Image brightness adjustment method, light adjustment device, and endoscope

Abstract

The application provides an image brightness adjusting method, a light adjusting device and an endoscope. The image brightness adjusting method is applied to the light adjusting device of the endoscope. The light adjusting device comprises a CMOS exposure time adjusting interval, a light source brightness adjusting interval and a CMOS gain adjusting interval. The image brightness adjusting method comprises the following steps: acquiring the average brightness of a current frame image and a preset target brightness; judging the current adjusting interval; calculating the adjusting proportion coefficient of the current adjusting interval according to the average brightness of the current frame image and the target brightness; and adjusting the image brightness in the current adjusting interval according to the adjusting proportion coefficient. Compared with the prior art, the application realizes dynamic adjustment of the image brightness by setting the adjusting proportion coefficient, widens the adjusting range, and improves the image quality as much as possible under the premise of achieving the same target brightness.

Description

Technical Field

[0001] This invention relates to the field of endoscopy technology, and more particularly to an image brightness adjustment method, a dimming device, and an endoscope. Background Technology

[0002] An electronic endoscope is a medical electro-optical instrument that integrates advanced optical, mechanical, and electronic technologies, allowing direct observation, diagnosis, and treatment of the body cavities and internal organs. During surgery on these cavities, doctors need to observe images captured by the endoscopic system to understand their condition. Because the distance between the endoscope lens and the object being observed changes during surgery, the images captured by the endoscopic system often suffer from overexposure or underexposure, making it difficult for doctors to observe clear images of the internal organs. Therefore, the brightness of the endoscopic images needs to be frequently adjusted.

[0003] Existing electronic endoscopes mainly adjust image brightness in three ways: (1) automatically adjusting CMOS exposure time, (2) automatically adjusting light source brightness, and (3) automatically adjusting CMOS gain. However, all three dimming methods have their limitations. The adjustment range of CMOS exposure time and gain is limited by the CMOS itself, and its overall adjustment range is limited. Furthermore, excessively high CMOS exposure time may cause image ghosting; while excessively high CMOS gain results in a low signal-to-noise ratio, high noise, and poor overall image quality. Adjusting light source brightness is limited by the light source brightness adjustment range. The linear range of brightness adjustment for different light sources (such as LEDs) is limited, and there is a general problem of insufficient brightness adjustment accuracy and limited dimming range at low brightness levels.

[0004] In view of this, it is indeed necessary to provide an image brightness adjustment method, a dimming device, and an endoscope to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an image brightness adjustment method with a wide adjustment range and good imaging quality.

[0006] To achieve the above objectives, the present invention provides an image brightness adjustment method applied to an endoscope's dimming device. The dimming device includes a CMOS exposure time adjustment range, a light source brightness adjustment range, and a CMOS gain adjustment range. The image brightness adjustment method includes:

[0007] Obtain the average brightness of the current frame image and the preset target brightness;

[0008] Determine the current adjustment range;

[0009] Calculate the adjustment ratio coefficient of the current adjustment range based on the average brightness of the current frame image and the target brightness;

[0010] The image brightness is adjusted within the current adjustment range based on the adjustment ratio coefficient.

[0011] As a further improvement of the present invention, the image brightness adjustment method further includes:

[0012] Compare the average brightness of the current frame image with the target brightness.

[0013] Based on the comparison between the average brightness and the target brightness, and the adjustment range of the adjustment parameters in the current adjustment range, determine whether to continue adjusting in the current adjustment range; if not, proceed to the adjacent adjustment range for adjustment.

[0014] As a further improvement of the present invention, the method for determining whether to continue adjusting within the current adjustment range based on the comparison result of the average brightness and the target brightness and the adjustment range of the current adjustment range includes:

[0015] S61: If the current light source brightness adjustment range is in the current light source brightness adjustment range, and the current light source brightness has reached the lower limit threshold of the light source brightness adjustment range, and the average brightness is greater than the target brightness, then enter the CMOS exposure time adjustment range.

