A method and device for detecting dark bands in a projected image

Abstract

Embodiments of the present disclosure disclose a method and device for detecting dark bands in a projected image. The method includes: obtaining a projected image, where the projected image is a white image projected by a projector to be detected; intercepting an edge portion of the projected image to obtain a detection region image; obtaining brightness values of pixel points in the detection region image; and determining the width of the dark band in the projected image according to the brightness values of the pixel points in the detection region image.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of projector detection, and more specifically, to a method and device for detecting dark bands in a projected image. Background Art

[0002] With the development of projection technology, the application of DLP (Digital Light Processing) technology projection imaging is becoming more and more widespread. During the assembly process of DLP projectors, due to installation errors, the light emitted by the LED light source assembly will be blocked, making the light propagation path abnormal, causing dark bands at the edge of the projected image, affecting the projection imaging effect.

[0003] In the prior art, whether the width of the dark band in the projected image meets the requirements is determined by manual observation, which results in large detection errors and cannot guarantee the consistency of the performance of the DLP projector. Summary of the invention

[0004] The purpose of the embodiments of the present disclosure is to provide a method for detecting dark bands in a projected image, which can solve the problem of large detection errors when judging whether the dark bands in the projected image meet the requirements through manual observation.

[0005] According to a first aspect of an embodiment of the present disclosure, a method for detecting dark bands in a projected image is provided, the method comprising:

[0006] Acquire a projection image, where the projection image is a white image projected by the projector to be detected;

[0007] intercepting the edge portion of the projection image to obtain a detection area image;

[0008] Obtaining the brightness value of the pixel points in the detection area image;

[0009] The width of the dark band in the projection image is determined according to the brightness values ​​of the pixels in the detection area image.

[0010] Optionally, determining the width of the dark band in the projection image according to the brightness value of the pixel points in the detection area image includes:

[0011] Determining the width of a dark band in the detection area image according to the brightness value of a pixel in the detection area image;

[0012] The width of the dark band in the projection image is determined according to the width of the dark band in the detection area image.

[0013] Optionally, the detected area image includes a plurality of pixel groups. Determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the detected area image includes:

[0014] Determining the average brightness value of the pixel points in each pixel group according to the brightness values of the pixel points in the detected area image;

[0015] Removing the pixel groups with average brightness values less than or equal to the brightness threshold from the plurality of pixel groups according to the average brightness values of the pixel points in each pixel group, to obtain the remaining pixel groups;

[0016] Determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the remaining pixel groups.

[0017] Optionally, determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the remaining pixel groups includes:

[0018] Dividing the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction;

[0019] Determining the width of the dark band in the detected area image according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group.

[0020] Optionally, dividing the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction includes:

[0021] Selecting a first number of pixel groups from the remaining pixel groups as the first pixel group according to the detection direction;

[0022] Taking the pixel groups other than the first pixel group in the remaining pixel groups as the second pixel group.

[0023] Optionally, determining the width of the dark band in the detected area image according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group includes:

[0024] Constructing a first curve reflecting the relationship between the positions of the pixel groups in the detected area image and the average brightness values of the pixel points in the pixel groups according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group;

[0025] Constructing a first straight line in the first curve according to the average brightness value of the pixel points in the first pixel group;

[0026] Determining the distance between the average brightness value of the pixel points in the second pixel group and the first straight line in the first curve;

[0027] Determine the first number of second pixel groups where the distance is greater than the distance threshold;

[0028] Determine the width of the dark band in the detected area image according to the first number.

[0029] Optionally, the determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the remaining pixel groups includes:

[0030] Determine the second number of the remaining pixel groups;

[0031] Determine the number of pixel points corresponding to each brightness value according to the brightness values of the pixel points in the remaining pixel groups;

[0032] Determine the width of the dark band in the detected area image according to the second number and the number of pixel points corresponding to each brightness value.

[0033] Optionally, the determining the width of the dark band in the detected area image according to the second number and the number of pixel points corresponding to each brightness value includes:

[0034] Determine the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the number of pixel points corresponding to each brightness value;

[0035] Determine the number of pixel points corresponding to each of the brightness peaks;

[0036] Determine the width of the dark band in the detected area image according to the second number and the number of pixel points corresponding to the brightness peaks.

[0037] Optionally, the determining the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the number of pixel points corresponding to each brightness value includes:

[0038] Construct a brightness histogram according to the number of pixel points corresponding to each brightness value; wherein, the abscissa of the brightness histogram is the brightness value, and the ordinate of the brightness histogram is the number of pixel points;

[0039] Determine the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the brightness histogram.

[0040] Optionally, the method further includes:

[0041] Determine the severity of the dark band in the detected area image according to the brightness peaks.

[0042] Optionally, the method further includes:

[0043] Determine whether the placement direction of the detected area image matches the detection direction;

[0044] In the case where the placement direction of the detected area image does not match the detection direction, adjust the placement direction of the detected area image to match the detection direction;

[0045] Split the detected area image into the multiple pixel groups according to the detection direction.

