An anamorphic projection distortion testing method and device

Abstract

The present application relates to the technical field of testing, in particular to a kind of special-shaped projection distortion test method and device.The method includes the flat processing to sand table bottom, and the sand table bottom surface is divided into multiple test areas;First measurement body with adjustable different height is placed in each test area of the sand table, and first color image is projected to the first measurement body, and first distortion value is calculated using color error area on the first measurement body;Second measurement body is placed in each test area of the sand table, and second color image is projected to the second measurement body, and second distortion value is calculated using color error area on the second measurement body;The first distortion value and second distortion value are weighted and summed, and the total distortion value of the sand table is obtained, when the total distortion value is less than distortion threshold, it represents that the sand table can be put into use.The present application can accurately judge whether special-shaped projection product can be put into use.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and in particular to a method and apparatus for testing irregular projection distortion. Background Technology

[0002] In museums, science and technology museums, and themed exhibitions, 3D irregular projection sand tables combine a 3D physical sand table with a laser projector to achieve a virtual-real fusion display based on an irregularly shaped projection surface, presenting history, technology, and art in a more immersive way. The application of 3D irregular projection is becoming increasingly widespread. 3D irregular projection is a virtual-real fusion technology that projects images onto the surface of a non-planar object, precisely matching the projected content with the object's geometry. The projected image must maintain its true size and be in the correct 3D position; that is, the projected object must not have significant distortion. Similar to the low distortion requirement of 2D projection, which ensures that the 2D image maintains its true size and is in the correct 2D position, 3D irregular projection also requires the projected image to maintain its true size and be in the correct 3D position. Irregular projection distortion testing can assess whether irregular projection products are suitable for use.

[0003] Current projection distortion testing methods, such as those described in application number 201910249736.5, provide a projector distortion correction method, device, and projector. This method focuses on a projector distortion correction approach where a standard grid image is projected onto a projection surface, acquired, and then the texture image is updated and projected again. Application number 201810240367.9 provides a projection distortion correction method, device, system, and storage medium, focusing on correction by acquiring depth information of the projection surface and calculating the deviation from the projected image. Application number 202410075019.6 provides a projection correction method, device, computer equipment, and storage medium, focusing on calculating the affine transformation matrix between the projected image and the original image of the calibration image, without involving a specific distortion testing method.

[0004] Current research on projection distortion testing, both domestically and internationally, suffers from the following problems: some studies focus on planar distortion testing, neglecting the testing of irregularly shaped projection surface distortion; others focus on calculating and correcting the differences between the projected image and the original image of the calibration image, without fully considering the differences between irregularly shaped projection and planar projection; and distortion calculations do not adequately account for distortion errors at different positions and heights. In summary, existing methods for testing irregularly shaped projection distortion cannot accurately evaluate irregularly shaped projection products or determine whether they are suitable for use.

[0005] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention proposes a method and device for testing irregular projection distortion, which can accurately determine whether irregular projection products can be put into use.

[0007] The embodiments of the present invention adopt the following technical solutions: In a first aspect, the present invention provides a method for testing irregular projection distortion, specifically: flattening the bottom of a sand table and dividing the bottom surface of the sand table into multiple test areas; A first measuring body adjustable to different heights is placed in each test area of ​​the sand table, and a first color image is projected onto the first measuring body. The first distortion value is calculated using the color error area on the first measuring body. The second measuring body is placed in each test area of ​​the sand table, and the second color image is projected onto the second measuring body. The second distortion value is calculated using the color error area on the second measuring body. The first distortion value and the second distortion value are weighted and summed to obtain the total distortion value of the sand table. When the total distortion value is less than the distortion threshold, it means that the sand table can be put into use.

[0008] Preferably, the step of placing a first measuring body adjustable to different heights in each test area of ​​the sand table, projecting a first color image onto the first measuring body, and calculating a first distortion value using the color error areas on the first measuring body includes: The bottom of the first measuring body is adjusted to a first height and placed in a test area of ​​the sand table. According to the height information, the first color image is projected onto the first measuring body. Using the color error area on the first measuring body, the comprehensive distortion value of a test area is calculated. The first measuring body is moved sequentially to each test area of ​​the sand table, and the comprehensive distortion value of each test area is calculated respectively. The weighted sum of the regional weights and the comprehensive distortion values ​​of each test area is calculated, and combined with the maximum comprehensive distortion value, the full field-of-view distortion value of the first measuring object at the first height is obtained. The bottom of the first measuring body was adjusted to multiple other heights in sequence, and the full field-of-view distortion value of the first measuring body at each of the multiple other heights was calculated. The first distortion value is obtained by averaging the full field-of-view distortion values ​​at all heights of the first measuring body.

[0009] Preferably, the first color image includes color image A, color image B, and color image C, and the method further includes: Within a test area, according to the height information, the color image B is projected onto the small circular platform of the first measuring body, the color image A is projected onto the large circular platform of the first measuring body, and the color image C is projected onto a projection surface other than the height of the small and large circular platforms. Obtain a top-down view image of the first sand table, which includes color region A, color region B, and color region C; Based on color regions A, B, and C in the top-view image of the sand table, the distortion values ​​of the large truncated cone and the small truncated cone are calculated respectively. The distortion values ​​of the large and small truncated cones are weighted and summed to obtain the comprehensive distortion value of a test area.