[0016] S62: If the current light source brightness adjustment range is in the current light source brightness adjustment range, and the current light source brightness has reached the upper limit threshold of the light source brightness adjustment range, and the average brightness is less than the target brightness, then enter the CMOS gain adjustment range.

[0017] S63: If the current CMOS exposure time adjustment range is in the current CMOS exposure time adjustment range, and the current CMOS exposure time has reached the upper limit threshold of the CMOS exposure time adjustment range, and the average brightness is less than the target brightness, then enter the light source brightness adjustment range.

[0018] S64: If the current CMOS gain adjustment range is in the CMOS gain adjustment range, and the current CMOS gain has reached the lower limit threshold of the CMOS gain adjustment range, and the average brightness is greater than the target brightness, then enter the light source brightness adjustment range.

[0019] S65: If the conditions of S61 to S64 are not met, the current adjustment range remains unchanged.

[0020] As a further improvement of the present invention, the adjustment ratio coefficient is equal to the a power of the ratio of the target brightness to the average brightness, where a is a constant and 0 < a < 1.

[0021] As a further improvement of the present invention, the method of adjusting the image brightness within the current adjustment range according to the adjustment ratio coefficient includes: multiplying the parameter value of the current frame image in the current adjustment range by the adjustment ratio coefficient corresponding to the adjustment range to obtain the parameter value of the next frame image.

[0022] As a further improvement of the present invention, if the result of multiplying the parameter value of the current frame image in the current adjustment interval by the adjustment ratio coefficient corresponding to the adjustment interval is greater than the upper limit threshold of the adjustment range of the adjustment interval, then the parameter value of the next frame image is adjusted to the upper limit threshold; if the result of multiplying the adjustment value of the current adjustment interval by the adjustment ratio coefficient corresponding to the adjustment interval is less than the lower limit threshold of the adjustment range of the adjustment interval, then the parameter value of the next frame image is adjusted to the lower limit threshold.

[0023] As a further improvement of the present invention, the lower limit threshold of the adjustment range of the adjustment interval is greater than or equal to P times the minimum adjustment step size of the adjustment parameter of the adjustment interval, where P > 1.

[0024] As a further improvement of the present invention, the image brightness adjustment method is completed during the gap in the data transmission time of two frames of images. Each frame of image is adjusted once by the image brightness adjustment method, and the image brightness adjustment method is repeated until the adjustment is completed.

[0025] Another object of the present invention is to provide a dimming device that applies the above-described image brightness adjustment method.

[0026] To achieve the above objectives, the present invention provides a dimming device, which includes a CMOS exposure time adjustment range, a light source brightness adjustment range, and a CMOS gain adjustment range. The dimming device further includes:

[0027] The parameter acquisition module is used to acquire the average brightness of the current frame image and the preset target brightness;

[0028] The judgment module determines the current adjustment range and the magnitude of the average brightness and the target brightness.

[0029] The calculation module calculates the adjustment ratio coefficient of the current adjustment range based on the average brightness and the target brightness;

[0030] The control module adjusts the image brightness using the aforementioned image brightness adjustment method.

[0031] The present invention also provides an endoscope, which includes the above-described dimming device.

[0032] The beneficial effects of this invention are as follows: Compared with the prior art, the image brightness adjustment method, dimming device, and endoscope of this invention, wherein the image brightness adjustment method determines the adjustment range of the current frame image and calculates the adjustment ratio coefficient corresponding to the current adjustment range to achieve dynamic adjustment of image brightness, thereby widening the adjustment range of image brightness and adjusting the image brightness to the target value within a very wide dynamic range. Simultaneously, by rationally allocating the parameters of CMOS exposure time, light source brightness, and CMOS gain, the signal-to-noise ratio of the image is maximized while achieving the same target brightness, thereby maximizing image quality. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating an image brightness adjustment method according to a preferred embodiment of the present invention.

[0034] Figure 2 This is a graph showing the relationship between the various adjustment ranges of the present invention and image brightness.

[0035] Figure 3 This is a flowchart illustrating an image brightness adjustment method according to another preferred embodiment of the present invention.

