A sparse representation based white balance method and an endoscope

Abstract

The application discloses a white balance method and an endoscope based on sparse representation, which comprises white balance calibration and white balance correction, and the white balance calibration is realized through the following steps: S1, calibrating n color temperatures: under the light sources of the n color temperatures, a standard color card is shot by an imaging system to obtain the RGB response values of each color; taking the chromaticity values of the standard color card under the standard illuminant as a target, a conversion model from the camera RGB response values to the standard chromaticity values is solved through an optimization method, and is respectively recorded as M1, M2,..., Mn; S2, selecting k characteristic models from M1, M2,..., Mn, and recording as Mf1, Mf2,..., Mfk, k < n; S3, adopting an optimization method. The white balance method and the endoscope based on sparse representation can realize white balance under different color temperature light sources, and the specific embodiments are as follows: when the color temperature of the light source changes in long-term use, color deviation of the electronic endoscope can be avoided, and after the endoscope replaces the light source, the overall color can be consistent.

Description

Technical Field

[0001] This invention relates to the field of image processing technology, specifically to a white balance method based on sparse representation and an endoscope. Background Technology

[0002] Lighting conditions in daily life are diverse, and different light sources have their own color temperature (CCT) characteristics. Light sources with high color temperatures tend to have a cooler tone, while light sources with low color temperatures tend to have a warmer tone. For the same electronic imaging system, when the light source is changed, people hope that the image color of the electronic imaging system will remain as consistent as possible before and after the change of light source. After the imaging system adopts white balance technology, the influence of lighting conditions on image color can be reduced.

[0003] A simple and practical white balance method is the manual white balance method. A light source is shone onto a standard white board, the imaging system captures an image of the white board, the RGB values ​​in the image are analyzed, and correction coefficients are calculated and substituted into the imaging system to correct the image. This method is cumbersome to operate, the correction effect depends heavily on the operator's skill level, stability is difficult to guarantee, and real-time white balance correction is not possible.

[0004] The white balance method based on color temperature calculation is a real-time white balance correction method, mainly including two-stage processing: illumination source estimation and image color correction. In photography scenarios such as cameras and mobile phones, the lighting conditions are unknown, and the image processor often automatically estimates the illumination based on scene information. White balance with automatic illumination estimation is called automatic white balance. Medical endoscopes are an important tool for disease examination. In the use of endoscopes, the illumination source is often fixed. Therefore, only the illumination is estimated, and the light source information is pre-calibrated and selected when in use. However, the color temperature characteristics of the endoscope light source will change with the extension of use time. In addition, due to production limitations, different batches of illumination sources may have significant color temperature differences. In the research and development and production of endoscope systems, it is difficult to calibrate the white balance of each endoscope individually. Therefore, a technology is needed to extend and adapt the color temperature based on pre-calibrated data.

[0005] Commonly used techniques for color temperature expansion adaptation include: 1. CCT segmented interpolation. Its implementation method is to calibrate two or three groups of CCTs to obtain the corresponding correction coefficients. When in use, according to the current CCT, segmented interpolation is performed through the calibrated correction coefficients to obtain the correction coefficient under this CCT. The disadvantage of this technology is that the calibration accuracy is limited. When the difference between the CCT and the pre-calibrated CCT is large, it is difficult to accurately correct the white balance through the interpolated correction coefficient. 2. Multi-CCT calibration. Its implementation method is to calibrate a sufficient number of CCTs, store the calibrated correction coefficients, and call the correction coefficients corresponding to the CCT when in use. The disadvantage of this technology is that a large number of groups of data need to be calibrated, resulting in a large amount of data, which is difficult to meet the implementation requirements of hardware (such as FPGA).

[0006] Therefore, we propose a white balance method and an endoscope based on sparse representation to solve the problems mentioned above. Summary of the Invention

[0007] The purpose of the present invention is to provide a white balance method and an endoscope based on sparse representation to solve the problems of limited accuracy in the above background technology. When the difference between the CCT and the pre-calibrated CCT is large, it is difficult to accurately correct the white balance through the interpolated correction coefficient, and a large number of groups of data need to be calibrated, resulting in a large amount of data, which is difficult to meet the implementation requirements of hardware (such as FPGA).

