TWI737049B - Projection calibration system and projection calibration method thereof - Google Patents

Abstract

A projection calibration system and a projection calibration method thereof are provided. A projection device projects test images on a projection screen. Each test image includes a pattern. Light sensing devices are disposed on a frame of the projection screen and sense light sensing information while the projection device is projecting the test images. The light sensing information varies in response to the location of the pattern is changed from a first position in a first test image to a second position in a second test image. A computing device determines an image boundary parameter according to the first position in response to the light sensing information varies from a first sensing value to a second sensing value. The projection device performs an image scaling process according to the image boundary parameter to project a calibrated image aligned with the frame of the projection screen.

Description

Projection correction system and projection correction method thereof

The present invention relates to a projection technology, and more particularly to a projection correction system and a projection correction method thereof.

The projector is a display device used to generate large-scale image frames. The imaging principle of the projector is to convert the illumination beam generated by the light source module into an image beam through the light valve device, and then project the image beam onto the projection screen or wall through the lens to form an image. With the advancement of projection technology and the reduction of manufacturing costs, the use of projectors has been expanded to various applications. The touch projection system is a projection system that allows users to perform touch operations on the projection screen. The touch area of the projection screen is used to receive touch input operations performed by the user, so that the user can touch The operation interacts intuitively with the projection system.

It should be noted that in this type of touch projection system, users often need to align the projection screen projected by the projector and the touch area provided by the projection screen, so that the projector can correctly respond to the touch. The touch operation received by the projection screen performs subsequent actions, so that the user and the touch projection system can interact smoothly. More specifically, the touch boundary of the touch area on the projection screen needs to be accurately aligned with the boundary of the image content in the projection screen, so that the touch projection system can accurately provide functions that meet the user's expectations for the touch position of the touch operation. . In a traditional calibration method, the user can move the position of the projector or the position of the projection screen to adjust the size and shape of the projection screen. However, this calibration method is not only easily limited by environmental constraints, but also difficult to obtain accurate calibration results. . In addition, in another traditional calibration method, the touch projection system can use the camera to shoot the projection result to perform the alignment correction of the touch boundary and the image content boundary, but this correction method needs to consider the camera parameters and camera calibration together, otherwise it will Cannot perform accurate projection correction. Or, in another traditional correction method, the user can manually set the image content boundary in the projection screen to shrink and perform alignment correction by subjective judgment of the human eye. However, the manual operation steps of this correction method are cumbersome and costly. Time, it is quite inconvenient for the user.

The "prior art" paragraph is only used to help understand the content of the present invention, so the contents disclosed in the "prior art" paragraph may include some conventional technologies that do not constitute the common knowledge in the technical field. The content disclosed in the "prior art" paragraph does not represent the content or the problem to be solved by one or more embodiments of the present invention, and has been known or recognized by those with ordinary knowledge in the technical field before the application of the present invention.

In view of this, the present invention provides a projection correction system and a projection correction method thereof, which can efficiently and accurately perform projection alignment correction, so that the boundary of the image content in the corrected screen can be aligned with the frame of the projection screen.

An embodiment of the present invention provides a projection correction system, which includes a projection device, a plurality of photosensitive elements, and an arithmetic device. The projection device projects multiple test images on the projection screen. Each test picture includes a totem, and these test pictures include a first test picture and a second test picture. A plurality of photosensitive elements are arranged on the frame of the projection screen, and the brightness sensing information is measured when the projection device projects each test image. The computing device is coupled to the photosensitive element and the projection device. In response to the change of the totem from the first position in the first test frame to the second position in the second test frame, the brightness sensing information changes from the first sensing value to the second sensing value. In response to the brightness sensing information changing from the first sensing value to the second sensing value, the computing device determines the frame boundary parameter according to the first position of the totem in the first test frame. The projection device performs image scaling processing according to the image boundary parameters to project the corrected image aligned with the frame of the projection screen.

In an embodiment of the present invention, the above-mentioned photosensitive elements are respectively located on a plurality of corner points of the frame of the projection screen, and the projection range of the projection device at least covers the frame.

In an embodiment of the present invention, the aforementioned totem includes a horizontal line, and the projection device generates a test image by changing the position of the horizontal line on the vertical axis.

In an embodiment of the present invention, the aforementioned computing device determines an upper and lower boundary parameter of the frame boundary parameters according to the first position of the horizontal line on the vertical axis in the first test frame.

In an embodiment of the present invention, the above-mentioned totem includes a vertical line, and the projection device generates a test image by changing the position of the vertical line on the horizontal axis.

In an embodiment of the present invention, the aforementioned computing device determines a left and right boundary parameter of the frame boundary parameters according to the first position of the vertical line on the horizontal axis in the first test frame.

In an embodiment of the present invention, the above-mentioned totem includes a horizontal line and a vertical line, and the projection device generates a test image by changing the position of the vertical line on the horizontal axis and the position of the horizontal line on the vertical axis.

In an embodiment of the present invention, the above-mentioned projection device reduces an original image from the computing device according to the frame boundary parameters, and fills in the peripheral image blocks around the reduced original image to generate a corrected image, and the corrected image is The edge of the original image is aligned with the frame.

In an embodiment of the present invention, the above-mentioned projection device generates test images according to totem parameters provided by the computing device, the totem parameters include totem position parameters, and the projection device generates multiple totem images as the test images according to the totem position parameters, and the totems are respectively Located in different positions in the totem screen, and the size of the totem is fixed.

In an embodiment of the present invention, the above-mentioned projection device generates a test image according to totem parameters provided by the computing device. The totem parameters include totem compression deformation parameters. The projection device compresses a totem image according to the totem compression deformation parameters, and fills in the image block. A test image is generated around the compressed totem screen. The position of the totem in the totem screen is fixed, and the size of the totem is reduced according to the compression deformation parameters of the totem.

In an embodiment of the present invention, the above-mentioned projection device further projects a first preset screen, and each photosensitive element measures a first brightness value when the projection device projects the first preset screen, and the projection device does not project the first preset screen. When the screen is preset, a second brightness value is measured, and the computing device determines whether the projection range of the projection device covers the photosensitive element on the frame according to the difference between the first brightness value and the second brightness value, wherein the first brightness value and the second brightness value The two brightness values are used to determine the first sensing value and the second sensing value.

In an embodiment of the present invention, each of the above-mentioned photosensitive elements measures the second brightness value when a second preset image is projected on the projection device or is not projected.

An embodiment of the present invention provides a projection correction method. The method includes the following steps. Project multiple test images on the projection screen by the projection device. Each test picture includes a totem, and these test pictures include a first test picture and a second test picture. When projecting each test image, the brightness sensing information is measured by a plurality of photosensitive elements located on the frame of the projection screen. In response to the change of the totem from the first position in the first test frame to the second position in the second test frame, the brightness sensing information changes from the first sensing value to the second sensing value. In response to the brightness sensing information changing from the first sensing value to the second sensing value, the frame boundary parameter is determined according to the first position of the totem in the first test frame. Perform image scaling processing according to the frame boundary parameters to project the corrected frame aligned with the frame of the projection screen.

In an embodiment of the present invention, the above-mentioned photosensitive elements are respectively located on a plurality of corner points of the frame of the projection screen, and the projection range of the projection device at least covers the frame.

