. When the hazard light is determined as ON at S280, the process proceeds to the transition to the right parallel-parking screen in S340. The transitions to the right rearward cropped screen and to the right parallel-parking screen are mentioned later.

On the other hand, when it is determined at S240that the shift position is at reverse, the process proceeds to S350. At S350, on the basis of the vehicle speed information acquired at the last S70, a vehicle speed of the vehicle3is acquired, and it is determined whether the vehicle speed is a predetermined vehicle speed V1or over. When the vehicle speed is V1or over, the process proceeds to S250, and when the vehicle speed is less than V1, the process proceeds to S360.

At S360, the screen of the display7remains unchanged (the type of the image to be displayed is not changed).

At S370, the shift position information is newly acquired and it is determined whether the shift position in the vehicle3has changed other than to the forward position. When the shift position has changed other than to the forward position, this processing ends, and when the shift position remains at the forward position, the process proceeds to S350.

(4) Next, the transition to the left rearward cropped screen is explained in reference to the flowchart ofFIG. 12.

At S410, an image to be displayed on the display7is set. Specifically, it is determined whether a vehicle speed acquired at S70is the “low vehicle speed,” “moderate vehicle speed,” or “high vehicle speed.” On the basis of the determination result, an image to be displayed on the display7is set as below.

In case of “low vehicle speed,” the “left rearward cropped image (vehicle is at low speed or rest)” is displayed.

In case of “moderate vehicle speed,” the “left rearward cropped image (vehicle is at moderate speed)” is displayed.

In case of “high vehicle speed,” the “left rearward cropped image (vehicle is at high speed)” is displayed.

When predetermined regulation speeds are Va, Vb (Va<Vb), the “low vehicle speed” is less than Va, the “medium vehicle speed” is equal to or over Va and less than Vb, and the “high vehicle speed” is Vb or over.

At S420, it is determined whether the image that is set at S410is different from the image currently displayed on the display7. When the images differ from one another, the process proceeds to S430, and when the images are the same, the process proceeds to S460.

At S430, a procedure for transferring the image on the display7is set.

The specific procedure is as follows.

(a) In case where the image currently displayed on the display7is the right rearward cropped image

The right rearward cropped image is first morphed to the rearward cropped image, and then to the left rearward cropped image that is set at S410. The rearward cropped image after the first morphing is the “rearward cropped image (vehicle is at low speed or rest)” when the left rearward cropped image that is set at S410is the “left rearward cropped image (vehicle is at low speed or rest). The rearward cropped image after the first morphing is the “rearward cropped image (vehicle is at moderate speed)” when the left rearward cropped image that is set at S410is the “left rearward cropped image (vehicle is at moderate speed). The rearward cropped image after the first morphing is the “rearward cropped image (vehicle is at high speed)” when the left rearward cropped image that is set at S410is the “left rearward cropped image (vehicle is at high speed).

(b) In case where the image currently displayed on the display7is the “left rearward cropped image (vehicle is at low speed or rest)” and the image that is set at S410is the “left rearward cropped image (vehicle is at high speed)”

The “left rearward cropped image (vehicle is at low speed or rest)” is first morphed to the “left rearward cropped image (vehicle is at moderate speed),” and then to the “left rearward cropped image (vehicle is at high speed).”

(c) In case where the image currently displayed on the display7is the “left rearward cropped image (vehicle is at high speed),” and the image that is set at S410is the “Left Rearward Cropped Image (Vehicle is at Low Speed Or Rest)”

The “left rearward cropped image (vehicle is at high speed)” is morphed to the “left rearward cropped image (vehicle is at moderate speed)” at first, and then to the “left-rearward cropped image (vehicle is at low speed or rest).”

(d) In case other than the above (a) to (c)

The image currently displayed on the display7is morphed to the left rearward cropped image that is set at S410.

A morphing speed is set at S440. Fundamentally, the morphing speed is set as follows in response to the screen that is set at S410.

In case of the “left rearward cropped image (vehicle is at low speed or rest),” the morphing speed is set as “low.”

