Student-side camera module developing and testing device in oral medicine multimedia teaching

Abstract

The utility model discloses a student-side camera module developing and testing device in oral medicine multimedia teaching, a linear slide rail is fixed on a base plate, a camera module support and a depth-of-field measuring jig support are respectively and slidably installed on the linear slide rail, and a graduated scale is arranged on the base plate or the linear slide rail. A camera module to be tested is installed on the camera module support, the depth-of-field measuring jig is installed on the depth-of-field measuring jig support, and the first positioning device and the second positioning device can position the camera module support and the depth-of-field measuring jig support on the linear sliding rail respectively. A plurality of step surfaces are formed on one side, facing the tested camera module, of the depth-of-field measurement jig, the cross sectional area of each step surface is synchronously increased along with step-by-step increase of the distance from the step surface to the camera module, and the camera module transmits an image shot by the depth-of-field measurement jig to the display in real time for display. According to the utility model, whether the camera module meets the use requirements of students can be rapidly tested and judged.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of oral medicine teaching equipment, in particular to a kind of oral medicine multimedia teaching student end camera module development test device. BACKGROUND

[0002] In the multimedia teaching of oral medicine, it is very common to use camera to shoot the operation process of teacher or student in the mouth of artificial head model. The traditional teaching camera is usually loaded in the oral shadowless lamp, because the installation space is spacious, and the oral shadowless lamp is usually far away from the patient's mouth, generally more than 70 cm, so the camera requires more than 20 times zoom, optical image stabilization, automatic focusing function. This leads to large camera size, high teaching cost, and generally only the teacher end is configured. If dozens of students in a classroom are equipped with such cameras, it will cause the school to bear too heavy a burden and be difficult to achieve. Therefore, the selection of cheap and beautiful camera module for student training operation shooting becomes a problem for multimedia teaching equipment suppliers.

[0003] The camera module generally includes lens assembly, image sensor (i.e. photosensitive chip) and image processor three parts. The lens assembly includes lens, zoom mechanism, focusing mechanism, aperture mechanism and optical image stabilization mechanism. The lens is divided into two types: fixed focus lens and zoom lens.

[0004] The operation of oral medicine clinical simulation training is carried out on the artificial head model. The most easily thought is to fix the camera on the shoulder of the artificial head model through the connecting device for shooting, which requires the camera module to be small and not to reduce the image quality. Therefore, small fixed focus lens is the first choice.

[0005] Because it is shot in the process of student operation, the lens must be at a certain distance from the mouth of the artificial head model, such as more than 40 cm. In order to display clearly on the display screen, the image of the artificial head model must fill the entire screen, which requires the use of long focus lens instead of short focus lens module commonly used in monitoring industry or live industry. The longer the focal length of the lens, the smaller the depth of field of the shot image. The aperture of the lens also affects the depth of field of the image. In addition, the size of the photosensitive chip selected in the camera module also affects the depth of field of the image. Therefore, it is very important to select the focal length of the lens, the aperture and the size of the photosensitive chip in the development of the camera module for student operation shooting. Therefore, accurate determination of the parameters of the best camera module is the key to the development of the student end oral medicine multimedia teaching system.

[0006] In summary, the student end to the camera module can be simplified as a long focal length lens with optical image stabilization, auto focus, fixed aperture, small size image sensor, and image processor with control optical image stabilization, auto focus function. Among them, the focal length, aperture value, image sensor size these three hardware parameters determine the field of view, working distance, depth of field, clarity of the captured image. Because the three hardware parameter combination of the camera module that fully meets the requirements is not easy to find in the current market, therefore, this kind of camera module needs to be customized by the manufacturer, on this basis, increase the optical image stabilization, auto focus function, so a camera module suitable for student end can be developed.

[0007] At present, the cheap student end camera on the market, the picture often is satisfied with the shooting range, but the depth of field is not satisfied; the depth of field is satisfied, the shooting range is not satisfied; the shooting range and the depth of field are satisfied, but the working distance is too close to the teeth, which hinders the operation of the student. There is also the use of too small photosensitive chip, resulting in a lot of picture noise. This is because the selection of each component on the camera module and the accurate test of the parameters are not realized.

[0008] In addition, although there is optical software, which can calculate the hardware parameters of the camera module according to the foregoing requirements in theory, but in practical application, the camera modules produced by different manufacturers with the same parameters will also lead to different test results. Therefore, as the application manufacturer of the camera module, it is necessary to have a device suitable for the application scene for detecting the depth of field, shooting range and working distance of the camera. Content of the utility model

[0009] In order to make up for the above shortcomings, the utility model provides a kind of student end camera module development test device in stomatology multimedia teaching, adopt this student end camera module development test device in stomatology multimedia teaching can test the depth of field, shooting range and working distance of camera module, it is favorable to guarantee that the camera module developed meets the needs of student end camera.