[0008] To achieve the above purpose, the present invention provides the following technical solution: A white balance method based on sparse representation, including white balance calibration and white balance correction. The white balance calibration is achieved through the following steps: S1. Calibrate n color temperatures: Under the light sources of n color temperatures, the imaging system takes pictures of the standard color card to obtain the RGB response values of each color. Taking the chromaticity values of the standard color card under the standard illuminant as the target, the conversion models from the camera RGB response values to the standard chromaticity values are solved through an optimization method, denoted as M1, M2... Mn respectively; S2. Select k characteristic models from M1, M2... Mn, denoted as Mf1, Mf2... Mfk, where k < n; S3. Adopt an optimization method to represent the conversion models under n color temperatures as a linear combination of k characteristic models, expressed as formula 1: ; S4. Record the coefficients an, bn... kn in the form of a look-up table; The white balance correction is achieved through the following steps: S1. Debug and set the current light source CCT and input it into the control module; S2. The control module retrieves the corresponding representation coefficients through the CCT value; S3. Use the representation coefficients of the previous step to calculate the white balance correction model using formula 1; S4. The control module transfers the correction model parameters of the previous step to the processing module to perform white balance correction on the input image.

[0009] The endoscope also includes an endoscope body, with a handle and an extension tube respectively located at the left and right ends of the endoscope body, and a lens installed inside the handle; it also includes: a fixing seat symmetrically fixed on the left side of the endoscope body, with limit grooves formed at equal angles on the opposite surfaces of the two fixing seats; a sliding groove is formed on the right side of the top of the handle, with a drive block slidably connected to the inner wall of the sliding groove; a first spring is installed between the end of the drive block and the inner wall of the sliding groove; limit blocks are connected to the right side of the inside of the handle, with a second spring installed between the opposite end of the limit block and the inner wall of the handle; and the opposite ends of the two limit blocks are fixedly connected to the side of the drive block by a traction rope.

[0010] Preferably, the handle is rotatably connected between two fixed seats via a shaft, and both limiting blocks are slidably disposed inside the handle, with opposite ends of the two limiting blocks extending out of the outer surface of the handle. The limiting blocks and the limiting grooves are connected by an insertion.

[0011] Preferably, a first movable block is bolted to the right end of the top of the handle, and a second movable block is fixed to the right side of the bottom of the handle. A liquid storage box and a housing are fixed to the top and bottom of the endoscope body, respectively. A storage airbag is provided on the right side inside the upper and lower housings. A squeezing plate is connected to the left side inside the upper and lower housings, and a third spring is installed between the squeezing plate and the housing. A suction tube is fixedly connected to the bottom of one storage airbag, and a drain tube is fixed to the top of the other storage airbag. A nozzle is installed on the side of the drain tube away from the storage airbag.

[0012] Preferably, the first movable block is arranged in an "L" shape, and the position of the first movable block corresponds to that of the upper extrusion plate, which is slidably disposed inside the housing.

[0013] Preferably, the second movable block corresponds to the position of the extrusion plate below, and the extrusion plate is arranged in a "T" shape, with the left end of the extrusion plate extending out of the outer surface of the housing.

[0014] Preferably, the end of the suction tube away from the storage airbag extends to the right side of the extension tube, and the storage airbag is connected to the inside of the suction tube.

[0015] Preferably, the end of the drain pipe away from the storage airbag extends into the interior of the extension pipe, the nozzle is inclined, the drain pipe is connected to the interior of the lower storage airbag, and the lower storage box stores rinsing fluid.

[0016] Preferably, an inlet pipe is fixedly connected between the storage airbag and the liquid storage box, and a one-way valve is installed inside the inlet pipe, the suction pipe and the discharge pipe. The inside of the storage airbag and the liquid storage box are connected through the inlet pipe, and a sealing cap is threaded through the opposite surfaces of the upper and lower liquid storage boxes.

