JP2014219748A - Map drawing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a map drawing device capable of adjusting a processing load applied on drawing according to current processing resources.SOLUTION: A map drawing device 10 generates a drawing object from drawing object data and outputs the drawing object to a display unit. The map drawing device 10 comprises: a simplicity level setting unit 5 for setting a simplicity level indicating the degree of display simplicity to at least a partial area on a display screen of the display unit so that the simplicity level changes continuously or discontinuously in one of increasing and decreasing directions from one end toward the other end of the area; and a drawing object generation unit 6 for generating, from the drawing object data, the drawing object simplified according to a display position on the display screen, and for outputting the drawing object to the display unit. The simplicity level setting unit 5 changes a mode of continuous change or a border of discontinuous change according to change in a predetermined parameter.

Description

  The present invention relates to a technique for adjusting a processing load applied to drawing of a map drawing apparatus.

  2. Description of the Related Art Conventionally, in a map drawing device that displays a map such as a car navigation device, a high-quality display is performed by displaying in detail the shape of a drawing object such as a 3D (three-dimensional) figure.

  However, if a large number of drawing objects are drawn, the processing load on the CPU (Central Processing Unit) and the GPU (Graphics Processing Unit) (hereinafter, these are collectively referred to simply as processing load) increases. In particular, in a car navigation device in which various functions operate simultaneously, in addition to drawing, CPU or GPU processing resources (hereinafter, both are collectively referred to as processing resources) are consumed. When trying to draw a drawing object in detail, a sufficient drawing speed could not be realized, which was unusable for the user.

  Therefore, in order to draw detailed figures such as 3D figures at high speed, it has been proposed to reduce the drawing load by adjusting LOD (Level of detail) according to the viewpoint distance (distance from the camera). (For example, prior document 1). In 3D display, as the number of polygons representing a drawing object is increased, more detailed expression is possible. However, since the drawing object is displayed smaller as the viewpoint distance increases, when the viewpoint distance of the drawing object is sufficiently long, there is almost no difference in the actual appearance even if the number of polygons is displayed coarsely. The LOD technology uses this characteristic, and drawing objects with a short viewpoint distance are displayed in detail with many polygons, while drawing objects with a long viewpoint distance are displayed in a simplified manner with a reduced number of polygons. Reduction of processing resources is possible.

JP 2008-198105 A

  However, in the conventional map drawing device, since the in-plane distribution of detail is fixed, even if processing resources are reduced for some reason, the in-plane distribution of detail is adjusted to reduce the processing load for drawing. It was difficult to adjust and it was difficult to maintain a sufficient drawing speed.

  In view of the above-described problems, an object of the present invention is to provide a map drawing apparatus capable of adjusting the processing load for drawing according to the current processing resources.

  The map drawing apparatus of the present invention generates a drawing object from drawing object data and outputs the drawing object to the display unit, and at least part of the region on the display screen of the display unit from one end to the other end of the region, A simplicity setting unit that sets the degree of simplification indicating the degree of simplification to continuously or discontinuously increase or decrease in one direction, and from the drawing object data to the display position on the display screen A drawing object generation unit that generates a simplified drawing object in response to the output and outputs the drawing object to the display unit, wherein the simplicity setting unit is configured to change the form of the continuous change or the discontinuity according to a change in a predetermined parameter. Change boundaries of change.

  The map drawing apparatus of the present invention generates a drawing object from drawing object data and outputs the drawing object to the display unit, and at least part of the region on the display screen of the display unit from one end to the other end of the region, A simplicity setting unit that sets the degree of simplification indicating the degree of simplification to continuously or discontinuously increase or decrease in one direction, and from the drawing object data to the display position on the display screen A drawing object generation unit that generates a simplified drawing object in response to the output and outputs the drawing object to the display unit, wherein the simplicity setting unit is configured to change the form of the continuous change or the discontinuity according to a change in a predetermined parameter. Change boundaries of change. Therefore, it is possible to suppress a decrease in the drawing speed by changing the simplicity setting unit as necessary and adjusting the CPU or GPU processing resources required for drawing.