In an embodiment of the present invention, the above-mentioned totem includes a horizontal line, and the method further includes: generating a test image by changing the position of the horizontal line on the vertical axis.

In an embodiment of the present invention, the step of determining the frame boundary parameter according to the first position of the totem in the first test frame in response to the brightness sensing information changing from the first sensed value to the second sensed value includes : According to the first position of the horizontal line on the vertical axis in the first test picture, determine an upper and lower boundary parameter of the picture boundary parameters.

In an embodiment of the present invention, the above-mentioned totem includes a vertical line, and the method further includes: generating a test image by changing the position of the vertical line on the horizontal axis.

In an embodiment of the present invention, the step of determining the frame boundary parameter according to the first position of the totem in the first test frame is reflected in the change of the brightness sensing information from the first sensed value to the second sensed value. Including: according to the first position of the vertical line on the horizontal axis in the first test picture, the computing device determines a left and right boundary parameter in the picture boundary parameters.

In an embodiment of the present invention, the above-mentioned totem includes a horizontal line and a vertical line, and the method further includes: generating a test image by translating the vertical line left and right along the horizontal axis and the horizontal line up and down along the vertical axis .

In an embodiment of the present invention, the above-mentioned step of performing image scaling processing according to the picture boundary parameters to project the corrected picture aligned with the frame of the projection screen includes: reducing an original image according to the picture boundary parameters, and filling the peripheral image block A corrected frame is generated around the reduced original image, and the image edges of the original image in the corrected frame are aligned with the frame.

In an embodiment of the present invention, the above-mentioned method further includes: generating a test picture according to the totem parameter, wherein the totem parameter includes a totem position parameter; and generating a plurality of totem pictures as the test picture according to the totem position parameter, and the totems are respectively located in the totem. Different positions in the screen, and the size of the totem is fixed.

In an embodiment of the present invention, the above method further includes: generating a test image according to totem parameters, the totem parameters including totem compression deformation parameters; and compressing a totem screen according to the totem compression deformation parameters, and filling the image block after compression Test images are generated around the totem screen, the position of the totem in the totem screen is fixed, and the size of the totem is reduced according to the totem compression deformation parameters.

In an embodiment of the present invention, the above method further includes: projecting a first preset image by the projection device; and measuring a first brightness value when the first preset image is projected on the projection device by each photosensitive element; Measure a second brightness value by each photosensitive element when the projection device is not projecting the first preset screen; and determine whether the projection range of the projection device covers the frame according to the difference between the first brightness value and the second brightness value On the photosensitive element, the first brightness value and the second brightness value are used to determine the first sensing value and the second sensing value.

In an embodiment of the present invention, the above method further includes: using each photosensitive element to project a second preset image on the projection device or measure the second brightness value when the projection device is not projected.

Based on the above, in the embodiment of the present invention, the projection device projects a plurality of test images including totems on the projection screen, and the position of the totems in each test image is changed. Moreover, when the projection device projects these test images on the projection screen, the brightness information of the test images is sensed by the photosensitive element arranged on the frame of the projection screen. Since the position of the totem will change with the switching of the test screen, the position of the photosensitive element relative to the projection range can be detected by continuously sensing the brightness sensing information, and the picture can be determined according to the position of the photosensitive element relative to the projection range Boundary parameters. In this way, the projector is allowed to perform image scaling processing according to the image boundary parameters to generate a corrected image that can be aligned with the frame of the projection screen, thereby providing an efficient and convenient projection correction method.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

The foregoing and other technical content, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, for example: up, down, left, right, front or back, etc., are only directions for referring to the attached drawings. Therefore, the directional terms used are used to illustrate but not to limit the present invention.

FIG. 1 is a schematic diagram of a projection correction system according to an embodiment of the invention. Please refer to FIG. 1, the projection correction system 10 includes a projection device 110, a plurality of photosensitive elements 120_1-120_4, a projection screen S1, and an arithmetic device 130.

The projection device 110 can project an image on the projection screen S1, which can be a liquid crystal projector (Liquid Crystal Projector, LCP), a digital light processing (Digital Light Processing, DLP) projector, or a reflective liquid crystal (Liquid Crystal On Silicon, LCOS) projection display device and so on. In this embodiment, the projection device 110 may also include a light source module, an opto-mechanical module, a lens module, and related optical and circuit control components. For example, the projection device 110 may also include an image processing circuit for image processing.

The projection screen S1 is used to display the projection screen projected by the projection device 110 and has a frame F1. In one embodiment, the touch-sensitive projection screen S1 may include a frame F1 and a touch panel embedded in the frame F1. The touch-sensitive projection screen S1 can display a projection screen according to the image beam projected by the projection device 110 and detect the touch operation issued by the user. The touch projection screen S1 can be a projected capacitive touch projection screen, an electromagnetic touch projection screen, a resistive touch projection screen, or other suitable touch projection screens, and the present invention is not limited thereto. In addition, in an embodiment, the projection screen S1 may also include a frame F1 and other display media that are embedded in the frame F1 and have no touch function, such as a projection screen.

The photosensitive elements 120_1 to 120_4 are arranged on the frame F1 of the projection screen S1. In this embodiment, the photosensitive elements 120_1 to 120_4 can be used to sense the brightness of the projection screen to output brightness sensing values. The photosensitive elements 120_1 to 120_4 are, for example, Charge Coupled Devices (CCD), Complementary Metal-Oxide Semiconductor (CMOS) elements, or other elements. In other embodiments, the photosensitive elements 120_1 to 120_4 may be, for example, color sensors for detecting the chromaticity of the color light, and the invention is not limited thereto. In an embodiment, the photosensitive elements 120_1 to 120_4 are respectively located on multiple corner points of the frame F1 of the projection screen S1, and the projection range R1 of the projection device 110 at least covers the frame F1.

It should be noted that, FIG. 1 takes four photosensitive elements 120_1 to 120_4 and is respectively arranged on the four corners of the frame F1 of the projection screen S1 as an example for description, but the present invention does not have any influence on the number and location of the photosensitive elements. To be restricted, it can be set according to the actual application. For example, the number of photosensitive elements may also be other numbers, such as 2 or 8, etc., and the photosensitive elements may be arranged at the middle point of each frame, for example. It should be noted that, in one embodiment, in order to obtain the rectangular display boundary defined by the frame F1 according to the brightness measurement result generated by the photosensitive element, the number of the photosensitive elements must be at least two and they are respectively located at two diagonals of the frame F1. Corner point.

The computing device 130 is coupled to the projection device 110 and the plurality of photosensitive elements 120_1 to 120_4, and includes a memory and at least one processor coupled to the memory. The computing device 130 may be a computer control system with computing capabilities such as a desktop computer, a notebook computer, a work station, an industrial computer, or a server host. The memory can be any type of non-transitory, volatile, and non-volatile data storage device, which is used to store buffered data, permanent data, and compiled code for executing the functions of the computing device 130. The processor may be a Field Programmable Array (FPGA), Programmable Logic Device (PLD), Application Specific Integrated Circuits (ASIC), and other similar devices Or a combination of these devices. The processor can also be a central processing unit (Central Processing Unit, CPU) or other programmable general-purpose or special-purpose microprocessors (Microprocessor), digital signal processor (DSP), graphics processing unit (Graphics Processing Unit, GPU), other similar devices, or a combination of these devices.