[0017] Preferably, the endoscope body includes a light source interface, a signal interface, an image sensor, and a color temperature sensor. The light source interface and the signal interface are respectively installed on the upper and lower right ends of the handle, and the light source interface and the signal interface are respectively connected to an external light source box and a computer. The color temperature sensor is installed at the front end inside the handle and is connected to the light source interface via a cable. The image sensor and the circuit board are installed inside the extension tube, and the image sensor is connected to the signal interface via a cable.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the white balance method and endoscope based on sparse representation adopt a novel structural design, the specific details of which are as follows:

[0019] White balance calibration of the endoscope is performed using multiple CCTs, and the calibration results are stored using a sparse representation method. When needed, the calibration matrix of the corresponding CCT is reconstructed through a coefficient lookup table of the sparse representation. This method can improve the calibration accuracy of the CCT piecewise interpolation method, while reducing the storage pressure of calibration data and facilitating hardware implementation.

[0020] When the doctor needs to change the grip position, the sliding drive block is used to pull the limiting block and the limiting groove apart by the traction rope, releasing the limitation on the handle. At this time, the handle can be rotated downward to change it from a horizontal to a vertical position, thereby effectively reducing hand fatigue and enabling the doctor to maintain a good operating state during a longer operation or examination, reducing the risk of operational errors caused by hand fatigue. Furthermore, after the handle is rotated downward, the drive block is released, allowing the drive block to return to its original position under the elastic force of the first spring. At the same time, the two limiting blocks return to their original position under the elastic force of the second spring and insert into the corresponding limiting grooves, which can fix the rotated handle.

[0021] When the handle is rotated downwards, the lower extrusion plate is moved by the second movable block, causing the lower extrusion plate to squeeze the lower storage airbag. At this time, the lower storage airbag pushes the internal flushing fluid into the drain pipe and sprays it out from the nozzle to flush the lens surface, washing away the attached dirt, blood, mucus, etc., thereby providing high-quality images, allowing doctors to clearly observe the fine structure of tissues and lesion characteristics, which helps to more accurately judge the condition and reduce the possibility of misdiagnosis and missed diagnosis.

[0022] When the first movable block stops pushing the upper squeezing plate, the upper squeezing plate resets under the elastic force of the third spring and stops squeezing the upper storage airbag, allowing the upper storage airbag to return to its original shape and generate suction to absorb the pus. This allows doctors to observe the lesion more clearly, which is beneficial for subsequent treatment operations, such as biopsy and surgical excision of infected lesions, thus improving the success rate of treatment.

[0023] The color temperature sensor measures the color temperature of the incident light and transmits this information to the imaging host. The white balance control module in the imaging host corrects the parameters using a numerical calculation model and then transmits the corrected parameters to the processing module to correct the image. As a result, the endoscope can achieve real-time white balance correction with high correction efficiency. Attached Figure Description

[0024] Figure 1 This is a sparse representation diagram of the white balance calibration method of the present invention;

[0025] Figure 2 This is a schematic diagram of the white balance correction method of the present invention;

[0026] Figure 3 This is a schematic diagram of the white balance calibration method of the present invention;

[0027] Figure 4 This is a three-dimensional structural diagram of the endoscope body, handle, and extension tube of the present invention;

[0028] Figure 5 This is a schematic diagram of the left cross-sectional structure of the handle portion of the present invention;

[0029] Figure 6 This is a schematic diagram of the downward rotating structure of the handle part of the present invention;

[0030] Figure 7 This is a schematic diagram of the cross-sectional structure of the shell of the present invention;

[0031] Figure 8 This is a schematic diagram of the connection structure of the suction tube, discharge tube, and extension tube of the present invention;

[0032] Figure 9 For the present invention Figure 5 Enlarged structural diagram at point A in the middle;

[0033] Figure 10 For the present invention Figure 6 Enlarged structural diagram at point B;

[0034] Figure 11 This is a schematic diagram of the connection structure between the color temperature sensor and the endoscope body of the present invention.

