JP4835900B2 - Image processing method and image processing apparatus for image data from a digital camera - Google Patents

Description

The present invention relates to an image processing technique for correcting the density of image data acquired by a digital camera in an image processing apparatus having a density correction algorithm for correcting the density of image data from a photographic film acquired via a film scanner. .

  Conventionally, printing of photographs has been performed by analog exposure in which light is irradiated onto a photographic film on which a shot frame image is formed, and light transmitted through the photographic film is directly irradiated onto photographic paper. Digital exposure in which blue, green, and red monochromatic light is radiated onto photographic paper based on image data obtained by reading a photographed frame image of a film with a film scanner or the like has become common. Various types of photographic prints for performing digital exposure have been proposed. As an example, those for scanning exposure of photographic paper while modulating laser light according to digital image data are widely used. Such a photographic printing apparatus is provided with a light source that generates laser light of each color component of blue, green, and red, and laser light of each color component modulated based on the input image data for each color component. Is deflected in the main scanning direction by a deflector such as a polygon mirror, and is irradiated onto the photographic paper via an optical system such as an fθ lens, and the line exposure is sequentially performed by moving the photographic paper in the sub-scanning direction. The photographed frame image is printed on the photographic paper.

  By the way, in image processing for photographic printing, image data at the time of input obtained by reading a photographed frame image on a photographic film with a scanner or the like is more than image data at the time of output (at the time of monitor display or print production). In general, the gradation is set to be rich (the color is deep). For example, image data input in 12 bits is finally converted into 8-bit image data and used for digital exposure. In this way, the gradation of the input image data is set more abundantly than the gradation of the output image data because the density expression range of the negative film (the same applies to the positive film) is designed to be very wide. This is because the wide density information of the negative film is converted into image data with high accuracy and the gradation of the output image data is matched to the color development characteristics of the photographic paper. In addition, the negative film density expression range is designed to be very wide, even for cameras that do not have an exposure adjustment function (for example, cameras with film), making it possible to shoot properly and even for camera-related amateurs. This is also to enable photography.

  Therefore, in the image processing for producing photographic prints from photographic film, the image data is converted to a gradation that matches the density characteristics (sensitivity characteristics) of the photographic film, and then the density characteristics of the photographic film and the image characteristics of the shot frame image Density correction (image correction) according to the above is performed and converted to a gradation suitable for digital exposure and monitor display. This kind of density correction algorithm is specialized for producing appropriate photographic prints in accordance with the characteristics of photographic film and the shot frame images formed on it, and various correction algorithms are known. Yes. The basic one is a density correction algorithm that makes the average value of the entire image neutral (see, for example, cited document 1). In addition, image portions that require color tone and / or contrast correction were selected from the photographed frame images of photographic film, and the accuracy of color tone and / or contrast reproducibility was improved for the selected image portions. There are also a correction algorithm (see, for example, cited document 2) and a correction algorithm (for example, cited document 3) that appropriately shifts a correction function so that color balance is not lost when density correction is performed while changing the gradation.

Japanese Patent Laid-Open No. 2002-118766 (paragraph numbers 0023-0029)

JP 2004-145399 A (paragraph numbers 0002-0027)

JP 2004-140553 A (paragraph numbers 0010-0026)

Recently, so-called digital cameras that do not use photographic film have become widespread, and there is an increasing demand for producing photographic prints with the above-described photographic printing apparatus from image data of photographed frame images acquired by digital cameras. However, the image data from the digital camera output from the photoelectric conversion element mounted on the digital camera has a density higher than that of the image data acquired through the film scanner with sufficient consideration of the characteristics of the photographic film described above. The characteristics are quite different, and a satisfactory result cannot be obtained even if the image correction algorithm as described above is created for image data from a photographic film. For this reason, in the conventional photo printing apparatus, in addition to the algorithm for correcting the image data from the photographic film, another algorithm for correcting the image data from the digital camera is prepared, or the image data from the digital camera is processed. However, there was only a measure to avoid such basic image correction. However, in the former case, the cost was high, and in the latter case, high quality results were obtained in response to the demand for photographic print output from digital cameras. The problem that it is not possible to give.
In view of the above circumstances, an object of the present invention is to provide an image processing technique capable of performing basic image correction on image data from a digital camera at a minimum cost in order to produce an appropriate photo print in a photo printing apparatus. Is to provide.