FIG. 2 is a flowchart of a projection correction method according to an embodiment of the present invention, and the method flow of FIG. 2 can be implemented by the components of the projection correction system 10 in FIG. 1. Please refer to FIG. 1 and FIG. 2 at the same time. The following is a description of the steps of the projection correction method of this embodiment in conjunction with various components of the projection correction system 10 in FIG. 1.

In step S201, a plurality of test images are projected on the projection screen S1 by the projection device 110. The projection device 110 projects an image beam on the projection screen S1, and the projection range R1 of the projection device 110 is wider than the projection screen S1 and at least covers the frame F1. In other words, the test image projected by the projection device 110 within the projection range R1 will cover the photosensitive elements 120_1 to 120_4.

In one embodiment, each test picture includes a totem and a picture background. The totem may include horizontal bars, vertical bars, or a combination thereof. Moreover, the colors of the totem and the screen background are different from each other. For example, the totem can be white and the screen background can be black, but the invention is not limited thereto. It should be noted that the positions of the totems in these test screens are changed. In other words, when the projection device 110 switches from projecting one of these test images to the other one of the projected test images, the display position of the totem will change, that is, when different test images are presented on the projection screen S1, the display of the totem is The distance of the position relative to the frame F1 will change.

For example, FIGS. 3A and 3B are examples of test screens drawn according to an embodiment of the present invention. Please refer to FIG. 3A, assuming that the totem is a white horizontal line L1 (indicated by a diagonal line in the figure) and the screen background is black, the projection device 110 can change the position of the white horizontal line L1 on the vertical axis (ie, the Y axis) And two test images It1 and It2 are generated. That is, the test picture It1 may include white horizontal lines L1 at the edge of the picture. Another test picture It2 may include white horizontal lines L1 near the edge of the picture. 3B, assuming that the totem is a white vertical line L2 (indicated by a diagonal line in the figure) and the screen background is black, the projection device 110 changes the position of the white vertical line L2 on the horizontal axis (that is, the X axis). Two test images It3 and It4 are generated. That is, the test picture It3 may include a white vertical line L2 at the edge of the picture. Another test picture It4 may include a white vertical line L2 near the edge of the picture. The implementation details of the projection device 110 generating the test image will be described later. However, FIGS. 3A and 3B are illustrated with two test images, but the present invention does not limit the number of test images.

Next, in step S202, when each test frame is projected sequentially, the brightness sensing information is measured by the multiple photosensitive elements 120_1 to 120_4 on the frame F1 of the projection screen S1. Specifically, when the projection device 110 projects each test frame, the multiple photosensitive elements 120_1 to 120_4 are used to measure the brightness sensing information associated with each test frame at different positions on the frame F1, and the photosensitive element 120_1 ~120_4 reports the brightness sensing information to the computing device 130. In the example of FIG. 1, when the projection device 110 projects multiple test images in sequence, the photosensitive elements 120_1 to 120_4 can measure the brightness at the four corner points on the frame F1, and output correspondingly corresponding to these corner points. 4 brightness sensing values on each test screen.

In one embodiment, the first test picture and the second test picture displayed in sequence are described, which reflects that the totem changes from the position in the first test picture (also referred to as the first position) to the second test picture. In the position (also referred to as the second position), some or all of the brightness sensing information sensed by the photosensitive elements 120_1 to 120_4 will be changed from the first sensing value to the second sensing value. Here, the first sensing value is a measurement result of brightness sensing for the first test image, and the second sensing value is a measurement result of brightness sensing for the second test image.

In detail, since the colors of the totems in these test images and the screen background are different, whether the totems in the first test image are displayed over the photosensitive elements 120_1 to 120_4 will affect the brightness sensing results of the photosensitive elements 120_1 to 120_4. That is, the brightness sensing values output by the photosensitive elements 120_1 to 120_4 can be used to reflect whether the display position of the totem and the measurement positions of the photosensitive elements 120_1 to 120_4 overlap. For example, if the display position of the totem in a certain test frame overlaps the measurement position of the photosensitive element 120_1, the photosensitive element 120_1 will output the first sensing value. If the display position of the totem in a certain test frame does not overlap the measurement position of the photosensitive element 120_1, the photosensitive element 120_1 will output a second sensing value different from the first sensing value. In one embodiment, the first sensing value and the second sensing value generated by the light-sensing elements 120_1 to 120_4 for brightness sensing depend on the ambient light source and the color of the totem and the screen background in the test screen.

Thus, in step S203, in response to the brightness sensing information changing from the first sensing value to the second sensing value, the computing device 130 can determine the frame boundary parameter according to the first position of the totem in the first test frame. More specifically, when the computing device 130 determines that the brightness sensing information reported by one of the photosensitive elements 120_1 to 120_4 has changed from the first sensing value to the second sensing value, it represents the totem in the first test frame. The first position overlaps the measurement position of the one of the photosensitive elements 120_1 to 120_4, so the computing device 130 can obtain a corner point of the frame F1 relative to the projection range R1 according to the first position of the totem in the first test frame Based on the position information of the screen, the boundary parameters of the screen are determined.

In one embodiment, when the brightness sensing information reported by the photosensitive elements 120_1 to 120_4 is changed from the first sensing value corresponding to the white totem to the second sensing value corresponding to the black screen background, the computing device 130 may The positions of the four corner points of the frame F1 relative to the projection range R1 are detected according to the totem position corresponding to the first sensing value, and the frame boundary parameters are determined accordingly. In one embodiment, the frame boundary parameters include upper and lower boundary parameters, left and right boundary parameters, or a combination thereof, which can be used to define the ideal display boundary defined by the frame F1 in the projection range R1. For example, in the example of FIG. 1, since the photosensitive elements 120_1 to 120_4 are respectively located at the four corner points of the frame F1 for brightness sensing, the left and right boundary parameters may include 4 X coordinate values and the upper and lower boundary parameters may include 4 The Y coordinate value, the four X-axis coordinate values and the four Y-axis coordinate values can be regarded as the positions of the four corner points of the frame F1 in the projection range R1. In summary, by projecting multiple test images in sequence and the photosensitive elements 120_1 to 120_4 continue to perform brightness sensing, the computing device 130 can estimate that the frame F1 is defined in the projection range R1 based on the brightness sensing information reported by the photosensitive elements 120_1 to 120_4 The ideal display boundary.

After that, in step S204, the projection device 110 may perform image scaling processing according to the image boundary parameters to project the corrected image aligned with the frame F1 of the projection screen S1. In one embodiment, the projection device 110 can reduce the original image from the computing device 130 according to the frame boundary parameters, and fill in the peripheral image blocks around the reduced original image to generate a corrected image. It should be noted that the image edge of the original image in the frame after this correction is aligned with the frame F1. In other words, the image content boundary of the original image will be aligned with the frame F1, so that the image content of the original image is presented within the frame F1, and the black peripheral image block will appear outside the frame F1.