[0010] The utility model discloses a student end camera module development test device in oral medicine multimedia teaching, including bottom plate, linear slide, camera module support, depth of field measuring tool, depth of field measuring tool support, first positioning device and second positioning device and display, the linear slide fixed mounting is in the bottom plate, and camera module support and depth of field measuring tool support can be installed on the linear slide along the sliding of linear slide respectively, be equipped with the scale rule of the mark size along the linear slide length direction arrangement on the bottom plate or linear slide, the camera module of being tested can be fixedly installed on the camera module support, and the depth of field measuring tool can be fixedly installed on the depth of field measuring tool support, first positioning device can stop positioning on the linear slide with camera module support, and second positioning device can stop positioning on the linear slide with depth of field measuring tool support, the depth of field measuring tool forms with several step surfaces to the side of the camera module of being tested, and the distance of each step surface to the camera module of being tested gradually increases, and the cross section area of each step surface also gradually increases, and the camera module of being tested can be imaged to the depth of field measuring tool, the display communicates with the camera module of being tested through wired or wireless mode, and the camera module of being tested transfers the image of shooting to the display in real time and displays.

[0011] As a further improvement of the utility model, the levels of the depth of field measuring tool are spliced to form a four-pyramid structure, the tip of the four-pyramid structure faces the camera module under test, and a test reference surface vertically extends on the tip surface, the bottom surface of the four-pyramid structure is fixedly connected with the depth of field measuring tool support, the direction of the depth of field measuring tool facing the camera module under test is the front direction, and the four-pyramid structure forms upper step surfaces, lower step surfaces, left step surfaces and right step surfaces arranged in levels between the tip and the bottom surface.

[0012] As a further improvement of the utility model, the left step surfaces and the right step surfaces of the four-pyramid structure are symmetrically arranged, and the upper step surfaces and the lower step surfaces of the four-pyramid structure are symmetrically arranged.

[0013] As a further improvement of the utility model, the left step surfaces, the right step surfaces, the upper step surfaces and the lower step surfaces of the depth of field measuring tool are arranged at equal distances in the front-rear direction, and the distance between the first-level left step surface and the right step surface at the front end of the depth of field measuring tool and the test reference surface is different from the distance between the first-level upper step surface and the lower step surface at the front end of the depth of field measuring tool and the test reference surface.

[0014] As a further improvement of the present application, the four-prism table structure of the depth of field measuring tool is hollowed out to form a hollow structure, the bottom surface of the four-prism table structure is connected to the side wall of the four-prism table structure by a linear, cross-shaped or rice-shaped rib, the first nut is arranged at the central position of the rib on the bottom surface of the four-prism table structure, the first through hole extending in the vertical direction is arranged on the upper end side wall of the depth of field measuring tool support, and the first adjusting bolt is further arranged, the diameter of the stud of the first adjusting bolt is smaller than the diameter of the first through hole, the first adjusting bolt can be screwed with the first nut through the first through hole, the first adjusting bolt is locked to fix and position the depth of field measuring tool on the depth of field measuring tool support, and the position of the depth of field measuring tool can be adjusted by loosening the first adjusting bolt.

[0015] As a further improvement of the present application, the distance mark from the step surface to the test reference surface and the length size mark of each step surface are arranged on each step surface of the depth of field measuring tool.

[0016] As a further improvement of the present application, the camera module support includes a camera module mounting shell and a support frame, the camera module to be tested can be fixed and accommodated in the camera module mounting shell, the second nut is arranged on the lower side surface of the camera module mounting shell, the horizontal support plate is formed on the upper end of the support frame, the second through hole is arranged on the horizontal support plate, and the second adjusting bolt is further arranged, the diameter of the stud of the second adjusting bolt is smaller than the diameter of the second through hole, the second adjusting bolt can be screwed with the second nut through the second through hole, the second adjusting bolt is locked to fix and position the camera module mounting shell on the horizontal support plate of the support frame, and the position of the camera module mounting shell can be adjusted by loosening the second adjusting bolt.

[0017] As a further improvement of the present application, the light-sensitive chip scale is further arranged on the camera module mounting shell, and the light-sensitive chip scale is aligned with the surface of the light-sensitive chip of the camera module mounted in the camera module mounting shell.

[0018] As a further improvement of the present application, the bottom plate is provided with a forward scale and a reverse scale on both sides of the linear slide rail, the scale starting point of the forward scale is located at the front end of the linear slide rail, and the scale starting point of the reverse scale is located at the rear end of the linear slide rail.

[0019] As a further improvement of the utility model, the first sliding table and the second sliding table are arranged on the linear guide rail and can slide along the linear guide rail, the first positioning device and the second positioning device are respectively a third adjusting bolt and a fourth adjusting bolt which are movably screwed on the side walls of the first sliding table and the second sliding table, the ends of the third adjusting bolt and the fourth adjusting bolt can abut against the side walls of the linear guide rail, thereby the first sliding table and the second sliding table are positioned by the linear guide rail, the camera module support and the depth of field measuring jig support are respectively fixedly installed on the first sliding table and the second sliding table, the second sliding table is further provided with a depth of field measuring scale, the 0 scale line of the depth of field measuring scale is aligned with the test reference surface of the depth of field measuring jig, and the scales of the depth of field measuring scale are one-to-one corresponding to the stepped surfaces of the depth of field measuring jig.

