A method for improving image quality

Abstract

The present application relates to the technical field of improving image quality, and discloses a method for improving image quality, which comprises the following steps: printing pretreatment; image recognition of each page to be printed by a printer firmware; if the page contains an image with a large difference in pixel value from other contents, the next step is performed; if no image is recognized, normal printing processing is performed without special interference, and the processing before step S2 is returned; the number of lines where the entire image is located is recorded; the pixel difference between the image and other images is analyzed, and the light power offset value to be adjusted is calculated; when the LSU is exposed, the light power of the LSU is finely adjusted only for the lines where the image is located; and finally, development is performed, and if no development is performed, the processing before step S2 is returned, so that fine lines can be clearly printed out without affecting the density of other images, the light power of the LSU is finely adjusted for local fine lines, and the printing quality is improved and the use cost of users is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of improving image quality, and particularly to a method for improving image quality. BACKGROUND

[0002] At present, the control of printing density in the laser printer industry is realized by adjusting the high voltage value or the light power of LSU for the whole operation. If the content in the same page of the document printed by the user is mixed with some thin lines.

[0003] If the thin lines are printed according to the unified density, the printed thin lines will be relatively blurred, and even the broken line phenomenon will occur; if the high voltage value and the light power of LSU are adjusted to be higher in order to make the thin lines clearer, the printing effect of the thin lines will be certainly clearer; however, the content other than the thin lines will be printed to be thicker, which will affect the printing quality, and the image density that should not be adjusted is adjusted to be too high, and even the fixing process will be affected; on the other hand, the toner is wasted, and the use cost of the user is increased. Therefore, a corresponding technical solution needs to be designed to solve the problem. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the defects in the prior art, the present application provides a method for improving image quality, which solves the technical problems that the thin lines printed according to the unified density are relatively blurred, and even the broken line phenomenon occurs, and the content other than the thin lines is printed to be thicker, which affects the printing quality, and the image density that should not be adjusted is adjusted to be too high, and even the fixing process is affected, and on the other hand, the toner is wasted, and the use cost of the user is increased.

[0006] (II) Technical scheme

[0007] In order to achieve the above object, the present application is realized by the following technical scheme: a method for improving image quality, the method steps include the following:

[0008] S1, printing pretreatment;

[0009] S2, image recognition of the printer firmware for each page to be printed;

[0010] S3, if the page contains an image with a large difference in pixel value from other content, the next step is performed;

[0011] S4, if no special interference is needed, the normal printing process can be performed, and the previous step S2 is reprocessed;

[0012] S5, the number of lines where the entire image is located is recorded;

[0013] S6, analyze the pixel difference between the image and other images, and calculate the light power offset value that needs to be adjusted;

[0014] S7, during LSU exposure, only for the line where the image is located, fine-tune the LSU light power;

[0015] S8, finally develop, if not developed back to step S2 reprocessing.

[0016] Preferably, when collecting data for LSU light power compensation experiment, the following environmental factors need to be considered: temperature, humidity, altitude, atmospheric pressure, wind speed, dust pollution, radiation, electromagnetic radiation, vibration, power supply voltage, light path and EMI protection.

[0017] Preferably, in step S6, the specific steps of analyzing the pixel difference between the image and other images are as follows:

[0018] Analyze the pixel difference;

[0019] Align the image A to be improved in quality with the high-quality reference image B;

[0020] Calculate the difference between the two images at each pixel position to obtain a difference image C;

[0021] Each pixel value in C is the pixel difference of A relative to B.

[0022] Preferably, in step S6, the specific steps of calculating the light power offset are as follows:

[0023] Assume that the quality of the image is mainly caused by light intensity non-uniformity;

[0024] Statistically analyze the difference image C to obtain the average difference value of each region;

[0025] According to empirical data, establish a corresponding relationship between the pixel difference and the light power offset value that needs to be adjusted;

[0026] According to the corresponding relationship, calculate the light power offset compensation value of each region according to the average difference value of each region in C;

[0027] Generate a light power offset map L.

[0028] Preferably, in step S6, the adoption of the original image A is compensated;

[0029] Apply the light power offset in L to the corresponding region in the original image A;

[0030] Generate a new image A' after compensation;

[0031] The quality of A' will be improved.

[0032] Preferably, in step S7, the method of fine-tuning the light power for the image line during LSU exposure is as follows:

[0033] Obtain image data and determine the target line that needs to be adjusted;

[0034] According to the photoelectric conversion characteristics, a corresponding relationship model between the target line pixel data and the LSU light power is established;

[0035] Analyze the target line pixel data and calculate the ideal light power value;

[0036] Before LSU exposure, output the light power control voltage for the target line through the DA converter;

[0037] Close-loop control the light power, read the output voltage value of the DA converter in real time, and read the light power data collected by the photodetector;

[0038] Through the PID control algorithm, adjust the output of the DA converter in real time, so that the photodetector reading approaches the ideal light power value calculated;

[0039] During LSU exposure, maintain the stable output of the light power control voltage, and realize the precise adjustment of the light power of the target line;

[0040] After exposure, turn off the light power control and restore the default working mode of the LSU.