[0035] In the figure: 1. Endoscope main body; 101. Light source interface; 102. Signal interface; 103. Image sensor; 104. Color temperature sensor; 2. Handle part; 3. Extension tube; 4. Lens; 5. Fixed seat; 6. Driving block; 7. Slide groove; 8. First spring; 9. Limit block; 10. Second spring; 11. Traction rope; 12. Limit groove; 13. Liquid storage box; 14. Shell; 15. First movable block; 16. Second movable block; 17. Stock air bag; 18. Third spring; 19. Liquid inlet pipe; 20. Liquid suction pipe; 21. Liquid discharge pipe; 22. Nozzle; 23. Extrusion plate. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Please refer to Figures 1-11 , the present invention provides the following technical solutions: A white balance method and an endoscope based on sparse representation;

[0038] Embodiment 1: To solve the problem in the prior art that the accuracy is limited. When the difference between the CCT and the pre-calibrated CCT is large, the correction coefficient obtained by interpolation is difficult to accurately correct the white balance, and a lot of data needs to be calibrated, resulting in a too large amount of data and it is difficult to meet the implementation requirements of hardware (such as FPGA). Therefore, the following solution is disclosed. Specifically refer to Figures 1-3 As shown, a white balance method based on sparse representation includes white balance calibration and white balance correction. The white balance calibration is achieved through the following steps: S1. Calibrate n color temperatures: Under the light sources of n color temperatures, the imaging system takes pictures of a standard color card to obtain the RGB response values of each color; taking the chromaticity value of the standard color card under the standard illuminant as the target, solve the conversion model from the camera RGB response value to the standard chromaticity value through an optimization method, and denote them as M1, M2... Mn respectively; S2. Select k characteristic models from M1, M2... Mn, and denote them as Mf1, Mf2... Mfk, where k < n; S3. Adopt an optimization method to represent the conversion models at n color temperatures by a linear combination of k characteristic models, which is expressed as Formula 1: S4. Record the coefficients an, bn...kn in the form of a lookup table; White balance correction is achieved through the following steps: S1. Debug and set the current light source CCT and input it into the control module; S2. The control module retrieves the corresponding representation coefficients through the CCT value; S3. Using the representation coefficients from the previous step, calculate the white balance correction model using Formula 1; S4. The control module passes the correction model parameters from the previous step to the processing module to perform white balance correction on the input image.

[0039] Using a lightbox as the lighting source, the color temperature of the lightbox was gradually increased from 3000K to 8000K in 500K increments. A set of 24 color chart images was captured. Based on the data obtained in the previous step, the white balance correction matrix Mt of the color chart at the corresponding color temperature t was obtained using the least squares method. Then, Mt at t=3000, t=5000, and t=8000 was selected as the feature matrix. The coefficients k3000(t), k5000(t), and k8000(t) were solved using multivariate linear regression. The coefficient results were saved to a lookup table. When needed, calculations were performed. The minimum, maximum, and step values ​​of the calibrated color temperature could be other values, and other optimization methods could be used. The white balance correction matrix at the corresponding color temperature t was solved based on the calibration data. At the same time, other numbers of feature matrices with corresponding color temperature values ​​could be selected, and other optimization methods could be used to solve the sparse representation coefficients.

[0040] Example 2: Unlike Example 1, this example allows the handle 2 to be rotated downwards, changing the doctor's grip posture and effectively reducing hand fatigue. See details... Figures 4-9 As shown, an endoscope is also disclosed, including an endoscope body 1, with a handle 2 and an extension tube 3 respectively provided at the left and right ends of the endoscope body 1, and a lens 4 installed inside the handle 2; it also includes: a fixing seat 5 symmetrically fixed on the left side of the endoscope body 1, and a limiting groove 12 is formed at the same angle on the opposite surfaces of the two fixing seats 5; a sliding groove 7 is formed on the right side of the top of the handle 2, and a driving block 6 is slidably connected to the inner wall of the sliding groove 7; a first spring 8 is installed between the end of the driving block 6 and the inner wall of the sliding groove 7; a limiting block 9 is connected to the right side of the inside of the handle 2, and a second spring 10 is installed between the opposite end of the limiting block 9 and the inner wall of the handle 2; the opposite ends of the two limiting blocks 9 are fixedly connected to the side of the driving block 6 by a traction rope 11; the handle 2 is rotatably connected between the two fixing seats 5 by a shaft; the two limiting blocks 9 are slidably disposed inside the handle 2, and the opposite ends of the two limiting blocks 9 extend out of the outer surface of the handle 2; the limiting blocks 9 and the limiting groove 12 are connected by an insertion.

