Display control device and non-transitory computer readable medium

1. A display control device for controlling display of a virtual image which is superimposed on foreground of a vehicle by projection of a display light image from an optical unit to a projection area, comprising:

a position setting unit that sets a projection position of the display light image, which is projected in the projection area, on the basis of a relative position of a superimposition object on which the virtual image is superimposed;

a measurement information obtaining unit that obtains a measurement information from one vehicle height sensor measuring a displacement in a vertical direction occurring in the vehicle;

a gradient information obtaining unit that obtains a gradient information indicating a gradient of a road on which the vehicle travels on the basis of three-dimensional map data; and

an orientation information obtaining unit that obtains orientation information including vehicle speed information indicating a travel speed of the vehicle and curve information indicating a curve radius of the road on which the vehicle travels and that estimates a roll angle of the vehicle based on the vehicle speed information and the curve information;

wherein the position setting unit corrects the projection position of the display light image on the basis of the measurement information and the gradient information and stops correction of the projection position in response to the estimated roll angle exceeding a preliminarily designated upper limit value.

2. The display control device according to claim 1 , wherein

the position setting unit corrects a displacement amount in the vertical direction according to a roll movement of the vehicle included in the measurement information by using the orientation information.

3. The display control device according to claim 1 , wherein

the upper limit value is designated on the basis of a display view angle in the vertical direction of the virtual image in the optical unit.

4. The display control device according to claim 1 , wherein

the position setting unit calculates a pitch angle of the vehicle on the basis of a displacement amount in the vertical direction indicated by the measurement information, and

a pitch angle corresponding to a unit displacement amount occurring in the vertical direction at the time of acceleration of the vehicle is different from a pitch angle corresponding to the unit displacement amount at the time of deceleration.

5. The display control device according to claim 4 , wherein

the vehicle height sensor measures the displacement in the vertical direction at a part rearward of the center in the front-rear direction of the vehicle, and

a pitch angle corresponding to the unit displacement amount at the time of acceleration is smaller than a pitch angle corresponding to the unit displacement amount at the time of deceleration.

6. The display control device according to claim 1 , wherein

the measurement information obtaining unit sets an output value of the vehicle height sensor in a no-load state where a load causing the displacement in the vertical direction in the vehicle does not act as a reference value of the vehicle height sensor.

7. A non-transitory computer readable medium storing a computer program product comprising instructions for controlling display of a virtual image which is superimposed on foreground of a vehicle by projection of a display light image from an optical unit to a projection area, the instructions being configured to, when executed by a processor, cause the processor to:

set a projection position of the display light image, which is projected in the projection area, on the basis of a relative position of a superimposition object on which the virtual image is superimposed;

obtain a measurement information from one vehicle height sensor measuring a displacement in a vertical direction occurring in the vehicle;

obtain a gradient information indicating a gradient of a road on which the vehicle travels on the basis of three-dimensional map data;

correct the projection position of the display light image on the basis of the measurement information and the gradient information;

obtain vehicle speed information indicating a travel speed of the vehicle and curve information indicating a curve radius of the road on which the vehicle travels;

estimate a roll angle of the vehicle based on the vehicle speed information and the curve information; and

stop correction of the projection position in response to the estimated roll angle exceeding a preliminarily designated upper limit value.

8. A display control device for controlling display of a virtual image which is superimposed on foreground of a vehicle by projection of a display light image from an optical unit to a projection area, comprising a processor configured to:

set a projection position of the display light image, which is projected in the projection area, on the basis of a relative position of a superimposition object on which the virtual image is superimposed;

obtain measurement information from one vehicle height sensor measuring a displacement in a vertical direction occurring in the vehicle;

obtain gradient information indicating a gradient of a road on which the vehicle travels on the basis of three-dimensional map data;

correct the projection position of the display light image on the basis of the measurement information and the gradient information;

obtain vehicle speed information indicating a travel speed of the vehicle and curve information indicating a curve radius of the road on which the vehicle travels;

estimate a roll angle of the vehicle based on the vehicle speed information and the curve information; and

stop correction of the projection position in response to the estimated roll angle exceeding a preliminarily designated upper limit value.