[0010] Preferably, the method further includes: Based on the centroid positions of color region A and color region B, calculate the first center of the projection areas of the small and large truncated cones. Based on the distances between the pixels with pixel value A and the pixels with pixel value B and the first center, a radius is obtained. circle and an inner diameter of Outer diameter is ring ; Based on the top-down view of the first sand table image, on the circle The number of pixels with a value of B within the range and the number of pixels in the circle The number of pixels with a value of C within the range is used to calculate the distortion value of the small frustum; based on the number of pixels with a value of C within the range, the distortion value of the small frustum is calculated; based on the number of pixels with a value of C within the ring. The number of pixels with a pixel value of A within the range and the number of pixels in the circle Calculate the distortion value of the large truncated cone by counting the number of pixels with a value of C within the range.

[0011] Preferably, the formula for calculating the distortion value of the large truncated cone is as follows: ; in, This represents the distortion value of the great frustum. Indicates in The number of pixels with a value of C within the specified range. Indicates in The number of pixels with a value of A within the specified range.

[0012] Preferably, the formula for calculating the distortion value of the small frustum is as follows: ; in, This represents the distortion value of the small frustum. Indicates in The number of pixels with a value of C within the specified range. Indicates in The number of pixels with a value of B within the specified range.

[0013] Preferably, the step of placing the second measuring body in each test area of ​​the sand table, projecting the second color image onto the second measuring body, and calculating the second distortion value using the color error areas on the second measuring body includes: The second measuring body is placed in a test area of ​​the sand table, and the second color image is projected onto each elevation band of the second measuring body; Obtain a top-down view image of the second sand table. Based on the color error areas on the top-down view image of the second sand table, calculate the distortion value of each elevation zone. Sum the distortion values ​​of each elevation zone with weights to obtain the comprehensive distortion value of a test area. The second measuring body is moved sequentially to each test area of ​​the sand table, and the comprehensive distortion value of each test area is calculated respectively. The weighted sum of the overall distortion values ​​for each test region is combined with the maximum overall distortion value to calculate the second distortion value.

[0014] Preferably, the method further includes: Based on the centroid position of the pixels on the top view image of the second sand table, the second center of each elevation zone projection area on the second measuring body is calculated; Based on the pixel values ​​in the top-down view image of the second sand table The distances between all pixels and the second center are used to obtain a radius of... circle ; According to the circle Pixel values ​​within the range The number of pixels, and in the circle Pixel values ​​within the range are not The number of pixels is used to calculate the distortion value of the first elevation band; While the distortion values ​​for all elevation zones have not yet been calculated, continue calculating the current pixel value. The distance between all pixels and the second center is used to obtain the inner diameter. Outer diameter is ring According to the ring The pixel value inside The number of pixels, and in the circle The pixel value within is not The number of pixels is used to obtain the distortion value of the elevation zone, and this process is repeated until the distortion values ​​of all elevation zones are obtained.

[0015] Preferably, elevation zone The formula for calculating the distortion value is as follows: ; in, Indicates elevation zone The distortion value, Indicates in The pixel value within the range The number of pixels, Indicates in Pixel values ​​within the range are not The number of pixels.

[0016] In a second aspect, the present invention provides an irregular projection distortion testing apparatus, the apparatus comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the processor to perform the irregular projection distortion testing method of the first aspect.

[0017] Thirdly, the present invention also provides a non-volatile computer storage medium storing computer-executable instructions that are executed by one or more processors to perform the irregular projection distortion test method described in the first aspect.

[0018] Compared with existing technologies, the advantages of this invention are as follows: It fully considers the characteristics of irregular projection, designs an irregular projection distortion test method, ensures that the projection optical center, distortion sensitivity and different height areas are fully considered when calculating distortion values, and achieves horizontal sampling by dividing the sand table into horizontal sections. It also achieves vertical area error calculation sampling by combining different measuring bodies (measuring bodies with different shapes and height ranges), and achieves distortion error calculation coverage in both the horizontal and vertical directions of the spatial plane. It uses measuring bodies to quantify the distortion value of the sand table. This method can accurately determine whether irregular projection products can be put into use. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 This is a schematic diagram of an irregular projection distortion testing system provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating a method for testing irregular projection distortion provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the method for calculating the first distortion value provided in an embodiment of the present invention; Figure 4 This is a flowchart illustrating the method for calculating the comprehensive distortion value of a test area during the calculation of the first distortion value provided in an embodiment of the present invention. Figure 5 This is a flowchart illustrating the method for calculating the distortion value of a large and small frustum provided in an embodiment of the present invention; Figure 6 This is a top view schematic diagram of the first sand table provided in an embodiment of the present invention; Figure 7 This is a flowchart illustrating the method for calculating the second distortion value provided in an embodiment of the present invention; Figure 8 This is a flowchart illustrating the method for calculating elevation band distortion values ​​provided in an embodiment of the present invention; Figure 9 This is a top-view schematic diagram of the second sand table provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of an irregular projection distortion testing device provided in an embodiment of the present invention; The reference numerals in the attached figures are as follows: 21: Processor; 22: Memory. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0023] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the corresponding features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0024] In the description of this invention, the expression “A and / or B” (where A and B are used to formally represent specific features) will be used. The corresponding expression includes the following three combinations: only A, only B, and a combination of A and B.