[0046] According to a second aspect of the embodiments of the present disclosure, there is provided a detecting device for dark bands in a projection image, the device including:

[0047] A projection image acquisition module, configured to acquire a projection image, where the projection image is a white image projected by a projector to be detected;

[0048] A detected area acquisition module, configured to intercept an edge portion of the projection image to obtain a detected area image;

[0049] A brightness value acquisition module, configured to acquire the brightness values of pixel points in the detected area image;

[0050] A dark band width determination module, configured to determine the dark band width in the projection image according to the brightness values of pixel points in the detected area image;

[0051] Or,

[0052] The device includes:

[0053] A memory, configured to store an executable computer program;

[0054] A processor, configured to execute the method for detecting dark bands in a projection image according to the first aspect of the present disclosure under the control of the executable computer program.

[0055] According to a third aspect of the embodiments of the present disclosure, there is provided a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program that can be read and executed by a computer, and the computer program is used to execute the method for detecting dark bands in a projection image according to the first aspect of the present disclosure when being read and run by the computer.

[0056] According to the embodiments of the present disclosure, a projection image is acquired, and an edge portion of the projection image is intercepted to obtain a detected area image, and then the dark band width in the projection image is determined according to the brightness values of pixel points in the detected area image. In this way, the automation of detecting the dark band width in a projection image can be achieved, the detection accuracy can be improved, and the detection consistency can be ensured.

[0057] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0059] Figure 1 is a schematic diagram of the hardware configuration of a detection system for dark bands in a projected image that can be used to implement an embodiment;

[0060] Figure 2 is a schematic diagram of the hardware configuration of an electronic device that can be used to implement the method of the embodiments of the present disclosure;

[0061] Figure 3 is a schematic flowchart of a method for detecting dark bands in a projected image according to an embodiment of the present disclosure;

[0062] Figure 4 is a schematic diagram of obtaining a projected image according to an embodiment of the present disclosure;

[0063] Figure 5 is a schematic diagram of a detected region image according to an embodiment of the present disclosure;

[0064] Figure 6 is a schematic diagram of the first curve according to an embodiment of the present disclosure;

[0065] Figure 7 is a schematic diagram of the brightness histogram according to an embodiment of the present disclosure;

[0066] Figure 8 is a schematic diagram of the hardware structure of a device for detecting dark bands in a projected image according to an embodiment of the present disclosure;

[0067] Figure 9 is a schematic diagram of the hardware structure of another device for detecting dark bands in a projected image according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0069] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present invention or its application or use.

[0070] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification.

[0071] In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0072] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof in subsequent figures is not necessary.

[0073] <Hardware Configuration>

[0074] Figure 1 is a schematic diagram of the hardware configuration of a detection system for dark bands in a projected image that can be used to implement an embodiment.

[0075] As Figure 1 shown, the system 100 may include an electronic device 1000, a camera 2000, a projector 3000 to be detected, a bracket 4000, and a screen 5000.

[0076] The electronic device 1000 is used to implement the scheduling control and software algorithm calculation of the entire system. The camera 2000 is used to capture the white image projected by the projector 3000 to be detected onto the screen 5000. The bracket 4000 is used to fix the projector 3000 to be detected. The screen 5000 is used to present the white image projected by the projector 3000 to be detected.

[0077] In one embodiment of the present disclosure, the entire system may be placed in a dark room.

[0078] Figure 2 is a schematic diagram of the hardware configuration of an electronic device that can be used to implement a method for detecting dark bands in a projected image.

[0079] In one embodiment, the electronic device 1000 may be as Figure 2 shown and includes a processor 1100, a memory 1200, an interface device 1300, a communication device 1400, a display device 1500, and an input device 1600.

[0080] Among them, the processor 1100 may include, for example, but is not limited to, a central processing unit (CPU), a microcontroller unit (MCU), etc. The memory 1200 includes, for example, a read-only memory (ROM), a random access memory (RAM), a non-volatile memory such as a hard disk, etc. The interface device 1300 includes, for example, various bus interfaces, such as a serial bus interface (including a USB interface), a parallel bus interface, etc. The communication device 1400 can perform wired or wireless communication, for example. The display device 1500 is, for example, a liquid crystal display screen, an LED display screen, a touch display screen, etc. The input device 1600 includes, for example, a touch screen, a keyboard, etc.

[0081] In one embodiment, the electronic device 1000 may further include a camera, which is used to obtain a projection image. The camera may be, for example, an industrial camera.

[0082] In this embodiment, the memory 1200 of the electronic device 1000 is used to store instructions for controlling the processor 1100 to operate to implement or support the implementation of the method for detecting a dark band in a projection image according to any embodiment. Those skilled in the art can design the instructions according to the solutions disclosed in this specification. How the instructions control the processor to operate is well known in the art, so it will not be described in detail here.

[0083] Those skilled in the art should understand that although multiple devices of the electronic device 1000 are shown in Figure 2 , the electronic device 1000 in the embodiments of this specification may only involve some of the devices, for example, only involve the processor 1100 and the memory 1200, etc. Figure 2 The illustrated electronic device 1000 is only illustrative and is by no means intended to limit this specification, its applications, or uses.

[0084] Next, various embodiments and examples according to the present disclosure will be described with reference to the accompanying drawings.

