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CN-121989552-A - High-fidelity printed card image reproduction method and system based on dynamic color calibration

CN121989552ACN 121989552 ACN121989552 ACN 121989552ACN-121989552-A

Abstract

The invention discloses a high-fidelity printed card image reproduction method and a system based on dynamic color calibration, aiming at solving the problem of color distortion caused by environmental change, material difference and equipment drift. According to the method, a physical standard color card is arranged on each card, the hyperspectral imaging is utilized to collect the reflection spectrum of each card in real time and synchronously sense the environmental parameters, a color characteristic curve is dynamically generated by combining a printing material identification technology, and then reverse mapping correction is carried out on an original image, and color drift is automatically compensated in continuous printing through a closed-loop feedback mechanism. The invention realizes the transition from static preset to dynamic self-adaptive calibration, obviously improves the accuracy and batch consistency of color reproduction, and is suitable for the high-end printing field with extremely high requirements on color fidelity.

Inventors

  • HUANG ZHIWEN
  • CAO DA
  • WEN XUEFENG
  • CAO YANG
  • ZHANG WEIQIANG

Assignees

  • 浙江旺兹文化科技有限公司

Dates

Publication Date
20260508
Application Date
20260120

Claims (10)

  1. 1. A method for reproducing an image of a high fidelity printed card based on dynamic color calibration, the method comprising: Before the printing operation is started, uniformly irradiating a standard color card area arranged on the surface of a printed card through a standard light source lighting device; Collecting reflection spectrum data of the standard color card area in the current environment by using a hyperspectral imaging sensor, and synchronously acquiring environment temperature and humidity parameters; Performing spectrum matching calculation based on the reflection spectrum data and a pre-stored standard color card reference spectrum database to generate a color characteristic curve of the current batch of printed cards; Inputting the color characteristic curve to a color conversion engine, performing inverse mapping correction on color space coordinates of an original digital image, and generating a corrected device-independent color description file; And loading the device-independent color description file to a printing control unit, and driving a printing head to execute ink-jet or transfer printing operation according to the corrected color parameters to complete high-fidelity image reproduction.
  2. 2. The method for reproducing a high-fidelity printed card image based on dynamic color calibration according to claim 1, wherein: the standard color card area is composed of 16 non-fluorescent standard color blocks, the color blocks are distributed to cover a high saturation area, a neutral gray axis and skin color key points, the area of each color block is not smaller than five square millimeters, and the color blocks are embedded in a non-visible corner area of the printed card in a matrix mode.
  3. 3. The method for reproducing a high-fidelity printed card image based on dynamic color calibration according to claim 2, wherein: The spectral response range of the hyperspectral imaging sensor is 380-780nm, the spectral resolution is 5nm, the spatial resolution is 120px/mm, and the optical lens is provided with an automatic focusing module and a polarizing filter for eliminating the specular reflection interference of the surface of the printing material.
  4. 4. A method of image reproduction of a high fidelity printed card based on dynamic color calibration according to claim 3, wherein: The standard color card reference spectrum database is stored in the local solid-state memory and comprises actual measurement reflection spectrum sets of the same standard color card on different printing base materials, the printing base materials comprise white cardboard, pearlescent paper, metal coated paper and PVC composite materials, and each base material corresponds to a group of reference spectrum data calibrated by a laboratory spectrophotometer.
  5. 5. The method for reproducing the image of the high-fidelity printed card based on the dynamic color calibration according to claim 4, wherein the spectrum matching calculation adopts a least square method to construct a linear transformation matrix between the current reflection spectrum and the reference spectrum, and specifically comprises the following steps: Normalizing the collected 16-channel reflection spectrum vector; calculating Euclidean distance between the base material and each reference spectrum vector under the corresponding base material category in the database; selecting a reference spectrum with the smallest distance as a matching object; And solving a third-order polynomial correction coefficient based on the deviation of the matching object and the actually measured spectrum to generate a dynamic color characteristic curve applicable to the current printing batch.
  6. 6. The method for reproducing a high-fidelity printed card image based on dynamic color calibration according to claim 5, wherein: The color conversion engine adopts a three-dimensional lookup table structure, the input of the three-dimensional lookup table structure is sRGB color coordinates of an original image, the output of the three-dimensional lookup table structure is corrected CMYK four-color dot percentage values, the node spacing of the three-dimensional lookup table is eight units, interpolation operation is carried out in Lab space, and the interpolation algorithm adopts a three-linear interpolation method to ensure that color transition is smooth and has no step.
  7. 7. The method for reproducing the image of the high-fidelity printed card based on the dynamic color calibration according to claim 6, wherein the system automatically triggers an on-line color monitoring process according to a preset interval in the continuous printing process, wherein the preset interval is N cards per printing, N is a positive integer and the default value is 50, and the on-line color monitoring process specifically comprises: the hyperspectral imaging sensor scans the standard color card area on the new printed card again, and calculates the delta E2000 color difference value between the current actual output color and the target color; if the color difference value is larger than 1.5, the color characteristic curve is immediately updated and reloaded to the printing control unit, so that closed-loop dynamic calibration is realized.
  8. 8. The method for reproducing a high-fidelity printed card image based on dynamic color calibration of claim 7, wherein: the environmental temperature and humidity parameters are acquired in real time by a digital temperature and humidity sensor integrated on a printing platform, the sampling frequency is once per second, and when the environmental temperature deviates from 25 ℃ by more than +/-3 ℃ or the relative humidity deviates from the absolute value of 50%RH by more than 10 percentage points, the image size and the screen point position are automatically subjected to micron-scale displacement correction, so that overprinting errors caused by substrate deformation are prevented.
  9. 9. A high-fidelity printed card image reproduction system based on dynamic color calibration, comprising: The standard light source illumination device is used for vertically illuminating a standard color card area on the printed card under the condition of constant color temperature of five kilokelvin and illuminance of one kilokelvin; the hyperspectral imaging sensor is used for collecting reflection spectrum data of the standard color card area; The environment sensing module is used for monitoring the temperature and the humidity of the printing environment in real time; The local storage unit is used for storing a standard color card reference spectrum database and a history calibration record; the color processing unit is internally integrated with a spectrum matching calculation module, a color characteristic curve generation module and a color conversion engine; the printing control unit is used for receiving the corrected color parameters and controlling the printing execution mechanism to finish image output; the closed loop feedback module is used for periodically verifying the output color precision and triggering calibration update in the continuous printing process; And the printing material identification module is used for identifying the type of the printing substrate of the current printed card based on the near infrared spectrum characteristics and sending a substrate type signal to the local storage unit so as to call the corresponding reference spectrum data.
  10. 10. The dynamic color calibration-based high-fidelity printed card image reproduction system of claim 9, wherein: The color processing unit adopts a special image signal processor chip, a spectrum processing instruction set is solidified in the color processing unit, 16-channel parallel spectrum data stream processing is supported, and the time for generating a single color characteristic curve is not more than 200 milliseconds; The printing control unit and the printing execution mechanism are communicated through the industrial real-time Ethernet, the communication period is one millisecond, and the color parameter updating instruction is ensured to be effective in the next printing period.