[0020] The utility model discloses the beneficial effect is: the utility model can test the range of depth of field, field of view, definition and distortion degree when shooting under the condition of different lens focal length, different aperture size, different working distance of lens module, the depth of field measuring jig designed in the utility model is the pyramid type hard material piece of four prismatic table structure, and the stepped surfaces of different starting points are respectively arranged on the upper, lower, left and right four inclined surfaces of the four prismatic table structure, the depth of field measuring jig makes the depth of field resolution effectively improve, and will not be blocked, ensures the test accuracy, the utility model discloses the depth of field measuring jig tip plane forms test reference surface, when testing, the test reference surface is very easy to be identified on the display picture and be adjusted to the picture center, when the depth of field measuring jig is tested by translation, with the shortening of the shooting distance, even if the test reference surface is placed very big on the display picture, can also focus according to the definition of the edge of the test reference surface and the definition of 0 scale mark on its surface, which is equivalent to the scene of shooting single tooth in the simulation clinical training, realizes high simulation test, and ensures the test result accuracy, the scale value mark on each stepped surface of the depth of field measuring jig is the value printed on the hard material, and the font edge is very clear, and focusing and reading are convenient, and it is also convenient to accurately judge whether the camera assembly meets the requirements, the utility model discloses the whole structure is simple, and the test is convenient, and the test precision is high, is favorable to the quick test and the judgment whether the camera module meets the student end use demand. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the first perspective drawing of the utility model;

[0022] Figure 2 It is the second perspective drawing of the utility model;

[0023] Figure 3 It is the third perspective drawing of the utility model;

[0024] Figure 4 It is the fourth perspective drawing of the utility model;

[0025] Figure 5 This is the front view of the present invention;

[0026] Figure 6 for Figure 5 Enlarged view of section A in the middle;

[0027] Figure 7 for Figure 5 Enlarged view of section B;

[0028] Figure 8 This is a top view of the present invention;

[0029] Figure 9 for Figure 8 Enlarged view of section C;

[0030] Figure 10 for Figure 8 Enlarged view of section D in the middle;

[0031] Figure 11 This is a bottom view of the present invention;

[0032] Figure 12 This is the left view of the present invention;

[0033] Figure 13 This is the right view of the present invention;

[0034] Figure 14 This is a first perspective view of the depth-of-field measuring fixture of this utility model;

[0035] Figure 15 This is a second perspective view of the depth-of-field measuring fixture of this utility model;

[0036] Figure 16 This is the front view of the depth-of-field measuring fixture of this utility model;

[0037] Figure 17 This is a bottom view of the depth-of-field measuring fixture of this utility model;

[0038] Figure 18 This is a right view of the depth-of-field measuring fixture of this utility model;

[0039] Figure 19 This is a rear view of the depth-of-field measuring fixture of this utility model. Detailed Implementation

[0040] Example: A test device for developing a student-side camera module in a multimedia teaching environment for oral medicine includes a base plate 1, a linear slide rail 2, a camera module 5 bracket, a depth measuring fixture 3, a depth measuring fixture bracket 4, a first positioning device, a second positioning device, and a display. The linear slide rail 2 is fixedly mounted on the base plate 1. The camera module 5 bracket and the depth measuring fixture bracket 4 are respectively slidably mounted on the linear slide rail 2. The base plate 1 or the linear slide rail 2 is provided with scales marked with dimensions arranged along the length of the linear slide rail 2. The camera module 5 to be tested can be fixedly mounted on the camera module 5 bracket, and the depth measuring fixture 3 can be fixedly mounted on the depth measuring fixture. On the bracket 4, the first positioning device can stop and position the camera module 5 bracket on the linear slide rail 2, and the second positioning device can stop and position the depth measuring fixture bracket 4 on the linear slide rail 2. The depth measuring fixture 3 has several stepped surfaces on the side facing the camera module 5 under test. The distance from each stepped surface to the camera module 5 under test increases step by step, and the cross-sectional area of ​​each stepped surface also increases step by step. The camera module 5 under test can capture images of the depth measuring fixture 3. The display communicates with the camera module 5 under test via wired or wireless means, and the camera module 5 under test transmits the captured images to the display in real time for display.

[0041] The depth-of-field measuring fixture bracket 4 and the camera module bracket 5 can be slidably mounted on the same long linear slide rail 2, which is fixed to a long base plate 1. By sliding the depth-of-field measuring fixture bracket 4 and the camera module bracket 5, their positions and the distance between them can be changed.

[0042] The guide rail length allows for testing of camera modules within an 850mm working range, which is sufficient for clinical simulation training camera range for students in oral medicine multimedia teaching.

