TWI448808B - System and method for adjusting focus of a projection automatically - Google Patents

Description

Projector auto focus system and method

The invention relates to a projector autofocus system and method.

Usually after the projector is turned on, the demonstrator needs to perform steps to adjust the focal length and position of the projector to ensure that the projection display is normal. These adjustment procedures are relatively cumbersome for business users who often change the environment in which the projector is used.

Conventional projectors cannot detect the distance between the projector and the projection plane, and automatically adjust the focal length to ensure that the projected display is clear. When the projector is placed at a certain angle with the projection plane, the projected image is distorted. To ensure the normal display of the screen, the user needs to spend a lot of time adjusting the screen, which reduces the efficiency of the projection presentation.

In view of the above, a preferred embodiment of the present invention provides a projector autofocus system for controlling a motor through a control wafer by calculating a resolution at which a user selects an analysis region on a projection surface and obtains a maximum resolution. Push the lens to the above position to achieve autofocus.

A projector autofocus system, the projector autofocus system running in a projector, the projector comprising: a control chip and a motor that pushes the lens to telescope, the lens projects a projection surface, the system includes : an area selection module, configured to select at least one analysis area on the projection surface;

a focal length setting module for setting a plurality of focal lengths in a zoom range of the lens; a resolution calculation module for calculating a resolution of the lens to the analysis area when the lenses are respectively at the end points of the focal lengths in the zoom range; and comparing a module for comparing the resolution of the analysis region of the lens to obtain a focal length of an endpoint corresponding to a maximum resolution; and a selection module for uniformly selecting a plurality of points in the acquired focal length The resolution calculation module is further configured to calculate a resolution of the lens to the analysis area when the lens is at each selected point; and the comparison module is further configured to analyze the comparison lens at each selected point The resolution of the region is to obtain a position of the point corresponding to the maximum resolution; and the control wafer pushes the lens to the position of the acquisition point through the control motor.

In view of the above, the preferred embodiment of the present invention further provides a projector autofocus method, the projector includes a control chip, and the control chip drives the lens through a control motor. The method includes the following steps: after the projector is powered on, Projecting a projection surface on a screen; selecting at least one analysis area on the projection surface; setting a plurality of focal lengths in the zoom range of the lens; and calculating the resolution of the lens on the analysis area when the lens is respectively at the end point of each focal length in the zoom range And comparing the resolution of the analysis region obtained by the above calculation to obtain a maximum resolution, and obtaining the focal length of the endpoint corresponding to the maximum resolution; uniformly selecting a plurality of points in the acquired focal length; calculating the shots in each selection The resolution of the analysis area by the point-time lens; and the resolution of the analysis area at each selected point of the comparison lens to obtain a maximum resolution, and obtaining the position of the maximum resolution corresponding to the selected point; and controlling the transmission of the wafer The motor is controlled to push the lens to the position of the acquisition point.

Compared with the prior art, the projector autofocus system and method can calculate the image resolution of the analysis area selected by the user when the lens is at each position, and push the lens to the analysis area by controlling the wafer control motor. The maximum resolution position is used to achieve autofocus, eliminating the need for manual focus adjustment, which greatly saves focus time and improves focus accuracy.

Referring to Figure 1, there is shown a hardware architecture diagram of a preferred embodiment of the projector autofocus system of the present invention. The projector autofocus system 12 operates in a projector 1. The projector 1 includes a control wafer 10, a motor 14, a memory 16 and a lens 18. The memory 16 can be a flash memory (FLASH) for storing pictures to be projected. The control wafer 10 is controlled by the motor 14 to expand and contract the lens 18 to adjust the focal length. The projector autofocus system 12 selects one or more analysis areas, such as A, B, C, D, and O analysis areas, through the projection surface 2 of the lens 18 on the screen (as shown in FIG. 4), at the lens 18 A plurality of focal lengths are set in the zoom range, and the resolution of the analysis region at the end points of each focal length of the lens 18 in the zoom range is calculated, and the alignment is analyzed to obtain the focal length of the endpoint corresponding to the maximum resolution, and the focal length corresponding to the maximum resolution is A plurality of points are uniformly selected, and the resolution of the analysis region when each of the selection points is at each of the selection points is calculated, and a maximum resolution is selected from the calculated resolutions and the position of the corresponding point of the maximum resolution is obtained. Finally, the control wafer 10 is pushed through the motor 14 to push the lens 18 to the position of the above-mentioned acquisition point for focusing purposes. The area of the above analysis areas A, B, C, D and O can be selected according to the actual situation, and can be a 50*50 pixel size area. Each of the above focal lengths can be set to 5 mm or other length, and a point can be selected every 1 mm on the focal length.

Referring to FIG. 2, it is a functional module diagram of the projector autofocus system of the present invention. The projector autofocus system 12 includes an area selection module 120, a focal length setting module 121, a resolution calculation module 122, a selection point module 123, and a comparison module 124.