In case of the “left rearward cropped image (vehicle is at moderate speed),” the morphing speed is set as “moderate.”

In case of the “left rearward cropped image (vehicle is at high speed),” the morphing speed is set as “high.”

In (a), the morphing speed is “high” in the morphing to the rearward cropped image. The morphing speed in the morphing to the left rearward cropped image is set in response to the screen set at S410, as described above.

In (b), the morphing speed in the morphing to the “left rearward cropped image (vehicle is at moderate speed)” is “moderate,” and the morphing speed in the morphing to the “left rearward cropped image (vehicle is at high speed)” is “high.”

In (c), the morphing speed in the morphing to the “left rearward cropped image (vehicle is at moderate speed)” is “moderate,” and the morphing speed in the morphing to the “left rearward cropped image (vehicle is at low speed or rest)” is “low.”

When the hazard information acquired at the previous S60(to “the last” S60by one main processing) is ON, the morphing speed is “high” regardless of the screen that is set at S410.

At S450, on the basis of the procedure of the image transition that is set at S430and the morphing speed that is set at S440, the image transition is performed.

On the other hand, at S420, when it is determined that the image set at S410is the same as the image currently displayed on the display7, the process proceeds to S460, at which the screen of the display7remains unchanged (the type of the displayed image is not changed).

(5) Next, the transition to the left parallel-parking screen is explained in reference to the flowchart ofFIG. 13.

At S510, on the basis of the shift position information acquired at the previous S40(to “the last” S40by one main processing), the previous shift position in the vehicle3is determined. When the previous shift position is at rest or reverse, the process proceeds to S520, and when the previous shift position is at forward, the process proceeds to S540.

At S520, the morphing speed is set as “low.”

At S530, the image displayed on the display7is morphed to the “left rearward cropped screen (vehicle is at low speed or rest).” The morphing speed at this time is “low” that is set at S520.

At S540, the morphing speed is set as “moderate.”

At S550, the image displayed on the display7is morphed to the left parallel-parking image. The morphing speed at this time is “moderate” that is set at S540

(6) Next, the transition to the rearward cropped image is explained in reference to the flowchart ofFIG. 14.

At S610, the image to be displayed on the display7is set. Specifically, it is determined whether a vehicle speed acquired at S70is “low vehicle speed,” “moderate vehicle speed,” or “high vehicle speed.” On the basis of the determination result, an image to be displayed on the display7is set as follows.

In case of “low vehicle speed,” the image to be displayed is the “rearward cropped image (vehicle is at low speed or rest).”

In case of “moderate vehicle speed,” the image to be displayed is the “rearward cropped image (vehicle is at moderate speed).”

In case of “high vehicle speed,” the image to be displayed is the “rearward cropped image (vehicle is at high speed).”

When predetermined reference speeds are set as Va, Vb (Va<Vb), the “low vehicle speed” is less than Va, the “moderate vehicle speed is equal to or over Va” and less than Vb, and the “high vehicle speed” is Vb or over.

At S620, it is determined whether the image that is set up at S610is different from the image currently displayed on the display7. When the images are different, the process proceeds to S630, and when the images are the same, the process proceeds to S660.

At S630, a procedure to transfer the image on the display7is set. Specifically, this setting is as follows.

(e) In case where the image currently displayed on the display7is the “rearward cropped image (vehicle is at low speed or rest)” and the image that is set at S610is the “rearward cropped image (vehicle is at high speed)”

The “rearward cropped image (vehicle is at low speed or rest)” is morphed to the “rearward cropped image (vehicle is at moderate speed)” at first, and then to the “rearward cropped image (vehicle is at high speed).”

(f) In case where the image currently displayed on the display7is the “rearward cropped image (vehicle is at high speed)” and the image that is set at S610is the “rearward cropped image (vehicle is at low speed or rest)”

The “rearward cropped image (vehicle is at high speed)” is morphed to the “rearward cropped image (vehicle is at moderate speed)” at first, and then to the “rearward cropped image (low vehicle speed or vehicle rest).”