[0041] After anesthesia takes effect, the doctor will slowly insert the extension tube 3 on the endoscope body 1 into the body through a natural cavity or surgical incision. During insertion, the doctor will closely observe the endoscopic image and adjust the angle and depth of insertion according to the patient's reaction and anatomical structure. Because the endoscope body 1 uses a white balance method, it can achieve white balance under different color temperature light sources. Specifically, this is reflected in the following two points: when the color temperature of the light source changes due to long-term use, it can prevent color deviation in the electronic endoscope; and after changing the light source, the overall color of the endoscope can be kept consistent. Then, when the doctor needs to change the holding posture, the drive block 6 is slid to adjust the position. By using the traction rope 11 to pull the limiting block 9 away from the limiting groove 12, the limitation on the handle part 2 is released. At this time, the handle part 2 can be rotated downward to change it from a horizontal state to a vertical state, thereby effectively reducing hand fatigue and enabling doctors to maintain a good operating state during a longer operation or examination, reducing the risk of operational errors caused by hand fatigue. After the handle part 2 is rotated downward, the drive block 6 is released, so that the drive block 6 is reset under the elastic force of the first spring 8. At the same time, the two limiting blocks 9 are reset under the elastic force of the second spring 10 and inserted into the corresponding limiting groove 12, which can fix the rotated handle part 2.

[0042] Example 3: Unlike Example 2, this example utilizes two storage airbags 17 to respectively aspirate pus and rinse the lens 4, thereby providing high-quality images. This allows doctors to more clearly observe the lesion, facilitating subsequent treatment procedures. See details for further information. Figures 4-8 and Figure 10As shown, a first movable block 15 is bolted to the right end of the top of the handle 2, and a second movable block 16 is fixed to the right side of the bottom of the handle 2. A reservoir 13 and a housing 14 are fixed to the top and bottom of the endoscope body 1, respectively. A storage airbag 17 is provided on the right side inside both the upper and lower housings 14. A compression plate 23 is connected to the left side inside both the upper and lower housings 14, and a third spring 18 is installed between the compression plate 23 and the housing 14. The first movable block 15 is L-shaped and corresponds to the position of the upper compression plate 23, which slides inside the housing 14. The second movable block 16 corresponds to the position of the lower compression plate 23, which is T-shaped. The left end of the compression plate 23 extends out of the outer surface of the housing 14. A suction device is fixedly connected to the bottom of one storage airbag 17. The liquid pipe 20 and the top of the other storage airbag 17 are fixed with a drain pipe 21. A nozzle 22 is installed on the side of the drain pipe 21 away from the storage airbag 17. The end of the suction pipe 20 away from the storage airbag 17 extends out to the right side of the extension pipe 3. The storage airbag 17 is connected to the inside of the suction pipe 20. The end of the drain pipe 21 away from the storage airbag 17 extends into the inside of the extension pipe 3. The nozzle 22 is set at an angle. The drain pipe 21 is connected to the inside of the lower storage airbag 17. The lower liquid storage box 13 stores rinsing liquid. An inlet pipe 19 is fixedly connected between the storage airbag 17 and the liquid storage box 13. A one-way valve is installed inside the inlet pipe 19, the suction pipe 20 and the drain pipe 21. The storage airbag 17 is connected to the inside of the liquid storage box 13 through the inlet pipe 19. The opposite surfaces of the upper and lower liquid storage boxes 13 are threaded with sealing caps.