[0085] <Method Embodiment>

[0086] Figure 3 The method for detecting a dark band in a projection image according to an embodiment is shown, and this detection method may be implemented, for example, by the electronic device 1000 as shown in Figure 2 . As shown in Figure 3 , the method for detecting a dark band in the projection image may include the following steps S3100 to S3400.

[0087] Step S3100: Obtain a projection image, where the projection image is a white image projected by a projector to be detected.

[0088] In one embodiment, acquiring the projection image includes: controlling an industrial camera to capture the projection image projected by the projector to be inspected, and acquiring the projection image captured by the industrial camera.

[0089] See also Figure 4 , which is a schematic diagram of obtaining a projection image in an embodiment of the present disclosure. Specifically, the projector 41 to be detected is set on one side of the projection screen 42, and the plane where the camera of the projector 41 to be detected is located is parallel to the plane where the projection screen 42 is located, and the projector 41 to be detected can project an image onto the projection screen 42. The industrial camera 43 is installed in the jig, and the optical axis of the optical component of the industrial camera 43 is perpendicular to the plane where the projection screen 42 is located. The industrial camera 43 is used to shoot the projection screen projected by the projector 41 to be detected onto the projection screen 42 to obtain a projection image.

[0090] In this embodiment, an industrial camera is used to capture the image projected by the projector to be inspected, and the captured projection image is transmitted to an electronic device so that the electronic device processes the projection image to detect the dark band in the projection image.

[0091] In one embodiment, the projected image is a white image. In this embodiment, due to the installation error of the DLP projector, the light emitted by the LED light source assembly will be blocked or reflected, affecting the normal light path, thereby generating a dark band at the edge of the projected image. When a white image is projected using a problematic projector, there is a difference in brightness at the edge of the projected image and the brightness at the edge of the image of a normal projector. Based on this, combined with subsequent steps, by processing the projected image, the width of the dark band obtained in the projected image can be determined.

[0092] Step S3200, cutting out the edge portion of the projection image to obtain a detection area image.

[0093] The detection area image is an image including the dark band area. In this embodiment, the dark band usually appears at the edge of the projection image, based on which the edge portion of the projection image is intercepted to obtain the detection area image. In addition, the calculation of the dark band width of the projection image based on the detection area image can reduce the amount of calculation and improve the detection speed.

[0094] In one embodiment, the step of intercepting the edge portion of the projection image to obtain the detection area image may further include:

[0095] The edge of the projected image is determined and cut out at a fixed size to obtain the detection area image.

[0096] In this embodiment, the detection area image may include one or more detection area images. Figure 5, which is a schematic diagram of a detection area image according to an embodiment of the present disclosure. Specifically, four edges (A, B, C, D) of the projection image 51 are determined. Among them, edge A is adjacent to edge B and edge D, edge B is adjacent to edge A and edge C, edge C is adjacent to edge B and edge D, and edge D is adjacent to edge A and edge C. It can be intercepted at a position set distance from the first edge based on the second edge with a fixed size to obtain the detection area image. Among them, the first edge and the second edge are adjacent.

[0097] In the example as Figure 5 shown, by intercepting in the above manner, eight detection area images can be obtained, including detection area image 52-1, detection area image 52-2, detection area image 52-3, detection area image 52-4, detection area image 52-5, detection area image 52-6, detection area image 52-7, and detection area image 52-8.

[0098] It should be noted that the number and size of the obtained detection area images can be set by those skilled in the art according to experience, and the embodiments of the present disclosure do not limit this.

[0099] Step S3300, obtain the brightness values of the pixel points in the detection area image.

[0100] In this embodiment, the brightness value of the pixel point can be represented by a value from 0 to 255.

[0101] Step S3400, determine the width of the dark band in the projection image according to the brightness values of the pixel points in the detection area image.

[0102] In an embodiment of the present disclosure, determining the width of the dark band in the projection image according to the brightness values of the pixel points in the detection area image may include steps S3410 to S3420 as shown below:

[0103] Step S3410, determine the width of the dark band in the detection area image according to the brightness values of the pixel points in the detection area image.

[0104] In this embodiment, the detection area image may include multiple pixel groups.

[0105] In the projection image, the brighter part is the projection screen, and the black edge is the background image. In the detection area image obtained by intercepting the edge part of the projection image, it may also include the black edge part and the projection screen part. Specifically, the detection area image can be split into multiple pixel groups according to the position of the black edge part in the detection area image.

[0106] In an embodiment of the present disclosure, the method may further include steps S4100 to S4300 as shown below:

[0107] Step S4100, determine whether the placement direction of the detected area image matches the detection direction.

[0108] In this embodiment, the detection direction can be set in advance according to the application scenario or specific requirements. For example, the detection direction can be the direction from top to bottom.

[0109] The placement direction of the detected area image can be determined by the position of the black edge part in the detected area image. When the detection direction is the direction from top to bottom, if the placement direction of the detected area image indicates that the black edge part is above the detected area image, it can be determined that the placement direction of the detected area image matches the detection direction.

[0110] Step S4200, when the placement direction of the detected area image does not match the detection direction, adjust the placement direction of the detected area image to match the detection direction.