(g) In case other than (e) to (f)

The image currently displayed on the display7is morphed to the left rearward cropped image that is set at S610.

The morphing speed is set at S640. Fundamentally, the morphing speed is set as follows in response to the screen that is at S610.

In case of the “rearward cropped image (vehicle is at low speed or rest),” the morphing speed is set as “low.”

In case of the “rearward cropped image (vehicle is at moderate speed),” the morphing speed is set as “moderate.”

In case of the “rearward cropped image (vehicle is at high speed),” the morphing speed is set as “high.”

In (e), the morphing speed in the morphing to the “rearward cropped image (vehicle is at moderate speed)” is “moderate,” and the morphing speed in the morphing to the “rearward cropped image (vehicle is at high speed)” is “high.”

In (f), the morphing speed in the morphing to the “rearward cropped image (vehicle is at moderate speed)” is “moderate,” and the morphing speed in the morphing to the “rearward cropped image (vehicle is at low speed or rest)” is “low.”

When the blinker information acquired at the previous S50(to “the last” S50by one main processing) shows other than no signal or when the hazard light information acquired at the previous S60(to “the last” S60by one main processing) shows ON, the morphing speed is “high” regardless of the screen that is set at S610.

When the shift position information acquired at the previous S40(to the “last” S40by one main processing) is at rest or reverse, the morphing speed is “low” regardless of the screen that is set at S610.

At S650, the image transition is performed on the basis of the procedure of the image transition that is set at S630and the morphing speed that is set at S640.

On the other hand, at S620, when it is determined that the image that is set at S610is the same as the image currently displayed on the display7, the process proceeds to S660, at which the screen on the display7remains unchanged (the type of the displayed image is not changed).

(7) Next, the transition to the rearward monitor screen is explained in reference to the flowchart ofFIG. 15.

At S710, on the basis of the shift position information acquired at the previous S40(to the “last” S40by one main processing), the previous shift position of the vehicle3is determined. When the shift position is at rest or reverse, the process proceeds to S720, and when the shift position is at forward, the process proceeds to S740.

At S720, the morphing speed is set as “low.”

At S730, the image displayed on the display7is morphed to the “rearward cropped image (vehicle is at low speed or rest).” The morphing speed at this time is “low” that is set at S720.

At S740, the morphing speed is set as “moderate.”

At S750, the image displayed on the display7is morphed to the rearward monitor image. The morphing speed at this time is “moderate” that is set at S740.

(8) Next, the transition to the right rearward cropped screen is explained in reference to the flowchart ofFIG. 16.

At S810, an image to be displayed on the display7is set. Specifically, it is determined whether the vehicle speed acquired at the last S70is “low vehicle speed,” “moderate vehicle speed,” or “high vehicle speed.” On the basis of the determination result, the image to be displayed on the display7is set as follows.

In case of “low vehicle speed,” the image to be displayed is the “right rearward cropped image (vehicle is at low speed or rest).”

In case of “moderate vehicle speed,” the image to be displayed is the “right rearward cropped image (vehicle is at moderate speed).”

In case of “high vehicle speed,” the image to be displayed is the “right rearward cropped image (vehicle is at high speed).”

When predetermined reference speeds are Va, Vb (Va<Vb), the “low vehicle speed” is under Va, the “moderate vehicle speed” is equal to or over Va and under Vb, and the “high vehicle speed” is Vb or over.

At S820, it is determined whether the image that is set at S810is different from the image currently displayed on the display7. When the images are different, the process proceeds to S830, and when the images are the same, the process proceeds to S860.

At S830, a procedure is set to transfer the image of the display7. Specifically, the transition is as follows.