[0043] The depth measurement fixture 3 is a key component of this device. The depth measurement fixture 3 of this application adopts a stepped structure with an area that increases with the distance, which can ensure that the depth resolution is effectively improved and will not be obstructed.

[0044] During testing, the assembled camera module 5 is mounted on the camera module 5 bracket. The camera module 5 is then positioned at a fixed location. The depth-of-field measuring fixture bracket 4 is slid horizontally to change the distance between the depth-of-field measuring fixture 3 and the camera module 5. Simultaneously, the camera module 5 captures an image of the depth-of-field measuring fixture 3. The camera module 5 can also be refocused during image capture. By observing the captured image on the monitor and comparing it to the scale on a ruler, the camera's performance can be tested. The depth-of-field measuring fixture 3 of this application can not only test the depth of field of different focal length lenses under different apertures, shooting distances, and sensor sizes, but also test the field of view under these different conditions, i.e., the height and width of the subject displayed on the monitor screen.

[0045] The depth-of-field measuring fixture 3 is assembled into a truncated pyramid structure with each step. The tip of the truncated pyramid structure faces the camera module 5 under test, and its tip surface forms a test reference surface 31 extending vertically. The bottom surface of the truncated pyramid structure is fixedly connected to the depth-of-field measuring fixture support 4. The direction of the depth-of-field measuring fixture 3 towards the camera module 5 under test is defined as the front. The truncated pyramid structure forms an upper step surface 32, a lower step surface 33, a left step surface 34, and a right step surface 35 arranged in succession between the tip and the bottom surface.

[0046] The depth-of-field measuring fixture 3 adopts a pyramid-shaped frustum structure. Its four triangular facets (left, right, top, and bottom) each have steps of uniform height. Its top surface is a small square plane, which is designated as the test reference plane 31 (0 plane). The depth-of-field measuring fixture 3 is mounted with the 0 plane facing the camera, and the center of this 0 plane is coaxial with the lens's central axis.

[0047] The depth-of-field measuring fixture 3 is a pyramid-shaped frustum structure made of rigid material. Its top, bottom, left, and right triangular inclined surfaces all have stepped surfaces, which improves depth-of-field resolution and prevents obstruction. Compared to traditional depth-of-field test cards that use folding to form inclined surfaces, the stepped surfaces of this depth-of-field measuring fixture 3 do not deform, making focusing convenient and accurate, and providing high precision in determining the depth-of-field range.

[0048] The depth-of-field measuring fixture 3 has a small square plane formed at the top center. This small plane serves as the test reference plane 31 and is easily identifiable and centered on the display screen. As the shooting distance decreases, this small plane will be magnified significantly on the display screen after focusing. We can still focus based on the sharpness of the edges of this small plane and the sharpness of the 0 mark, which is equivalent to simulating the scene of photographing a single tooth during clinical training.

[0049] The left step surface 34 and the right step surface 35 of the truncated pyramid structure are symmetrically arranged, and the upper step surface 32 and the lower step surface 33 of the truncated pyramid structure are symmetrically arranged, or they can be asymmetrically arranged, depending on the needs.

[0050] The left step surface 34, right step surface 35, upper step surface 32, and lower step surface 33 of the depth measuring fixture 3 are arranged at equal distances along the front-back direction. The distance between the first-level left step surface 34 and right step surface 35 at the foremost end of the depth measuring fixture 3 and the test reference surface 31 is different from the distance between the first-level upper step surface 32 and lower step surface 33 at the foremost end of the depth measuring fixture 3 and the test reference surface 31.

[0051] Because the starting points of a series of step surfaces in the left-right and up-down directions are different, that is, the distances between the step surface and the nearest 0 surface are different, the difference in the up-down direction is 2.5mm (for example), and the difference in the left-right direction is 5mm. However, the subsequent spacing between adjacent step surfaces is 5mm (for example). Therefore, the step surfaces in the left-right and up-down directions are staggered. Thus, the distances of the left step surface and the right step surface 35 relative to the foremost (top) 0 surface are 5mm, 10mm, 15mm... respectively, and the distances of the upper step surface and the lower step surface 33 relative to the foremost (top) 0 surface are 2.5mm, 7.5mm, 12.5mm... respectively. Thus, the resolution of the depth measurement is 2.5mm (for example).