It is a figure which shows operation | movement of the map drawing apparatus of this invention. It is a block diagram which shows the structure of the map drawing apparatus of this invention. It is a flowchart which shows operation | movement of the map drawing apparatus of this invention. It is a figure which shows the integrated range of a drawing object according to simplicity. It is a figure which shows operation | movement of the map drawing apparatus of this invention. It is a figure which shows operation | movement of the map drawing apparatus of this invention. It is a figure which shows operation | movement of the map drawing apparatus of this invention. It is a figure which shows operation | movement of the map drawing apparatus of this invention. It is a figure which shows operation | movement of the map drawing apparatus of this invention. It is a figure which shows operation | movement of the map drawing apparatus of base technology.

<A. Prerequisite technology>
FIG. 10 shows a display of the map drawing apparatus of the base technology using the LOD technology. When a 3D map is used to represent a feature that is viewed obliquely downward from the top of the map, the viewpoint distance becomes farther toward the upper side of the display screen, and the drawing object is displayed smaller. Therefore, while displaying the drawing object in the lower half of the display screen in detail, if the drawing object in the upper half of the display screen is displayed in a simplified manner, the load of the drawing process can be reduced by the simplified display. I can do it. In FIG. 10, five buildings (drawing objects) are integrated into one on the upper side of the display screen. Thus, the number of drawing objects can be reduced, and the load of drawing processing is reduced.

  If the area where the drawing object is displayed in detail is the detailed area, and the area where the drawing object is simply displayed is the simple area, according to the base technology, the position of the boundary line between the detailed area and the simple area is fixed on the display screen. (FIG. 1 (b)). That is, the simplicity of the drawing object as the entire display screen is always constant, and cannot be flexibly adjusted according to the processing resources of the map drawing apparatus. For this reason, for example, when the processing resources for drawing are small, there is a problem that a sufficient drawing speed cannot be secured.

<B. Embodiment 1>
In view of the problems of the base technology, in the present invention, the processing load related to drawing is adjusted by changing the distribution of simplicity according to the operation status of the apparatus, and the reduction in drawing speed is suppressed. FIG. 1A shows an example of changing the distribution of simplicity, and the position of the boundary line between the detailed area and the simplified area is variable. In other words, when there is a margin for processing resources, move the boundary line in the direction to increase the detailed area and perform detailed drawing. When the processing resources are not enough, move the boundary line in the direction to increase the simple area. Reduces drawing load and suppresses reduction in drawing speed.

<B-1. Configuration>
FIG. 2 is a block diagram showing the configuration of the car navigation device 10 which is an example of the map drawing device of the present invention. The car navigation device 10 includes an operation input unit 1, a control unit 2, a data storage unit 3, a state monitoring unit 4, a simplicity setting unit 5, a drawing object generation unit 6, an image composition unit 7, and a display unit 8. .

  The operation input unit 1 is an input interface of the car navigation device 10 and accepts user operations. The operation input unit 1 is constituted by, for example, a mechanical or electronic switch, and may be constituted by a car navigation device 10 and a remote controller in a separate housing. User operations accepted by the operation input unit 1 include map screen scroll information (scroll direction, scroll speed, scroll amount), map screen enlargement or scale operation, and the like.

  The state monitoring unit 4 stores state information indicating the state of the device. The state of the device includes the operation mode of the car navigation device 10 in addition to the CPU resource and the GPU resource of the car navigation device 10. The operation mode includes a normal mode and a power saving mode that consumes less power than the normal mode, and the control unit 2 determines which mode to operate in accordance with a predetermined condition, for example. Alternatively, the user may input and determine one of the operation modes from the operation input unit 1.

  The data storage unit 3 stores drawing object data (drawing object data) representing a map, and is configured by a storage medium such as a hard disk (Hard Disk Drive) or a memory. Or you may acquire drawing object data at any time by the radio | wireless communication from the server outside the car navigation apparatus 10. FIG. Here, the drawing object is a polygon that represents each feature on the map such as a house or a facility.

