Oral cavity image plate scanner

Abstract

The invention relates to an oral cavity image plate scanner, which comprises a laser, a diaphragm, a galvanometer, a plane mirror and an IP plate, and also discloses a working method of the oral cavity image plate scanner, and the working method comprises the following steps: the laser emits light to generate an elliptical light spot; after the elliptical light spot passes through a diaphragm which rotates anticlockwise and circularly in a fixed plane perpendicular to the light beam propagation direction, the shape of the elliptical light spot is restrained to be a circular light spot; the newly formed circular light spot is reflected by the galvanometer; a reflecting lens of the galvanometer circularly moves from left to right under the control of a driving signal; the rotation of the diaphragm and the circulating motion of the galvanometer lens are synchronously matched through a preset initial relative position, and it is ensured that a circular light spot reflected by the galvanometer is reflected by the plane mirror and then is scanned and irradiated to an IP plate, and an IP plate signal is excited. The light spot formed by scanning on the IP board is ensured to be a round light spot with stable size and uniform intensity distribution, signals in the IP board can be excited more intensively, the final image is better in impression, higher in contrast ratio and higher in resolution, the shape of the light spot does not need to be manually adjusted, the risk of blind eyes of workers is avoided, and the working efficiency is improved. And the working efficiency of the scanner is also improved.

Description

Technical Field

[0001] The present invention relates to an oral image plate scanner, and in particular to an oral image plate scanner applied in the field of image plate scanners. Background Art

[0002] Oral imaging plate scanner is also called indirect digital X-ray imaging technology. Its aliases include: CR, PSP scanner, dental film treasure, oral digital imaging plate scanner ETC. The main principle is to use storage phosphor imaging. It uses an imaging plate composed of phosphor crystals, that is, an IP plate to absorb X-ray information. The IP plate is sensitive to light to form a latent image, which is then scanned and converted into a digital signal that enters the computer system for image processing. It has the advantages of being easy to use, flexible, comfortable and reusable.

[0003] In practical applications, the existing laser spot cannot reach the most ideal state due to various reasons such as insufficient optical path. The laser light spot is elliptical. When the elliptical light spot is irradiated on the IP board, it will stimulate the signal in a larger area, resulting in a low signal-to-noise ratio and low resolution of the image.

[0004] The ideal light spot is circular, which requires manual adjustment. The adjustment process not only takes extra time but also requires the naked eye to observe the laser spot, which greatly increases the risk of blindness caused by the laser.

[0005] Application Contents

[0006] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the light spot emitted by the existing laser is elliptical, and manual adjustment is slow and risky.

[0007] To solve the above problems, the present invention provides an oral image plate scanner, which includes a laser, an aperture, a galvanometer, a plane mirror, and an IP plate. The working method of the oral image plate scanner includes the following steps:

[0008] S1. The laser emits light, generating an elliptical spot. After the elliptical spot passes through an aperture that rotates counterclockwise in a fixed plane perpendicular to the direction of beam propagation, its shape is constrained to a circular spot.

[0009] S2. The newly formed circular light spot is reflected by the galvanometer; the reflective lens of the galvanometer performs a circular motion from left to right under the control of the driving signal; the rotation of the aperture and the circular motion of the galvanometer lens are synchronized through the preset initial relative position to ensure;

[0010] S3. The circular light spot reflected by the galvanometer is reflected by the plane mirror and then scanned onto the IP plate. The cyclic rotation of the aperture and the cyclic motion of the galvanometer lens work together to ensure that the light spot finally scanned on the IP plate is a circular light spot with stable size and uniform intensity distribution.

[0011] The system debugging method of the oral imaging plate scanner includes the following steps:

[0012] B1: Turn on the galvanometer, aperture drive device, laser, and stepper motor; adjust the initial relative position of the aperture and galvanometer, and adjust the initial position of the overall light spot on the IP board;

[0013] B2: Send the drive signal of the galvanometer and start the diaphragm rotation to test the scanning track position of the circular light spot irradiated on the IP plate to see whether it can cover the entire IP plate and whether the light spot shape is stable;

[0014] B3: Start the scanning program. The galvanometer performs a circular motion from left to right, and the aperture continues to rotate counterclockwise. Each time the light spot scans a line, the stepper motor moves forward until the entire IP board is scanned.

[0015] B4: The stepper motor returns to its initial position.