For example, FIG. 4 is a schematic diagram of a corrected picture according to an embodiment of the present invention. Please refer to Figure 4. In the example of Figure 1, it is assumed that the picture boundary parameters can include 4 X-axis coordinate values X ₁ , X ₂ , X ₃ , X ₄ and 4 Y-axis coordinate values Y ₁ , Y ₂ , Y ₃ , Y ₄ , the projection device 110 can perform image deformation processing including image scaling processing on the original image Img_ori according to the above eight coordinate elements to generate a reduced original image Img_ori. In addition, the projection device 110 will fill the peripheral image block ZB on the periphery of the reduced original image Img_ori according to the above-mentioned eight coordinate elements to generate a corrected frame CF1 including the reduced original image Img_ori and the peripheral image block ZB. Among them, the positions of the four corner pixels of the reduced original image Img_ori in the corrected frame CF1 are (X ₁ , Y ₁ ), (X ₂ , Y ₂ ), (X ₃ , Y ₃ ), (X ₄ ,Y ₄ ). When the projection device 110 projects the corrected screen CF1, the image content boundary E1 of the original image Img_ori will be aligned with the frame F1 of the projection screen S1.

FIG. 5 is a schematic diagram of a projection device according to an embodiment of the invention. Please refer to FIG. 5, the projection device 110 may include a totem generating module 111, a picture deforming module 112, and a light valve device 113. The totem generating module 111 and the screen deforming module 112 can be implemented by software programs, firmware, hardware circuits, or a combination thereof, and are not limited here. The light valve device 113 is, for example, a transmissive LCD panel, a liquid crystal on silicon (LCOS) panel, or a digital micromirror device (DMD).

In one embodiment, the projection device 110 may generate multiple test images according to the totem parameters provided by the computing device 130, and the position of the totem in each test image is determined according to the totem parameters. The totem parameters may include the totem position parameter CMD1 or Totem compression deformation parameter CMD2. The totem generating module 111 can obtain the totem position parameter CMD1 from the computing device 130, and generate at least one totem image ImgP according to the totem position parameter CMD1 from the computing device 130. The screen deformation module 112 can obtain the totem compression deformation parameter CMD2 from the computing device 130, and is used to perform a screen deformation process according to the totem compression deformation parameter CMD2. Two implementations for generating test images are listed below.

In one embodiment, the totem generating module 111 of the projection device 110 can generate multiple totem images ImgP as multiple test images ImgT according to the totem position parameter CMD1. That is, the image deformation module 112 does not perform image deformation processing, and the multiple totem images ImgP generated by the totem generating module 111 are used as the multiple test images ImgT received by the light valve device 113. In addition, in response to the change of the totem position parameter CMD1, the totems are located at different positions in the multiple totem pictures ImgP. For example, the positions of the totems respectively located in the multiple totem pictures ImgP will move from the edge of the picture to the center of the picture, so that the totem projected by the light valve device 113 can gradually approach the photosensitive element 120_1 as the test pictures ImgT are projected one by one. 120_4. It should be noted that, since the image deformation module 112 does not perform image deformation processing, the size of the totems in the multiple totem screens ImgP is fixed.

For example, FIG. 6 is a schematic diagram of generating a test image according to totem position parameters according to an embodiment of the present invention. Referring to FIGS. 5 and 6, the totem is set to include two horizontal lines Pa1 and Pa2, and the totem image generated by the totem generating module 111 is used as a test image. First, the totem generating module 111 may first generate a test screen It5 according to the totem position parameter CMD1. The test image It5 includes horizontal lines Pa1 and Pa2 at the edges of the upper and lower images, and the widths of the horizontal lines Pa1 and Pa2 in the test image It5 are all W1 (pixel units). Then, the totem generating module 111 can first generate another test frame It6 according to the totem position parameter CMD1. The test picture It6 includes horizontal lines Pa1 and Pa2 near the edges of the upper and lower pictures, and the widths of the horizontal lines Pa1 and Pa2 in the test picture It6 are all W1. The horizontal lines Pa1 and Pa2 in the test picture It6 are relative to those in the test picture It5. The horizontal lines Pa1 and Pa2 are closer to the center of the test image. Then, the totem generating module 111 may first generate another test screen It7 according to the totem position parameter CMD1. The test image It7 includes horizontal lines Pa1 and Pa2 near the edges of the upper and lower images, and the widths of the horizontal lines Pa1 and Pa2 in the test image It7 are all W1. The horizontal lines Pa1 and Pa2 in the test image It7 are relative to those in the test image It6. The horizontal lines Pa1 and Pa2 are closer to the center of the test image. It can be seen that the two horizontal lines Pa1 and Pa2 will gradually move to the center of the screen as the test screens It5 to It7 are sequentially displayed.

In addition, in one embodiment, the totem generating module 111 of the projection device 110 can generate a totem image ImgP according to the fixed totem position parameter CMD1. The image deformation module 112 of the projection device 110 then compresses the height or width of the totem image ImgP according to the totem compression deformation parameter CMD2, and fills the image block around the compressed totem image to generate multiple test images ImgT. In more detail, in response to the change of the totem compression deformation parameter CMD2, the totem image ImgP will be compressed according to different zoom magnifications to generate multiple test images ImgT accordingly. Therefore, the size of the totem in the multiple test images ImgT is deformed according to the totem compression deformation. The parameter CMD2 is reduced. In addition, since the totem generating module 111 generates a totem screen ImgP according to the fixed totem position parameter CMD1, the position of the totem in the totem screen ImgP is fixed.

For example, FIG. 7 is a schematic diagram of generating a test image according to totem compression deformation parameters according to an embodiment of the present invention. Please refer to Figures 5 and 7, the totem is set to include two horizontal lines Pa3 and Pa4. The totem generating module 111 may first generate a totem screen according to the totem position parameter CMD1. The totem compression deformation parameter CMD2 can be the zoom magnification. First, when the zoom magnification is 1, the screen distortion module 112 can generate the test screen It8 according to the totem compression distortion parameter CMD2. The test image It8 includes horizontal lines Pa3 and Pa4 at the edges of the upper and lower images, and the width of the horizontal lines Pa3 and Pa4 in the test image It8 are both W1 (pixel units). Then, when the zoom ratio is changed to α (α>1), the screen deformation module 112 can compress the height (vertical length) of the totem screen according to the totem compression deformation parameter CMD2 to generate a compressed totem screen It8', And fill the image blocks Z1 and Z2 around the compressed totem frame It8' to generate the test frame It9. The widths of the horizontal lines Pa3 and Pa4 in the test image It9 are both W2, and W2 is smaller than W1. Then, when the zoom ratio is changed to β (β>α>1), the screen deformation module 112 can compress the height (vertical length) of the totem screen according to the totem compression deformation parameter CMD2 to generate a compressed totem screen It8 '' and fill the image blocks Z3 and Z4 around the compressed totem frame It8" to generate the test frame It10. The widths of the horizontal lines Pa3 and Pa4 in the test image It10 are both W3, and W3 is smaller than W2 and W1. It can be seen that the two horizontal lines Pa3 and Pa4 will gradually move to the center of the screen as the test screens It8 to It10 are sequentially displayed.

The following will further explain how to obtain the frame boundary parameters according to the brightness sensing information of the test frame and the photosensitive element. For the convenience of description, the following embodiments will take the totem in the test screen as white and the screen background as black as an example for description.