[0025] As used in this invention, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from a particular value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0026] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Example 1: This invention also provides an irregular projection distortion testing system for use in conjunction with the irregular projection distortion testing method. The irregular projection distortion testing system includes a first measuring body, a second measuring body, a depth camera supporting RGB (Red, Green and Blue) information acquisition, and sand table irregular projection distortion testing software. (See reference...) Figure 1The first measuring body is a structure with two horizontal frustums, with an adjustable height module at the bottom and a white surface; the second measuring body is a cone-shaped structure with a white surface; the depth camera supporting RGB information acquisition is a structured light depth camera or a binocular stereo vision camera, which can simultaneously acquire RGB color information and depth information; the sand table irregular projection distortion test software is deployed on the host connected to the projector and depth camera, and has contour line display function, which can project different colors onto three-dimensional terrain at different elevations. When conducting irregular projection distortion test, the origin of the test space coordinate system is located at the center of the upper surface of the four sides of the sand table. The projector and depth camera are placed at the center of the sand table and connected to the host (the example in the figure is a graphics workstation) where the sand table irregular projection distortion test software is deployed. During the test, the bottom of the sand table is first leveled, and then the first or second measuring body is placed on the bottom of the sand table. The irregular projection product in this method is an irregular projection sand table.

[0028] Currently, irregularly shaped projections exhibit a certain degree of distortion. By quantifying and evaluating this distortion, as long as the calculated distortion value is within the allowable range, the irregularly shaped projection product can be considered to meet the usage requirements and be put into use. This embodiment uses a sand table as the application scenario for irregularly shaped projection. Due to the uneven surface of the sand table, if the projection system were completely distortion-free, a pure color image projected at the same height area should present a uniform color. However, due to distortion, even if a single color is projected at the same height on the sand table, other colors will still be mixed in the actual display effect. This embodiment utilizes this distortion phenomenon to calculate the distortion value. In addition, since the sand table is made of stacked sand, it exhibits rich height variations. These height values ​​range widely, making it difficult to directly project corresponding colors based on different heights of the sand table to calculate its distortion value. Therefore, this embodiment introduces a measuring body with a regular structure to reduce the number of height levels and uses a defined height value to quantify the degree of distortion of the irregularly shaped projection sand table.

[0029] like Figure 2 As shown, based on Figure 1 The present invention provides a method for testing irregular projection distortion, which includes the following steps: (The system and embodiment 1 of this invention provide a method for testing irregular projection distortion.) Step 101: Flatten the bottom of the sand table and divide the bottom surface of the sand table into multiple test areas.

[0030] In one embodiment, since a measuring volume is used to simulate the possible height distribution of the sand table, the bottom of the sand table needs to be leveled (e.g., the bottom of the sand table is smoothed) before distortion testing. The bottom surface of the sand table can be divided into multiple test areas to achieve horizontal sampling, such as a 9-grid (dividing the sand table bottom surface into 9 test areas), and each test area can be assigned a weight according to its importance. For example, the regional weight of the central test area is set to the highest, and the regional weight of the test area further away from the center is lower. Here, the value of i ranges from 1 to n, and n is the total number of test areas. It is necessary to satisfy that the sum of the regional weights of all test areas is 1.

[0031] Step 102: Place the first measuring body, which can be adjusted to different heights, in each test area of ​​the sand table, and project the first color image onto the first measuring body. Calculate the first distortion value using the color error area on the first measuring body.

[0032] In one embodiment, the first measuring body is adjusted to different heights to simulate different heights of the sand table. When the first measuring body is at different heights, it is placed in each test area to calculate the distortion value of that test area. That is, the distortion value of each test area is calculated for the first measuring body at each determined height. The first color image includes multiple colors (e.g., yellow, blue, and red). Using sand table irregular projection distortion testing software, based on the height information, the same height in the space below the projector is projected as the same color, and different heights are projected as different colors. Due to the existence of distortion, other colors will be mixed in the color area at the same height; these other colors are the error colors. The color error area refers to the area on the surface of the measuring body (such as the surface of a cone or the surface of a small or large frustum of two horizontal truncated cones) that displays an error color in the specified color projection area within the planar area captured and displayed by the depth camera. The first distortion value can then be calculated based on the different colors appearing within the same color.

[0033] Step 103: Place the second measuring body in each test area of ​​the sand table, project the second color image onto the second measuring body, and calculate the second distortion value using the color error area on the second measuring body.

[0034] In one embodiment, to simulate the height of the sand table in a real-world scenario as much as possible, a second measuring body can be introduced. The height of the second measuring body is fixed. It is placed in each test area of ​​the sand table. In each test area, the sand table irregular projection distortion test software is set up. Based on the height information, the space below the projector is projected with the same color at the same height, and different colors at different heights. Similarly, due to the existence of distortion, other colors will be mixed in the color area at the same height. The second distortion value can be calculated based on the different colors appearing in the same color.

[0035] Step 104: Perform a weighted summation of the first distortion value and the second distortion value to obtain the total distortion value of the sand table. When the total distortion value is less than the distortion threshold, it means that the sand table can be put into use.

[0036] In one embodiment, the distortion level of the sand table is quantified by multiple measuring bodies to obtain the total distortion value of the sand table. When the total distortion value is less than the distortion threshold, it means that the distortion level of the sand table meets the requirements and can be put into use. The distortion threshold can be set based on experience to evaluate whether the sand table is usable. The formula for calculating the total distortion value of the entire field of view of the irregular projection is as follows: ; in, This represents the total distortion value. This is the first distortion value; This is the second distortion value; and For weighted parameters, and , and It can be set based on experience.

[0037] In this embodiment, the characteristics of irregular projection are fully considered, and an irregular projection distortion test method is designed to ensure that the projection optical center, distortion sensitivity, and different height areas are fully considered when calculating the distortion value. By dividing the sand table into horizontal sections, horizontal sampling is achieved. Combined with different measuring bodies (measuring bodies with different shapes and height ranges), vertical area error calculation sampling is achieved, realizing the coverage of distortion error calculation in both the horizontal and vertical directions of the spatial plane. The distortion value of the sand table is quantified by the measuring bodies. This method can accurately determine whether the irregular projection product can be put into use.