An image processing method for correcting the density of image data acquired by a digital camera in an image processing apparatus having a density correction algorithm for correcting the density of image data from a photographic film acquired via a film scanner. In order to solve the problem, the present invention adapts the step of adapting the density characteristics of the image data from the digital camera to the density characteristics of the image data from the photographic film, and the image data from the adapted digital camera as the image data. Ri Do and a step of density correction using a density correction algorithm, the adaptation step, gradient adaptation step for adapting the gradation of the image data of the gradation of the image data from the photographic film from the digital camera And the difference between the sensitivity of photographic film and the sensitivity of a digital camera A sensitivity adaptation step for reducing the density value of the image data from the digital camera to compensate, and a reference density area adaptation step for shifting the density area of the image data from the digital camera to the reference density area of the photographic film. An image processing method including these is proposed.

  In this image processing method, the image data from the digital camera is used for the image data from the photographic film by performing pre-processing to match the density characteristic of the image data from the digital camera to the density property of the image data from the photographic film. Satisfactory results can be obtained even if processed by the density correction algorithm created in the previous section. Since the density correction algorithm itself is also used as a density correction algorithm for image data from photographic film examined through a long history, only a pre-processing step is added, which can be realized at low cost.

General image data has a 8-bit gray scale from the digital camera, since the image data has a 12-bit gradation from photographic film obtained by a film scanner, floors this difference in gradient The furniture adaptation step is solved. In addition, the difference between the sensitivity of photographic film and the image sensor sensitivity of digital cameras, that is, the density range of image data acquired with a general digital camera is much smaller than the density range of photographic film. Compensation step compensates. Furthermore, since the reference density area of the shot frame image formed on the photographic film (density area that produces good color) and the reference density area of the shot frame image with the digital camera are different, the reference density area adaptation step is a digital camera. The reference density area on the side is shifted so that both reference density areas are substantially matched.

この式は、デジタルカメラで一般的な８ビット階調画像データを入力として、写真フィルムからの画像データの特性に類似させた１２ビット階調画像データに変換出力するものである。なお、デジタルカメラの画像データはlog化（自然対数化）されているのでその８ビット入力値はlog値である。８ビット入力値を２５５で除算してlog(4095)を乗算している項は、階調度適合化ステップとして機能し、この演算により８ビット入力値は単純に１２ビット化される。「4095」なる数は１２ビット数値の最大値である。この階調度適合化演算値に１／２を乗算している項は感度適合化ステップとして機能する。つまり、一般的なデジタルカメラで取得される画像データの濃度幅は写真フィルムの濃度幅の１／４と言われているが、本発明者の知見によると、この事実から単純にデジタルカメラの画像データの画素値としての濃度値を１／４にすると濃度幅が狭すぎるので、１／２を乗算することで写真フィルムとの整合性が良くなったのである。さらに、このようない階調度適合化と感度適合化の演算結果を、log(1000)から引き算している項は、基準濃度領域適合化ステップとして機能する。log(1000)は写真フィルムにおいてノーマル濃度と呼ばれる発色が最もよいところであり、この値を基準にしてデジタルカメラからの画像データをシフトさせて、写真フィルムからの画像データの基準濃度領域に近づけている。log(1000)から引き算を行っているのは、後段処理としての濃度補正アルゴリズムがネガフィルムを対象としているため、ここで濃度の反転処理も同時に行っているからである。上述したような簡単な変換式（通常はルックアップテーブル化される）を用いてデジタルカメラからの画像データを前処理するだけで、出力された画像データは従来からの写真フィルム用濃度補正アルゴリズムを適正にうけることが可能となる。 The pre-processing for the adaptation can be carried out in one preferred embodiment of the invention according to the following very simple equation:

This equation receives 8-bit gradation image data, which is common in digital cameras, and converts it into 12-bit gradation image data similar to the characteristics of image data from a photographic film. Since the image data of the digital camera is converted into a log (natural logarithm), the 8-bit input value is a log value. The term obtained by dividing the 8-bit input value by 255 and multiplying by log (4095) functions as a gradation adapting step, and the 8-bit input value is simply converted into 12 bits by this calculation. The number “4095” is the maximum value of a 12-bit numerical value. The term that multiplies the gradation adapting calculation value by 1/2 functions as a sensitivity adapting step. In other words, the density width of image data acquired by a general digital camera is said to be 1/4 of the density width of a photographic film. According to the knowledge of the present inventor, the image of a digital camera is simply calculated from this fact. When the density value as the pixel value of the data is set to 1/4, the density width is too narrow, so that the consistency with the photographic film is improved by multiplying by 1/2. Further, the term that subtracts the calculation results of gradation adjustment and sensitivity adjustment from log (1000) does not function as a reference density region adaptation step. log (1000) is the place where color development called normal density is the best in photographic film, and the image data from the digital camera is shifted based on this value to bring it closer to the reference density area of the image data from the photographic film. . The reason for subtracting from log (1000) is that the density inversion algorithm is also performed at the same time because the density correction algorithm as the latter stage processing is intended for the negative film. By simply pre-processing image data from a digital camera using a simple conversion formula as described above (usually converted into a look-up table), the output image data can be processed using a conventional density correction algorithm for photographic film. It becomes possible to receive properly.