8A and 8B are schematic diagrams of a projection correction method according to an embodiment of the invention. 8A and 8B are illustrated by taking as an example the totem position in the test screen is changed according to the totem position parameter and the totem size is fixed.

Please refer to Fig. 8A. In the horizontal alignment correction stage, taking the test images It5~It7 of Fig. 6 as an example, the totem may include two horizontal lines Pa1 and Pa2, and these two horizontal lines Pa1 and Pa2 will follow the test images It5~ It7 is displayed in sequence while moving the position.

First, the projection device 110 projects a test picture It5. Since the horizontal lines Pa1 and Pa2 in the test image It5 projected by the projection device 110 do not cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the second sensing value associated with the black screen background. The photosensitive elements 120_1 to 120_4 report the second sensed value to the computing device 130, so that the computing device 130 controls the projection device 110 to project the next test image It6. Since the horizontal lines Pa1 and Pa2 in the test image It6 projected by the projection device 110 cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the first sensing value associated with the white totem. The photosensitive elements 120_1 to 120_4 report the first sensing value to the computing device 130, so that the computing device 130 controls the projection device 110 to project the next test image It7.

Since the horizontal lines Pa1 and Pa2 in the test image It7 projected by the projection device 110 do not cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the second sensing value associated with the black screen background. The photosensitive elements 120_1 to 120_4 report the second sensing value to the computing device 130. In response to the brightness sensing information of the photosensitive elements 120_1 to 120_4 being changed from the first sensing value to the second sensing value, the computing device 130 can determine the upper and lower boundary parameter Y according to the positions of the two horizontal lines Pa1 and Pa2 in the test screen It6 ₁ , Y ₂ , Y ₃ , Y ₄ . More specifically, by scanning the two horizontal lines Pa1 and Pa2, the computing device 130 can learn that the photosensitive elements 120_1 to 120_4 are located in the coverage range of the horizontal lines Pa1 and Pa2 in the test frame It6 according to the brightness sensing information. _{Therefore, the computing device 130 can determine the upper and lower boundary parameters Y 1} , Y ₂ , Y ₃ , and Y _{4 of the} frame boundary parameters according to the position of the horizontal line in the test frame It6 on the vertical axis.

In one embodiment, the horizontal line Pa1 in the test image It6 is located between the Y-axis pixel coordinate Y _a and the Y-axis pixel coordinate Y _b on the vertical axis. Based on this, the computing device 130 can obtain the upper and lower boundary parameters Y _{1 according to the Y-axis pixel coordinates Y a} and the Y-axis pixel coordinates Y _b . In an embodiment, the computing device 130 may take other Y-axis pixel coordinates between the Y-axis pixel coordinates Y _a and the Y-axis pixel coordinates Y _b as the upper and lower boundary parameters Y ₁ . Taking the width of the horizontal line Pa1 as 8 pixels as an example, assuming that the Y-axis pixel coordinate Y _a is 8 and the Y-axis pixel coordinate Y _b is 15, then the computing device 130 can determine that the upper and lower boundary parameter Y ₁ is 11. Similarly, the computing device 130 can also obtain the upper and lower boundary parameters Y _{3 according to the Y-axis pixel coordinates Y c} and the Y-axis pixel coordinates Y _d where the horizontal line Pa2 in the test image It6 is located on the vertical axis.

In the scenario of FIG. 8A, during the projection of It5 to It7, the brightness information reported by the photosensitive elements 120_1 and 120_2 are the same. Therefore, the upper and lower boundary parameters Y ₁ and the upper and lower boundary parameters Y ₂ are based on the same totem position (ie Y Axis pixel coordinates Y _a and Y axis pixel coordinates Y _b ). In addition, in the process of projecting It5 to It7, the brightness information reported by the photosensitive elements 120_3 and 120_4 are the same. Therefore, the upper and lower boundary parameters Y ₃ and the upper and lower boundary parameters Y ₄ are based on the same totem position (that is, the Y-axis pixel coordinates Y _c And Y-axis pixel coordinates Y _d ).

It is worth mentioning that, in one embodiment, after the process shown in FIG. 8A is executed, the projection device 110 can scan the Y axis with a narrower horizontal line (for example, the line width can be changed from 8 pixels to 4 pixels). The range between the pixel coordinate Y _a and the Y-axis pixel coordinate Y _b to obtain more accurate upper and lower boundary parameters.

Next, referring to FIG. 8B, in the vertical alignment correction stage, the totem may include two vertical lines Pa5 and Pa6, and the two horizontal lines Pa5 and Pa6 will move positions as the test images It11 to It13 are sequentially displayed.

First, the projection device 110 projects a test picture It11. Since the vertical lines Pa5 and Pa6 in the test image It11 projected by the projection device 110 do not cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the second sensing value associated with the black screen background. The photosensitive elements 120_1 to 120_4 report the second sensed value to the computing device 130, so that the computing device 130 controls the projection device 110 to project the next test image It12. Since the vertical lines Pa5 and Pa6 in the test image It12 projected by the projection device 110 cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the first sensing value associated with the white totem. The photosensitive elements 120_1 to 120_4 report the first sensed value to the computing device 130, so that the computing device 130 controls the projection device 110 to project the next test image It13.

Since the vertical lines Pa5 and Pa6 in the test image It13 projected by the projection device 110 do not cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the second sensing value associated with the black screen background. The photosensitive elements 120_1 to 120_4 report the second sensing value to the computing device 130. In response to the brightness sensing information of the photosensitive elements 120_1 to 120_4 being changed from the first sensing value to the second sensing value, the computing device 130 can determine the left and right boundary parameters X according to the positions of the two vertical lines Pa5 and Pa6 in the test screen It12 ₁ , X ₂ , X ₃ , X ₄ . More specifically, by scanning the two vertical lines Pa5 and Pa6, the computing device 130 can know that the photosensitive elements 120_1 to 120_4 are located in the coverage range of the vertical lines Pa5 and Pa6 in the test frame It12 according to the brightness sensing information. Therefore, the computing device 130 can determine the left and right boundary parameters X ₁ , X _{in the screen boundary parameters according to the X-axis pixel coordinates X a} , X _b , X _c , and X _d on the horizontal axis of the vertical lines Pa5 and Pa6 in the test image It12 _2. X ₃ , X ₄ . However, the method for determining the left and right boundary parameters X ₁ , X ₂ , X ₃ , and X ₄ is similar to the method for determining the above boundary parameters Y ₁ , Y ₂ , Y ₃ , and Y ₄ , and will not be repeated here.

It should be noted that, in the context of FIGS. 8A and 8B, the photosensitive elements 120_1 to 120_4 are simultaneously covered by the horizontal lines Pa1 and Pa2 of the same test picture It6, and the photosensitive elements 120_1 to 120_4 are covered by the same test picture It12. The vertical lines Pa5 and Pa6 cover at the same time, but the present invention is not limited to this. In other application scenarios, the photosensitive elements 120_1 to 120_4 may be covered by totems of different test images. That is, the upper and lower boundary parameters Y ₁ , Y ₂ , Y ₃ , Y ₄ and the left and right boundary parameters X ₁ , X ₂ , X ₃ , and X ₄ corresponding to the four photosensitive elements 120_1 to 120_4 can be based on different test images. It depends on the position of the totem.