[0041] (Three) beneficial effects

[0042] Compared with the prior art, the beneficial effects of the present application are: it ensures that fine lines can be clearly printed out, and does not affect the density of other images; in the case of unchanged overall printing density (unchanged high pressure value and LSU light power), for local fine lines, the printing quality is improved and the user's use cost is reduced through precise adjustment of the LSU light power. BRIEF DESCRIPTION OF DRAWINGS

[0043] Fig. 1 is the flowchart of the present application;

[0044] Fig. 2 is the schematic diagram of the LSU light power compensation value calculation scheme of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0046] Referring to Figs. 1-2 The embodiment of the present application provides a technical scheme: a method for improving image quality, the method steps comprising the following:

[0047] S1, printing pretreatment;

[0048] S2, the printer firmware identifies the image of each page to be printed;

[0049] S3, if the page contains an image with a large difference in pixel value from other content, proceed to the next step;

[0050] S4, if no special interference is identified, normal printing processing can be performed, and the processing before step S2 is returned;

[0051] S5, record the number of rows where the entire image is located;

[0052] S6, analyze the pixel difference between the image and other images, and calculate the light power offset value that needs to be adjusted;

[0053] S7, when the LSU is exposed, only the image row is fine-tuned for the LSU light power;

[0054] S8, finally develop, if not developed, return to the processing before step S2.

[0055] As Fig. 2 shown, the black block is the original pixel of image recognition, and the dark gray block is the LSU light power compensation point.

[0056] Mark 1 is a single point original pixel; Mark 2 is a single point accessory LSU light power compensation; Mark 3 is a single point vertical line LSU light power compensation; Mark 4 is a single point horizontal line LSU light power compensation; Mark 5 is a single point short diagonal line LSU light power compensation; Mark 6 is a single point diagonal line LSU light power compensation.

[0057] LSU (Laser Scanning Unit) is a key component in the printer, which is responsible for scanning the laser beam onto the sensing drum. The LSU light power compensation value is to compensate for the image quality difference caused by laser power fluctuations under different working environments and printing speeds;

[0058] The theoretical calculation of printing speed usually involves parameters such as the speed of the mechanical components of the printer, the scanning speed of the laser beam, and the processing capacity of the printer. Through mathematical models, the relationship between these parameters and the printing speed is described, and based on this, prediction and optimization are carried out.

[0059] Further improvement, when collecting data, the following environmental factors should be considered: temperature, humidity, altitude, atmospheric pressure, wind speed, dust pollution, radiation, electromagnetic radiation, vibration, power supply voltage, light path and EMI protection.

[0060] High temperature or low temperature can affect the output power of the laser and the mechanical performance of the printer; high humidity can cause corrosion of the internal parts of the printer, affecting its performance; the higher the altitude, the thinner the air, which may affect the propagation of the laser; changes in atmospheric pressure will affect the refractive index of the air, thereby affecting light transmission; strong wind will make the optical fiber move, affecting the stability of the light power; the deposition of dust will reduce the light transmittance of the optical fiber; strong radiation such as direct sunlight will affect the stability of the light detector; strong electromagnetic radiation in the surrounding environment may interfere with the optical signal; environmental vibration may cause unstable connection and affect the test results; fluctuations in power supply voltage will also affect the test; the light path needs to be ensured not to move or attenuate; the photoelectric device needs to be temperature-controlled to ensure stable performance; shield the influence of external electromagnetic interference.

[0061] Further improvement, in step S6, the specific steps of analyzing the pixel difference between the image and other images are as follows:

[0062] Analyze the pixel difference;

[0063] Align the image A to be improved in quality with the high-quality reference image B;

[0064] Calculate the difference between the two images at each pixel position to obtain a difference map C;

[0065] Each pixel value in C is the pixel difference of A relative to B.

[0066] Further improvement, in step S6, the specific steps of calculating the light power offset are as follows:

[0067] Assume that the quality of the image is mainly caused by the non-uniformity of light intensity;

[0068] Statistically analyze the difference map C to obtain the average difference value of each region;

[0069] According to the empirical data, establish a corresponding relationship between the pixel difference and the light power offset to be adjusted;

[0070] According to the corresponding relationship, calculate the light power offset compensation value of each region according to the average difference value of each region in C;

[0071] Generate a light power offset map L.