[0016] The optical path debugging method of the oral imaging plate scanner includes the following steps:

[0017] C1: First, insert the laser into the slot and adjust the entire laser to a horizontal state;

[0018] C2: The laser spot (mainly the initial elliptical part) is then adjusted through the lens on the laser so that its waist is at a preset distance (e.g. 95mm).

[0019] C3: Add the galvanometer, diaphragm, and plane mirror to the optical path; ensure that the diaphragm is mounted on its specific rotation drive;

[0020] C4: Observe the size and shape of the light spot after the aperture (it should be close to a circle); adjust the front-to-back distance of the laser and observe / measure the shape and intensity distribution of the light spot to achieve the optimal shape and beam waist position, and then fix the laser;

[0021] C5: Simultaneously apply a drive signal to the galvanometer and start the aperture rotation drive. At this time, the dot-shaped circular light spot reflected by the galvanometer becomes a scanning light. Adjust the synchronization relationship between the rotation speed / phase of the aperture and the scanning motion of the galvanometer (fine-tuning may be required through the preset relative phase angle) until a uniformly distributed, well-shaped circular scanning light spot or scanning line is observed on the IP board.

[0022] The image processing method of the oral image plate scanner includes the following steps:

[0023] D1, 30 blank images after exposure are continuously photographed by using an X-ray machine to obtain 30 bright field images, and a mean value is obtained after mean value processing;

[0024] D2, 30 images under darkroom conditions are collected to obtain 30 blank dark field images, and a mean value is obtained after mean value processing;

[0025] D3, a target image after exposure of the object is photographed;

[0026] D4, the bright field mean value image is subtracted from the dark field mean value image to obtain a bright field calibration image, and a Mean value of the bright field calibration image is calculated;

[0027] D5, a code is used for calculation: the target image is subtracted from the dark field mean value image, and then the result is divided by the bright field correction image, and the final flat field correction image is obtained after the bias matrix is multiplied by the Mean value.

[0028] In summary, the device is provided with a diaphragm, the laser light spot is circular, the signal in the IP plate can be excited more concentratedly, the final image is better in visual perception, the contrast is higher, the resolution is higher, the shape of the light spot does not need to be adjusted manually, the risk of blindness of the staff is avoided, and the working efficiency of the scanner is improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural diagram of the scanner in the embodiment of the application;

[0030] Figure 2 It is an optical path diagram of a scanning galvanometer in the embodiment of the application;

[0031] Explanation of reference numerals in the drawing:

[0032] 1, laser; 2, diaphragm; 3, galvanometer; 4, plane mirror; 5, IP plate. DETAILED DESCRIPTION

[0033] The embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0034] Figure 1-2 A kind of oral image plate scanner is shown, including laser 1, diaphragm 2, galvanometer 3, plane mirror 4 and IP plate 5, the working method of oral image plate scanner includes the following steps:

[0035] S1, laser 1 light, generates elliptical spot; after the elliptical spot passes through a diaphragm 2 that is counterclockwise circularly rotated in a fixed plane perpendicular to the direction of light beam propagation, the shape is constrained as circular spot;

[0036] S2, the newly formed circular light spot is reflected by the galvanometer 3; the reflective lens of the galvanometer performs a circular motion from left to right under the control of the driving signal; the rotation of the aperture and the circular motion of the galvanometer lens are synchronized through the preset initial relative position to ensure;

[0037] S3, the circular light spot reflected by the galvanometer is reflected by the plane mirror 4 and then scanned onto the IP plate 5; the cyclic rotation of the aperture 2 and the cyclic motion of the galvanometer lens work together to ensure that the final light spot scanned on the IP plate 5 is a circular light spot with stable size and uniform intensity distribution.

[0038] The system debugging method of the oral imaging plate scanner includes the following steps:

[0039] B1: Turn on the galvanometer 3, the aperture drive device 2, the laser 1, and the stepper motor; adjust the initial relative position of the aperture 2 and the galvanometer 3, and adjust the initial position of the overall light spot on the IP plate 5;

[0040] B2: Send the drive signal of the galvanometer 3 and start the rotation of the aperture 2 to test the scanning track position of the circular light spot irradiated on the IP plate 5 to see whether it can cover the entire IP plate 5 and whether the light spot shape is stable;

[0041] B3: Start the scanning program. The galvanometer 3 performs a circular motion from left to right, and the aperture 2 continues to rotate counterclockwise. Each time the spot scans a line, the stepper motor moves forward until the entire IP plate 5 is scanned.