[0043] When the handle 2 rotates downwards, the second movable block 16 pushes the lower squeezing plate 23 to move, causing the lower squeezing plate 23 to squeeze the lower storage airbag 17. At this time, the lower storage airbag 17 pushes the internal flushing fluid into the drain pipe 21 and sprays it out from the nozzle 22 to flush the surface of the lens 4, washing away the attached dirt, blood, mucus, etc., thereby providing high-quality images, allowing doctors to clearly observe the fine structure of tissues and lesion characteristics, which helps to more accurately judge the condition and reduce the possibility of misdiagnosis and missed diagnosis. When the handle 2 returns to its original position, the second movable block 16 no longer pushes the lower squeezing plate 23, so that the lower squeezing plate 23 returns to its original position under the elastic force of the third spring 18 and no longer squeezes the lower storage airbag 17, allowing the storage airbag 17 to return to its original position. The flushing fluid inside the lower storage box 13 is then drawn up by the inlet pipe 19 for replenishment for the next flushing. Then the handle 2 returns to its original position. In the current state, the first movable block 15 continuously pushes the upper squeezing plate 23 to squeeze the upper storage airbag 17. When the handle part 2 is in the vertical state, the first movable block 15 no longer pushes the upper squeezing plate 23, so that the upper squeezing plate 23 is reset under the elastic force of the third spring 18 and no longer squeezes the upper storage airbag 17. This allows the storage airbag 17 to return to its original state and absorb the pus through the suction tube 20, so that the doctor can observe the lesion site more clearly, which is conducive to subsequent treatment operations, such as biopsy and surgical excision of infected lesions, and improves the success rate of treatment. Furthermore, the one-way valves set on the inlet tube 19, suction tube 20 and drain tube 21 can prevent the liquid from flowing turbulently. Subsequently, the sealing caps on the two storage boxes 13 can be rotated to open the through holes on the storage boxes 13, so that the pus in the upper storage box 13 can be cleaned out and the flushing fluid can be added to the lower storage box 13.

[0044] Example 4: Unlike Example 3, this example utilizes a color temperature sensor 104 to measure the color temperature of the current illumination source in real time and transmits the measured value to the control module of the imaging host in real time. This allows for real-time white balance correction during endoscopy use. See details... Figure 11 As shown, the endoscope body 1 includes a light source interface 101, a signal interface 102, an image sensor 103, and a color temperature sensor 104. The light source interface 101 and the signal interface 102 are respectively installed on the upper and lower right ends of the handle 2, and the light source interface 101 and the signal interface 102 are respectively connected to an external light source box and a computer. The color temperature sensor 104 is installed at the front end inside the handle 2, and the color temperature sensor 104 is connected to the light source interface 101 through a cable. The image sensor 103 and a circuit board are installed inside the extension tube 3, and the image sensor 103 is connected to the signal interface 102 through a cable.

[0045] The color temperature sensor 104 measures the color temperature of the incident light and transmits this information to the imaging host. The white balance control module within the imaging host corrects the parameters using a numerical calculation model and then transmits the corrected parameters to the processing module to correct the image. This allows the endoscope to achieve real-time white balance correction with high efficiency. The color temperature sensor 104 has two usage modes: S1, Manual: The color temperature sensor 104 is not located at the front end of the handle 2, but rather outside the application area or directly on the imaging host. In this mode, the light source module is first aligned with the color temperature sensor 104 to measure the color temperature. Temperature measurement: The color temperature sensor 104 transmits the measurement result to the control module for calibration, and then memorizes the parameter value, so that the endoscope can be used for examination or surgery. This method is comparable to the manual white balance method, which has higher stability and reproducibility than the method using a standard white board, and is more convenient to operate. S2, Automatic: The color temperature sensor 104 is installed at the front end of the handle 2. Some light is sent from the light source optical fiber to the color temperature sensor 104 for measurement. The color temperature sensor 104 measures the color temperature of the current lighting source in real time and transmits the measurement value to the host control module in real time, and corrects the white balance in real time during the use of the endoscope.

[0046] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A white balance method based on sparse representation, characterized in that, It includes white balance calibration and white balance correction. The white balance calibration is achieved through the following steps: S1. Calibrate n color temperatures: Under the light sources of n color temperatures, the imaging system captures a standard color card to obtain the RGB response values of each color. Taking the chromaticity values of the standard color card under the standard illuminant as the target, the conversion models from the camera RGB response values to the standard chromaticity values are solved through an optimization method, denoted as M1, M2... Mn respectively; S2. Select k characteristic models from M1, M2... Mn, denoted as Mf1, Mf2... Mfk, where k < n; S3. Adopt an optimization method to represent the conversion models at n color temperatures by a linear combination of k characteristic models, expressed as formula 1: ; S4. Record the coefficients an, bn... kn in the form of a look-up table. The white balance correction is achieved through the following steps: S1. Debug and set the current light source CCT and input it into the control module; S2. The control module retrieves the corresponding representation coefficients through the CCT value; S3. Using the representation coefficients from the previous step, the white balance correction model is calculated using Formula 1; S4. The control module passes the correction model parameters from the previous step to the processing module to perform white balance correction on the input image.