[0036] Figure 4 This is a flowchart illustrating the process of determining whether to change the adjustment range in a preferred embodiment of the present invention.

[0037] Figure 5 This is a structural block diagram of the dimming device of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0040] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] Please see Figure 1-4As shown, the present invention provides an image brightness adjustment method according to a preferred embodiment, which is applied to a dimming device 100 of an electronic endoscope with CMOS imaging. The dimming device 100 includes a CMOS exposure time adjustment range 11, a light source brightness adjustment range 12, and a CMOS gain adjustment range 13.

[0042] The image brightness adjustment method includes:

[0043] S1: Obtain the average brightness of the current frame image and the preset target brightness.

[0044] Specifically, the average brightness of the current frame image and the preset target brightness are obtained by the parameter acquisition module 20 of the dimming device 100. Optionally, the parameter acquisition module 20 acquires the RGB image data of the current frame image, then converts the RGB image data into YCbCr image data, and calculates the average brightness of the current frame image.

[0045] S2: Determine the current adjustment range.

[0046] The CMOS exposure time adjustment range 11, the light source brightness adjustment range 12, and the CMOS gain adjustment range 13 of the dimming device 100 are arranged from low to high image brightness, such as... Figure 1 As shown, the image brightness corresponding to the CMOS exposure time adjustment range 11 is relatively low, the image brightness corresponding to the CMOS gain adjustment range 13 is relatively high, and the light source brightness adjustment range 12 is located between the CMOS exposure time adjustment range 11 and the CMOS gain adjustment range 13. The current adjustment range of the dimming device 100 is determined by the judgment module 30 of the dimming device 100.

[0047] S3: Calculate the adjustment ratio coefficient K of the current adjustment range based on the average brightness of the current frame image and the target brightness.

[0048] The calculation module 40 of the dimming device 100 calculates the adjustment ratio coefficient K of the current adjustment range based on the average brightness of the current frame image and the target brightness.

[0049] Furthermore, the adjustment ratio K is a dynamic value, related to the average brightness of the current frame and the preset target brightness. That is, the adjustment ratio K is equal to the power of a (the ratio of target brightness to average brightness), where a is a constant and 0 < a < 1. By adjusting the ratio K to the power of a (the ratio of target brightness to average brightness), the image brightness adjustment process is made smoother, i.e., the transition between the brightness of two frames is smoother, improving visual comfort.

[0050] Specifically, the CMOS exposure time adjustment range 11 corresponds to the first adjustment ratio coefficient K1, where K1 = (target brightness / average brightness).a1 Preferably, in this embodiment, a1 = 0.2.

[0051] The light source brightness adjustment range 12 corresponds to the second adjustment ratio coefficient K2, where K2 = (target brightness / average brightness). a2 Preferably, in this embodiment, a2 = 0.3.

[0052] The CMOS gain adjustment range 13 corresponds to the third adjustment ratio coefficient K3, where K3 = (target brightness / average brightness). a3 Preferably, in this embodiment, a3 = 0.1.

[0053] In this embodiment, a1, a2, and a3 in the first adjustment proportional coefficient K1, the second adjustment proportional coefficient K2, and the third adjustment proportional coefficient K3 are different. In other embodiments, a1, a2, and a3 may be the same or partially the same. This invention does not limit this. That is, the constant a is an empirical value and can be adjusted according to actual conditions.

[0054] The control module 50 adjusts the image brightness within the current adjustment range according to the adjustment ratio coefficient K.

[0055] S4: Adjust the image brightness within the current adjustment range according to the adjustment ratio coefficient K.

[0056] Further, step S4, which adjusts the image brightness within the current adjustment range according to the adjustment ratio coefficient K, includes step S41: multiplying the parameter value of the current frame image within the current adjustment range by the adjustment ratio coefficient K corresponding to the adjustment range to obtain the parameter value of the next frame image.

[0057] The control module 50 adjusts the current adjustment range or enters an adjacent adjustment range based on the parameter values ​​of the next frame image calculated by the calculation module 40.