9A and 9B are schematic diagrams of a projection correction method according to an embodiment of the invention. 9A and 9B are illustrated by taking as an example that the totem position in the test screen is changed according to the totem compression deformation parameter and the totem size is not fixed.

Please refer to Fig. 9A. In the horizontal alignment correction stage, taking the test images It8～It10 of Fig. 7 as an example, the totem may include two horizontal lines Pa3 and Pa4. These two horizontal lines Pa3 and Pa4 will follow the test images It8～It8. It10 is displayed in order while moving the position.

First, the projection device 110 projects a test picture It8. Since the horizontal lines Pa3 and Pa4 in the test image It8 projected by the projection device 110 do not cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the second sensing value associated with the black screen background. The photosensitive elements 120_1 to 120_4 report the second sensed value to the computing device 130, so that the computing device 130 controls the projection device 110 to project the next test image It9. Since the horizontal lines Pa3 and Pa4 in the test image It9 projected by the projection device 110 cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the first sensing value associated with the white totem. The photosensitive elements 120_1 to 120_4 report the first sensing value to the computing device 130, so that the computing device 130 controls the projection device 110 to project the next test image It10.

It should be noted that, in one embodiment, the peripheral image blocks Z1 and Z2 in the test frame It9 are also black. Since the horizontal lines Pa3 and Pa4 in the test image It10 projected by the projection device 110 do not cover the photosensitive elements 120_1 to 120_4, the photosensitive elements 120_1 to 120_4 sense the black screen background (ie peripheral image blocks Z1, Z2) The second sensed value. The photosensitive elements 120_1 to 120_4 report the second sensing value to the computing device 130. In response to the brightness sensing information of the photosensitive elements 120_1 to 120_4 being changed from the first sensing value to the second sensing value, the computing device 130 can determine the upper and lower boundary parameters Y according to the positions of the two horizontal lines Pa3 and Pa4 in the test screen It9 ₁ , Y ₂ , Y ₃ , Y ₄ . More specifically, by scanning the two horizontal lines Pa3 and Pa4, the computing device 130 can learn that the photosensitive elements 120_1 to 120_4 are located in the coverage range of the horizontal lines Pa3 and Pa4 in the test frame It9 according to the brightness sensing information. _{Therefore, the computing device 130 can determine the upper and lower boundary parameters Y 1} , Y ₂ , Y ₃ , and Y _{4 of the} frame boundary parameters according to the position of the horizontal line in the test frame It9 on the vertical axis. It should be noted that the width of the two horizontal lines Pa3 and Pa4 will gradually become narrower in response to the zoom magnification used to generate the test images It8 to It10. Similar to FIG. 8A illustrate, computing device 130 may be based on test screen It9 horizontal lines Pa3, Pa4 the Y-axis pixel coordinates Y _E on the vertical _{axis, Y f, Y g, Y} h to obtain the upper and lower boundary parameters Y _1, Y ₂ , Y ₃ , Y ₄ .

Next, referring to FIG. 9B, in the vertical alignment correction stage, the totem may include two vertical lines Pa7 and Pa8, and the two vertical lines Pa7 and Pa8 will move positions as the test images It14 to It16 are sequentially displayed. The test images It15 to It16 respectively include image blocks Z5, Z6, Z7, and Z8, and the image blocks Z5, Z6, Z7, and Z8 can be black and regarded as the screen background. Similar to the operation flow of FIG. 8A, FIG. 8B and FIG. 9A, in the process of sequentially displaying the test screens It14 to It16, the brightness sensing information reflected by the photosensitive elements 120_1 to 120_4 is changed from the first sensing value to the second sensing value. According to the measured value, the computing device 130 can determine the left and right boundary parameters X ₁ , X ₂ , X _{according to the X-axis pixel coordinates X e} , X _f , X _g , and X _h on the horizontal axis of the test frame It15 of the two vertical lines Pa7 and Pa8 _3. X ₄ .

Referring to FIGS. 8A, 8B, 9A, and 9B, it can be seen that after the operation flow of the horizontal alignment correction stage and the vertical alignment correction stage, the computing device 130 can obtain the upper and lower boundary parameters Y ₁ , Y ₂ , Y ₃ , Y ₄ and the left and right boundaries. Parameters X ₁ , X ₂ , X ₃ , X ₄ . Thus, the projection device 110 can perform image deformation processing on the image to be projected according to the upper and lower boundary parameters Y ₁ , Y ₂ , Y ₃ , Y ₄ and the left and right boundary parameters X ₁ , X ₂ , X ₃ , X _{4 to generate a corrected image.} The aforementioned image deformation processing may include image scaling processing or geometric deformation processing, so that the four vertex coordinates of the screen content boundary in the corrected screen are (X ₁ , Y ₁ ), (X ₂ , Y ₂ ), (X ₃ , Y ₃ ), (X ₄ ,Y ₄ ). In this way, by generating the corrected image according to the image boundary parameters, the projection content of the projection device 110 can be aligned with the frame F1.

FIG. 10 is a schematic diagram of a projection correction method according to an embodiment of the present invention. FIG. 10 is an example of changing the totem position in the test screen according to the totem position parameter and the totem size is fixed as an example for illustration. 10, the totem may include two horizontal lines Pa9 and Pa10 and two vertical lines Pa11 and Pa12. The horizontal lines Pa9 and Pa10 and the vertical lines Pa11 and Pa12 will move positions as the test pictures It20-It22 are sequentially displayed. The horizontal lines Pa9 and Pa10 are arranged below the screens of the test images It20 to It22, and the vertical lines are arranged above the screens of the test images It20 to It22.

Similar to the operation flow of FIGS. 8A, 8B, 9A, and 9B, in the process of sequentially displaying the test screens It20 to It22, the brightness sensing information reflected by the photosensitive elements 120_1 to 120_4 is changed from the first sensing value to _{For the second sensing value, the computing device 130 can determine the left and right boundary parameters X 1} and X ₂ according to the position of the two vertical lines Pa11 and Pa12 on the horizontal axis of the test image It21, and determine the left and right boundary parameters X 1 and X 2 according to the two horizontal lines Pa9 and Pa10 on the test image. The upper position of the vertical axis in It21 determines the lower boundary parameters Y ₃ and Y ₄ .

In one embodiment, the projection device 110 can _{perform image scaling processing according to the left and right boundary parameters X 1} , X ₂ and the lower boundary parameters Y ₃ , Y ₄ to project the corrected image aligned with the frame F1. In another embodiment, after the test images It20 to It22 are displayed in sequence, the projection device 10 projects a plurality of test images with horizontal lines set at the top of the screen and vertical lines set at the bottom of the screen, so as to obtain similar operation procedures in sequence. The left and right boundary parameters X ₃ , X ₄ corresponding to the photosensitive elements 120_3 and 120_4 and the upper boundary parameters Y ₁ , Y ₂ corresponding to the photosensitive elements 120_1 and 120_2. After that, the projection device 110 can perform image scaling processing according to the left and right boundary parameters X ₁ , X ₂ , X ₃ , X ₄ and the upper and lower boundary parameters Y ₁ , Y ₂ , Y ₃ , and Y ₄ , and the projection is aligned with the frame F1 after correction Picture.