(h) In case where the image currently displayed on the display7is the left rearward cropped image

The left rearward cropped image is morphed to the rearward cropped image at first, and then to the right rearward cropped image that is set at S810. The rearward cropped image after the first morphing is the “rearward cropped image (vehicle is at low speed or rest)” when the right rearward cropped image that is set at S810is the “right rearward cropped image (vehicle is at low speed or rest).” The rearward cropped image after the first morphing is the “rearward cropped image (vehicle is at moderate speed)” when the right rearward cropped image that is set at S810is the “right rearward cropped image (vehicle is at moderate speed).” The rearward cropped image after the first morphing is the “rearward cropped image (vehicle is at high speed)” when the right rearward cropped image that is set at S810is the “right rearward cropped image (vehicle is at high speed).”

(i) In case where the image currently displayed on the display7is the “right rearward cropped image (vehicle is at low speed or rest)” and the image that is set at S810is the “right rearward cropped image (vehicle is at high speed)”

The “right rearward cropped image (vehicle is at low speed or rest)” is morphed to the “right rearward cropped image (vehicle is at moderate speed)” at first, and then to the “right rearward cropped image (vehicle is at high speed).”

(j) In case where the image currently displayed on the display7is the “right rearward cropped image (vehicle is at high speed)” and the image that is set at S810is the “right rearward cropped image (vehicle is at low speed or rest)”

The “right rearward cropped image (vehicle is at high speed)” is morphed to the “right rearward cropped image (vehicle is at moderate speed)” at first, and then to the “right rearward cropped image (vehicle is at low speed or rest).”

(k) Case other than (h) to (j)

The image currently displayed on the display7is morphed to the right rearward cropped image that is set at S810.

The morphing speed is set at S840. Fundamentally, the morphing speed is set as follows in response to the screen set at S810.

In case of the “right rearward cropped image (vehicle is at low speed or rest),” the morphing speed is set as “low.”

In case of the “right rearward cropped image (vehicle is at moderate speed),” the morphing speed is set as “moderate.”

In case of the “right rearward cropped image (vehicle is at high speed),” the morphing speed is set as “high.”

In (h), the morphing speed is “high” in the morphing to the rearward cropped image. The morphing speed in the morphing to the right rearward cropped image is set in response to the screen that is set at S810, as described above.

In (i), the morphing speed in the morphing to the “right rearward cropped image (vehicle is at moderate speed)” is “moderate,” and the morphing speed in the morphing to the “right rearward cropped image (vehicle is at high speed)” is “high.”

In (j), the morphing speed in the morphing to the “right rearward cropped image (vehicle is at moderate speed)” is “moderate,” and the morphing speed in the morphing to the “right rearward cropped image (vehicle is at low speed or rest)” is “low.”

When the hazard information acquired at the previous S60(to “the last S60” by one main processing) is ON, the morphing speed is “high” regardless of the screen that is set at S810.

At S850, on the basis of the procedure of the image transition that is set at S830and the morphing speed that is set at S840, the image transition is performed.

On the other hand, when it is determined at S820that the image that is set at S810is the same as the image currently displayed on the display7, the process proceeds to S860, at which the screen on the display7remains unchanged (the type of the displayed image is not changed).

(9) Next, the transition to the right parallel-parking screen is explained in reference to the flowchart ofFIG. 17.

At S910, on the basis of the shift position information acquired at the previous S40(to “the last” S40by one main processing), the previous shift position of the vehicle3is determined. When the previous shift position is at rest or reverse, the process proceeds to S920, and when the previous shift position is at forward, the process proceeds to S940.

At S920, the morphing speed is set as “low.”

At S930, the image displayed on the display7is morphed to the “right rearward cropped screen (vehicle is at low speed or rest).” The morphing speed at this time is “low” that is set at S920.

At S940, the morphing speed is set as “moderate.”

At S950, the image displayed on the display7is morphed to the right parallel-parking image. The morphing speed at this time is “moderate” that is set at S940.

4. Advantageous effects by the rearward view assistance apparatus1

(1) According to the rearward view assistance apparatus1, a rearward image taken by the camera5can be displayed on the display7. Therefore, rearward viewing is possible even when passengers are present on the seats in the second and third rows in the vehicle3.

(2) The rearward view assistance apparatus1is capable of displaying, on the display7, the images (the rearward cropped image, left rearward cropped image, and right rearward cropped image) of a partial region cropped from an image taken by the camera5when the vehicle travels forward. Accordingly, a driver can view rearward easier than when the overall image (vehicle rearward image) taken by the camera5is displayed.

