Historical image file digitization method based on digital intermediate sheet technology

Abstract

The invention belongs to the technical field of archive digitization, and particularly discloses a historical image archive digitization method based on a digital intermediate sheet technology. The method comprises the following steps: carrying out pixel information acquisition on an original film by using an equivalent full-frame macro lens; after multiple groups of pixel matrixes with different exposures are sampled, performing high dynamic range image synthesis on sample data to obtain a digital negative film; converting the digital negative film into a positive film through image flipping to obtain a digital intermediate film; and performing digital image restoration on the digital intermediate sheet to obtain a digital image. According to the scheme, the technical problems of low digital resolution, low reduction degree and low utilization rate of a traditional historical image file are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of archive digitization, and in particular relates to a method for digitizing historical image archives based on digital intermediate film technology. Background Art

[0002] Archives departments store a large number of historical image archives on traditional carriers. They are of great value and have great demand for use. The digitization of traditional historical image archives is to separate the archival content information on traditional carriers and store them in digital archives, thereby reducing the frequency of use of the original archives and protecting the original archives.

[0003] The digitization of traditional historical media image archives is generally carried out by scanning and digitizing, and the scanned objects are photos. Due to the technical limitations of traditional film printing, the printed photos lose a lot of picture details, and scanning the photos will further reduce the picture details. Therefore, a scanned and transcribed electronic photo often has only a few hundred KB of data. However, the original data volume of the film is surprisingly large. Taking the commonly used 135 silver halide film as an example, the calculation formula for its theoretical maximum recorded data volume is as follows: 135 film data volume z (bit) = the state number of photosensitive ions a (bit) × ln (the number of photosensitive ion group layers x (Count) + 1) × 135 film area b (um^) / the area of ​​the photosensitive ion group y (um^). Since silver salt can only record two states: photosensitive and non-photosensitive, a = 1; the diameter of the ion group of silver bromide positive film is generally 0.3um, and the shape is approximately a cube; the number of photosensitive ion group layers is generally 14-17 (we take 15 for convenience of calculation). The calculation result is: 1*ln(15+1)*36*24*10^6 / 0.3^2=38400*10^6, the data volume is about 38.4G bits, which is equivalent to 4.8GByte, a whole single-layer DVD.

[0004] By comparison, it can be seen that the digital image archives obtained by traditional scanning technology have huge information missing, resulting in low resolution and low restoration degree. At the same time, it cannot meet the role that historical image archives should play in corporate development and archival work. Summary of the invention

[0005] The purpose of the present invention is to provide a method for digitizing historical image archives based on digital intermediate film technology to solve the technical problems of low resolution, low restoration and low utilization rate of traditional digitization of historical image archives.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for digitizing historical image archives based on digital intermediate film technology includes: using an equivalent full-frame macro lens to collect pixel information from original film; after sampling multiple groups of pixel matrices with different exposures, synthesizing the sample data into high dynamic range images to obtain a digital negative film; converting the digital negative film into a positive film by image flipping to obtain a digital intermediate film; and performing digital image restoration on the digital intermediate film to obtain a digitized image.

[0008] A historical image archive digitization system based on digital intermediate film technology includes: an acquisition unit for acquiring pixel information of original film using an equivalent full-frame macro lens; a synthesis unit for performing high dynamic range image synthesis on sample data after sampling multiple groups of pixel matrices with different exposures to obtain a digital negative film; a conversion unit for converting the digital negative film into a positive film by image flipping to obtain a digital intermediate film; and a restoration unit for performing digital image restoration on the digital intermediate film to obtain a digitized image.

[0009] A computer-readable storage medium stores a computer program, wherein the computer program is configured to execute the above-mentioned historical image archive digitization method based on digital intermediate film technology when running.

[0010] An electronic device includes a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the method for digitizing historical image archives based on digital intermediate film technology through the computer program.