The area selection module 120 is configured to select one or more analysis areas on the projection surface 2, and the analysis area may be distributed on any position on the projection face, such as the analysis areas A, B, C, D in FIG. O. In the present embodiment, the analysis area O is located at the center of the projection surface 2, and the remaining analysis areas A, B, C, and D are located at the four corners of the projection surface 2, respectively. The following is a convenient description, and an analysis area O is selected as an example.

The focal length setting module 121 is configured to set a plurality of focal lengths within the zoom range. In this embodiment, the focal length division may be determined according to actual conditions, such as one focal length per 5 mm.

The resolution calculation module 122 is configured to calculate the resolution of the lens 18 to the selected analysis region O when the lens 18 is at the end point of each focal length in the zoom range. Next, the analysis area O with an area of 50*50 pixels is selected every 5 mm as a focal length, so that the resolution of the analysis area O at the end points of each focal length of the lens 18 is calculated. For example, the zoom range is divided into multiple focal lengths [0, 5], [5, 10], [10, 15], [15, 20], [20, 25], etc.; Points 0, 5mm, 10mm, 15mm, 20mm and 25mm. When the lens 18 is at the origin 0, its resolution is 0.0745; at 5 mm, its resolution is 0.152; at 10 mm, its resolution is 0.367; at 15 mm, its resolution is 0.379; At 20 mm, the resolution is 0.352; at 25 mm, the resolution is 0.149.

The comparison module 124 compares the analysis area resolution obtained when the lens 18 is located at each end point of each focal length to obtain the maximum resolution, and obtains the focal length of the endpoint corresponding to the maximum resolution. After the above comparison, the resolution of the lens 18 is 1067, the resolution is 0.367; at 15mm, the resolution is 0.379; when it is 20mm, the resolution is 0.352; the maximum resolution of the analysis area O is known. It is 0.379, and its corresponding end point is 15mm. The focal length of this end point is 10mm~15mm and 15mm~20mm.

The selection point module 123 is used for uniformly selecting a plurality of points in the obtained focal length, for example, uniformly selecting a plurality of points in the focal lengths of 10 mm to 15 mm and 15 mm to 20 mm, for example, every 1 mm in the focal lengths of 10 mm to 15 mm and 15 mm. ~20mm evenly select points, you can select 10 points.

The resolution calculation module 122 is configured to calculate the resolution of the selected analysis region by the lens 18 at each of the selected points.

The comparison module 122 compares the resolution of the lens pair at the above-mentioned selected points with the lens pair analysis area to obtain a maximum resolution, and acquires the position of the selected point corresponding to the maximum resolution. For example, by comparison, the resolution at 18 mm is the largest.

The control wafer 10 controls the motor 14 to push the lens 18 to the position of the acquisition point described above to bring the lens 18 to the optimal focus position.

3 is a flow chart showing the operation of the projector autofocus method of the present invention. In step S301, the user turns on the projector 1 to power on.

In step S302, the lens 18 projects the picture stored in the memory 16 onto a screen to obtain the projection surface 2.

In step S303, the area selection module 120 selects one or more analysis areas, such as analysis areas A, B, C, D, and O, on the projection surface 2. In the present embodiment, the analysis area O is located at the center of the projection surface 2, and the analysis areas A, B, C, and D are respectively located at the four corners on the projection surface 2. For convenience of explanation, the analysis area O is selected as an example.

In step S304, the focal length setting module 121 sets a plurality of focal lengths in the zoom range of the lens. In this embodiment, the focal length division may be determined according to actual conditions, such as 5 mm being a focal length.

Step S305, calculating the resolution of the selected analysis area O at the end points of each focal length of the lens 18 in the zoom range. Next, the analysis area O with an area of 50*50 pixels is selected every 5 mm as a focal length, so that the resolution of the analysis area O at the end points of each focal length of the lens 18 is calculated. For example, the zoom range is divided into multiple focal lengths [0, 5], [5, 10], [10, 15], [15, 20], [20, 25], etc.; Points 0, 5mm, 10mm, 15mm, 20mm and 25mm. When the lens 18 is at the origin 0, its resolution is 0.0745; at 5 mm, its resolution is 0.152; at 10 mm, its resolution is 0.367; at 15 mm, its resolution is 0.379; At 20 mm, the resolution is 0.352; at 25 mm, the resolution is 0.149.

In step S306, the comparison module 124 compares the resolution calculation module 122 to calculate the analysis region resolution obtained when the lens 18 is located at each end point of each focal length to obtain the maximum resolution, and acquires the maximum resolution corresponding end. The focal point of the point. After the above comparison, the resolution of the lens 18 is 1067, the resolution is 0.367; at 15mm, the resolution is 0.379; when it is 20mm, the resolution is 0.352; the maximum resolution of the analysis area O is known. It is 0.379, and its corresponding end point is 15mm. The focal length of this end point is 10mm~15mm and 15mm~20mm.