[0038] Furthermore, the distortion value can be calculated using the standard configuration of the irregular projection sand table (depth camera and laser projector), without the need for special measurement equipment, making the operation of calculating the distortion value simple and easy.

[0039] like Figure 3 As shown, this embodiment provides a method for calculating the first distortion value, which specifically includes the following steps: Step 201: Adjust the bottom of the first measuring body to a first height and place it in a test area of ​​the sand table. According to the height information, project the first color image onto the first measuring body. Calculate the comprehensive distortion value of a test area using the color error area on the first measuring body.

[0040] In one embodiment, the first measuring body includes a small truncated cone and a large truncated cone with upper and lower structures. The first measuring body also includes a bottom disk for supporting the first measuring body. The bottom disk is adjustable, and the maximum height of the bottom disk can be adjusted to be [missing information]. The bottom adjustment height can be set to three different levels. , and And the height of the small truncated cone is The height of the great truncated cone is First, adjust the bottom disc of the first measuring body to the first height. The first measuring object is placed in a test area of ​​the sand table, and the measurement of the first measuring object is calculated. The overall distortion value of a test area at a given height.

[0041] Step 202: Move the first measuring body sequentially to each test area of ​​the sand table, and calculate the comprehensive distortion value of each test area.

[0042] In one embodiment, the height of the bottom disk of the first measuring body is a first height. Under the premise of this, the first measuring body is moved to another test area, and the comprehensive distortion value in the test area is calculated according to the method of step 201. The first measuring body is moved to different test areas of the sand table in turn, and the comprehensive distortion value of the first measuring body in each test area is calculated respectively.

[0043] Step 203: Calculate the full field-of-view distortion value of the first measuring body at the first height by weighting the regional weight of each test area and the comprehensive distortion value of each test area, and combining the maximum comprehensive distortion value.

[0044] In one embodiment, the comprehensive distortion value of each test region is obtained based on the method in step 202, and combined with the region weights set in step 101, the distortion value of the first measurement body is calculated. The formula for the full field-of-view distortion value at height is as follows: ; in, This represents the overall distortion value across the entire field of view. The weighted average of all test regions. This represents the largest overall distortion value across all test areas. and The weighting coefficients can be set based on experience, but it is necessary to ensure that... .

[0045] In one embodiment, the weighted average The calculation formula is as follows: ; in, For weighted average, Let be the overall distortion value of the i-th test region. The regional weights for each test region must be ensured. The value of i ranges from 1 to n, where n is the total number of test regions.

[0046] Step 204: Adjust the bottom of the first measuring body to multiple other heights in sequence, and calculate the full field-of-view distortion value of the first measuring body at each of the multiple other heights.

[0047] In one embodiment, the height of the bottom disk of the first measuring body is adjusted to and To simulate the different heights of the sand table surface in the actual scene as much as possible, and to calculate the height of the first measuring body according to the methods in steps 202 and 203 respectively. The full field-of-view distortion value at height, and the first measurement body at... Full field-of-view distortion value at height.

[0048] Step 205: Take the average of the full field-of-view distortion values ​​for all heights of the first measuring body to obtain the first distortion value.

[0049] In one embodiment, the average of the comprehensive distortion values ​​of the entire field of view calculated at the three heights is taken to obtain the first distortion value of the entire field of view corresponding to the first measuring body. When the first measuring body is placed in different test areas of the sand table, multiple measurements (e.g., 3 times) can be performed on the same test area and the average can be taken to reduce random errors.

[0050] like Figure 4 As shown in the figure, this embodiment provides a method for calculating the overall distortion value of a test area, which specifically includes the following steps: Step 301: Within a test area, according to the height information, project the color image B onto the small circular platform of the first measuring body, project the color image A onto the large circular platform of the first measuring body, and project the color image C onto a projection surface other than the heights of the small and large circular platforms.

[0051] In one embodiment, the bottom height of the first measuring body is... Under the premise of [presumably a specific condition], the first measuring object is placed in a test area of ​​the sand table, and a projection color is set for each height in the sand table irregular projection distortion test software to ensure that the projection color corresponding to each height is different. For example, blue is used as color image B, yellow as color image A, and red as color image C. That is, at a height of [presumably a specific height], the projection color is set for each height. The projection surface projects blue as a texture image, at a height of The projection surface at one height projects yellow as a texture image, and the projection surface at other heights projects red as a texture image. Here, the projection surface refers to the virtual projection surface at different heights in the space below the projector. If there is a physical object on the virtual projection surface at this height, the color can be projected onto it. The above color setting is just an example and does not limit this embodiment. The colors projected onto the large and small truncated cones can also be set to other colors.

[0052] Step 302: Obtain the first sand table top view image, which includes color area A, color area B and color area C.

[0053] In one embodiment, the sand table irregular projection distortion test software initiates the first measurement body frustum distortion value calculation function, and acquires the first sand table top view image currently captured by the depth camera (including color region A, color region B, and color region C). All subsequent calculations related to the first measurement body are based on the first sand table top view image (see...). Figure 6 )conduct.

[0054] Step 303: Calculate the distortion values ​​of the large truncated cone and the small truncated cone based on color regions A, B, and C in the top view image of the sand table.