[0011] In the present invention, pixel information of the original film is collected by utilizing an equivalent full-frame macro lens; after sampling a plurality of groups of pixel matrices with different exposures, high dynamic range image synthesis is performed on the sample data to obtain a digital negative; the digital negative is converted into a positive by image flipping to obtain a digital intermediate; digital image restoration is performed on the digital intermediate to obtain a digitized image, thereby restoring the information on the original film to the greatest extent through pixel matrix information collection, high dynamic range image synthesis, and digital image restoration, thereby solving the technical problems of low resolution, low restoration degree, and low utilization rate of the traditional digitization of historical image archives, and achieving the technical effects of high resolution, high restoration degree, and high utilization rate of the digitization of image archives. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of a process of a method for digitizing historical image archives based on digital intermediate technology in an embodiment of the present invention;

[0013] Figure 2 It is a schematic diagram of an implementation process of a method for digitizing historical image archives based on digital intermediate technology in an embodiment of the present invention;

[0014] Figure 3 It is a schematic diagram of a specific example of a method for digitizing historical image archives based on digital intermediate technology and a traditional method in an embodiment of the present invention;

[0015] Figure 4 It is a structural schematic diagram of a historical image archive digitization system based on digital intermediate film technology in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0017] It should be noted that, in order to clearly explain the content of the present invention, the present invention specifically cites multiple embodiments to further illustrate different implementations of the present invention, wherein the multiple embodiments are enumerated rather than exhaustive. In addition, for the sake of brevity of explanation, the contents mentioned in the previous embodiments are often omitted in the subsequent embodiments. Therefore, the contents not mentioned in the subsequent embodiments can refer to the previous embodiments accordingly.

[0018] Example 1

[0019] A method for digitizing historical image archives based on digital intermediate technology, such as Figure 1 As shown, the method includes:

[0020] S102, collecting pixel information of the original film using an equivalent full-frame macro lens;

[0021] S104, after sampling multiple groups of pixel matrices with different exposures, synthesizing the sample data into high dynamic range images to obtain a digital negative film;

[0022] S106, converting the digital negative film into a positive film by image flipping to obtain a digital intermediate film;

[0023] S108, performing digital image restoration on the digital intermediate film to obtain a digitized image.

[0024] Optionally, the method for digitizing historical image archives based on digital intermediate technology includes but is not limited to the steps of pixel matrix information acquisition, high dynamic range image synthesis, and digital image restoration, thereby displaying the information of the original film.

[0025] In pixel matrix acquisition, not limited to the darkroom, a macro lens is used to capture pixel information of the original film, and a reference digital negative is obtained through exposure.

[0026] As an optional implementation, before collecting pixel information of the original film using an equivalent full-frame macro lens, the method further includes: placing a light box in a dark room and ensuring that the light box is the single light source when collecting pixel information.

[0027] In a darkroom, including but not limited to light boxes, the light boxes are placed in the darkroom to block natural light from entering, ensuring that the light source of the light box is a single light source when collecting information. There are not limited to no obstructions around the light box, so as to prevent the reflection of the light box light source from affecting the sampling results. The brightness of the light box is not limited to be greater than or equal to 25000LUX.

[0028] As an optional implementation, pixel information of the original film is collected using an equivalent full-frame macro lens, including: adjusting the brightness of the light box to a preset value and fixing the original film on the light box; and collecting pixel information of the original film in a dark room using an equivalent full-frame macro lens.

[0029] As an optional implementation, using an equivalent full-frame macro lens to collect pixel information from the original film includes: using a macro lens adjusted to preset parameters to collect pixel information from the original film.

[0030] It is not limited to ensuring that when the aperture coefficient of the acquisition device is ≥ F12, there is still sufficient light input during the information acquisition process of the original film, so as to eliminate the influence of the depth of field on the image quality of the acquisition result. The macro lens is not limited to using a 100mm equivalent full-frame macro lens to capture pixel information of the original film. By reducing the object distance, the information accuracy of the original film pixel capture is improved, and the image of the final sampling result is reduced due to lens distortion.

[0031] The pixel matrix acquisition sensitivity (ISO) setting is not limited to being equal to or less than the camera's baseline sensitivity, ensuring that the photosensitive components are in the best working state and reducing the generation of noise, ghosting, and artifacts. The image recording mode is set to RAW format to ensure that the color data within the wide color gamut of the sampled recording information is accurate and to obtain the maximum amount of collected data, which is conducive to the accuracy of the later acquisition data reconstruction.