[0058] Furthermore, the image brightness adjustment method also includes step S01: setting the adjustment range of CMOS exposure time adjustment range 11, light source brightness adjustment range 12 and CMOS gain adjustment range 13, and determining the upper limit threshold and lower limit threshold of each adjustment range.

[0059] The selection principles for the upper and lower thresholds of the adjustment range of CMOS exposure time adjustment range 11 are as follows: the lower threshold of CMOS exposure time adjustment range 11 is greater than or equal to P1 times the minimum adjustment step size of CMOS exposure time parameter, and the upper threshold of the adjustment range of CMOS exposure time adjustment range 11 should be selected as the highest exposure time parameter under the premise that there is no obvious ghosting in the actual image.

[0060] The selection principles for the upper and lower threshold values ​​of the adjustment range of the light source brightness adjustment interval 12 are as follows: the lower threshold value of the adjustment range of the light source brightness adjustment interval 12 is greater than or equal to P2 times the minimum adjustment step size of the light source brightness, and the upper threshold value of the adjustment range of the light source brightness adjustment interval 12 is not greater than the highest brightness of the light source. Furthermore, within the light source brightness adjustment range, the brightness adjustment is a strictly monotonic and approximately linear adjustment.

[0061] The selection principles for the upper and lower thresholds of the CMOS gain adjustment range 13 are as follows: the lower threshold of the CMOS gain adjustment range 13 should be greater than or equal to P3 times the minimum adjustment step size of the CMOS gain parameter, and the upper threshold of the CMOS gain range should be selected as the highest value of the image noise within the acceptable range.

[0062] In this embodiment, the lower limit threshold of the adjustment range for each adjustment interval is greater than or equal to P times the minimum adjustment step size of the adjustment parameter for that interval, where P > 1. By setting the lower limit threshold of the adjustment range for each adjustment interval to be greater than or equal to P times the minimum adjustment step size of the adjustment parameter for that interval, the adjustment parameters of each adjustment interval can be adjusted proportionally. Preferably, P is an empirical value, and the selection of P is related to hardware settings such as CMOS and light source. If the value of P is too small, the adjustment is not precise enough; if the value of P is too large, the overall adjustment range is limited. Therefore, the selection of P needs to be moderate. In this embodiment, P1 equals 32, P2 equals 128, and P3 equals 16.

[0063] Furthermore, the image brightness adjustment method also includes setting the optimal adjustment state of the CMOS exposure time adjustment range 11, the light source brightness adjustment range 12, and the CMOS gain adjustment range 13.

[0064] The optimal adjustment state of the parameters in the CMOS exposure time adjustment range 11 is as follows: the light source brightness is maintained at the lower limit threshold of the adjustment range of the light source brightness adjustment range 12, the CMOS gain is maintained at the lower limit threshold of the adjustment range of the CMOS gain adjustment range, and the CMOS exposure time parameters are automatically adjusted within the adjustment range of the CMOS exposure time adjustment range 11.

[0065] The optimal adjustment state of the parameters in the light source brightness adjustment range 12 is as follows: the CMOS exposure time is maintained at the upper limit threshold of the adjustment range of the CMOS exposure time adjustment range 11, the CMOS gain is maintained at the lower limit threshold of the adjustment range of the CMOS gain adjustment range, and the light source brightness parameters are automatically adjusted within the adjustment range of the light source brightness adjustment range 12.

[0066] The optimal adjustment state of the parameters in the CMOS gain adjustment range 13 is as follows: the CMOS exposure time is maintained at the upper limit threshold of the adjustment range of the CMOS exposure time adjustment range 11, the light source brightness is maintained at the upper limit threshold of the adjustment range of the light source brightness adjustment range 12, and the CMOS gain parameters are automatically adjusted within the adjustment range of the CMOS gain adjustment range 13.

[0067] Further, in step S41: the parameter value of the current frame image in the current adjustment interval is multiplied by the adjustment ratio coefficient corresponding to the adjustment interval to obtain the parameter value of the next frame image. If the parameter value of the next frame image exceeds the adjustment range of the adjustment interval, the parameter value is truncated.