  The control unit 2 controls each component of the car navigation device 10. In particular, the control unit 2 acquires the state information of the state monitoring unit 4 and controls the simplicity setting unit 5 based on this.

  The simplicity setting unit 5 divides the display screen into a plurality of regions based on instructions from the control unit 2, and sets the simplicity of the drawing object for each region. Therefore, if the state information changes, the drawing object distribution also changes accordingly. In the present specification, the degree of simplification indicates the degree of simplification, and is defined as a drawing processing amount necessary for drawing a drawing object per unit area. An example of simplification is to integrate adjacent drawing objects into one drawing object. As the degree of simplicity increases, a wider range of drawing objects are integrated. Another example is to reduce the number of vertices of one drawing object. The greater the simplicity, the less the number of vertices the drawing object is represented. Another example is to unify the display colors of adjacent drawing objects. As the degree of simplicity increases, a wider range of drawing objects is expressed in the same color.

  In response to an instruction from the control unit 2, the drawing object generation unit 6 acquires drawing object data from the data storage unit 3, and further acquires the simplicity of the drawing object from the simplicity setting unit 5. The drawing object generation unit 6 includes a detailed drawing object generation unit 61, an intermediate drawing object generation unit 62, and a simple drawing object generation unit 63 that generate images of drawing objects according to the degree of simplicity. Here, an example is shown in which three areas having a degree of simplicity of 0, 1, and 2 are set on the display screen. The detailed drawing object generation unit 61 generates a drawing object image composed of drawing objects with a simplicity of 0, and similarly, the intermediate drawing object generation unit 62 generates a drawing object image with a simplicity of 1, and the simplified drawing object generation unit 63 simplifies. Each drawing object of degree 2 is generated. Specific generation contents will be described later with reference to FIG.

  The image composition unit 7 acquires the drawing object images generated for each simplicity by the drawing object generation unit 6, and outputs a display image created by combining them to the display unit 8.

  The display unit 8 is a monitor such as a liquid crystal display, and displays an image synthesized by the image synthesis unit 7. When the operation input unit 1 is configured with a touch panel, the operation input unit 1 and the display unit 8 are configured integrally.

  The control unit 2, simplicity setting unit 5, drawing object generation unit 6, and image composition unit 7 are realized by a CPU (Central Processing Unit) that executes a program stored in a memory such as a RAM (Random Access Memory). . The state monitoring unit 4 is realized by a memory such as a RAM (Random Access Memory).

<B-2. Display operation>
Next, the image display operation of the car navigation device 10 will be described with reference to the flowchart of FIG. First, when the car navigation device 10 is powered on, the control unit 2 determines whether or not the operation input unit 1 has detected a user scroll operation (step S1). If the scroll operation is not detected (No in step S1), the process waits until it is detected. When a scroll operation is input to the operation input unit 1 (Yes in step S1), information related to scrolling such as direction and speed is sent from the operation input unit 1 to the control unit 2. The control unit 2 determines whether or not there is a change in the scroll speed (step S2). Here, it is determined that the change has occurred when the change in the scroll speed is equal to or greater than the predetermined value, and when the scroll operation is detected for the first time, the change is calculated with the previous scroll speed set to zero. If there is no change in the scroll speed (No in step S2), the process returns to step S1.

  If there is a change in the scroll speed (Yes in step S2), the simplicity setting unit 5 sets the simplicity of the drawing object according to the instruction of the control unit 2 (step S3). FIG. 4 shows, as an example of simplification, the processing contents of the drawing object generation unit 6 when simplification is performed by integration processing of adjacent drawing objects according to the degree of simplification. When the simplicity is 0, the integration process is not performed. That is, the drawing object is generated according to the drawing object data without performing any simplification process with any drawing object adjacent to the drawing object. When the simplicity is 1, adjacent buildings (drawing objects) are integrated. When the simplicity is 2, a wider range of buildings (drawing objects) is integrated than when the simplicity is 1. When the simplicity is 3, all buildings (drawing objects) in the same section are integrated. In this way, the drawing object generation unit 6 increases the range of drawing objects for which the integration process is performed as the simplicity increases.