[0032] Keep the camera aperture setting and the relative position with the film unchanged, and shoot digital negatives with multiple exposures in sequence by adjusting the camera shutter speed; collect and obtain detailed information characteristics of the film under various brightness conditions.

[0033] As an optional implementation, performing multiple sets of pixel matrix sampling with different exposures includes: fixing the relative distance between the camera and the original film; and performing multiple sets of pixel matrix sampling with different exposures by adjusting the camera shutter speed.

[0034] As an optional implementation, high dynamic range image synthesis is performed on the sample data to obtain a digital negative, including: synthesizing the information features of the original film obtained by multiple exposure acquisitions under various brightness conditions into a digital negative containing complete highlights and shadow details.

[0035] After obtaining multiple sets of pixel matrix samples with different exposures, the sample data is synthesized into high dynamic range images, and detailed information features of the film under various brightness conditions are obtained by collecting under different exposure modes, and synthesized into a digital negative film containing complete highlights and dark details. The digital negative film is converted into a positive film by image flipping to obtain a digital intermediate film.

[0036] As an optional implementation, performing digital image restoration on the digital intermediate to obtain a digitized image includes: performing damage restoration, color adjustment, and high contrast processing on the digital intermediate to obtain a digitized image.

[0037] As an optional implementation, the digital intermediate film is damaged and repaired, including: repairing image scratches, light leakage, mildew spots, and wrinkles of the digital intermediate film.

[0038] As an optional implementation, high contrast processing is performed on the digital intermediate to obtain a digitized image, including: high contrast preservation processing is performed on a copy layer of the digital intermediate; and it is superimposed with the original layer to obtain a digitized image.

[0039] Digital image restoration is not limited to repairing film defects such as scratches, light leakage, mildew, wrinkles, etc., and restoring the historical appearance of the film. Through image comparison, compared with traditional film restoration methods, digital intermediate film technology eliminates the risk of damage to the film during the restoration process and preserves the original information of the film to the greatest extent. The overall image is clearer and brighter, and the details are more complete and true. At the same time, it is not limited to outputting RAW and JPEG formats to cope with different usage scenarios.

[0040] Specifically, the above-mentioned historical image archive digitization method based on digital intermediate film technology, when producing the digital intermediate film of the historical image archive, restores the information on the original film to the greatest extent through pixel matrix information collection, high dynamic range image synthesis, and digital image restoration. Figure 2 As shown, the following steps are included:

[0041] The first step is to place the light box in the dark room to block the entry of natural light and ensure that the light source of the light box is a single light source during data collection. There are no obstructions around the light box to prevent the reflection of the light source from affecting the sampling results. The brightness must be greater than or equal to 25000LUX. To ensure that there is still sufficient light input when the aperture coefficient of the acquisition device is ≥F12 during the information collection process of the original film, so as to eliminate the impact of the depth of field on the image quality of the acquisition results. Use a 100mm equivalent full-frame macro lens to capture pixel information of the original film. By reducing the object distance, the accuracy of the information captured by the original film pixels is improved, and the image of the final sampling result is reduced due to lens distortion. After the preparation work is completed, clean the dust on the surface of the film, place the film in a dark room, adjust the brightness of the light box to 25000LUX, and fix the film on the light box.

[0042] The second step is to collect pixel matrix, and set the sensitivity (ISO) to the base sensitivity to ensure that the photosensitive components are in the best working state and reduce the generation of noise, ghosting, and artifacts. The image recording mode is set to RAW format to ensure the accuracy of the color data within the wide color gamut of the sampled recording information, and to obtain the maximum amount of collected data, so as to facilitate the accuracy of the later data collection and reconstruction. The aperture coefficient is ≥ F12, and a macro lens is used to keep the camera aperture setting and the relative position with the film unchanged. By adjusting the shutter speed, continuous sampling is performed, and digital negatives with multiple exposures of -1EV, -0.5EV, 0.5EV, and 1EV are shot in turn to obtain detailed information characteristics of the film under various brightness conditions.

[0043] The third step is to obtain multiple sets of pixel matrix samples with different exposures, import the image samples into the computer, perform high dynamic range synthesis, and use different exposure modes to obtain detailed information characteristics of the film under various brightness conditions, and synthesize them into a digital negative film containing complete highlights and dark details. The negative film is flipped by image flipping to obtain a positive film, and a digital intermediate film is obtained.