2. An endoscope applied to the white balance method based on sparse representation as described in claim 1, characterized in that, An endoscope was also disclosed, including an endoscope body (1). The endoscope body (1) has a handle (2) and an extension tube (3) at its left and right ends respectively. A lens (4) is installed inside the handle (2). A fixing seat (5) is symmetrically fixed on the left side of the endoscope body (1). Limiting grooves (12) are opened at equal angles on the opposite surfaces of the two fixing seats (5). A sliding groove (7) is opened on the right side of the top of the handle (2). A driving block (6) is slidably connected to the inner wall of the sliding groove (7). A first spring (8) is installed between the end of the driving block (6) and the inner wall of the sliding groove (7). Limiting blocks (9) are connected to the right side of the inside of the handle (2). A second spring (10) is installed between the opposite end of the limiting block (9) and the inner wall of the handle (2). The opposite ends of the two limiting blocks (9) are fixedly connected to the side of the driving block (6) by a traction rope (11).

3. An endoscope according to claim 2, characterized in that: The handle (2) is rotatably connected between two fixed seats (5) via a shaft. The two limiting blocks (9) are slidably disposed inside the handle (2), and the opposite ends of the two limiting blocks (9) extend out of the outer surface of the handle (2). The limiting blocks (9) and the limiting groove (12) are connected by insertion.

4. An endoscope according to claim 2, characterized in that: The right end of the top of the handle (2) is bolted to a first movable block (15), and the right side of the bottom of the handle (2) is fixed to a second movable block (16). The top and bottom of the endoscope body (1) are respectively fixed to a liquid storage box (13) and a shell (14). The right side of the interior of the upper and lower shells (14) is provided with a storage airbag (17). The left side of the interior of the upper and lower shells (14) is connected to a squeezing plate (23). A third spring (18) is installed between the squeezing plate (23) and the shell (14). The bottom of one storage airbag (17) is fixedly connected to a suction tube (20), and the top of the other storage airbag (17) is fixed to a drain pipe (21). A nozzle (22) is installed on the side of the drain pipe (21) away from the storage airbag (17).

5. An endoscope according to claim 4, characterized in that: The first movable block (15) is arranged in an "L" shape, and the position of the first movable block (15) corresponds to that of the upper extrusion plate (23), which is slidably disposed inside the housing (14).

6. An endoscope according to claim 4, characterized in that: The second movable block (16) corresponds to the position of the extrusion plate (23) below, and the extrusion plate (23) is arranged in a "T" shape, with the left end of the extrusion plate (23) extending out of the outer surface of the housing (14).

7. An endoscope according to claim 4, characterized in that: The end of the suction tube (20) away from the storage airbag (17) extends out to the right side of the extension tube (3), and the storage airbag (17) is connected to the inside of the suction tube (20).

8. An endoscope according to claim 4, characterized in that: The end of the drain pipe (21) away from the storage airbag (17) extends into the interior of the extension pipe (3). The nozzle (22) is set at an angle. The drain pipe (21) is connected to the interior of the storage airbag (17) below. The liquid storage box (13) below stores rinsing liquid.

9. An endoscope according to claim 4, characterized in that: The storage airbag (17) and the liquid storage box (13) are fixedly connected by an inlet pipe (19), and the inlet pipe (19), the suction pipe (20) and the discharge pipe (21) are all equipped with one-way valves. The storage airbag (17) and the liquid storage box (13) are connected through the inlet pipe (19). The upper and lower liquid storage boxes (13) are threadedly connected to the opposite surfaces with sealing caps.

10. An endoscope according to claim 2, characterized in that: The endoscope body (1) includes a light source interface (101), a signal interface (102), an image sensor (103), and a color temperature sensor (104). The upper and lower right ends of the handle (2) are respectively equipped with the light source interface (101) and the signal interface (102), and the light source interface (101) and the signal interface (102) are respectively connected to the external light source box and the computer. The front end of the handle (2) is equipped with a color temperature sensor (104), and the color temperature sensor (104) is connected to the light source interface (101) through a cable. The inside of the extension tube (3) is equipped with an image sensor (103) and a circuit board, and the image sensor (103) is connected to the signal interface (102) through a cable.

Images