[0111] When the detection direction is the direction from top to bottom, if the placement direction of the detected area image indicates that the black edge part is below, on the left or on the right of the detected area image, it can be determined that the placement direction of the detected area image does not match the detection direction.

[0112] Taking Figure 5 the shown detected area images as an example, determine the detection direction as from top to bottom. The placement directions of detected area images 52-1 and 52-2 match the detection direction. The detected area images 52-5 and 52-6 can be rotated 180°, the detected area images 52-7 and 52-8 can be rotated 90° clockwise, and the detected area images 52-3 and 52-4 can be rotated 90° counterclockwise.

[0113] In this embodiment, by adjusting the placement direction of each detected area image to match the detection direction in advance, the dark band width of each detected area image can be further judged in the same way, so that the processing algorithm can be simplified and the consistency of detection can be ensured.

[0114] Step S4300, split the detected area image into multiple pixel groups according to the detection direction.

[0115] In this embodiment, when the detection direction is the direction from top to bottom, each row of pixel points in the detected area image can be used as a pixel group in the order from top to bottom.

[0116] In an embodiment of the present disclosure, determining the dark band width in the detected area image according to the brightness value of the pixel points in the detected area image may include steps S3411 to S3413 shown below:

[0117] Step S3411: Determine the average brightness value of the pixel points in each pixel group according to the brightness values of the pixel points in the detection area image.

[0118] In this embodiment, for each pixel group, the average of the brightness values of the pixel points in the pixel group may be calculated to obtain the average brightness value of the pixel points in the pixel group.

[0119] Step S3412: Remove the pixel groups with an average brightness value less than or equal to the brightness threshold from the multiple pixel groups according to the average brightness value of the pixel points in each pixel group, and obtain the remaining pixel groups.

[0120] In this embodiment, the brightness threshold may be set in advance according to the application scenario or specific requirements. For example, the brightness threshold may be 5 or 10.

[0121] If the average brightness value of the pixel points in a pixel group is less than or equal to the brightness threshold, it may be determined that the pixel group is the row where the black edge in the detection area image is located.

[0122] Step S3413: Determine the width of the dark band in the detection area image according to the brightness values of the pixel points in the remaining pixel groups.

[0123] In the first embodiment of the present disclosure, determining the width of the dark band in the detection area image according to the brightness values of the pixel points in the remaining pixel groups may include the following steps S5100 - S5200:

[0124] Step S5100: Divide the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction.

[0125] In one embodiment, dividing the remaining pixel groups into a first pixel group and a second pixel group according to the target direction may include the following steps S5110 - S5120:

[0126] Step S5110: Select a first number of pixel groups from the remaining pixel groups as the first pixel group according to the detection direction.

[0127] When the detection direction is from top to bottom, the pixel groups formed by the first number of rows of pixel points at the bottom of the detection area image in the remaining pixel groups may be selected as the first pixel group.

[0128] In this embodiment, the first number may be set in advance according to the application scenario or specific requirements. For example, the first number may be 50.

[0129] Step S5120: Use the pixel groups other than the first pixel group in the remaining pixel groups as the second pixel group.

[0130] In this embodiment, it may be to remove the first pixel group from the remaining pixel groups to obtain a second pixel group.

[0131] Step S5200: Determine the width of the dark band in the detected area image according to the average brightness of the pixel points in the first pixel group and the average brightness of the pixel points in the second pixel group.

[0132] In an embodiment of the present disclosure, determining the width of the dark band in the detected area image according to the average brightness of the pixel points in the first pixel group and the average brightness of the pixel points in the second pixel group may include steps S5210 to S5250 as follows:

[0133] Step S5210: Construct a first curve reflecting the relationship between the position of the pixel group in the detected area image and the average brightness of the pixel points in the pixel group according to the average brightness of the pixel points in the first pixel group and the average brightness of the pixel points in the second pixel group.

[0134] In this embodiment, it may be to pre-construct a coordinate system, where the abscissa of the coordinate system represents the position of the pixel group in the detected area image, and the ordinate of the coordinate system represents the average brightness of the pixel points in the pixel group.

[0135] It may be to represent in the coordinate system the coordinate points reflecting the position of each remaining pixel group in the detected area image and the average brightness of the pixel points in each remaining pixel group. Connect all the coordinate points according to the detection direction to obtain the first curve, as Figure 6 shown.

[0136] When a pixel group is a row of pixels in the detected area image, the position of the pixel group in the detected area image may be the row number from top to bottom of the pixel group in the detected area image. Then, each coordinate point in the coordinate system may represent the row number from top to bottom of a remaining pixel group in the detected area image and the average brightness of the pixel points in the remaining pixel group.

[0137] Step S5220: Construct a first straight line in the first curve according to the average brightness of the pixel points in the first pixel group.

[0138] In this embodiment, it may be to fit a straight line, that is, the first straight line, according to the average brightness of the pixel points in the first pixel group in the first curve, as Figure 6 shown.

[0139] Step S5230: Determine the distance between the average brightness of the pixel points in the second pixel group and the first straight line in the first curve.