[0044] The fourth step is to perform digital image restoration. Digitally restore the damaged parts, repair the film defects such as scratches, light leakage, mildew, wrinkles, etc., and restore the historical appearance of the film. Adjust the color and restore the normal white balance; copy the layer, retain the high contrast, and superimpose the original layer to obtain a digitized image. The comparison between this method and the traditional method for image digitization is not limited to the following: Figure 3 As shown in the figure, through image comparison, compared with traditional film restoration methods, digital intermediate technology eliminates the risk of film damage during the restoration process and preserves the original information of the film to the greatest extent. The overall image is clearer and brighter, and the details are more complete and real. Output RAW and JPEG formats to cope with different usage scenarios.

[0045] In the embodiment of the present application, the digital intermediate film technology is used to realize the digitization of historical image archives. Through high dynamic range digital scanning, the image is digitized with high resolution. On this basis, a series of work such as editing, repairing, and color processing are performed and the final image file is completed. Compared with traditional image scanning, the overall picture of the digital intermediate film image is clearer and brighter, and the detailed information is more complete and true. After digital transcription and encoding processing, it can be stored in the computer archive management system platform. It has the characteristics of low cost, small memory, and high reliability. It can make the storage, retrieval, processing, and retrieval of historical image archives more convenient, improve the efficiency of archive management, and the digital intermediate film technology design meets the needs of historical image archives in enterprise development and archive work.

[0046] Example 2

[0047] A historical image archive digitization system based on digital intermediate technology, such as Figure 4 As shown, the system includes:

[0048] The acquisition unit 402 is used to acquire pixel information of the original film using an equivalent full-frame macro lens;

[0049] A synthesis unit 404 is used to synthesize high dynamic range images of sample data after sampling multiple groups of pixel matrices with different exposures to obtain a digital negative film;

[0050] A conversion unit 406, configured to convert the digital negative film into a positive film by image flipping to obtain a digital intermediate film;

[0051] The restoration unit 408 is used to perform digital image restoration on the digital intermediate to obtain a digitized image.

[0052] Optionally, before the acquisition unit 402 uses an equivalent full-frame macro lens to acquire pixel information from the original film, the method further includes: placing a light box in a dark room and ensuring that the light box is a single light source when acquiring pixel information.

[0053] Optionally, the acquisition unit 402 acquires pixel information of the original film using an equivalent full-frame macro lens, including: adjusting the brightness of the light box to a preset value and fixing the original film on the light box; and acquiring pixel information of the original film using an equivalent full-frame macro lens in a dark room.

[0054] Optionally, the acquisition unit 402 acquires pixel information from the original film using an equivalent full-frame macro lens, including: acquiring pixel information from the original film using a macro lens adjusted to preset parameters.

[0055] Optionally, the acquisition unit 402 performs a plurality of pixel matrix samplings with different exposures, including: fixing the relative distance between the camera and the original film; and performing a plurality of pixel matrix samplings with different exposures by adjusting the camera shutter speed.

[0056] Optionally, the synthesis unit 404 performs high dynamic range image synthesis on the sample data to obtain a digital negative, including: synthesizing information features of the original film obtained by multiple exposure acquisitions under various brightness conditions into a digital negative containing complete highlights and shadow details.

[0057] Optionally, the restoration unit 408 performs digital image restoration on the digital intermediate to obtain a digitized image, including: performing damage restoration, color adjustment, and high contrast processing on the digital intermediate to obtain a digitized image.

[0058] Optionally, the repair unit 408 performs damage repair on the digital intermediate film, including: repairing image scratches, light leakage, mildew spots, and wrinkles on the digital intermediate film.

[0059] Optionally, the restoration unit 408 performs high contrast processing on the digital intermediate to obtain a digitized image, including: performing high contrast retention processing on a copy layer of the digital intermediate; and superimposing it with the original layer to obtain a digitized image.