[0042] B4: The stepper motor returns to its initial position.

[0043] The above operation steps can adjust the optical power of the laser and the driving signal frequency of the galvanometer.

[0044] The optical path debugging method of the oral imaging plate scanner includes the following steps:

[0045] C1: First, insert the laser 1 into the slot and adjust the entire laser 1 to a horizontal state. Let the light emitted by the laser 1 shine on the white board for detection. Move the white board horizontally and observe whether the light spot on the white board moves up and down. If the light spot moves up and down, it means that the laser 1 is not in a horizontal state. If the light spot does not move up and down, it means that the laser 1 is in a horizontal state.

[0046] C2: Then adjust the light spot (mainly the initial elliptical part) through the lens on the laser 1 so that its waist is at 95mm. Experiments have shown that the light spot quality of our current laser is best and the waist is smallest at 95mm. In this process, we usually adjust the laser head 1 first, then move the IP plate 5 left and right to observe where the light spot is smallest. After observing the minimum, measure the distance to see if it is 95mm. Repeat the above steps several times until the measured distance is 95mm.

[0047] C3: Add galvanometer mirror 3 and plane mirror 4 to the optical path. During this process, ensure that the light spot appears at the center of galvanometer mirror 3 and plane mirror 4. Then adjust the angle of plane mirror 4 to ensure that the incident angle of the light spot on IP board 5 meets the requirements.

[0048] C4: Observe the size and shape of the light spot after passing through aperture 2 (it should be close to a circle); adjust the front-to-back distance of laser 1 and observe / measure the light spot shape and intensity distribution to achieve the optimal shape and beam waist position. Fix laser 1. In the above steps, ensure that the light spot appears at the center of the object.

[0049] C5: Simultaneously apply a drive signal to the galvanometer 3 and start the rotation drive of the aperture 2. At this time, the dot-shaped circular light spot reflected by the galvanometer 3 becomes a scanning light. Adjust the synchronization relationship between the rotation speed / phase of the aperture 2 and the scanning motion of the galvanometer 3 (may need to be fine-tuned by the preset relative phase angle) until a uniformly distributed and well-shaped circular scanning light spot or scanning line is observed on the IP board 5. The adjustment is complete.

[0050] The image processing method of the oral image plate scanner includes the following steps:

[0051] D1. Use an X-ray machine to continuously shoot 30 blank images after exposure to obtain 30 bright field images, and obtain the bright field average image after averaging.

[0052] D2. Collect 30 images in a darkroom to obtain 30 blank dark field images, and perform average processing to obtain a dark field average image;

[0053] D3, shoot the target image of the object after exposure;

[0054] D4. Subtract the dark field mean image from the bright field mean image to obtain the bright field calibration image, and calculate the Mean value of the bright field calibration image.

[0055] D5. Use code or related software to calculate: subtract the dark field mean image from the target image, divide the result by the bright field correction image, obtain the bias matrix, and then multiply it by the mean value to obtain the final flat field correction image.

[0056] After the usual calibration, the brightness of the upper and lower parts of the image is more uniform and the consistency becomes better.

[0057] In summary, by adding the aperture 2, the device makes the light spot of the laser 1 circular, which can more concentratedly excite the signal in the IP board 5, making the final image look better, with higher contrast and higher resolution. There is no need to manually adjust the shape of the light spot, which not only avoids the risk of blindness of the staff, but also improves the working efficiency of the scanner.

[0058] The image processing part of the scanner:

[0059] Because the hardware scanning method of the image needs to determine the first number of each scan to prevent the image from being misplaced or distorted, in order to solve this problem, a mask value needs to be transmitted before the formal scan each time, and the valid data of each line is after the mask value.

[0060] Solution: Determine the Mask value in the code and add a false recognition function. The presence of the flag bit helps to transform the number of valid data rows and can better help us restore the valid data to its real position. When wrapping the line, we need to determine whether the read flag bit appears a fixed number of times in a row to prevent false recognition. When the read data is a continuous flag bit, it means that a new row of valid data appears, and the subsequent data needs to be wrapped.