[0052] A preferred embodiment is as follows: The bottom surface of the depth-of-field measuring fixture is a square with a side length of 110mm. Based on the typical 4:3 aspect ratio of the image sensor and display, the width and height of the subject filling the entire frame can reach 147mm and 110mm respectively. 147mm is equivalent to the average human face width, and 110mm is equivalent to the average human jawbone width. At this working distance, this field of view is very suitable for shooting in the most common multimedia clinical simulation teaching and training in oral medicine. The central test reference surface (0 surface) at the top of the depth-of-field measuring fixture is a square with a side length of 5mm. This size facilitates coaxial alignment between the fixture and the camera module lens. 3D-printed intaglio lettering of the corresponding size on this plane is easier to distinguish and focus on. The depth-of-field measuring fixture is positioned vertically and horizontally... The triangular inclined planes are symmetrical, and the left and right triangular inclined planes are symmetrical. Each of the four triangular inclined planes has a stepped surface with a height of 5mm at equal intervals. Because the step surface of the upper and lower triangular inclined planes that is closest to the 0 face is 2.5mm away from the 0 face, and the step surface of the left and right triangular inclined planes that is closest to the 0 face is 5mm away from the 0 face, the stepped surfaces on the upper and lower and left and right triangular inclined planes are arranged in an alternating pattern at equal intervals. The distances between the stepped surfaces and the 0 face in the upper direction are 2.5mm, 7.5mm, 12.5mm... respectively, and the distances between the stepped surfaces and the 0 face in the left and right directions are 5mm, 10mm, 15mm... respectively. Thus, the depth of field resolution is 2.5mm. The width of each step of the depth of field measuring fixture is designed to be 3.5mm. On a plane of this size, the corresponding sized engraved text is easier to distinguish clearly when 3D printed, thus making it easier to focus.

[0053] The depth-of-field measuring fixture 3 has a hollowed-out frustum structure, forming a shell-like structure. The bottom surface of the frustum structure is connected to the side wall of the frustum structure by straight, cross, or star-shaped ribs 36. A first nut 37 is provided at the center of the ribs 36 on the bottom surface of the frustum structure. A first through hole extending vertically is provided on the upper side wall of the depth-of-field measuring fixture support 4, and a first adjusting bolt 41 is also provided. The diameter of the stud of the first adjusting bolt 41 is smaller than the diameter of the first through hole. The first adjusting bolt 41 passes through the first through hole and can be screwed to the first nut 37. Tightening the first adjusting bolt 41 can fix the depth-of-field measuring fixture 3 on the depth-of-field measuring fixture support 4, and loosening the first adjusting bolt 41 can adjust the position of the depth-of-field measuring fixture 3.

[0054] The depth measurement fixture is manufactured by 3D printing, so the dimensions of the depth measurement fixture can completely comply with the designer, unlike injection molding and die casting processes which must consider the demolding draft angle, resulting in a stepped surface, and unlike mechanical turning, which is limited by the machining tools; its internal hollow design reduces weight, and the bottom surface is reinforced with a cross-shaped rib 36. The first nut 37 is pre-embedded in the central hole of the cross-shaped rib 36 on the bottom surface for fixing on the corresponding depth measurement fixture bracket 4.

[0055] The first adjusting bolt 41 is screwed into the first nut 37 on the bottom surface of the depth measuring fixture 3 through the first through hole (large round hole) on the vertical plate of the depth measuring fixture bracket 4 for fixation. The first through hole on the vertical plate of the depth measuring fixture bracket 4 is designed to be larger than the outer diameter of the first adjusting bolt 41 so that the depth measuring fixture 3 can be adjusted left, right, up, and down to ensure that the center of its 0 plane is located in the center of the display screen. The depth measuring fixture 3 can also be rotated to ensure that each step surface is parallel and perpendicular to the display screen. This can also be used to test whether there is distortion at the edge of the image output by the camera module 5.

[0056] Each step surface of the depth-of-field measuring fixture 3 is marked with a distance mark 38 from the step surface to the test reference surface and a length mark 39 for each step surface.

[0057] These distance values ​​are clearly engraved in the center of the step surface (for example) so that they can be clearly identified in focus;

[0058] like Figure 14 As shown, the distance from the step surface to the test reference surface 31 (0 surface) is indicated by a ** scale on the step surface of the depth-of-field measuring fixture 3. The test reference surface 31 (0 surface) is the 0-position focusing surface, and the scale on it is represented by "0". The surface mark on the upper step surface 32 and the lower step surface 33, which are closest to the test reference surface 31 (0 surface), is "2.5", indicating that their distance from the 0 surface is 2.5mm. The subsequent step interval distances are all 5, namely 7.5, 12.5, 17.5mm... The surface mark on the left step surface 34 and the right step surface 35, which are closest to the test reference surface 31 (0 surface), is "5", indicating that their distance from the 0 surface is 5mm. The subsequent step interval distances are all 5, namely 10, 15, 20mm... The height difference between adjacent step surfaces in two directions is 2.5mm, which is the minimum resolution of this depth-of-field measuring fixture 3.

[0059] like Figure 16 As shown, the depth-of-field measuring fixture 3 uses "-**-" (** is a numerical value) to indicate the length of the step surface, so as to identify the length and width of the captured image, i.e., the field of view.

[0060] The scale values ​​on the center of the left, right, top, and bottom sides of the fixture are symmetrical, which can indicate the position of the focus plane and the depth of field.