Description

High-fidelity printed card image reproduction method and system based on dynamic color calibration Technical Field The invention relates to the technical field of high-end printing and industrial automation, in particular to a method and a system for reproducing a high-fidelity printed card image based on dynamic color calibration. Background With the vigorous development of the digital entertainment industry, game cards are used as solid media integrating collection, competition and artistic expression, and have huge user groups and highly active market ecology in the global scope. High-fidelity image reproduction is one of the core requirements of game card manufacture, and is directly related to the visual appeal, brand recognition and anti-counterfeiting capability of the card. Currently, a static color configuration scheme based on a standard color card (such as Pantone or ISO 12647) is generally adopted in the mainstream printing process, and mass production is realized through preset CMYK or spot color ink proportions. However, the method has significant limitations in practical application, such as aging of printing equipment, fluctuation of ambient temperature and humidity, batch difference of printing materials and tiny chromatic aberration among ink batches, which can cause the final output color to deviate from a designed manuscript, and particularly has obvious manifestation in complex color gamut areas such as gradual change, metallic color or fluorescent color. In addition, the game card always needs to keep consistent visual effect under different illumination conditions, but static calibration cannot dynamically compensate color perception difference of human eyes under different light sources, so that the phenomenon of 'same card different colors' is caused, and user experience and product consistency are seriously affected. In the prior art, part of high-end printing systems introduce an online spectrophotometer for color detection and combine with ICC profiles for one-time correction. However, such a scheme usually performs a single calibration only before the printing operation starts, and cannot cope with the dynamic drift continuously occurring in the printing process, and meanwhile, the calibration model is mostly based on the assumption of general paper and standard light source, and is not optimized for special materials (such as pearlescent film and laser film) and specific ornamental scenes (such as indoor LED lamps and sunlight) commonly used for game cards. More importantly, the existing flow lacks modeling of subjective visual perception characteristics of human eyes, so that the measured value of an instrument is disjointed from the actual look and feel of a user. Therefore, in the field of game card printing with high added value and high visual requirement, a high-fidelity image reproduction method and system capable of fusing multidimensional sensing data, dynamically updating color mapping relation and considering human eye perception consistency are needed. Disclosure of Invention In view of this, the present invention provides a method and a system for reproducing images of high-fidelity printed cards based on dynamic color calibration, so as to solve the problem of color distortion caused by environmental changes, material differences and equipment drift in the prior art, thereby realizing high-fidelity and high-consistency image reproduction. A method of high fidelity printed card image reproduction based on dynamic color calibration, the method comprising: Before the printing operation is started, uniformly irradiating a standard color card area arranged on the surface of a printed card through a standard light source lighting device; Collecting reflection spectrum data of the standard color card area in the current environment by using a hyperspectral imaging sensor, and synchronously acquiring environment temperature and humidity parameters; Performing spectrum matching calculation based on the reflection spectrum data and a pre-stored standard color card reference spectrum database to generate a color characteristic curve of the current batch of printed cards; Inputting the color characteristic curve to a color conversion engine, performing inverse mapping correction on color space coordinates of an original digital image, and generating a corrected device-independent color description file; And loading the device-independent color description file to a printing control unit, and driving a printing head to execute ink-jet or transfer printing operation according to the corrected color parameters to complete high-fidelity image reproduction. In the above method, optionally, the standard color card area is formed by 16 non-fluorescent standard color blocks, the color blocks are distributed to cover a high saturation area, a neutral gray axis and a skin color key point, and each color block area is not less than five square millimeters and is embedded in a non-visibl