[0068] Specifically, if the result of multiplying the parameter value of the current frame image in the current adjustment interval by the adjustment ratio coefficient corresponding to the adjustment interval is greater than the upper limit threshold of the adjustment range of the adjustment interval, then the parameter value of the next frame image is adjusted to the upper limit threshold; if the result of multiplying the adjustment value of the current adjustment interval by the adjustment ratio coefficient corresponding to the adjustment interval is less than the lower limit threshold of the adjustment range of the adjustment interval, then the parameter value of the next frame image is adjusted to the lower limit threshold.

[0069] In other words, if the current CMOS exposure time adjustment range is 11, the upper limit threshold of the adjustment range of CMOS exposure time adjustment range 11 is E. 上 The lower threshold is E 下 Assuming the CMOS exposure time parameter value of the current frame image is E1, if the result of E1*K1 is less than E... 下 Then, the CMOS exposure time parameter E2 of the next frame image will be adjusted to this value. 下 If the result of E1*K1 is greater than E 上 Then the CMOS exposure time parameter E2 of the next frame image will be adjusted to E 上 If neither of the above two situations applies, then adjust the CMOS exposure time parameter E2 of the next frame image to E1*K1.

[0070] If the current brightness adjustment range is within range 12, the upper limit threshold of the adjustment range within range 12 is B. 上 The lower threshold is B. 下 Assuming the light source brightness of the current frame image is B1, if the result of B1*K2 is less than B... 下 Then the parameter value B2 of the light source brightness in the next frame image will be adjusted to this value. 下 If the result of B1*K2 is greater than B 上 Then the parameter value B2 of the light source brightness in the next frame image will be adjusted to B. 上If neither of the above two situations applies, then the parameter value B2 of the light source brightness in the next frame image will be adjusted to B1*K2.

[0071] If the current CMOS gain adjustment range is 13, the upper limit threshold of the adjustment range of CMOS gain adjustment range 13 is G. 上 The lower threshold is G 下 Assuming the CMOS gain parameter value of the current frame image is G1, if the result of G1*K3 is less than G... 下 Then the CMOS gain parameter G2 of the next frame image will be adjusted to this value. 下 If the result of G1*K3 is greater than G 上 Then the CMOS gain parameter G2 of the next frame image will be adjusted to G. 上 If neither of the above two situations applies, then adjust the CMOS gain parameter G2 of the next frame image to G1*K3.

[0072] Repeat steps S1-S4 until the image brightness adjustment is complete or you need to enter an adjacent adjustment range for further adjustment.

[0073] Furthermore, if the average brightness that matches the target brightness cannot be obtained in the current adjustment range, the adjustment can be performed in an adjacent adjustment range as appropriate.

[0074] Specifically, the image brightness adjustment method further includes:

[0075] S5: Compare the average brightness of the current frame image with the target brightness;

[0076] S6: Based on the comparison results of the average brightness and the target brightness, and the adjustment range of the adjustment parameters in the current adjustment range, determine whether to continue adjusting in the current adjustment range; if not, enter the adjacent adjustment range for adjustment.

[0077] Furthermore, step S6, based on the comparison results of the average brightness and the target brightness, and the adjustment range of the current adjustment range, determines whether to continue adjusting within the current adjustment range, including:

[0078] S61: If the current light source brightness adjustment range 12 is in the current light source brightness adjustment range 12, and the current light source brightness has reached the lower limit threshold of the light source brightness adjustment range, and the average brightness is greater than the target brightness, then enter the CMOS exposure time adjustment range 11.

[0079] S62: If the current light source brightness adjustment range 12 is in the current light source brightness adjustment range 12, and the current light source brightness has reached the upper limit threshold of the light source brightness adjustment range, and the average brightness is less than the target brightness, then enter the CMOS gain adjustment range 13.

[0080] S63: If the current CMOS exposure time adjustment range 11 is in, and the current CMOS exposure time has reached the upper limit threshold of the CMOS exposure time adjustment range, and the average brightness is less than the target brightness, then enter the light source brightness adjustment range 12.