[0061] The distance markers representing the distance from the step surface to the test reference surface are all arranged in the center of the triangular face. When the center of the image is 0, these scales are exactly arranged on the horizontal and vertical center lines of the image, which is beneficial for the depth measurement fixture to be positioned correctly.

[0062] The dimensions of this fixture are designed according to the field of vision requirements during oral treatment. For example, a width of 110mm is the average width of the human mandible. Using a 4:3 aspect ratio, the camera's field of vision is set at 147mm:110mm. This 147mm is exactly the average width of the human face, which perfectly meets the needs of multimedia teaching video recording in oral treatment.

[0063] For example, when the field of vision exactly fills the width of "-82-", this field of vision is roughly the width of a person's mouth when showing the entire dentition with an mouth opener during oral treatment; the width of "-54-" is roughly the width of a person's mouth when they normally smile with their teeth showing, exposing the 8 upper teeth.

[0064] The scale values ​​on each step surface of the depth-of-field measuring fixture 3 are printed on a rigid material, with very clear font edges, making focusing and reading convenient. Compared to traditional depth-of-field test cards with black and white printed fonts on the inclined surface, focusing and reading are more convenient and accurate.

[0065] The camera module 5 bracket includes a camera module mounting shell 6 and a support frame 7. The camera module 5 under test can be fixedly housed in the camera module mounting shell 6. A second nut is provided on the lower side of the camera module mounting shell 6. A horizontal support plate 71 is formed on the upper end of the support frame 7. A second through hole and a second adjusting bolt 72 are provided on the horizontal support plate 71. The stud diameter of the second adjusting bolt 72 is smaller than the diameter of the second through hole. The second adjusting bolt 72 passes through the second through hole and can be screwed to the second nut. Tightening the second adjusting bolt 72 can fix the camera module mounting shell 6 on the horizontal support plate 71 of the support frame 7. Loosening the second adjusting bolt 72 can adjust the position of the camera module mounting shell 6.

[0066] The camera module 5 to be tested is installed in the camera module mounting housing 6, forming a camera. The fixed-focus lens on the camera module 5 is mounted in front of the image sensor inside the camera module 5 via a threaded connector, and focusing is achieved by rotating the fixed-focus lens. A mechanical aperture of a specified aperture is installed between the fixed-focus lens and the image sensor. Different camera specifications are formed by combining fixed-focus lenses with different focal lengths and mechanical apertures of different apertures for testing.

[0067] The camera module mounting shell 6 is fixed to the support frame 7 by hand-tightening the second adjusting bolt 72. The second through hole is designed to be larger than the outer diameter of the second adjusting bolt 72 so that the position of the camera module mounting shell 6 on the support frame 7 can be adjusted back and forth and left and right to ensure that the plane where the photosensitive chip is located is aligned with the scale line on the scale and to adjust the camera axis.

[0068] The camera module bracket 5 and the depth measurement fixture bracket 4 are both made of sheet metal bending, which makes them very easy to manufacture.

[0069] The camera module mounting housing 6 is also provided with photosensitive chip scale lines 61, which are aligned with the surface of the photosensitive chip of the camera module 5 mounted inside the camera module mounting housing 6. Figure 9 As shown, a vertically extending scribe line is provided on one side of the camera module mounting housing 6 to form a photosensitive chip scribe line 61. This photosensitive chip scribe line 61 coincides with the photosensitive chip surface on the camera module 5 inside the camera module mounting housing 6. Ideally, this photosensitive chip scribe line 61 also coincides with the leading edge of the support bracket 7 and the leading edge of the slider on the linear slide rail 2. The leading edge of the slider on the linear slide rail 2 coincides with the 0 mark on the scale on the base plate 1. This makes it easier to see whether the photosensitive chip scribe line 61 coincides with the 0 mark on the scale on the base plate 1, and thus makes it easier to read the working distance. In this way, the shooting distance we measure later refers to the distance from the photosensitive chip to the step surface designated for focusing on the depth-of-field measuring fixture 3. In this application, the position of the photosensitive chip in the camera module is indicated by a scribe line on the camera module mounting housing 6, and the distance from the photosensitive chip to the focusing plane is calculated as the working distance. This ensures that even when changing to different focal length lenses or when moving the lens to focus, the position of this reference starting point will not change, thus guaranteeing the accuracy of the working distance used for measurement.

[0070] The base plate 1 is provided with a forward scale 11 and a reverse scale 12 on both sides of the linear slide rail 2. The starting point of the scale of the forward scale 11 is located at the front end of the linear slide rail 2, and the starting point of the scale of the reverse scale 12 is located at the rear end of the linear slide rail 2.

[0071] On the base plate 1, a forward scale 11 and a reverse scale 12 are respectively attached to both sides of the linear slide rail 2. The forward scale 11 and the reverse scale 12 are attached in opposite directions to each other. The purpose is to allow for the calculation of the shooting distance from both the camera and the depth-of-field measuring fixture 3. Figure 10 As shown, the 0-face of the depth-of-field measuring fixture 3 is aligned with the 50-degree mark on the positive scale 11, indicating that the distance between the 0-face of the depth-of-field measuring fixture 3 and the photosensitive chip is 50cm.