[0055] In one embodiment, blue is used as color image B, yellow as color image A, and red as color image C. Figure 6 To illustrate the color-coded projection during the testing of the first measuring object, the following steps are taken: The first measuring object is placed in different testing areas within the sand table. The contour display function of the sand table irregular projection distortion testing software is activated. Based on the heights of the small and large truncated cone surfaces of the first measuring object, blue and yellow are projected onto the corresponding elevation areas, while red is projected onto other elevation areas. The top-down view represents the actual situation. A top-down image of the first sand table with the first measuring object placed is captured by a depth camera. The small and large truncated cone surfaces of the first measuring object correspond to circular and annular areas in the depth camera image, displayed in blue and yellow respectively, while other areas are displayed in red. During the distortion calculation, the center of the projection area of ​​the small and large truncated cones is calculated based on the blue and yellow areas in the depth camera image. The red area between the blue and yellow areas is the color error area visible to the naked eye. The color error area also includes the red area at the outer edge of the yellow area, which is difficult to distinguish with the naked eye. The distortion calculation method described above for the first measuring body test can be used for actual calculation. The color error areas on the projection surfaces of the small and large truncated cones are obtained respectively. The distortion value (error area / total area of ​​the truncated cone) of each cone is calculated based on the color error area, and the distortion value δi1_cur of the small cone and the distortion value δi2_cur of the large cone are obtained. The above color setting is just an example and does not limit this embodiment. When performing irregular projection tests, the colors projected onto the large and small truncated cones can also be set to other colors.

[0056] Step 304: Perform a weighted summation of the distortion values ​​of the large truncated cone and the small truncated cone to obtain a comprehensive distortion value for a test area.

[0057] In one embodiment, the weights of the small and large frustums are set based on the importance of the two heights of the large and small frustums of the first measuring body; the calculation method for the comprehensive distortion value of a test area is as follows: ; in, Let be the overall distortion value of the i-th test region. Let be the distortion value of the small frustum. Let be the distortion value of the great truncated cone. Let be the weight of the small frustum. For the weight of the large truncated cone, it is necessary to ensure .

[0058] like Figure 5 As shown, this embodiment provides a method for calculating the distortion value of a large and small frustum, which specifically includes the following steps: Step 401: Calculate the first center of the projection area of ​​the small and large truncated cones based on the centroid position of color area A and the centroid position of color area B.

[0059] In one embodiment, blue is used as color image B, yellow as color image A, and red as color image C, so that in step 301, at a height of The projection surface projects blue as a texture image, at a height of Taking the example of projecting a yellow texture image onto a projection surface and a red texture image onto projection surfaces at other heights, the centroid positions of all pixels with a current pixel value of blue are calculated. The coordinates are Calculate the centroid position of all pixels with a current pixel value of yellow. The coordinates are Calculation points and points The average of the coordinates of two points, the corresponding point is denoted as point A. Let G be the first center of the projection area of ​​the small and large truncated cones.

[0060] Step 402: Based on the distances between the pixels with pixel value A and pixel value B on the first sand table top-view image and the first center, obtain a radius of... circle and an inner diameter of Outer diameter is ring .

[0061] In one embodiment, based on the example of step 401, the calculation is performed on all pixels in the first sand table top-down image whose current pixel value is blue. The distance is denoted as the maximum distance. , with point With the center of the circle, Divide a circle by its radius. ; Calculate the sum of all pixels with a current pixel value of yellow on the top-down view of the first sand table image. The distance is denoted as the maximum distance. , with point With the center of the circle, Inner diameter Divide the outer diameter into a ring In the first sand table top view image, the small and large frustum surfaces of the first measuring body correspond to circular and annular areas, respectively, and are displayed in blue and yellow, while other areas are displayed in red.

[0062] Step 403: Based on the circle The number of pixels with a value of B within the range and the number of pixels in the circle The number of pixels with a value of C within the range is used to calculate the distortion value of the small frustum; based on the number of pixels with a value of C within the range, the distortion value of the small frustum is calculated; The number of pixels with pixel value A within the range and in the circle Calculate the distortion value of the large truncated cone by counting the number of pixels with a value of C within the range.

[0063] In one embodiment, since there is a certain height difference between the surfaces of the small and large frustums of the first measuring body, and distortion often occurs between projection planes at adjacent heights, when distortion occurs, the small frustum is assumed to be circular in the top view image of the first sand table. Within the specified range, only the error color with pixel value C will appear; the error color with pixel value A will not appear. Based on the example in step 401, this means that in the corresponding area of ​​the small circular platform projection surface in the first sand table top-view image, only the error color red will appear, and the error color yellow will not appear. Similarly, the large circular platform is assumed to be the ring in the first sand table top-view image. Within the specified range, only erroneous colors with a pixel value of C will appear; erroneous colors with a pixel value of B will not appear. The formula for calculating the combined distortion value of the small and large frustums is based on the above theory. By extension, when calculating the distortion value of the small frustum, it can also be calculated based on the ratio of the number of pixels with a color other than B in the corresponding area of ​​the small frustum's projection surface to the total number of pixels in that area. Similarly, when calculating the distortion value of the large frustum, it can be calculated based on the ratio of the number of pixels with a color other than A in the corresponding area of ​​the large frustum's projection surface to the total number of pixels in that area.

[0064] Taking step 401 as an example, the pixel with pixel value C is the pixel with pixel value red. The formula for the comprehensive distortion value of the small frustum is as follows: ; in, This represents the distortion value of the small frustum. Indicates in The number of pixels with a value of C within the specified range. Indicates in The number of pixels with a value of B within the specified range.

[0065] If we take the example from step 401 (i.e., using blue as color image B and red as color image C), then the formula for the overall distortion value of the small frustum is as follows: ; in, This represents the distortion value of the small frustum. Indicates in The pixel value within the range is the number of red pixels. Indicates in The pixel value within the range is the number of blue pixels.