[0140] In this embodiment, it may be to determine the distance between the coordinate point corresponding to the average brightness of the pixel points in each second pixel group in the first curve and the first straight line.

[0141] Step S5240: Determine the first number of second pixel groups whose distance is greater than the distance threshold.

[0142] In this embodiment, the distance threshold may be preset according to the application scenario or specific requirements. For example, the distance may be 10.

[0143] Specifically, the first number may be the number of second pixel groups whose distance is greater than the distance threshold.

[0144] Step S5250: Determine the width of the dark band in the detected area image according to the first number.

[0145] In one embodiment, the first number may be used as the width of the dark band in the detected area image.

[0146] In this embodiment, according to the brightness change direction of the detected area image, the detected area image is divided into multiple pixel groups. According to the average brightness of the multiple pixel groups and the positions of the pixel groups in the detected area image, a first curve is generated. According to the first curve, the width of the dark band in the detected area image is determined. In the embodiments of the present disclosure, taking pixel rows or pixel columns as units to determine the width of the dark band in the detected area image can improve the detection accuracy while reducing the amount of computation and improving the detection speed.

[0147] In the second embodiment of the present disclosure, determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the remaining pixel groups may include steps S5300 to S5500 as follows:

[0148] Step S5300: Determine the second number of the remaining pixel groups.

[0149] Specifically, the second number may be the number of the remaining pixel groups.

[0150] Step S5400: Determine the number of pixel points corresponding to each brightness value according to the brightness values of the pixel points in the remaining pixel groups.

[0151] The brightness value may be any value within 0 to 255. Therefore, it may be to count the number of each pixel point with a brightness value from 0 to 255 in the remaining pixel groups.

[0152] Step S5500: Determine the width of the dark band in the detected area image according to the second number and the number of pixel points corresponding to each brightness value.

[0153] In one embodiment of the present disclosure, determining the width of the dark band in the detected area image according to the second group of numbers and the number of pixel points corresponding to each brightness value may include steps S5510 to S5530 as shown below:

[0154] Step S5510: Determine the two brightness values corresponding to the largest number of pixel points among the pixel points corresponding to each brightness value as the brightness peaks.

[0155] In one embodiment of the present disclosure, it may be to sort the brightness values in descending order according to the number of pixel points, determine the sorting values of each brightness value, and select the two brightness values with the smallest sorting values as the brightness peaks.

[0156] In another embodiment of the present disclosure, it may also be to construct a brightness histogram according to the number of pixel points corresponding to each brightness value; determine the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the brightness histogram. Among them, the abscissa of the brightness histogram is the brightness value, and the ordinate of the brightness histogram is the number of pixel points. The brightness histogram may be as Figure 7 shown.

[0157] In this embodiment, before determining the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the brightness histogram, the brightness histogram may also be filtered to make the obtained brightness peaks more accurate.

[0158] Specifically, it may be to determine the two peaks of the brightness histogram and determine the brightness corresponding to the two peaks as the brightness peaks.

[0159] Step S5520: Determine the number of pixel points corresponding to each brightness peak.

[0160] Step S5530: Determine the width of the dark band in the detected area image according to the second group of numbers and the number of pixel points corresponding to the brightness peaks.

[0161] Specifically, the brightness value corresponding to the largest number of pixel points may be used as the first brightness peak, and the brightness value corresponding to the second largest number of pixel points may be used as the second brightness peak.

[0162] When the second group of numbers is N, the number of pixel points corresponding to the first brightness peak is Pix1_num, and the number of pixel points corresponding to the second brightness peak is Pix2_num, the width W of the dark band may be determined by the following formula:

[0163] W = N * (Pix2_num / Pix1_num)

[0164] In this embodiment, according to the brightness change direction of the detection area image, the detection area image is divided into multiple pixel groups. According to the number of pixel points corresponding to each brightness value, a brightness histogram is constructed, and the dark band width of the detection area image is determined based on the brightness histogram. In the embodiments of the present disclosure, taking pixel rows or pixel columns as units to determine the dark band width of the detection area image can improve the detection accuracy while reducing the computation amount and increasing the detection speed.

[0165] In an embodiment of the present disclosure, when the dark band width of the detection area image is greater than or equal to a preset first width threshold, the method may further include: determining the severity of the dark band in the detection area image according to the brightness peak.

[0166] Wherein, the first width threshold may be preset according to the application scenario or specific requirements.

[0167] Specifically, the brightness value corresponding to the largest number of pixel points may be used as the first brightness peak, and the brightness value corresponding to the second largest number of pixel points may be used as the second brightness peak.

[0168] When the first brightness peak is Y1_peak and the second brightness peak is Y2_peak, the severity K of the dark band in the detection area image may be determined by the following formula:

[0169] K = Y2_peak / Y1_peak

[0170] Step S3420, determining the dark band width in the projection image according to the dark band width in the detection area image.

[0171] When the number of detection area images is one, the dark band width in the detection area image may be used as the dark band width in the projection image.

[0172] When the number of detection area images is at least two, the maximum value of the dark band widths in all detection area images may be determined as the dark band width in the projection image.