  FIG. 4 shows four simplifications (simplifications 0 to 3), but the number of simplifications, that is, the number of display screen sections is not limited to this. FIG. 1A shows a case where the display screen is divided into two areas with different simplicity, and FIG. 5 shows a case where the display screen is divided into three areas with different simplicity. In FIG. 5, the display screen is divided into a detailed area (simplicity 0), an intermediate area (simplification 1), and a simple area (simplification 2) in order from the bottom. Thus, the simplicity setting unit 5 sets the simplicity so as to increase stepwise from the lower end to the upper end of the display screen.

  In FIG. 5, the simplicity is set so that the simplicity changes in one direction with respect to the entire display screen. However, when performing map display using a part of the display screen, The above setting may be performed for at least a part of the area in the display screen.

  Returning to FIG. 3, next, the drawing object generation unit 6 generates an image of the drawing object for each simplicity (step S <b> 4). The generated images for each degree of simplicity are combined into one image by the image combining unit (step S5) and output to the display unit 8 (step S6).

  Next, the control unit 2 determines whether or not the drawing program is finished (step S7). If the program is not finished, the process returns to step S1, and if the program is finished, the process is finished.

  In FIG. 3, the flow for setting the simplicity of the drawing object when the change in the scroll speed is detected (step S2) has been described. However, the change in the scroll speed is an example of a trigger for setting the simplicity (step S3). For example, when a change in the processing resource of the car navigation device 10 is detected, the operation after step S3 may be performed.

<B-3. Simplification setting>
The simplicity setting unit 5 increases the simplicity of the entire display screen as the scroll speed increases or as the processing resource decreases.

  FIG. 6 shows an example of setting the simplicity. A case where the scroll speed is sufficiently small or a case where the CPU resource is sufficiently large is defined as an initial state, and a change from the initial state will be described. 6A, 6B, and 6C, the display screen is divided into a detailed area and a simplified area in an initial state, and both areas are divided by a boundary line parallel to the horizontal direction of the display image. . In FIG. 6A, as the CPU resource decreases or the scroll speed increases, the boundary line between both regions moves in the direction in which the area of the simplified region increases.

  In FIG. 6B, as in FIG. 6A, as the CPU resource decreases or the scroll speed increases, the boundary line between both regions moves in the direction in which the area of the simplified region increases. However, when the height of the detailed area reaches a predetermined value, the boundary line stops moving, and then the simplified area expands from the upper side of the display screen, and the three areas having different degrees of simplicity divide the display area. In other words, the simplicity setting unit 5 adds a simplified area as the CPU resource decreases or the scroll speed increases. When the CPU resource is further reduced or the scroll speed is increased, the boundary line between the intermediate area and the simplified area moves in the direction of increasing the simplified area, and finally the display screen has a lower detailed area and an upper simplified area. Divided into two. In other words, the simplicity setting unit 5 deletes the intermediate area in accordance with a decrease in CPU resources. According to the simplicity setting method shown in FIG. 6B, it is possible to adjust the drawing load while securing a detailed area in a certain range below the display image.

  In FIG. 6C, as in FIG. 6B, the boundary line between the two regions moves to the detailed region side as the CPU resource decreases. The difference from FIG. 6B is that the simplified area extends from the upper side of the display image in accordance with the movement of the boundary line between the two areas without waiting for the height of the detailed area to be reduced to a predetermined value. is there.

  FIG. 6 shows an example in which the boundary line of each region is set in parallel with the horizontal direction of the display screen, and the boundary line moves in the vertical direction of the display screen. However, as shown in FIG. 7, the direction of the boundary line and the moving direction are not limited to this.

  In FIG. 7, the case where the scroll speed is sufficiently low or the case where the CPU resource is sufficiently large is defined as an initial state, and a change from the initial state will be described. 7A to 7D, in the initial state, the display screen is divided into a lower detailed area and an upper simplified area by a horizontal boundary line. As the CPU resource decreases or the scroll speed increases, the boundary line moves in the direction of increasing the area of the simplified region, as in FIG.