[0072] The linear slide rail 2 is equipped with a first slide table 21 and a second slide table 22 that can slide along the extension direction of the linear guide rail. The first positioning device and the second positioning device are respectively a third adjusting bolt 8 and a fourth adjusting bolt 9 that are movably screwed onto the side walls of the first slide table 21 and the second slide table 22. The ends of the third adjusting bolt 8 and the fourth adjusting bolt 9 can press tightly against the side wall of the linear guide rail, thereby stopping and positioning the first slide table 21 and the second slide table 22 with the linear guide rail. The camera module 5 bracket and the depth measuring fixture bracket 4 are respectively fixedly installed on the first slide table 21 and the second slide table 22. The side wall of the second slide table 22 is also provided with a depth measuring scale 221. The 0 mark of the depth measuring scale 221 is aligned with the test reference surface 31 of the depth measuring fixture 3. The scale of the depth measuring scale 221 corresponds one-to-one with each step surface on the depth measuring fixture 3.

[0073] The support frame 7 of the camera module 5 bracket is fixed to the first slide 21 with screws, and the depth-of-field measuring fixture bracket 4 is fixed to the second slide 22 with screws. The first slide 21 and the second slide 22 are mounted on the same slide rail and can slide along the slide rail. A depth-of-field measuring scale 221 is attached to the side of the second slide 22. The 0 line of the depth-of-field measuring scale 221 coincides with the 0 surface of the depth-of-field measuring fixture 3. This depth-of-field measuring scale 221 is also marked with graduations at 2.5mm intervals, which corresponds exactly to the distance of each step surface on the depth-of-field measuring fixture 3 from the 0 line.

[0074] The depth-of-field measuring scale 221 on the side of the second slider under the aforementioned depth-of-field measuring fixture 3 coincides with the 0-position plane on the top of the fixture 3. If this 0-position plane is used as the focusing plane, the scale value indicated by the scale on the base plate 1 corresponding to the leading edge of the second slider is the working distance at that time. Using the 0-position plane of the depth-of-field measuring fixture 3 as the focusing plane has a drawback, because the depth-of-field range includes the foreground depth-of-field distance in front of the focusing plane and the background depth-of-field distance behind the focusing plane. If the 0-position plane of the depth-of-field measuring fixture 3 is used as the diagonal plane, we can only obtain the background depth-of-field distance. Therefore, it is necessary to move the focusing plane to the rear step surface, and try to move it to a position on a step surface in the center of the front-to-back direction of the fixture. In this way, counting forward and backward steps can calculate both the foreground depth-of-field distance (depth-of-field distance is also called depth-of-field range) and the background depth-of-field distance. The scale value on the step surface coincides with the same value on the scale on the side of the slider below. The scale value indicated on the bottom scale is the working distance from the photosensitive chip to the focusing plane. Each step surface on the depth-of-field measuring fixture 3 can be used as a focusing positioning plane, and can be selected according to actual needs.

[0075] The second slide 22 below the depth-of-field measuring fixture 3 has a depth-of-field measuring scale 221 attached to its side, which is completely aligned and overlapped with the depth-of-field distance scale on the step surface of the depth-of-field measuring fixture 3. This allows the working distance to be easily read even if the focusing surface is set on the step surface at the center position before and after the depth-of-field measuring fixture 3.

Claims

1. A student end camera module development test device in oral medicine multimedia teaching, characterized in that: The application relates to a depth-of-field measuring tool, which comprises a base plate (1), a linear slide rail (2), a camera module support, a depth-of-field measuring tool (3), a depth-of-field measuring tool support (4), a first positioning device, a second positioning device and a display, the linear slide rail is fixedly installed on the base plate, the camera module support and the depth-of-field measuring tool support are respectively slidably installed on the linear slide rail, a scale ruler with marked sizes is arranged on the base plate or the linear slide rail along the length direction of the linear slide rail, a camera module (5) to be tested can be fixedly installed on the camera module support, the depth-of-field measuring tool can be fixedly installed on the depth-of-field measuring tool support, the first positioning device can stop and position the camera module support on the linear slide rail, the second positioning device can stop and position the depth-of-field measuring tool support on the linear slide rail, the depth-of-field measuring tool is formed with a plurality of stepped surfaces towards the side of the camera module to be tested, the distance between each stepped surface and the camera module to be tested gradually increases, and the cross-sectional area of each stepped surface also gradually increases, the camera module to be tested can image the depth-of-field measuring tool, and the display communicates with the camera module to be tested in a wired or wireless mode, and the camera module to be tested transmits the imaged image to the display in real time for display.