[0173] According to the embodiments of the present disclosure, a projection image is obtained, and the edge part of the projection image is intercepted to obtain a detection area image. Then, according to the brightness values of the pixel points in the detection area image, the dark band width in the projection image is determined. In this way, the automation of the dark band width detection in the projection image can be realized, the detection accuracy can be improved, and the detection consistency can be ensured.

[0174] In an embodiment of the present disclosure, the maximum value of the severity of the dark band in the detection area image may also be used as the severity of the dark band in the projection image.

[0175] In an embodiment of the present disclosure, the qualification of the dark band detection of the projector to be detected can be determined according to the width of the dark band in the projection image.

[0176] Specifically, it can be determined that the dark band detection of the projector to be detected is qualified when the width of the dark band in the projection image is less than or equal to a preset second width threshold.

[0177] Wherein, the second width threshold can be set in advance according to the application scenario or specific requirements.

[0178] Furthermore, when the width of the dark band in the projection image is greater than the second width threshold, it can be determined whether the severity of the dark band in the projection image is less than or equal to a preset severity threshold. When the severity of the dark band in the projection image is less than or equal to the severity threshold, it can be determined that the dark band detection of the projector to be detected is qualified.

[0179] Wherein, the severity threshold can be set in advance according to the application scenario or specific requirements.

[0180] Still further, when the width of the dark band in the projection image is greater than the second width threshold and the severity of the dark band in the projection image is greater than the severity threshold, it can be determined that the dark band detection of the projector to be detected is unqualified.

[0181] <Device Embodiment>

[0182] This embodiment provides a detection device for dark bands in a projection image. As Figure 8 shown, the detection device 500 for dark bands in the projection image may include a projection image acquisition module 510, a detection area acquisition module 520, a brightness value acquisition module 530, and a dark band width determination module 540. The projection image acquisition module 510 is configured to acquire a projection image, and the projection image is a white image projected by the projector to be detected; the detection area acquisition module 520 is configured to intercept an edge portion of the projection image to obtain a detection area image; the brightness value acquisition module 530 is configured to acquire the brightness values of the pixel points in the detection area image; the dark band width determination module 540 is configured to determine the width of the dark band in the projection image according to the brightness values of the pixel points in the detection area image.

[0183] In an embodiment of the present disclosure, the dark band width determination module 540 may further be configured to:

[0184] Determine the width of the dark band in the detection area image according to the brightness values of the pixel points in the detection area image;

[0185] Determine the width of the dark band in the projection image according to the width of the dark band in the detection area image.

[0186] In one embodiment of the present disclosure, the detection area image includes a plurality of pixel groups. Determining the width of the dark band in the detection area image according to the brightness values of the pixel points in the detection area image includes:

[0187] Determine the average brightness value of the pixel points in each pixel group according to the brightness values of the pixel points in the detection area image;

[0188] Remove the pixel groups with an average brightness value less than or equal to the brightness threshold from the plurality of pixel groups according to the average brightness value of the pixel points in each pixel group, to obtain the remaining pixel groups;

[0189] Determine the width of the dark band in the detection area image according to the brightness values of the pixel points in the remaining pixel groups.

[0190] In one embodiment of the present disclosure, determining the width of the dark band in the detection area image according to the brightness values of the pixel points in the remaining pixel groups includes:

[0191] Divide the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction;

[0192] Determine the width of the dark band in the detection area image according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group.

[0193] In one embodiment of the present disclosure, dividing the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction includes:

[0194] Select a first number of pixel groups from the remaining pixel groups as the first pixel group according to the detection direction;

[0195] Take the pixel groups other than the first pixel group in the remaining pixel groups as the second pixel group.

[0196] In one embodiment of the present disclosure, determining the width of the dark band in the detection area image according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group includes:

[0197] Construct a first curve reflecting the relationship between the position of the pixel group in the detection area image and the average brightness value of the pixel points in the pixel group according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group;

[0198] Construct a first straight line in the first curve according to the average brightness value of the pixel points in the first pixel group;

[0199] Determine the distance between the average brightness value of the pixel points in the second pixel group and the first straight line in the first curve;

[0200] Determine the first number of sets of second pixel groups whose distances are greater than the distance threshold;

[0201] Determine the width of the dark band in the detected area image according to the first number of sets.

[0202] In an embodiment of the present disclosure, determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the remaining pixel groups includes:

[0203] Determine the second number of sets of the remaining pixel groups;

[0204] Determine the number of pixel points corresponding to each brightness value according to the brightness values of the pixel points in the remaining pixel groups;

[0205] Determine the width of the dark band in the detected area image according to the second number of sets and the number of pixel points corresponding to each brightness value.

[0206] In an embodiment of the present disclosure, determining the width of the dark band in the detected area image according to the second number of sets and the number of pixel points corresponding to each brightness value includes:

[0207] Determine the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the number of pixel points corresponding to each brightness value;

[0208] Determine the number of pixel points corresponding to each brightness peak;

[0209] Determine the width of the dark band in the detected area image according to the second number of sets and the number of pixel points corresponding to the brightness peaks.