In the present invention, a program that causes a computer to execute the above-described image processing method and an image processing apparatus that implements the above-described image processing method are also subject to rights. For example, an image processing apparatus according to the present invention having a density correction algorithm for correcting the density of image data from a photographic film obtained via a film scanner, an image input unit that captures image data obtained by a digital camera, An adaptation unit that adapts density characteristics of image data from the digital camera to density characteristics of image data from the photographic film, and density correction of the image data from the adapted digital camera using the density correction algorithm. A gradation correction module that adjusts the gradation of the image data from the digital camera to the gradation of the image data from the photographic film, and a photographic film sensitivity. From the digital camera to compensate for the difference between the image sensor sensitivity of the digital camera And sensitivity adaptation module to reduce the concentration values of the image data, and a, and the reference density region adaptation module to shift the density region of the image data from the digital camera to the reference concentration region of the photographic film. While Naturally, such an image processing apparatus and a program for executing an image processing method on a computer is also the working effects and all additional features described with respect to the image processing method described above can be provided with advantages thereof.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external view showing a photographic print system incorporating an image processing unit adopting an image processing method according to the present invention. This photographic print system is a photograph for performing exposure processing and development processing on photographic paper P. Print data used in the print station 1B by processing a photographed image taken from an image input medium such as a print station 1B as a printer and a developed photographic film (hereinafter simply referred to as film) 2a or a memory card 2b for a digital camera And an operation station 1A for generating / transferring.

  This photo printing system is also called a digital minilab. As can be understood from FIG. 2, the printing station 1B pulls out the roll-shaped printing paper P stored in the two printing paper magazines 11 and prints it with the sheet cutter 12. The back print unit 13 prints print processing information such as color correction information and frame number on the back side of the photographic paper P, and the print exposure unit 14 cuts the print paper P into the size. A photographed image is exposed on the surface of the photographic paper P, and the exposed photographic paper P is sent to a processing tank unit 15 having a plurality of development processing tanks for development processing. After drying, the photographic paper P, that is, the photographic prints P, sent to the sorter 17 from the transverse feed conveyor 16 at the upper part of the apparatus is collected in a plurality of trays of the sorter 17 in a state of being sorted in units of orders (see FIG. ).

  A photographic paper transport mechanism 18 is laid to transport the photographic paper P at a transport speed in accordance with various processes for the photographic paper P described above. The photographic paper transport mechanism 18 is composed of a plurality of nipping and transporting roller pairs including a chucker type photographic paper transport unit 18a disposed before and after the print exposure unit 14 in the photographic paper transport direction.

  The print exposure unit 14 applies R (red), G (green), and B (blue) to the printing paper P conveyed in the sub-scanning direction based on print data from the operation station 1A along the main scanning direction. 3) a line exposure head for irradiating the three primary colors of laser beams. The processing tank unit 15 includes a color developing tank 15a for storing a color developing processing liquid, a bleach-fixing tank 15b for storing a bleach-fixing processing liquid, and a stabilizing tank 15c for storing a stable processing liquid.

  A film scanner 20 for acquiring image data representing the shot frame image from the film 2a is arranged at the upper position of the desk-like console of the operation station 1A, and is used as a shot image recording medium 2b attached to a digital camera or the like. A media reader 21 that acquires image data representing a shot frame image from various semiconductor memories and CD-Rs used is incorporated in a general-purpose personal computer that functions as the controller 3 of the photo print system. The general-purpose personal computer is also connected with a monitor 23 for displaying various information, and a keyboard 24 and a mouse 25 as operation input devices used as an operation input unit used for various settings and adjustments.