[0060] In an embodiment of the present application, pixel information of the original film is collected by utilizing an equivalent full-frame macro lens; after sampling multiple groups of pixel matrices with different exposures, the sample data is subjected to high dynamic range image synthesis to obtain a digital negative; the digital negative is converted into a positive by image flipping to obtain a digital intermediate; the digital intermediate is digitally restored to obtain a digitized image, thereby restoring the information on the original film to the greatest extent through pixel matrix information collection, high dynamic range image synthesis, and digital image restoration, thereby solving the technical problems of low resolution, low restoration, and low utilization rate of the traditional digitization of historical image archives, and achieving the technical effect of high resolution, high restoration, and high utilization rate of the digitization of image archives.

[0061] Example 3

[0062] Another aspect of the embodiments of the present invention further provides an electronic device for implementing the above-mentioned method for digitizing historical image archives based on digital intermediate technology, and the electronic device is not limited to being a terminal device or a server in the system. The electronic device is not limited to including a memory and a processor, the memory stores a computer program, and the processor is configured to execute the steps in any of the above-mentioned method embodiments through the computer program.

[0063] Example 4

[0064] Another aspect of the embodiments of the present invention provides a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method provided in various optional embodiments of the method for digitizing historical image archives based on digital intermediate technology. The computer program is configured to execute the steps of any of the above method embodiments when it is run.

Claims

1. A method for digitizing historical image archives based on digital intermediate technology, characterized in that: include: Use an equivalent full-frame macro lens to collect pixel information from the original film; After sampling multiple sets of pixel matrices with different exposures, the sample data is synthesized into high dynamic range images to obtain a digital negative film; The digital negative is converted into a positive film by image flipping to obtain a digital intermediate film; Perform digital image restoration on the digital intermediate film to obtain a digitized image.

2. The method for digitizing historical image archives based on digital intermediate technology according to claim 1, characterized in that: Before collecting pixel information of the original film using an equivalent full-frame macro lens, it also includes: Place the light box in a dark room and ensure that the light box is the only light source when collecting pixel information.

3. The method for digitizing historical image archives based on digital intermediate technology according to claim 2, characterized in that: Use an equivalent full-frame macro lens to collect pixel information from the original film, including: Adjust the brightness of the light box to the preset value and fix the original film on the light box; In a darkroom, pixel information of the original film is collected using an equivalent full-frame macro lens.

4. The method for digitizing historical image archives based on digital intermediate technology according to claim 1, characterized in that: Use an equivalent full-frame macro lens to collect pixel information from the original film, including: The pixel information of the original film is collected using a macro lens adjusted to preset parameters.

5. The method for digitizing historical image archives based on digital intermediate technology according to claim 1, characterized in that: Perform pixel matrix sampling of multiple groups with different exposures, including: Fix the relative distance between the camera and the original film; By adjusting the camera shutter speed, multiple sets of pixel matrix sampling with different exposures are performed.

6. The method for digitizing historical image archives based on digital intermediate technology according to claim 1, characterized in that: The sample data is synthesized into a high dynamic range image to obtain a digital negative film, including: The information features of the original film obtained under various brightness conditions by multiple sets of exposure collection are synthesized into a digital negative film containing complete highlights and shadow details.

7. The method for digitizing historical image archives based on digital intermediate technology according to claim 1, characterized in that: Performing digital image restoration on the digital intermediate to obtain a digitized image includes: The digital intermediate film is damaged and repaired, color adjusted, and subjected to high contrast processing to obtain a digitized image.

8. The method for digitizing historical image archives based on digital intermediate technology according to claim 7, characterized in that: Repairing the digital intermediate film, including: The digital intermediate film is damaged and repaired for scratches, light leakage, mildew spots and wrinkles.

9. The method for digitizing historical image archives based on digital intermediate technology according to claim 7, characterized in that: The digital intermediate film is subjected to high contrast processing to obtain a digitized image, including: performing high contrast preservation processing on the digital intermediate copy layer; Superimpose with the original layer to obtain a digital image.

10. A historical image archive digitization system based on digital intermediate technology, characterized in that: include: An acquisition unit, used for acquiring pixel information of the original film using an equivalent full-frame macro lens; A synthesis unit, for synthesizing the sample data into high dynamic range images after sampling multiple sets of pixel matrices with different exposures, to obtain a digital negative film; A conversion unit, used for converting a digital negative film into a positive film by image flipping to obtain a digital intermediate film; The restoration unit is used to perform digital image restoration on the digital intermediate film to obtain a digitized image.

Images