[0081] S64: If the current CMOS gain adjustment range 13 is in the current CMOS gain adjustment range 13, and the current CMOS gain has reached the lower limit threshold of the CMOS gain adjustment range, and the average brightness is greater than the target brightness, then enter the light source brightness adjustment range 12.

[0082] S65: If the conditions of S61 to S64 are not met, the current adjustment range remains unchanged.

[0083] Furthermore, the image brightness adjustment method also includes step S02: initializing the dimming device 100.

[0084] In this embodiment, the dimming device 100 is initialized in the following state: the CMOS exposure time is set to the upper limit threshold E of its adjustment range. 上 The light source brightness is set to the middle value within its adjustment range, and the CMOS gain is set to the lower limit threshold G of its adjustment range. 下 This setting ensures that the image brightness adjustment method described above defaults to the light source brightness adjustment range 12. Of course, in other embodiments, the initialization state of the dimming device 100 can also be set differently, and this invention does not limit this.

[0085] In this embodiment, the default setting is the light source brightness adjustment range 12. If the light source brightness of the current frame image has reached the lower limit threshold B of the light source brightness adjustment range... 下 Meanwhile, if the average brightness of the current frame image is greater than the target brightness, then the CMOS exposure time adjustment range 11 is entered. If the light source brightness of the current frame image has reached the upper limit threshold B of the light source brightness adjustment range... 上 Meanwhile, if the average brightness of the current frame image is less than the target brightness, then the CMOS gain adjustment range 13 is entered. If the above conditions are not met, the adjustment continues in the light source brightness adjustment range 12.

[0086] Similarly, if the current frame is in CMOS exposure time adjustment range 11, and the CMOS exposure time of the current frame image has reached the upper limit threshold E of the CMOS exposure time adjustment range. 上 Simultaneously, if the average brightness is less than the target brightness, the system moves up to the light source brightness adjustment range 12. If the system is currently in the CMOS gain adjustment range 13, and the CMOS gain of the current frame image has reached the lower limit threshold G of the CMOS gain adjustment range... 下Meanwhile, if the average brightness is greater than the target brightness, it will enter the light source brightness adjustment range 12.

[0087] Furthermore, each frame of the image is adjusted once using the aforementioned image brightness adjustment method. That is, for each frame, the average brightness is calculated, compared to the target brightness, and the adjustment ratio coefficient K for each adjustment interval is calculated based on the average brightness. Then, adjustment is performed based on the adjustment ratio coefficient K and the current adjustment interval. After adjustment, the calculation and iteration for the next frame begin. These steps are repeated until the image brightness adjustment is complete.

[0088] Furthermore, the image brightness adjustment method is performed during the gap in the data transmission time between two image frames, and this process is repeated until the adjustment is complete. That is, steps S1-S6 are repeated until the image brightness adjustment is finished. Performing the image brightness adjustment method during the gap in the data transmission time between two image frames is done because no data is transmitted between the two frames. Performing the adjustment during this gap avoids adjusting the image halfway through data transmission, which would result in an image that is half bright and half dark, affecting image quality and the calculation of average image brightness. In other words, by performing the image brightness adjustment method during the gap in the data transmission time between two image frames, image quality can be improved, and the calculation of the average brightness of the next frame is made more reliable.

[0089] The principle of the image brightness adjustment method of the present invention is as follows: For electronic endoscopes using CMOS imaging, under ideal conditions, the approximate calculation method for the brightness of each pixel of the CMOS sensor is as follows:

[0090] Brightness of a single pixel = CMOS exposure time * CMOS gain * Light intake

[0091] The longer the CMOS exposure time, the higher the CMOS gain, or the greater the amount of light entering the image, the brighter the individual pixel. Based on the monotonicity relationship, the overall brightness of the image can be expressed by the following formula:

[0092] Image brightness = F(CMOS exposure time, CMOS gain, light source brightness).