[0072] Further improvement, in step S6, compensate for the adoption of the original image A;

[0073] Apply the light power offset in L to the corresponding area in the original image A;

[0074] Generate a new image A' after compensation;

[0075] The image quality of A' will be improved.

[0076] By analyzing the differences in image content to guide the compensation adjustment of light power, it is an effective method to improve image quality.

[0077] Further improved, the method of fine-tuning the light power of the image line during LSU exposure is as follows:

[0078] Obtain image data and determine the target line that needs to be adjusted;

[0079] According to the photoelectric conversion characteristics, establish a corresponding relationship model between the target line pixel data and the LSU light power;

[0080] Analyze the target line pixel data and calculate its ideal light power value;

[0081] Before LSU exposure, output the light power control voltage of the target line through the DA converter;

[0082] Close-loop control of light power, real-time reading of DA converter output voltage value, and reading of light power data collected by photodetector;

[0083] Through the PID control algorithm, real-time adjustment of the DA converter output makes the photodetector reading close to the ideal light power value calculated;

[0084] During LSU exposure, maintain the stable output of light power control voltage to achieve precise adjustment of the light power of the target line;

[0085] After exposure, turn off the light power control and restore the default working mode of LSU.

[0086] Through the methods of pixel data analysis, modeling fitting, and closed-loop control, the light power of LSU can be adjusted in real time for the image line to achieve precise compensation and improve image quality.

[0087] The components of the present application are all general standard components or components known to those skilled in the art, the structure and principle of which can be known by technical personnel through technical manuals or through conventional experimental methods, the problem solved by the present application is that the fine line printed by the unified concentration is relatively blurred, even the fine line is broken, the content printed outside the fine line is thicker, which affects the printing quality on the one hand, the concentration of some images that should not be adjusted is adjusted too high, which may even affect the fixing, on the other hand, waste toner increases the user's use cost, the present application combines the above components with each other, which can ensure that the fine line can be clearly printed, and does not affect the concentration of other images, in the case that the overall printing concentration is unchanged (the light power of LSU and the high pressure value are unchanged), for the local small line, the light power of LSU is adjusted accurately, the printing quality is improved, and the user's use cost is reduced.

[0088] The above shows and describes the basic principles and main features of the present application and the advantages of the present application, for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0089] In addition, it should be understood that although the present application is described in terms of embodiments, not every embodiment contains only one independent technical solution, the description manner of the specification is only for the sake of clarity, those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method of improving image quality, characterized by, The method steps include the following: S1, printing pre-processing; S2, the printer firmware image recognition for each page to be printed; S3, if the page contains a large difference in pixel value from other content, the next step is performed; S4, if no special interference is identified, normal printing processing can be performed, and the process returns to step S2 for reprocessing; S5, record the number of rows where the entire image is located; S6, analyze the pixel difference between the image and other images, and calculate the light power offset value that needs to be adjusted; The specific steps for analyzing the pixel difference between the image and other images are as follows: Analyze the pixel difference; Align the image A to be improved in quality with the high-quality reference image B; Calculate the difference between the two images at each pixel position to obtain a difference image C; Each pixel value in C is the pixel difference of A relative to B; The specific steps for calculating the light power offset are as follows: Assume that the quality of the image is mainly caused by light intensity non-uniformity; Statistical analysis of difference image C gives the average difference value of each region; According to empirical data, a corresponding relationship between pixel difference and light power offset adjustment is established; According to this corresponding relationship, the light power offset compensation value of each region is calculated based on the average difference value of each region in C; Generate a light power offset map L; Compensate for the adoption of the original image A; Apply the light power offset in L to the corresponding region in the original image A; Generate a new compensated image A'; The quality of A' will be improved; S7, during LSU exposure, only the image row is fine-tuned for the light power of LSU; The method for fine-tuning the light power of the image row during LSU exposure is as follows: Obtain image data to determine the target row that needs to be adjusted; According to the photoelectric conversion characteristics, a corresponding relationship model between the target row pixel data and the light power of LSU is established; Analyze the target row pixel data to calculate the ideal light power value; Before LSU exposure, output the light power control voltage of the target row through the DA converter; Close-loop control the light power, read the output voltage value of the DA converter in real time, and read the light power data collected by the photodetector; Through the PID control algorithm, the output of the DA converter is adjusted in real time to make the photodetector reading approach the ideal light power value calculated; During LSU exposure, the light power control voltage is kept stable to achieve precise adjustment of the light power of the target row; After exposure, the light power control is turned off to restore the default working mode of LSU; S8, finally develop, if not developed, return to step S2 for reprocessing.

2. The method of claim 1, wherein: When collecting data for LSU light power compensation experiments, the following environmental factors need to be considered: temperature, humidity, altitude, atmospheric pressure, wind speed, dust pollution, radiation, electromagnetic radiation, vibration, power supply voltage, light path, and EMI protection.

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