  However, in FIG. 7A, the boundary line does not translate downward, but rather moves downward from its left and right ends. Similarly, in FIGS. 7B to 7D, it moves downward preferentially from the right side of the boundary line. The shape of the boundary line in the middle of movement is a straight line in FIG. 7B, and a curve in FIGS. 7C and 7D.

  In the above description, a method has been described in which two or three regions having different degrees of simplicity are set on the display screen, and the boundary lines of the regions are moved based on CPU resources or the like. In this way, when the display screen is divided into a finite number of regions and different simplicity is assigned, the change in simplicity is, for example, stepwise from the bottom to the top of the display image as shown in FIG. The simplicity setting unit 5 changes the boundary line of each region, that is, the boundary of discontinuous change in simplicity, according to changes in parameters such as CPU resources and scroll speed. As described above, the number of display screen sections is not limited to three in FIG. 8 and may be larger. If the number of divisions is increased as much as possible, the step width of the simplicity shown in FIG. 8 becomes extremely small, and it can be considered that the simplicity changes continuously as shown in FIG.

  In this case, the simplicity setting unit 5 defines a function f (x, y, v, E) of simplicity instead of dividing the display screen into a plurality of areas and assigning simplicity. The function f uses the scroll speed v and the CPU or GPU resource E as parameters for the position on the display screen defined by the xy coordinates. The simplicity setting unit 5 sets the function f so that the simplicity f (x, y) increases as the scroll speed v increases or the CPU or GPU resource E decreases. In other words, the simplicity setting unit 5 changes the form of continuous change of simplicity according to the change of parameters. Thereby, it is possible to adjust the drawing load and suppress a reduction in drawing speed.

<B-4. Modification>
Although the example which applied the map drawing apparatus of this invention to the car navigation apparatus was demonstrated in the above description, the map drawing apparatus of this invention can be mounted in a vehicle, PND (Portable Navigation Device), and portable terminal ( For example, the present invention can also be applied to a navigation apparatus constructed as a system by appropriately combining a mobile phone, a smartphone, a tablet, and the like) and a server. In this case, each function or each component of the car navigation device 10 described above is distributed and arranged in each device constituting the system.

  Further, although the present invention has been described with respect to simplification of a drawing object in 3D display, the present invention can also be applied to a bird view in which a 2D map is expressed from a viewpoint from above. In this case, simplification is possible by, for example, integrating 2D drawing objects, reducing the number of vertices, or unifying display colors.

<B-5. Effect>
In the car navigation device 10 (map drawing device) according to the present invention, the degree of simplification indicating the degree of simplification of the display is continuous from at least one region on the display screen of the display unit 8 from one end to the other end of the region. Generating a simplified drawing object according to the display position on the display screen from the drawing object data, and the simplicity setting unit 5 that is set so as to change in one direction of increasing or decreasing automatically or discontinuously, And a drawing object generation unit 6 that outputs to the display unit, and the simplicity setting unit 5 changes the form of continuous change or the boundary of discontinuous change according to the change of the predetermined parameter. Therefore, detailed display can be performed within a range in which the drawing speed does not become slow by increasing or decreasing the drawing load in accordance with the change of the predetermined parameter.

  The simplicity setting unit 5 sets a plurality of display areas to which the drawing object is assigned for each predetermined simplicity in at least a part of the area on the display screen, and displays a plurality of displays according to a change in the predetermined parameter. Move at least part of the border of the region. Thereby, the simplicity of the drawing object as the whole display screen can be adjusted.

  Further, the simplicity setting unit 5 changes the simplicity assigned to the display area according to the change of the predetermined parameter. Thereby, the simplicity of the drawing object as the whole display screen can be adjusted.

  In addition, the simplicity setting unit 5 sets a plurality of display areas in the vertical direction of the display screen, and sets a display area to which drawing object data having a greater simplicity is assigned to the upper side of the display screen. In 3D display or bird view, the drawing object displayed on the upper side of the display screen has a small viewpoint distance and is displayed small, so that the drawing load can be reduced within a range that does not affect the actual appearance as much as possible.