[0066] In one embodiment, the formula for the overall distortion value of the large frustum is as follows: ; in, This represents the distortion value of the great frustum. Indicates in The number of pixels with a value of C within the specified range. Indicates in The number of pixels with a value of A within the specified range.

[0067] If we take the example from step 401 (i.e., using yellow as color image A and red as color image C), then the formula for the overall distortion value of the large frustum is as follows: ; in, This represents the distortion value of the great frustum. Indicates in The pixel value within the range is the number of red pixels. Indicates in The pixel value within the range is the number of yellow pixels.

[0068] like Figure 7 As shown, this embodiment provides a method for calculating the second distortion value, which specifically includes the following steps: Step 501: Place the second measuring body in a test area of ​​the sand table and project the second color image onto each elevation band of the second measuring body.

[0069] In one embodiment, the elevation zones divided from top to bottom by the second measuring body are denoted as... (j=1,2,…,m, from 1 to m assumed to be arranged from high to low), different colors are preset for elevation bands of different heights, and the corresponding colors are set to (j=1,2,…,m, where 1 to m are assumed to be arranged from high to low), the elevation band is projected as a texture image using a set color (not red), and red is projected as the texture image for other elevation projection surfaces. The dynamic mapping relationship from elevation to projection color is shown below: ; in, The colors that need to be set for the sand table irregular projection distortion test software. The three-dimensional coordinate elevation values ​​measured by the depth camera. The preset color, .

[0070] For example, the inclined surface of the measuring body is discretized into three elevation zones. According to the different elevation zones of the second measuring body, blue, green and yellow are projected in the corresponding elevation areas in order from top to bottom, and red is projected in other elevation areas. The above color settings are just examples and do not limit this embodiment. When performing irregular projection tests, the color projected onto the elevation zone can also be set to other colors.

[0071] Step 502: Obtain the top-down view image of the second sand table. Based on the color error areas on the top-down view image of the second sand table, calculate the distortion value of each elevation zone. Perform a weighted summation of the distortion values ​​of each elevation zone to obtain the comprehensive distortion value of a test area.

[0072] In one embodiment, the overall distortion value is the average proportion of projection color error areas in different discrete elevation zones within the test area. The contour display function of the sand table irregular projection distortion test software is enabled, and different colors are set according to the different elevation zones of the second measuring object. The second measuring object is placed in different test areas i within the sand table, and the overall distortion value of the second measuring object in the current test area is calculated. The elevation zone weights are set based on the importance of different elevation zones of the second measurement body.

[0073] In one embodiment, the sand table irregular projection distortion test software initiates the second measurement body comprehensive distortion value calculation function to obtain the second sand table top view image currently acquired by the depth camera (see...). Figure 9 All calculations related to the second measurement body described below are based on the top-down view of the second sand table.

[0074] Figure 9The image is a top-down view of the second sand table. During the test of the second measuring body, the second measuring body is placed in different test areas of the sand table. The inclined surface of the measuring body is discretized into three elevation zones. The contour display function of the sand table irregular projection test distortion software is turned on. According to the different elevation zones of the second measuring body, blue, green and yellow are projected in the corresponding elevation areas in order from top to bottom, and red is projected in other elevation areas. The top-down view shows the actual situation. The image is a top-down view of the second sand table with the second measuring body placed. The different elevation zones of the second measuring body correspond to circular areas and two annular areas in the image acquired by the depth camera. They are displayed in blue, green and yellow from the inside to the outside, and other areas are displayed in red. During distortion calculation, the center of each elevation zone projection area of ​​the second measuring body is calculated according to the blue, green, and yellow areas in the depth camera image. The red area between the blue, green, and yellow areas is a color error area visible to the naked eye. The color error area also includes the red area at the outer edge of the yellow area, which is difficult to distinguish with the naked eye. When calculating the elevation zone distortion value, the color error area is not limited to the red area in the elevation zone projection area. For example, for an elevation zone projection area that should be a blue area, pixels whose projection color is not blue in the corresponding projection area of ​​the elevation zone will be counted as pixels in the error area. The distortion calculation method described above for the second measuring body test can be used for actual calculation. The color setting described above is just an example and does not limit this embodiment. When performing irregular projection tests, the color projected onto the elevation zone can also be set to other colors.

[0075] In one embodiment, the comprehensive distortion value is calculated. The formula is as follows: ; in, This represents the overall distortion value of the second measuring body in the current test area. For the weight of the j-th elevation zone, it is necessary to ensure , Let be the distortion value of the j-th elevation zone, where j ranges from 1 to m, and m is the number of elevation zones.

[0076] Step 503: Move the second measuring body to each test area of ​​the sand table in sequence, and calculate the comprehensive distortion value of each test area.

[0077] In one embodiment, the second measuring body is moved to another test area, and the comprehensive distortion value in that test area is calculated according to the method in step 502. The second measuring body is moved to different test areas of the sand table in sequence, and the comprehensive distortion value of the second measuring body in each test area is calculated respectively.

[0078] Step 504: Calculate the second distortion value by weighted summation of the comprehensive distortion values ​​of each test area and combining it with the maximum comprehensive distortion value.

[0079] In one embodiment, the formula for calculating the second distortion value is as follows: ; in, This is the second distortion value. The weighted average of all test regions. This represents the largest overall distortion value across all test areas. and As a weighting parameter, it can be set based on experience, but it is necessary to ensure that... .