2. The student end camera module development test device for multimedia teaching of stomatology according to claim 1, characterized in that: The stepped surfaces of the depth-of-field measuring tool are spliced to form a quadrangular pyramid structure, the tip of the quadrangular pyramid structure faces the camera module to be tested, and a vertical test reference surface (31) is formed on the tip surface of the quadrangular pyramid structure, the bottom surface of the quadrangular pyramid structure is fixedly connected with the depth-of-field measuring tool support, the direction of the depth-of-field measuring tool towards the camera module to be tested is the front direction, and the quadrangular pyramid structure is located between the tip and the bottom surface to form a step-by-step arranged upper stepped surface (32), a lower stepped surface (33), a left stepped surface (34) and a right stepped surface (35).

3. The student end camera module development test device for multimedia teaching of stomatology according to claim 2, characterized in that: The left stepped surface and the right stepped surface of the quadrangular pyramid structure are symmetrically arranged, and the upper stepped surface and the lower stepped surface of the quadrangular pyramid structure are symmetrically arranged.

4. The student end camera module development test device for multimedia teaching of stomatology according to claim 3, characterized in that: The left stepped surface, the right stepped surface, the upper stepped surface and the lower stepped surface of the depth-of-field measuring tool are equidistantly arranged along the front-rear direction, and the distance between the first-level left stepped surface and the right stepped surface at the front end of the depth-of-field measuring tool and the test reference surface is different from the distance between the first-level upper stepped surface and the lower stepped surface at the front end of the depth-of-field measuring tool and the test reference surface.

5. The student end camera module development test device for multimedia teaching of stomatology according to claim 4, characterized in that: The quadrangular pyramid structure of the depth-of-field measuring tool is hollow to form a hollow shell structure, the bottom surface of the quadrangular pyramid structure is connected with the side wall of the quadrangular pyramid structure through a linear type, a cross type or a rice type rib (36), the first nut (37) is arranged at the central position of the rib on the bottom surface of the quadrangular pyramid structure, the first threaded hole extending in the vertical direction is arranged on the upper end side wall of the depth-of-field measuring tool support, the first adjusting bolt (41) is further arranged, the diameter of the stud of the first adjusting bolt is smaller than the diameter of the first threaded hole, the first adjusting bolt passes through the first threaded hole and is screwed with the first nut, the first adjusting bolt is locked to fix and position the depth-of-field measuring tool on the depth-of-field measuring tool support, and the first adjusting bolt is loosened to adjust the position of the depth-of-field measuring tool.

6. The student end camera module development testing device for multimedia teaching of stomatology according to claim 2, characterized in that: The distance mark (38) and the length mark (39) are arranged on each step surface of the depth of field measuring tool.

7. The student end camera module development testing device for multimedia teaching of stomatology according to claim 1, characterized in that: The camera module support includes a camera module mounting shell (6) and a support frame (7), the camera module to be tested can be fixed and accommodated in the camera module mounting shell, the second nut is arranged on the lower side of the camera module mounting shell, the horizontal support plate (71) is formed on the upper end of the support frame, the second through hole is arranged on the horizontal support plate, and the second adjusting bolt (72) is further arranged, the stud diameter of the second adjusting bolt is smaller than the diameter of the second through hole, the second adjusting bolt can be screwed with the second nut through the second through hole, the second adjusting bolt can be locked to fix and position the camera module mounting shell on the horizontal support plate of the support frame, and the second adjusting bolt can be loosened to adjust the position of the camera module mounting shell.

8. The student end camera module development test device for multimedia teaching of stomatology of claim 7, characterized in that: The camera module mounting shell is further provided with a photosensitive chip scale line (61), and the photosensitive chip scale line is aligned with the surface of the photosensitive chip of the camera module mounted in the camera module mounting shell.

9. The student end camera module development testing device for multimedia teaching of stomatology according to claim 1 or 7, characterized in that: The bottom plate is provided with a forward scale (11) and a reverse scale (12) on both sides of the linear guide rail, and the starting point of the scale of the forward scale is located at the front end of the linear guide rail, and the starting point of the scale of the reverse scale is located at the rear end of the linear guide rail.

10. The student end camera module development testing device for multimedia teaching of stomatology according to claim 2, characterized in that: The first slide table (21) and the second slide table (22) are arranged on the linear guide rail and can slide along the extension direction of the linear guide rail, the first positioning device and the second positioning device are respectively the third adjusting bolt (8) and the fourth adjusting bolt (9) movably screwed on the side walls of the first slide table and the second slide table, the end portions of the third adjusting bolt and the fourth adjusting bolt can abut against the side walls of the linear guide rail, so that the first slide table and the second slide table are positioned and stopped by the linear guide rail, the camera module support and the depth of field measuring tool support are respectively fixed and mounted on the first slide table and the second slide table, the depth of field measuring scale (221) is further arranged on the side wall of the second slide table, the 0 scale line of the depth of field measuring scale is aligned with the test reference surface of the depth of field measuring tool, and the scale of the depth of field measuring scale corresponds to each step surface of the depth of field measuring tool.

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