However, in one embodiment, before using the totem to detect the range defined by the frame F1, environment detection can be performed to ensure that the positions of the photosensitive elements 120_1 to 120_4 are covered by the projection range R1 of the projection device 110, and the ambient light source Taking this into consideration, the first sensing value and the second sensing value suitable for the environment of the projection system 10 are defined.

FIG. 11 is a flowchart of a projection correction method according to an embodiment of the present invention, and the method flow of FIG. 11 can be implemented by the components of the projection correction system 10 in FIG. 1. Please refer to FIG. 1 and FIG. 11 at the same time. The following is a description of the steps of the projection correction method of this embodiment with the components of the projection correction system 10 in FIG. 1.

In step S1101, a first preset image is projected by the projection device 110. The color of the first preset picture is the same as the color of the totem in the test picture. For example, the first preset picture may be a white picture, and the totem in the test picture is white. In step S1102, the first brightness value is measured when the projection device 110 is projecting the first preset image by the photosensitive elements 120_1 to 120_4. In step S1103, the second brightness value is measured by each photosensitive element 120_1 to 120_4 when the projection device 110 is not projecting the first preset image. In an embodiment, each of the photosensitive elements 120_1 to 120_4 can measure the second brightness value when the projection device 110 is projecting the second preset image or is not projecting. The color of the second preset picture is the same as the color of the picture background in the test picture. For example, the second preset picture may be a black picture, and the picture background in the test picture is black. That is to say, in one embodiment, the projection device 110 can project a white frame and a black frame in sequence, and the photosensitive elements 120_1 to 120_4 can respectively sense the brightness information of the white frame and the black frame (that is, the first brightness value and the second brightness value). Brightness value).

In step S1104, the calculation device 130 determines whether the projection range R1 of the projection device 110 covers the photosensitive elements 120_1 to 120_4 on the frame F1 according to the difference between the first brightness value and the second brightness value. Specifically, when the projection range R1 covers the photosensitive elements 120_1 to 120_4 on the frame F1, the first brightness values generated by the respective photosensitive elements 120_1 to 120_4 by sensing the brightness of the white picture and the black picture (or no picture is projected) ) The difference between the second brightness values generated by brightness sensing will be greater than the threshold value. Correspondingly, in the case that the projection range R1 does not cover the photosensitive elements 120_1 to 120_4 on the frame F1, the first brightness value generated by the photosensitive elements 120_1 to 120_4 on the first preset screen by brightness sensing will be similar to the first brightness value generated by the first preset image. The second brightness value generated by the brightness sensing of the two preset frames, so the difference between the first brightness value and the second brightness value will be smaller than the threshold value. That is, the computing device 130 can determine whether the projection range R1 of the projection device 110 covers the photosensitive elements 120_1 to 120_4 on the frame F1 according to whether the difference between the first brightness value and the second brightness value is greater than the threshold value.

After determining that the projection range R1 of the projection device 110 covers the photosensitive elements 120_1 to 120_4 on the frame F1, the first brightness value and the second brightness value can be used to determine the first sensing value and the second sensing value, and the first sensing The value and the second sensing value will subsequently be used to detect whether the photosensitive elements 120_1 to 120_4 are covered by the totem in the test frame. In other words, through the environment detection process in steps S1101 to S1104, in addition to confirming whether the projection range R1 of the projection device 110 covers the photosensitive elements 120_1 to 120_4 on the frame F1, the computing device 130 can compare the first sensed value with the first The two sensing values are respectively set as the first brightness value and the second brightness value measured in the actual projection environment.

In step S1105, a plurality of test images are projected on the projection screen S1 by the projection device 110. In step S1106, when projecting each test image, the computing device 130 measures the brightness sensing information through the plurality of photosensitive elements 120_1 to 120_4 located on the frame F1 of the projection screen S1. In step S1107, in response to the brightness sensing information changing from the first sensing value to the second sensing value, the computing device 130 determines the frame boundary parameter according to the first position of the totem in the first test frame. In step S1108, the computing device 130 performs image scaling processing according to the frame boundary parameters to project the corrected frame aligned with the frame F1 of the projection screen S1.

To sum up, in the embodiment of the present invention, the projection device projects a plurality of test images including totems on the projection screen, and the position of the totems in each test image is changed. Moreover, when the projection device projects these test images on the projection screen, the brightness information of the test images is sensed by the photosensitive element arranged on the frame of the projection screen. Since the position of the totem will change with the sequential display of the test images, the position of the photosensitive element relative to the projection range can be detected by continuously sensing the brightness sensing information. Since the photosensitive element is arranged on the frame, the image boundary parameters can be determined according to the position of the photosensitive element relative to the projection range. In this way, the projector will perform image scaling processing according to the image boundary parameters to generate a corrected image that can be aligned with the frame of the projection screen, thereby providing an efficient and convenient projection correction method.

In addition, in the embodiment of the present invention, since the user does not need to manually perform the projection calibration process and does not need to consider the camera parameters and camera calibration, a more convenient and fast projection calibration method is provided. In addition, accurate picture boundary parameters can be obtained by scanning totems, thereby further improving the display quality of the projection device. Furthermore, other objectives and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be subject to those defined by the attached patent application scope.

10: Projection correction system 110: Projection device 111: Totem Generation Module 112: Screen Deformation Module 113: Light Valve Module 120_1～120_4: photosensitive element 130: computing device S1: Projection screen F1: Border R1: projection range L1: White horizontal lines L2: White vertical lines It1～It16, It21～It22, ImgT: test screen CF1: Picture after correction E1: Image content boundary Img_ori: Original image ZB: peripheral image block CMD1: Totem position parameter CMD2: Totem compression deformation parameters ImgP: Totem screen Pa1, Pa2, Pa3, Pa4, Pa9, Pa10: horizontal lines It8’, It8’’: Totem screen after compression Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8: image block Pa5, Pa6, Pa7, Pa8, Pa11, Pa12: vertical lines S201~S204, S1101~S1108: steps

FIG. 1 is a schematic diagram of a projection correction system according to an embodiment of the invention. FIG. 2 is a flowchart of a projection correction method according to an embodiment of the invention. 3A and 3B are examples of test screens drawn according to an embodiment of the invention. FIG. 4 is a schematic diagram of a corrected screen according to an embodiment of the invention. FIG. 5 is a schematic diagram of a projection device according to an embodiment of the invention. FIG. 6 is a schematic diagram of generating a test screen according to totem position parameters according to an embodiment of the present invention. FIG. 7 is a schematic diagram of a test screen generated according to totem compression deformation parameters according to an embodiment of the present invention. 8A and 8B are schematic diagrams of a projection correction method according to an embodiment of the invention. 9A and 9B are schematic diagrams of a projection correction method according to an embodiment of the invention. FIG. 10 is a schematic diagram of a projection correction method according to an embodiment of the present invention. FIG. 11 is a flowchart of a projection correction method according to an embodiment of the invention.