[0093] Where F is a function that satisfies the following characteristics: among the three parameters of CMOS exposure time, CMOS gain, and light source brightness, the other two parameters remain unchanged, and if any single parameter is monotonically increasing, then F is monotonically increasing.

[0094] For electronic endoscopes used within human body cavities, almost all light intake comes from illumination by a light source. Considering ideal conditions, in this example, the amount of light intake is approximately proportional to the brightness of the light source. Therefore, the overall image brightness can be approximated using the following formula:

[0095] Image brightness ≈ CMOS exposure time * CMOS gain * Light source brightness * Scale factor

[0096] The above formula is derived under ideal conditions. The actual situation is much more complex, but we can draw a general conclusion: by adjusting a single parameter of the three parameters—CMOS exposure time, CMOS gain, and light source brightness—in a certain proportion, the final brightness of the image will approximately change in the same proportion.

[0097] Based on considerations of image signal-to-noise ratio (SNR), under the same target brightness, a better external lighting environment (stronger light intensity), a longer CMOS exposure time, and a lower gain will result in a higher image SNR, lower image noise, and higher image quality. Therefore, to achieve the same target brightness, the following should be achieved: high CMOS exposure time, high light source brightness, and low CMOS gain.

[0098] This invention obtains the average brightness of the current frame image and a preset target brightness, determines the adjustment range of the current frame image, calculates the adjustment ratio coefficient corresponding to the current adjustment range, and dynamically adjusts the image brightness according to this adjustment ratio coefficient K, thereby widening the adjustment range of image brightness and adjusting the image brightness to the target value within a very wide dynamic range. Simultaneously, by rationally allocating parameters such as CMOS exposure time, light source brightness, and CMOS gain, the signal-to-noise ratio of the image is maximized while achieving the same target brightness, thus improving image quality as much as possible.

[0099] It should be noted that the above-described image brightness adjustment method is a preferred embodiment of the control method of the present invention, but it is not limited thereto. In other embodiments, the order of the steps in the image brightness adjustment method can be changed, deleted, or combined as needed, and the present invention does not limit this.

[0100] Please see Figure 5 As shown, the present invention further provides a dimming device 100 applying the above-described image brightness adjustment method. This dimming device 100 is applied to a CMOS imaging endoscope for imaging internal cavities of the human body. The dimming device 100 includes a CMOS exposure time adjustment range 11, a light source brightness adjustment range 12, and a CMOS gain adjustment range 13. The dimming device 100 also includes: a parameter acquisition module 20 for acquiring the average brightness of the current frame image and a preset target brightness; a judgment module 30 for judging the current adjustment range and the magnitude of the average brightness and the target brightness; a calculation module 40 for calculating the adjustment ratio coefficient of the current adjustment range based on the average brightness and the target brightness; and a control module 50 for adjusting the image brightness using the above-described image brightness adjustment method.

[0101] The present invention also provides an endoscope (not shown), which is a CMOS imaging electronic endoscope. The endoscope includes the above-mentioned dimming device 100 and applies the above-mentioned image brightness adjustment method to achieve dynamic adjustment of image brightness, widen the adjustment range, and improve image quality.

[0102] In summary, the image brightness adjustment method, dimming device 100, and endoscope of the present invention, wherein the image brightness adjustment method dynamically adjusts the image brightness by determining the adjustment range of the current frame image and calculating the adjustment ratio coefficient corresponding to the current adjustment range, thereby widening the adjustment range of image brightness and adjusting the image brightness to the target value within a very wide dynamic range. Simultaneously, by rationally allocating parameters such as CMOS exposure time, light source brightness, and CMOS gain, the signal-to-noise ratio of the image is maximized while achieving the same target brightness, thereby maximizing image quality.