  The film scanner 20 reads a shot frame image formed on a photographic film as 12-bit gradation color image data, and the image data from the digital camera handled by the media reader 21 is 8-bit gradation color image data.

  The controller 3 of this photographic print system uses a CPU as a core member, and constructs a functional unit for performing various processes for photographic print output including image processing by hardware and / or software. As shown in FIG. 3, as a functional unit particularly related to the present invention, an image that is captured image data read by a film scanner 20 or a media reader 21 and is transferred to the memory 30 for the next processing. A graphic for generating a control command from the input unit 31 and creation of a graphic operation screen including various windows and various operation buttons, and user operation input through such a graphic operation screen (using a pointing device such as the keyboard 24 and the mouse 25). User interface (hereinafter abbreviated as GUI) ), A basic image processing unit 40 that performs image correction such as basic density conversion on the image data transferred to the memory 30, and image data that has undergone basic image correction. On the other hand, an image processing unit including a main image processing unit 50 that performs image processing instructed by an operator through pre-judge work or the like well known in the photographic printing industry, and a photographic frame based on image data developed in the memory 30. A video control unit 33 that generates a video signal for displaying the image or graphic data sent from the GUI unit 32 on the monitor 23, and print exposure that is installed in the print station 1B based on the final corrected image data. Print data generation unit 34 for generating print data suitable for the unit 14, and customer requests Etc. formatter 35 and the like to format like raw captured image data and corrected captured image data which the image correction is complete format for writing to CD-R depending.

  When the image input unit 31 uses the film 2a on which a frame image taken by the silver salt camera is recorded as an input medium, the image data read in the prescan mode of the film scanner 20 is used as the low resolution image data in the main scan mode. The read image data is transferred to the memory 30 as high-resolution image data, and is compressed by jpeg or the like generally sent through the media reader 21 when the memory card 2b on which the digital camera's photographed frame image is recorded is used as an input medium. The captured frame image is expanded and transferred to the memory 30 as high-resolution image data. The low-resolution image data of the shot frame image acquired by the digital camera is created by thinning out from the high-resolution image data transferred to the memory 30 as will be described later. Thus, by preparing two types of high resolution data and low resolution data as image data representing one photographed frame image, the conversion table is set in the image correction processing using the low resolution data, and this low resolution is set. In this embodiment, a configuration for correcting the image of the high resolution data using the conversion table determined based on the data is employed for the purpose of reducing the calculation load of the controller 3. The use of data and high-resolution data is not limited in the present invention, and a configuration in which specific or all image correction processing is directly performed on high-resolution data as necessary is not excluded.

  The image input unit 31 is accompanied by a log conversion unit 31a that performs log (natural logarithm) conversion of image data sent through the film scanner 20. Since the image data of the shot frame image acquired by the digital camera has already been log-converted on the digital camera side, the log converter 31a is skipped. That is, the image data transferred to the memory 30 via the image input unit 31 is all log data.

  The basic image processing unit 40 is basically constructed by a computer program and a data group generated by the program or a data group prepared in advance. In FIG. 3, these configurations are schematically shown. An image size conversion unit 40A that creates low resolution image data of about 640 × 480 pixels by thinning out from high resolution image data exceeding megapixels of a captured frame image acquired by a digital camera, and a low resolution image from the digital camera An adapting unit 40B that adapts the density characteristics of the data or the high-resolution image data (low-resolution image data in this embodiment) so as to be compatible with a density correction process to be performed later, and the adapting unit 40B. Appropriate photographic image data from digital cameras and image data from photographic film And a density correction unit 40C corrected using a density correction algorithm so that.

  An important function of the adapting unit 40B is that the density correction unit 40C, in which a density correction algorithm originally designed to correct the density of image data from a photographic film, is mounted, can also be used for image data from a digital camera. Furthermore, the density characteristics of the image data from the digital camera are adapted to the density characteristics of the image data from the photographic film, and the gradation level of the image data from the digital camera is changed to the gradation level of the image data from the photographic film. A gradation adapting module 41 for adapting, and a sensitivity adapting module 42 for reducing a density value as a pixel value of image data from the digital camera in order to compensate for a difference between the photographic film sensitivity and the image sensor sensitivity of the digital camera; Shift the density area of image data from digital camera to the standard density area of photographic film Includes reference density region adapted module 43 that.