S201~S204: steps

Claims (24)

A projection correction system includes: a projection device, a plurality of photosensitive elements, and an arithmetic device; wherein, The projection device projects a plurality of test pictures on a projection screen, wherein each of the test pictures includes a totem, and the test pictures include a first test picture and a second test picture; The photosensitive elements are arranged on the frame of the projection screen to measure the brightness sensing information when the projection device projects the test images; and The computing device is coupled to the photosensitive elements and the projection device, Wherein in response to the change of the totem from the first position in the first test frame to the second position in the second test frame, the brightness sensing information changes from the first sensing value to the second sensing value, Wherein, in response to the brightness sensing information being changed from the first sensing value to the second sensing value, the computing device determines the frame boundary parameter according to the first position of the totem in the first test frame, The projection device performs image scaling processing according to the picture boundary parameters to project a corrected picture aligned with the frame of the projection screen. According to the projection correction system described in the first item of the scope of patent application, the photosensitive elements are respectively located on a plurality of corner points of the frame of the projection screen, and the projection range of the projection device at least covers the frame. According to the projection correction system described in claim 1, wherein the totem includes a horizontal line, and the projection device generates the test images by changing the position of the horizontal line on the vertical axis. The projection correction system according to item 3 of the scope of patent application, wherein the arithmetic device determines an upper and lower boundary parameters of the frame boundary parameters according to the first position of the horizontal line on the vertical axis in the first test frame . According to the projection correction system described in claim 1, wherein the totem includes a vertical line, and the projection device generates the test images by changing the position of the vertical line on the horizontal axis. According to the projection correction system described in item 5 of the scope of patent application, the arithmetic device determines a left and right boundary parameter of the frame boundary parameters according to the first position of the vertical line on the horizontal axis in the first test frame . The projection correction system described in item 1 of the scope of patent application, wherein the totem includes a horizontal line and a vertical line, and the projection device changes the position of the vertical line on the horizontal axis and changes the horizontal line on the vertical axis The location of these test screens. For the projection correction system described in item 1 of the scope of patent application, the projection device reduces an original image from the computing device according to the frame boundary parameters, and fills in the peripheral image blocks around the original image after the reduction to generate the The corrected picture, and the image edge of the original image in the corrected picture is aligned with the frame. For example, the projection correction system described in item 1 of the scope of patent application, wherein the projection device generates the test images according to the totem parameters provided by the computing device, the totem parameters include totem position parameters, and the projection device generates the respective test images according to the totem position parameters. As the multiple totem pictures of the test pictures, the totems are respectively located in different positions in the totem pictures, and the size of the totem is fixed. The projection correction system according to the first item of the scope of patent application, wherein the projection device generates the test images according to the totem parameters provided by the computing device, the totem parameters include totem compression deformation parameters, and the projection device is based on the totem compression deformation parameters Compressing a totem screen and filling image blocks around the compressed totem screen to generate the test frames, the position of the totem in the totem screen is fixed, and the size of the totem is reduced according to the totem compression deformation parameter. The projection correction system according to the first item of the scope of patent application, wherein the projection device further projects a first preset image, and each of the photosensitive elements measures a first brightness when the projection device projects the first preset image Value and measure a second brightness value when the projection device is not projecting the first preset screen, the computing device determines the projection range of the projection device according to the difference between the first brightness value and the second brightness value Whether to cover the photosensitive elements on the frame, wherein the first brightness value and the second brightness value are used to determine the first sensing value and the second sensing value. According to the projection correction system described in item 11 of the scope of patent application, the second brightness value is measured when each of the photosensitive elements is projecting a second preset image on the projection device or is not projecting. A projection correction method, the method includes: Projecting multiple test pictures on a projection screen by a projection device, wherein each of the test pictures includes a totem, and the test pictures include a first test picture and a second test picture; When projecting each of the test images, the brightness sensing information is measured by a plurality of photosensitive elements located on the frame of the projection screen, which reflects that the totem changes from the first position in the first test image to the In the second position in the second test frame, the brightness sensing information is changed from the first sensing value to the second sensing value; In response to the brightness sensing information changing from the first sensing value to the second sensing value, the frame boundary parameter is determined according to the first position of the totem in the first test frame; and Image scaling processing is performed according to the frame boundary parameter to project a corrected frame aligned with the frame of the projection screen. According to the projection correction method described in item 13 of the scope of patent application, the photosensitive elements are respectively located on a plurality of corner points of the frame of the projection screen, and the projection range of the projection device at least covers the frame. The projection correction method according to claim 13, wherein the totem includes a horizontal line, and the method further includes: generating the test images by changing the position of the horizontal line on the vertical axis. The projection correction method according to claim 15, wherein the brightness sensing information is changed from the first sensing value to the second sensing value according to the totem in the first test frame. The step of determining the frame boundary parameter by the first position includes: determining an upper and lower boundary parameter of the frame boundary parameters according to the first position of the horizontal line on the vertical axis in the first test frame. According to the projection correction method of claim 13, wherein the totem includes a vertical line, the method further includes: generating the test images by changing the position of the vertical line on the horizontal axis. The projection correction method according to claim 17, wherein the brightness sensing information is changed from the first sensing value to the second sensing value according to the totem in the first test frame. The step of determining the frame boundary parameter by the first position includes: according to the first position of the vertical line on the horizontal axis in the first test frame, the computing device determines a left and right boundary parameter of the frame boundary parameters. The projection correction method according to item 13 of the scope of patent application, wherein the totem includes a horizontal line and a vertical line, and the method further includes: shifting the vertical line left and right along the horizontal axis and shifting up and down along the vertical axis The horizontal lines generate the test images. The projection correction method according to item 13 of the scope of patent application, wherein the step of performing image scaling processing according to the frame boundary parameter to project the corrected frame aligned with the frame of the projection screen includes: reducing a frame according to the frame boundary parameter The original image and fill the periphery of the reduced original image with a peripheral image block to generate the corrected frame, and the image edge of the original image in the corrected frame is aligned with the frame. As the projection correction method described in item 13 of the scope of patent application, the method further includes: Generating the test images according to totem parameters, where the totem parameters include totem position parameters; and According to the totem position parameter, a plurality of totem pictures are generated as the test pictures, the totems are respectively located in different positions in the totem pictures, and the size of the totem is fixed. As the projection correction method described in item 13 of the scope of patent application, the method further includes: Generate the test images according to totem parameters, where the totem parameters include totem compression deformation parameters; and Compress a totem screen according to the totem compression deformation parameters, and fill the image blocks around the compressed totem screen to generate the test frames, the position of the totem in the totem screen is fixed, and the size of the totem is compressed according to the totem The deformation parameters are reduced. As the projection correction method described in item 13 of the scope of patent application, the method further includes: Projecting a first preset screen by the projection device; Measuring a first brightness value when the projection device projects the first preset frame by each of the photosensitive elements; Measuring a second brightness value by each of the photosensitive elements when the projection device is not projecting the first preset frame; and According to the difference value between the first brightness value and the second brightness value, it is determined whether the projection range of the projection device covers the photosensitive elements on the frame, wherein the first brightness value and the second brightness value are used to determine The first sensing value and the second sensing value. According to the projection correction method described in item 23 of the scope of patent application, the method further includes: using each of the photosensitive elements to project a second preset image on the projection device or measure the second brightness value when the projection device is not projected.

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