[0080] In one embodiment, the formula for calculating the weighted average of all test areas of the second measuring body is as follows:

[0081] in, For weighted average, Let be the overall distortion value of the i-th test region. The regional weights for each test region must be ensured. The value of i ranges from 1 to n, where n is the total number of test regions.

[0082] like Figure 8 As shown in the figure, this embodiment provides a method for calculating the distortion value of an elevation zone, which specifically includes the following steps: Step 601: Calculate the second center of each elevation zone projection area on the second measuring body based on the centroid position of the pixel points on the second sand table top view image.

[0083] In one embodiment, the current pixel value on the top-down image of the second sand table is calculated. Centroid position of all pixels ,point The coordinates are Calculation points The average of the coordinates, the corresponding point is denoted as point. , will point As the second center of the projection area of ​​each elevation zone of the second measuring body, j ranges from 1 to m, where m is the number of elevation zones.

[0084] Step 602: Based on the pixel values ​​of the second sand table top view image The distances between all pixels and the second center are used to obtain a radius of... circle .

[0085] In one embodiment, the current pixel value on the top-down image of the second sand table is calculated. All pixels and points The distance is denoted as the maximum distance. , with point With the center of the circle, Divide a circle by radius .

[0086] Step 603: According to the circle Pixel values ​​within the range The number of pixels, and in the circle Pixel values ​​within the range are not The number of pixels is used to calculate the distortion value of the first elevation band.

[0087] In one embodiment, the distortion value of the elevation band is the proportion of the projected color error area within the projection area corresponding to the elevation band of the second measuring body in the test area. The formula for calculating the distortion value of the first elevation band is as follows: ; in, This represents the distortion value for the first elevation zone. For in the circle The pixel value within the range The number of pixels, For in the circle The pixel value within the range is not The number of pixels.

[0088] Step 604: While the distortion values ​​for all elevation zones have not yet been calculated, continue calculating the current pixel value. The distance between all pixels and the second center is used to obtain the inner diameter. Outer diameter is ring According to the ring The pixel value inside The number of pixels, and in the circle The pixel value within is not The number of pixels is used to obtain the distortion value of the elevation zone, and this process is repeated until the distortion values ​​of all elevation zones are obtained.

[0089] In one embodiment, after calculating the distortion value of the first elevation band, j is incremented by 1 and compared with m. If j is less than m, it means that there are still elevation band distortion values ​​that have not been calculated, and then the current pixel value is calculated. All pixels and points The distance is denoted as the maximum distance. , with point With the center of the circle, Inner diameter Divide the outer diameter into a ring In the example based on step 501, the different elevation zones of the second measuring body correspond to a circular area and two annular areas in the top view image of the second sand table, displayed in blue, green, and yellow respectively from the inside out, while other areas are displayed in red. The formula for calculating the distortion value of the next elevation zone is as follows: ; in, Let be the distortion value of the j-th elevation zone. For the ring The pixel value within the range The number of pixels, For the ring The pixel value within the range is not The number of pixels, j ranges from 2 to m, where m is the number of elevation zones. The elevation zone distortion value is calculated until all elevation zone distortion values ​​have been calculated.

[0090] In addition, when the second measuring body is placed in different test areas of the sand table, multiple measurements (e.g., 3 times) can be taken for the same test area and the average can be taken to reduce random errors.

[0091] Example 2: Based on the irregular projection distortion testing method provided in the foregoing embodiments, the present invention also provides an apparatus for implementing the above-described irregular projection distortion testing method, such as... Figure 10 The diagram shown is a schematic representation of the device architecture according to an embodiment of the present invention. The device for testing irregular projection distortion in this embodiment includes one or more processors 21 and a memory 22. Figure 10 Take a processor 21 as an example.

[0092] Processor 21 and memory 22 can be connected via a bus or other means. Figure 10 Taking the example of a connection between China and Israel via a bus.

[0093] The memory 22 serves as a non-volatile computer-readable storage medium for irregular projection distortion testing. It can be used to store non-volatile software programs and non-volatile computer-executable programs, such as the irregular projection distortion testing method in the aforementioned embodiments. The processor 21 executes various functional applications and data processing of the irregular projection distortion testing device by running the non-volatile software programs, instructions, and modules stored in the memory 22, thereby implementing the irregular projection distortion testing method of the aforementioned embodiments.

[0094] Memory 22 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 22 may include memory remotely located relative to processor 21, which can be connected to processor 21 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0095] The program instructions / modules are stored in memory 22. When executed by one or more processors 21, they perform the irregular projection distortion test method described in the foregoing embodiments, for example, the method described above. Figures 2-5 and Figure 7 , Figure 8 The steps shown.

[0096] This invention also provides a non-volatile computer storage medium storing computer-executable instructions that are executed by one or more processors, for example... Figure 10 One of the processors 21 can enable the above-described one or more processors to execute the irregular projection distortion test method in the foregoing embodiments, for example, to perform the above-described... Figures 2-5 and Figure 7 , Figure 8 The steps shown.

[0097] It is worth noting that the information interaction and execution process between the modules and units in the above-mentioned device and system are based on the same concept as the processing method embodiment of the present invention. For details, please refer to the description in the method embodiment of the present invention, and will not be repeated here.

[0098] Those skilled in the art will understand that all or part of the steps in the various methods of the embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing irregular projection distortion, characterized in that, include: The bottom of the sand table is leveled, and the bottom surface of the sand table is divided into multiple test areas; A first measuring body, adjustable to different heights, is placed in each test area of ​​the sand table, and a first color image is projected onto the first measuring body. The first distortion value is calculated using the color error area on the first measuring body. The second measuring body is placed in each test area of ​​the sand table, and the second color image is projected onto the second measuring body. The second distortion value is calculated using the color error area on the second measuring body. The first distortion value and the second distortion value are weighted and summed to obtain the total distortion value of the sand table. When the total distortion value is less than the distortion threshold, it means that the sand table can be put into use.