[0061] Specific process:

[0062] Image data scanned using CR has a certain degree of non-uniformity in the brightness output of each sensor due to natural manufacturing tolerances. Each pixel may respond differently to the same amount of light, which will result in image artifacts caused by the sensor's pixel-to-pixel sensitivity variations and optical path distortion.

[0063] Solution: Use flat-field correction to improve digital imaging quality. Correct pixel-to-pixel sensitivity and dark current variations. After flat-field calibration, image uniformity is effectively improved and some noise caused by system factors is eliminated.

[0064] In view of current actual needs, the protection scope of the above-mentioned implementation mode adopted in this application is not limited to this. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. An oral imaging plate scanner, comprising a laser (1), an aperture (2), a galvanometer (3), a plane mirror (4) and an IP plate (5), characterized in that: The working method of the oral imaging plate scanner comprises the following steps: S1, the laser (1) emits light, generating an elliptical spot; after the elliptical spot passes through an aperture (2) that rotates counterclockwise in a fixed plane perpendicular to the propagation direction of the light beam, the shape of the spot is constrained to a circular spot; S2, the newly formed circular light spot is reflected by the galvanometer (3); the reflective lens of the galvanometer (3) performs a circular motion from left to right under the control of the driving signal; the rotation of the aperture (2) and the circular motion of the galvanometer lens are synchronized through a preset initial relative position to ensure; S3, the circular light spot reflected by the galvanometer (3) is reflected by the plane mirror (4) and then scanned and irradiated onto the IP plate (5); the cyclic rotation of the aperture (2) and the cyclic movement of the galvanometer lens cooperate to ensure that the light spot finally scanned and formed on the IP plate (5) is a circular light spot with stable size and uniform intensity distribution. The system debugging method of the oral imaging plate scanner comprises the following steps: B1: Turn on the galvanometer (3), the aperture drive device, the laser (1), and the stepper motor, adjust the initial relative position of the aperture (2) and the galvanometer (3), and adjust the initial position of the overall light spot on the IP plate (5); B2: Sending a drive signal to the galvanometer (3) and starting the rotation of the aperture (2) to test the scanning track position of the circular light spot irradiated on the IP plate (5) to see whether it can cover the entire IP plate (5) and whether the light spot shape is stable; B3: Start the scanning program, the galvanometer (3) performs a circular motion from left to right, and the aperture (2) continues to rotate counterclockwise. Each time the spot scans a line, the stepper motor moves forward until the entire IP plate (5) is scanned. B4: The stepper motor returns to its initial position. The optical path debugging method of the oral imaging plate scanner comprises the following steps: C1: First, insert the laser (1) into the slot and adjust the entire laser (1) to a horizontal state; C2: Then adjust the light spot (mainly the initial elliptical part) through the lens on the laser (1) so that its waist is at 95mm; C3: Add the galvanometer (3), diaphragm (2) and plane mirror (4) to the light path; ensure that the diaphragm (2) is mounted on its specific rotation drive C4: Observe the size and shape of the light spot output after passing through the aperture (2) (should be close to a circle); adjust the front-back distance of the laser (1), and observe / measure the shape and intensity distribution of the light spot to achieve the optimal shape and beam waist position, and then fix the laser (1); C5: Simultaneously apply a drive signal to the galvanometer (3) and start the rotation drive of the aperture (2). At this time, the dot-shaped circular light spot reflected by the galvanometer (3) becomes a scanning light; adjust the synchronization relationship between the rotation speed / phase of the aperture (2) and the scanning movement of the galvanometer (3) (may need to be fine-tuned by a preset relative phase angle) until a uniformly distributed and well-shaped circular scanning light spot or scanning line is observed on the IP plate (5).

2. The oral imaging plate scanner according to claim 1, characterized in that: The image processing method of the oral image plate scanner comprises the following steps: D1. Use an X-ray machine to continuously shoot 30 blank images after exposure to obtain 30 bright field images, and obtain the bright field average image after averaging. D2. Collect 30 images in a darkroom to obtain 30 blank dark field images, and perform average processing to obtain a dark field average image; D3, shoot the target image of the object after exposure; D4. Subtract the dark field mean image from the bright field mean image to obtain the bright field calibration image, and calculate the Mean value of the bright field calibration image. D5. Use the code to calculate: subtract the dark field mean image from the target image, divide the result by the bright field correction image, obtain the bias matrix, and then multiply it by the mean value to obtain the final flat field correction image.

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