[0210] In an embodiment of the present disclosure, determining the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the number of pixel points corresponding to each brightness value includes:

[0211] Construct a brightness histogram according to the number of pixel points corresponding to each brightness value; wherein, the abscissa of the brightness histogram is the brightness value, and the ordinate of the brightness histogram is the number of pixel points;

[0212] Determine the two brightness values corresponding to the largest number of pixel points as the brightness peaks according to the brightness histogram.

[0213] In an embodiment of the present disclosure, the dark band detection device 500 in the projection image may further include:

[0214] A module for determining the severity of the dark band in the detected area image according to the brightness peaks.

[0215] In an embodiment of the present disclosure, the dark band detection device 500 in the projection image may further include:

[0216] A module for determining whether the placement direction of the detection area image matches the detection direction;

[0217] A module for adjusting the placement direction of the detection area image to match the detection direction when the placement direction of the detection area image does not match the detection direction;

[0218] A module for splitting the detection area image into multiple pixel groups according to the detection direction.

[0219] This embodiment also provides another detection device for dark bands in a projection image, as Figure 9 shown. The detection device 600 for dark bands in the projection image includes a memory 620 and a processor 610. The memory 620 is used to store executable computer programs. The processor 610 is used to execute the method for detecting dark bands in a projection image according to the control of the executable computer program according to the method embodiment of the present disclosure.

[0220] The detection device 600 for dark bands in the projection image can be the electronic device 1000 as Figure 1 shown, or a device with other hardware structures, which is not limited herein.

[0221] In one embodiment, each module of the above detection device 600 for dark bands in a projection image can be implemented by the processor 610 running the computer instructions stored in the memory 620.

[0222] <Medium Embodiment>

[0223] In this embodiment, a computer-readable storage medium is also provided. The computer-readable storage medium stores a computer program that can be read and run by a computer. The computer program is used to execute the method for detecting dark bands in a projection image according to any of the above method embodiments of the present invention when being read and run by the computer.

[0224] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. However, those skilled in the art should clearly understand that the above embodiments can be used alone or in combination as needed. Additionally, for the device embodiments, since they correspond to the method embodiments, they are described relatively simply. For the relevant parts, refer to the description of the corresponding parts of the method embodiments. The system embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separated.

[0225] The present invention may be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to implement aspects of the present invention.

[0226] A computer-readable storage medium may be a tangible device that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium may be, for example—but not limited to—an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanically encoded device such as a punch card or raised structures in a groove having instructions stored thereon, and any suitable combination of the foregoing. The computer-readable storage medium as used herein is not to be construed as a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through an optical fiber cable), or an electrical signal transmitted through a wire.

[0227] The computer-readable program instructions described herein may be downloaded to respective computing / processing devices from a computer-readable storage medium or may be downloaded to an external computer or external storage device through a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may include copper transmission cables, optical fiber transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing / processing device.

[0228] The computer program instructions for performing the operations of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine - related instructions, microcode, firmware instructions, state - setting data, or source code or object code written in any combination of one or more programming languages, including object - oriented programming languages such as Smalltalk, C++, etc., and conventional procedural programming languages such as "C" language or similar programming languages. The computer - readable program instructions may be executed entirely on the user's computer, partially on the user's computer, executed as a stand - alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via an Internet service provider through the Internet). In some embodiments, by using the state information of the computer - readable program instructions to customize an electronic circuit, such as a programmable logic circuit, a field - programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute the computer - readable program instructions to implement various aspects of the present invention.

[0229] Aspects of the present invention are described herein with reference to the flowchart and / or block diagram of a method, apparatus (system), and computer program product according to embodiments of the present invention. It should be understood that each block of the flowchart and / or block diagram, and combinations of blocks in the flowchart and / or block diagram, can be implemented by computer - readable program instructions.

[0230] These computer - readable program instructions can be provided to a processor of a general - purpose computer, a special - purpose computer, or other programmable data - processing device, thereby producing a machine such that when these instructions are executed by the processor of the computer or other programmable data - processing device, a device is produced that implements the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer - readable program instructions can also be stored in a computer - readable storage medium, and these instructions cause the computer, programmable data - processing device, and / or other devices to work in a specific manner. Thus, the computer - readable medium storing the instructions includes a manufacture, which includes instructions for implementing various aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0231] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device, causing a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process such that the instructions executed on the computer, other programmable data processing apparatus, or other device implement the functions / acts specified in one or more boxes of the flowchart and / or block diagram.

[0232] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of an instruction, which contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block of the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or acts, or by a combination of dedicated hardware and computer instructions. As is well known to those skilled in the art, implementation by hardware, implementation by software, and implementation by a combination of software and hardware are equivalent.

[0233] The embodiments of the present invention have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A method for detecting dark bands in a projected image, characterized in that, The method includes: Obtaining a projection image, which is a white image projected by a projector to be detected; Cropping an edge portion of the projection image to obtain a detection region image; Obtaining the brightness values of the pixel points in the detection region image; Determining the width of the dark band in the projection image according to the brightness values of the pixel points in the detection region image; The determining the width of the dark band in the projection image according to the brightness values of the pixel points in the detection region image includes: Determining the width of the dark band in the detection region image according to the brightness values of the pixel points in the detection region image; Determining the width of the dark band in the projection image according to the width of the dark band in the detection region image; wherein, when the number of the detection region images is one, taking the width of the dark band in the detection region image as the width of the dark band in the projection image; when the number of the detection region images is at least two, taking the maximum value of the widths of the dark bands in all the detection region images as the width of the dark band in the projection image.