2. The method for testing irregular projection distortion according to claim 1, characterized in that, The process of placing a first measuring body adjustable to different heights in each test area of ​​the sand table, projecting a first color image onto the first measuring body, and calculating a first distortion value using the color error areas on the first measuring body includes: The bottom of the first measuring body is adjusted to a first height and placed in a test area of ​​the sand table. According to the height information, the first color image is projected onto the first measuring body. Using the color error area on the first measuring body, the comprehensive distortion value of a test area is calculated. The first measuring body is moved sequentially to each test area of ​​the sand table, and the comprehensive distortion value of each test area is calculated respectively. The weighted sum of the regional weights and the comprehensive distortion values ​​of each test area is calculated, and combined with the maximum comprehensive distortion value, the full field-of-view distortion value of the first measuring object at the first height is obtained. The bottom of the first measuring body was adjusted to multiple other heights in sequence, and the full field-of-view distortion value of the first measuring body at each of the multiple other heights was calculated. The first distortion value is obtained by averaging the full field-of-view distortion values ​​at all heights of the first measuring body.

3. The method for testing irregular projection distortion according to claim 2, characterized in that, The first color image includes color image A, color image B, and color image C, and the method further includes: Within a test area, according to the height information, the color image B is projected onto the small circular platform of the first measuring body, the color image A is projected onto the large circular platform of the first measuring body, and the color image C is projected onto a projection surface other than the height of the small and large circular platforms. Obtain a top-down view image of the first sand table, which includes color region A, color region B, and color region C; Based on color regions A, B, and C in the top-view image of the sand table, the distortion values ​​of the large truncated cone and the small truncated cone are calculated respectively. The distortion values ​​of the large and small truncated cones are weighted and summed to obtain the comprehensive distortion value of a test area.

4. The method for testing irregular projection distortion according to claim 3, characterized in that, The method further includes: Based on the centroid positions of color region A and color region B, calculate the first center of the projection areas of the small and large truncated cones. Based on the distances between pixels with pixel value A and pixel value B on the first sand table top-view image and the first center, a radius is obtained. circle and an inner diameter of Outer diameter is ring ; Based on the circle The number of pixels with a value of B within the range and the number of pixels in the circle The number of pixels with a value of C within the range is used to calculate the distortion value of the small frustum; based on the number of pixels with a value of C within the range, the distortion value of the small frustum is calculated; based on the number of pixels with a value of C within the ring. The number of pixels with a pixel value of A within the range and the number of pixels in the circle Calculate the distortion value of the large truncated cone by counting the number of pixels with a value of C within the range.

5. The method for testing irregular projection distortion according to claim 4, characterized in that, The formula for calculating the distortion value of the large frustum is as follows: ； in, This represents the distortion value of the great frustum. Indicates in The number of pixels with a value of C within the specified range. Indicates in The number of pixels with a value of A within the specified range.

6. The method for testing irregular projection distortion according to claim 4, characterized in that, The formula for the overall distortion value of the small truncated cone is as follows: ； in, This represents the distortion value of the small frustum. Indicates in The number of pixels with a value of C within the specified range. Indicates in The number of pixels with a value of B within the range.

7. The method for testing irregular projection distortion according to claim 1, characterized in that, The step of placing the second measuring body in each test area of ​​the sand table, projecting the second color image onto the second measuring body, and calculating the second distortion value using the color error areas on the second measuring body includes: The second measuring body is placed in a test area of ​​the sand table, and the second color image is projected onto each elevation band of the second measuring body; Obtain a top-down view image of the second sand table. Based on the color error areas on the top-down view image of the second sand table, calculate the distortion value of each elevation zone. Sum the distortion values ​​of each elevation zone with weights to obtain the comprehensive distortion value of a test area. The second measuring body is moved sequentially to each test area of ​​the sand table, and the comprehensive distortion value of each test area is calculated respectively. The weighted sum of the overall distortion values ​​for each test region is combined with the maximum overall distortion value to calculate the second distortion value.

8. The method for testing irregular projection distortion according to claim 7, characterized in that, The method further includes: Based on the centroid position of the pixels on the top view image of the second sand table, the second center of each elevation zone projection area on the second measuring body is calculated; Based on the pixel values ​​in the top-down view image of the second sand table The distances between all pixels and the second center are used to obtain a radius of... circle ; According to the circle Pixel values ​​within the range The number of pixels, and in the circle Pixel values ​​within the range are not The number of pixels is used to calculate the distortion value of the first elevation band; While the distortion values ​​for all elevation zones have not yet been calculated, continue calculating the current pixel value. The distance between all pixels and the second center is used to obtain the inner diameter. Outer diameter is ring According to the ring The pixel value inside The number of pixels, and in the ring The pixel value within is not The number of pixels is used to obtain the distortion value of the elevation zone, and this process is repeated until the distortion values ​​of all elevation zones are obtained.

9. The method for testing irregular projection distortion according to claim 8, characterized in that, Elevation zone The formula for calculating the distortion value is as follows: ； in, Indicates elevation zone The distortion value, Indicates in The pixel value within the range The number of pixels, Indicates in The pixel value within the range is not The number of pixels.

10. A device for testing irregular projection distortion, characterized in that, include: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the processor for performing the irregular projection distortion test method according to any one of claims 1-9.

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