(3) In the rearward view assistance apparatus1, the lower portions of the rearward cropped image, left rearward cropped image, right rearward cropped image, left parallel-parking image, and right parallel-parking image displayed on the display7are each overlaid with the mask11that covers the lower portions of the images and the outline13that shows the shape of the vehicle3. The images being overlaid with the mask11, the region where a road appears to move during forward travel is made small in the images, so that the driver has less stress. Additionally, the outline13showing the shape of the rear portion of the vehicle3is displayed, so that the driver can intuitively realize a positional relationship between the subject vehicle (vehicle3) and a following vehicle, which follows the subject vehicle, displayed on the display7.

(4) The rearward view assistance apparatus1sets the cropped image smaller as the speed of the vehicle3is higher when displaying the rearward cropped image, left rearward cropped image, and right rearward cropped image on the display7. In general, as a vehicle speed is higher, a following distance is longer. Thus, a following vehicle is displayed small in an image not yet cropped. As described above, a region of a cropped image is made smaller as a vehicle speed is higher, so that a ratio of occupation of a following vehicle is made high in the cropped image for easy viewing.

(5) The rearward view assistance apparatus1uses morphing to transfer the image displayed on the display7. This enables smooth image transition, so that the driver does not feel uncomfortable. The speed of morphing is set higher as the vehicle speed of the vehicle3is higher. Accordingly, when the speed of the vehicle3is high and a rearward view may be needed quickly, the morphing does not continue for too long a time.

(6) In the rearward view assistance apparatus1, when the blinker shows a right turn, a more rightward image (right rearward cropped image) is displayed on the display7than when the blinker shows no signal. In addition, when the blinker shows a left turn, a more leftward image (left rearward cropped image) is displayed on the display7than when the blinker shows no signal. Thus, in response to the drive condition, the driver can ensure a necessary view.

(7) In the rearward view assistance apparatus1, the speed of morphing when the blinker stops showing a right or left turn is higher than that when the blinker starts showing a right or left turn. In general, when the blinker stops showing a right or left turn, a lane change is complete and instantly a rearview may be needed. As mentioned above, the speed of morphing in this case is made high to end the morphing for a short time and thereby to obtain a rearview instantly.

(8) In the rearward view assistance apparatus1, when the hazard light is ON, the cropped image displayed on the display7is made larger than when the hazard light is OFF. In general, when the hazard light is ON, a wide rearview may be needed, for example, for parallel parking. As described above, when the hazard light is ON and a region of the cropped image displayed on the display7is made large for easy parallel parking etc.

(9) In the rearward view assistance apparatus1, when transferring the image displayed on the display7greatly, the image transitions to an intermediate image once, and then to a final image. Specifically, when the right rearward cropped image transitions to the left rearward cropped image, the right rearward cropped image transitions to the rearward cropped image once, and then to the left rearward cropped image. When the left rearward cropped image transitions to the right rearward cropped image, the left rearward cropped image transitions to the rearward cropped image once, and then to the right rearward cropped image.

When the “rearward cropped image (vehicle is at high speed)” transitions to the “rearward cropped image (vehicle is at low speed or rest),” the “rearward cropped image (vehicle is at high speed)” transitions to the “rearward cropped image (vehicle is at moderate speed)” once, and then to the “rearward cropped image (vehicle is at low speed or rest).” When the “rearward cropped image (vehicle is at low speed or rest)” transitions to the “rearward cropped image (vehicle is at high speed),” the “rearward cropped image (vehicle is at low speed or rest)” transitions to the “rearward cropped image (vehicle is at moderate speed)” once, and then to the “rearward cropped image (vehicle is at high speed).” When the left rearward cropped image and the right rearward cropped image at a high vehicle speed transitions to ones at a low speed or rest and in case of its reverse transition, the same transitions as the above are performed.