2. The method according to claim 1, characterized in that, The detection region image includes a plurality of pixel groups, and the determining the width of the dark band in the detection region image according to the brightness values of the pixel points in the detection region image includes: Determining the average brightness value of the pixel points in each pixel group according to the brightness values of the pixel points in the detection region image; Removing the pixel groups with the average brightness value less than or equal to the brightness threshold from the plurality of pixel groups according to the average brightness value of the pixel points in each pixel group to obtain the remaining pixel groups; Determining the width of the dark band in the detection region image according to the brightness values of the pixel points in the remaining pixel groups.

3. The method according to claim 2, wherein The determining the width of the dark band in the detection region image according to the brightness values of the pixel points in the remaining pixel groups includes: Dividing the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction; Determining the width of the dark band in the detection region image according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group.

4. The method according to claim 3, characterized in that The dividing the remaining pixel groups into a first pixel group and a second pixel group according to the detection direction includes: Selecting a first number of pixel groups from the remaining pixel groups as the first pixel group according to the detection direction; Taking the pixel groups other than the first pixel group in the remaining pixel groups as the second pixel group.

5. The method according to claim 3, wherein The determining the width of the dark band in the detection region image according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group includes: Constructing a first curve reflecting the relationship between the position of the pixel group in the detection region image and the average brightness value of the pixel points in the pixel group according to the average brightness value of the pixel points in the first pixel group and the average brightness value of the pixel points in the second pixel group; Constructing a first straight line in the first curve according to the average brightness value of the pixel points in the first pixel group; Determining the distance between the average brightness value of the pixel points in the second pixel group and the first straight line in the first curve; Determining the first number of the second pixel groups with the distance greater than the distance threshold; Determine the width of the dark band in the detected area image according to the first group of numbers.

6. The method according to claim 2, characterized in that, The determining the width of the dark band in the detected area image according to the brightness values of the pixel points in the remaining pixel groups includes: Determine a second group of numbers of the remaining pixel groups; According to the brightness values of the pixel points in the remaining pixel groups, determine the number of pixel points corresponding to each brightness value; Determine the width of the dark band in the detected area image according to the second group of numbers and the number of pixel points corresponding to each brightness value.

7. The method according to claim 6, characterized in that The determining the width of the dark band in the detected area image according to the second group of numbers and the number of pixel points corresponding to each brightness value includes: According to the number of pixel points corresponding to each brightness value, determine two brightness values with the largest number of corresponding pixel points as brightness peaks; Determine the number of pixel points corresponding to each of the brightness peaks; Determine the width of the dark band in the detected area image according to the second group of numbers and the number of pixel points corresponding to the brightness peaks.

8. The method according to claim 7, characterized in that, The determining two brightness values with the largest number of corresponding pixel points as brightness peaks according to the number of pixel points corresponding to each brightness value includes: Construct a brightness histogram according to the number of pixel points corresponding to each brightness value; wherein, the abscissa of the brightness histogram is the brightness value, and the ordinate of the brightness histogram is the number of pixel points; According to the brightness histogram, determine two brightness values with the largest number of corresponding pixel points as brightness peaks.

9. The method according to claim 7, wherein The method further includes: Determine the severity of the dark band in the detected area image according to the brightness peaks.

10. The method according to claim 2, wherein The method further includes: Determine whether the placement direction of the detected area image matches the detection direction; In the case where the placement direction of the detected area image does not match the detection direction, adjust the placement direction of the detected area image to match the detection direction; According to the detection direction, split the detected area image into the multiple pixel groups.

11. A detection device for dark bands in a projected image, characterized in that, The device includes: A projection image acquisition module, configured to acquire a projection image, where the projection image is a white image projected by a projector to be detected; A detected area acquisition module, configured to intercept an edge part of the projection image to obtain a detected area image; A brightness value acquisition module, configured to acquire the brightness values of the pixel points in the detected area image; A dark band width determination module, configured to determine the width of the dark band in the projection image according to the brightness values of the pixel points in the detected area image; The dark band width determination module is further configured to determine the width of the dark band in the detected area image according to the brightness values of the pixel points in the detected area image; determine the width of the dark band in the projection image according to the width of the dark band in the detected area image; wherein, when the number of detected area images is one, use the width of the dark band in the detected area image as the width of the dark band in the projection image; when the number of detected area images is at least two, use the maximum value of the widths of the dark bands in all detected area images as the width of the dark band in the projection image; Or, The device includes: A memory, configured to store an executable computer program; A processor, configured to execute a method for detecting a dark band in a projected image according to any one of claims 1-10 under the control of the executable computer program.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that can be read and executed by a computer. The computer program is configured to execute a method for detecting a dark band in a projected image according to any one of claims 1-10 when being read and run by the computer.

Images