[0103] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An image brightness adjustment method, applied to the dimming device of an endoscope, characterized in that, The dimming device includes a CMOS exposure time adjustment range, a light source brightness adjustment range, and a CMOS gain adjustment range. The image brightness adjustment method includes: Obtain the average brightness of the current frame image and the preset target brightness; Determine the current adjustment range; Calculate the adjustment ratio coefficient of the current adjustment range based on the average brightness of the current frame image and the target brightness; The image brightness is adjusted within the current adjustment range based on the adjustment ratio coefficient. Compare the average brightness of the current frame image with the target brightness. Based on the comparison between the average brightness and the target brightness, and the adjustment range of the adjustment parameters in the current adjustment range, determine whether to continue adjusting within the current adjustment range; if not, proceed to the adjacent adjustment range; specifically including: S61: If the current light source brightness adjustment range is in the current light source brightness adjustment range, and the current light source brightness has reached the lower limit threshold of the light source brightness adjustment range, and the average brightness is greater than the target brightness, then enter the CMOS exposure time adjustment range. S62: If the current light source brightness adjustment range is in the current light source brightness adjustment range, and the current light source brightness has reached the upper limit threshold of the light source brightness adjustment range, and the average brightness is less than the target brightness, then enter the CMOS gain adjustment range. S63: If the current CMOS exposure time adjustment range is in the current CMOS exposure time adjustment range, and the current CMOS exposure time has reached the upper limit threshold of the CMOS exposure time adjustment range, and the average brightness is less than the target brightness, then enter the light source brightness adjustment range. S64: If the current CMOS gain adjustment range is in the CMOS gain adjustment range, and the current CMOS gain has reached the lower limit threshold of the CMOS gain adjustment range, and the average brightness is greater than the target brightness, then enter the light source brightness adjustment range. S65: If the conditions of S61 to S64 are not met, the current adjustment range remains unchanged; The image brightness adjustment method further includes: initializing the dimming device, wherein the initialization state of the dimming device is: the CMOS exposure time is set to the upper limit threshold E of its adjustment range. 上 The light source brightness is set to the middle value within its adjustment range, and the CMOS gain is set to the lower limit threshold G of its adjustment range. 下 .

2. The image brightness adjustment method according to claim 1, characterized in that: The adjustment ratio coefficient is equal to the ratio of the target brightness to the average brightness raised to the power of a, where a is a constant and 0 < a < 1.

3. The image brightness adjustment method according to claim 1, characterized in that, The method for adjusting the image brightness within the current adjustment range according to the adjustment ratio coefficient includes: multiplying the parameter value of the current frame image within the current adjustment range by the adjustment ratio coefficient corresponding to the adjustment range to obtain the parameter value of the next frame image.

4. The image brightness adjustment method according to claim 3, characterized in that: If the result of multiplying the parameter value of the current frame image in the current adjustment range by the adjustment ratio coefficient corresponding to the adjustment range is greater than the upper limit threshold of the adjustment range, then the parameter value of the next frame image will be adjusted to the upper limit threshold. If the result of multiplying the adjustment value of the current adjustment range by the adjustment ratio coefficient corresponding to the adjustment range is less than the lower limit threshold of the adjustment range, then the parameter value of the next frame image will be adjusted to the lower limit threshold.

5. The image brightness adjustment method according to claim 1, characterized in that, The lower limit threshold of the adjustment range of the adjustment interval is greater than or equal to P times the minimum adjustment step size of the adjustment parameter of the adjustment interval, where P > 1.

6. The image brightness adjustment method according to any one of claims 1 to 5, characterized in that: The image brightness adjustment method is performed during the gap between the data transmission times of two image frames. Each image frame is adjusted once by the image brightness adjustment method, and the image brightness adjustment method is repeated until the adjustment is completed.

7. A dimming device, characterized in that, The dimming device includes a CMOS exposure time adjustment range, a light source brightness adjustment range, and a CMOS gain adjustment range. The dimming device also includes: The parameter acquisition module is used to acquire the average brightness of the current frame image and the preset target brightness; The judgment module determines the current adjustment range and the magnitude of the average brightness and the target brightness. The calculation module calculates the adjustment ratio coefficient of the current adjustment range based on the average brightness and the target brightness; The control module adjusts the image brightness using the image brightness adjustment method as described in any one of claims 1 to 6.

8. An endoscope, characterized in that, include: The dimming device as described in claim 7.

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