In such a transition as the above, the image transition is not performed suddenly greatly, but becomes smooth, so that the driver does not feel uncomfortable greatly.

(10) In the rearward view assistance apparatus1, when the shift position is changed from reverse (the state where the rest/reverse image is displayed) to forward, the rest/reverse image remains displayed on the display7unless the vehicle speed becomes V1or over or the shift position is changed again (see S240, S350, S360, and S370). Therefore, when forward and reverse are shifted frequently, the image displayed on the display7is not changed frequently, and thus the driver does not feel uncomfortable.

It is noted that the present invention is not limited by the above embodiments, and various configurations and modifications are possible without departing from the scope of the present invention.

For example, the image transition using a “high” speed morphing may be performed instantly without morphing.

The types of the cropped images are not limited to the images of three stages: low vehicle speed or vehicle rest; moderate vehicle speed; and high vehicle speed. For example, the number of the stages may be two, four, five, six, or so on. In proportion to the vehicle speed, a size of a region of the cropped image may be set without stages (linearly).

While aspects of the disclosure described herein are already recited in the preceding summary, further optional aspects thereto may be set out as follows.

For instance, as an optional aspect of the disclosure, in the rearward view assistance apparatus, the control circuit may overlay a lower portion of the cropped image with a mask. By overlaying the lower portion of the cropped image with the mask, a region where a road appears to move is made small in the cropped image. Therefore, the driver does not feel uncomfortable greatly.

Further, as an optional aspect of the disclosure, the control circuit may display a rear portion of the vehicle itself in the cropped image or on the mask with which the lower portion of the cropped image is overlaid. By displaying an indication (for example, an outline showing a shape of the rear portion of the vehicle itself) corresponding to the rear portion of the vehicle, a positional relationship between the vehicle and a following vehicle can be understood intuitively.

Further, as an optional aspect of the disclosure, a vehicle speed detection device may be included to detect a speed of the vehicle. The control circuit may set the cropped image smaller as the vehicle speed is higher. In general, as a vehicle speed is higher, a following distance is longer and a following vehicle is displayed smaller on the vehicle rearward image. As described above, as the vehicle speed is higher, a region of the cropped image is made smaller to increase a ratio of occupation of the following vehicle in the cropped image for easy viewing.

Further, in the above optional aspect, the control circuit may change the cropped image in response to a change of the vehicle speed, and use morphing when transferring the cropped image displayed on the display device. A speed of the morphing may be higher as the vehicle speed in the transition is higher.

The morphing is used for smooth transition of the cropped image displayed on the display device, so that a driver does not feel uncomfortable greatly. As the vehicle speed is higher, the speed of morphing is set higher. Therefore, when the vehicle speed is higher and a rearward view may be required instantly, the morphing does not continue for too long a time.

Further, as an optional aspect of the disclosure, a blinker detection device may be included to detect a state of a blinker of the vehicle. The control circuit may set a position of the cropped image in the vehicle rearward image more rightward when the blinker shows a right turn than when the blinker shows no signal. The control circuit may set a position of the cropped image in the vehicle rearward image more leftward when the blinker shows a left turn than when the blinker shows no signal. In such a way, a required view can be ensured for a driver in response to a driving condition.

In the above optional aspect, the control circuit may change the cropped image in response to a state of the blinker, and use morphing when transferring the cropped image displayed on the display device. A speed of the morphing when the blinker stops indicating a right or left turn may be higher than that of the morphing when the blinker starts indicating a right or left turn.

In general, when the blinker stops indicating a right or left turn, a lane change is completed and a rearview may be instantly required. As mentioned above, the morphing speed in this case is made high to complete the morphing for a short time and accordingly to obtain a rearview quickly.

Further, as an optional aspect of the disclosure, a hazard detection device may be included to detect a state of a hazard light of the vehicle. When the hazard light is ON, the control circuit may make the cropped image larger than when the hazard light is OFF. In general, when the hazard light is ON, a wide rearview may be required such as in case of parallel parking. As described above, when the hazard light is ON, the cropped image is made large, parallel parking becomes easy.