  The predetermined parameter includes a scrolling speed of the display screen of the display unit 8. For example, as the scroll speed increases, the processing resources decrease. Therefore, the reduction of the drawing speed can be suppressed by reducing the drawing load. In particular, the drawing load can be reduced by moving the boundary line between two adjacent display areas in a direction in which the area of the display area having a greater simplicity is increased.

  Alternatively, the predetermined parameter includes a CPU resource or a GPU resource of the map drawing device. By reducing the drawing load as the CPU resource or GPU resource decreases, the reduction in drawing speed can be suppressed. In particular, the drawing load can be reduced by moving the boundary line between two adjacent display areas in a direction in which the area of the display area having a greater simplicity is increased.

  In addition, when the map drawing apparatus is in the power saving mode, the simplicity setting unit 5 increases the area of the display area where the simplicity is larger than the normal mode in the boundary line between two adjacent display areas. By moving in this direction, the drawing load can be reduced and the power consumption can be suppressed.

  In addition, the simplicity setting unit 5 can flexibly adjust the drawing load while ensuring the minimum display detail by always keeping the area of the display area with the smallest simplicity at a certain value or more. it can.

  In the present invention, the embodiments can be appropriately modified and omitted within the scope of the invention.

  1 operation input unit, 2 control unit, 3 data storage unit, 4 state monitoring unit, 5 simplicity setting unit, 6 drawing object generation unit, 7 image composition unit, 8 display unit, 10 car navigation device, 61 detailed drawing object generation 62, an intermediate drawing object generation unit, 63 a simple drawing object generation unit.

Claims (10)

A map drawing device that generates a drawing object from drawing object data and outputs the drawing object to a display unit,
One direction in which at least a part of the display screen of the display unit has a degree of simplification that continuously or discontinuously increases or decreases from one end to the other end of the region. A simplicity setting unit for setting to change to
A drawing object generation unit that generates the drawing object having the simplicity according to the display position on the display screen from the drawing object data, and outputs the drawing object to the display unit;
With
The simplicity setting unit changes the form of the continuous change or the boundary of the discontinuous change according to a change of a predetermined parameter.
Map drawing device. The simplicity setting unit sets a plurality of display areas to which the drawing object is assigned for each predetermined simplicity in at least a part of the area on the display screen, and the plurality of display areas are set according to a change in the predetermined parameter. Move at least part of the border of the display area of
The map drawing apparatus according to claim 1. The simplicity setting unit adds or deletes the display area according to a change in the predetermined parameter.
The map drawing apparatus according to claim 1 or 2. The simplicity setting unit sets the plurality of display areas in the vertical direction of the display screen, and sets the display area to which the drawing object data having a greater simplicity is assigned to the upper side of the display screen.
The map drawing apparatus in any one of Claims 1-3. The predetermined parameter includes a scrolling speed of the display screen of the display unit.
The map drawing apparatus in any one of Claims 1-4. The simplicity setting unit moves a boundary line between two adjacent display areas in a direction in which the area of the display area having a greater simplicity becomes larger as the scrolling speed increases.
The map drawing apparatus according to claim 5. The predetermined parameter includes a CPU resource or a GPU resource of the map drawing device,
The map drawing apparatus in any one of Claims 1-6. The simplicity setting unit moves a boundary line between two adjacent display areas in a direction in which the area of the display area having a greater simplicity becomes larger as the CPU resource decreases.
The map drawing apparatus according to claim 7. When the map drawing device is in the power saving mode, the simplicity setting unit displays the boundary line between the two adjacent display regions as compared with the normal mode, and the area of the display region with the greater simplicity. Move in the direction of increasing,
The map drawing apparatus in any one of Claims 1-8. The simplicity setting unit keeps the area of the display area having the smallest simplicity at a certain value or more.
The map drawing apparatus in any one of Claims 1-9.