In step S307, the selection module 123 uniformly selects a plurality of points in the acquired focal length, for example, uniformly selecting a plurality of points in the focal lengths of 10 mm to 15 mm and 15 mm to 20 mm, such as 10 mm to 15 mm in the focal length every 1 mm and Select points from 15mm to 20mm and select 10 points.

In step S308, the resolution calculation module 122 is configured to calculate the resolution of the selected analysis region by the lens 18 at each of the selected points.

In step S309, the comparison module 122 compares the resolution of the analysis area with the resolution of the lens 18 at the above selected points to obtain a maximum resolution, and acquires the position of the selected point corresponding to the maximum resolution. For example, by comparison, the resolution at 18 mm is the largest.

In step S309, the control wafer 10 pushes the lens 18 through the control motor 14 to the position of the acquired point, and the final lens 18 is in the best focus position.

Figure 4 is a schematic illustration of the projection surface 2 of the lens 18 of the present invention on a screen. The user can arbitrarily select the analysis areas A, B, C, D, and O on the projection surface 2. The center point of the analysis area O coincides with the center point position of the projection face 2 . The distance from the center point of any of the analysis areas A, B, C, and D to the center point of the projection surface 2 is 0.3 to 0.5 of the diagonal length.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application.

Projector. . . 1

Control the chip. . . 10

Projector autofocus system. . . 12

motor. . . 14

Memory. . . 16

Lens. . . 18

Area selection module. . . 120

Focus section setting module. . . 121

Resolution calculation module. . . 122

Select the module. . . 123

Alignment module. . . 124

1 is a hardware architecture diagram of a projector autofocus system of the present invention.

2 is a functional block diagram of the projector autofocus system of the present invention.

3 is a flow chart of a preferred embodiment of the projector autofocus method of the present invention.

4 is a schematic view showing a projection surface of the projector lens of the present invention on a screen.

Projector autofocus system. . . 12

Area selection module. . . 120

Focus section setting module. . . 121

Resolution calculation module. . . 122

Select the module. . . 123

Alignment module. . . 124

Claims (10)

A projector autofocus system, the projector autofocus system running in a projector, the projector comprising: a control chip and a motor that pushes the lens to telescope, the lens projects a projection surface, the system includes : an area selection module for selecting at least one analysis area on the projection surface; a focal length setting module for setting a plurality of focal lengths in a zoom range of the lens; and a resolution calculation module for calculating that the lenses are respectively in a zoom range The resolution of the lens to the analysis area at the end point of each focal length; and the comparison module, configured to compare the resolution of the lens pair analysis area obtained by the above calculation to obtain a maximum resolution, and obtain the maximum resolution corresponding to a focal point segment of the endpoint; a selection point module for uniformly selecting a plurality of points in the acquired focal length; the resolution calculation module is further configured to calculate an analysis of the analysis region by the lens when the lens is at each selected point And the comparison module is also used to compare the resolution of the lens pair analysis area at each selected point of the lens to obtain a maximum resolution And obtaining maximum resolution corresponding to the position of the selected point; and push the lens through the control chip to control the motor position acquisition point. The projector autofocus system of claim 1, wherein the analysis area is at any position on the projection surface. The projector autofocus system according to claim 1, wherein the area of the analysis area is 50*50 pixels. The projector autofocus system of claim 1, wherein the focal length is set to 5 mm. The projector autofocus system according to claim 1, wherein the selection module selects one point per 1 mm in the acquired focal length. A projector autofocus method, the projector includes a control chip, and the control chip drives a lens through a control motor, the method comprising the steps of: projecting a projection surface on a screen after the projector is powered on; Selecting at least one analysis area on the surface; setting a plurality of focal lengths in the zoom range of the lens; calculating a resolution of the lens to the analysis area when the lenses are respectively at the end points of each focal length in the zoom range; and comparing the calculated calculations The resolution of the region is obtained to obtain a maximum resolution, and the focal length of the endpoint corresponding to the maximum resolution is obtained; a plurality of points are uniformly selected within the acquired focal length; and the lens is calculated for the analysis region when the lens is at each selected point And the resolution of the analysis area at each selected point of the lens to obtain a maximum resolution, and obtain the position of the corresponding point of the maximum resolution; and control the wafer to push the lens to the acquisition point through the control motor s position. The projector autofocus method according to claim 6, wherein the analysis area is at any position on the projection surface. The projector autofocus method according to claim 6, wherein the area of the analysis area is 50*50 pixels. The projector autofocus method of claim 6, wherein the focal length is set to 5 mm. The projector autofocus method according to claim 6, wherein the selection point is one point every 1 mm.