従って、階調度適合化モジュール４１は、８ビット入力値を２５５で除算してlog(4095)を乗算する処理を受け持ち、８ビット入力値を単純に１２ビット化する。「4095」なる数は１２ビット数値の最大値である。感度適合化モジュール４２は、階調度適合化モジュール４１による演算結果にさらに１／２を乗算することで写真フィルムにおける撮影コマ画像とデジタルカメラによる撮影コマ画像との間の感度の違いを整合している。基準濃度領域適合化モジュール４３は、感度適合化モジュール４２の演算結果を、log(1000)から引き算することで、デジタルカメラからの画像データをシフトさせて、写真フィルムからの画像データの基準濃度領域に近づけている。log(1000)は写真フィルムにおいてノーマル濃度と呼ばれる発色が最もよいところであり、これを基準として画像データを反転シフトしており、結果的にネガフィルムを対象としている濃度補正アルゴリズムへのこの点での整合も考慮されている。 In this embodiment, the processing in the adapting unit 40B receives 8-bit gradation image data as input and converts it into 12-bit gradation image data similar to the characteristics of the image data from the photographic film. By a very simple transformation of

Therefore, the gradation adapting module 41 is responsible for dividing the 8-bit input value by 255 and multiplying by log (4095), and simply converts the 8-bit input value to 12 bits. The number “4095” is the maximum value of a 12-bit numerical value. The sensitivity adaptation module 42 matches the difference in sensitivity between the photographed frame image on the photographic film and the photographed frame image by the digital camera by multiplying the calculation result of the gradation adaptation module 41 by 1/2. Yes. The reference density area adaptation module 43 shifts the image data from the digital camera by subtracting the calculation result of the sensitivity adaptation module 42 from log (1000), and thereby the reference density area of the image data from the photographic film. It is close to. log (1000) is the place where color development called normal density is the best in photographic film, and the image data is inverted and shifted on the basis of this, resulting in a density correction algorithm for negative film as a result. Consistency is also considered.

  By receiving the preprocessing in the adapting unit 40B based on the simple conversion formula as described above, the image data from the digital camera is appropriately subjected to the image correction by the density correcting unit 40C in which the photographic film density correcting algorithm is mounted. be able to.

  The density correction unit 40C is provided with a density correction algorithm for photographic film, and a density correction obtained by converting a conversion formula based on a density correction conversion curve obtained as a result of the density correction calculation by the density correction algorithm into a look-up table. An LUT 44 is provided. That is, based on the density correction LUT 44 set based on the density correction calculation, corresponding high-resolution image data serving as source data for final photo print output is processed.

  Various density correction algorithms implemented in the density correction unit 40C are known in the field of photo print processing technology, but the present invention does not limit the algorithms, and various algorithms are used. It is possible. Examples of such algorithms are also described in the cited document 1, cited document 2, and cited document 3 described above.

  An important function of the main image processing unit 50 is that the image data corrected by the basic image processing unit 40 for optimizing a photographic print image is subjected to more precise color correction and trimming based on an operator instruction. And filter processing for special effects. Therefore, the main image processing unit 50 can perform image processing of various items, such as a pre-judge processing unit 51 that performs control processing of pre-judge work instructing correction processing while designating a specific captured frame image. An image processing unit 52 that can be used is provided. In the pre-judge work, it is also possible to specify the necessity of printing for each shot frame image, the number of prints, and the print size. In addition, since a simulated image as an expected finished print image is displayed on the monitor 23 during pre-judge work, the image processing unit 52 also includes a simulation image generation function.

  Next, a typical flow when performing image correction processing on the image data of the photographed frame image in order to make the input photographed frame image an appropriate photographic print using this image processing unit is a flowchart of FIG. Will be described.

  The film scanner 20 or the media reader 21 is used according to the type of the photo recording medium brought by the customer as a print source. In any case, the acquired image data obtained by digitizing the shot frame image is sent through the image input unit 31. When the photo recording medium is the memory card 2b, when the memory card 2b is loaded into the media reader 21 (# 01), the image file is read from the memory card 2b and compressed. Is expanded in the memory 30 as high resolution image data (# 02). Further, the image size conversion unit 40A thins out the high resolution image data to create low resolution image data, and transfers it to the memory 30 (# 03).

  Next, the gradation level adaptation module 41 of the adaptation unit 40B performs gradation conversion from 8 bits to 12 bits based on the low resolution image data developed in the memory 30 (# 10). The 12-bit image data obtained by this conversion process is multiplied by ½ by the sensitivity adaptation module 42 to match the film sensitivity. (# 11). Further, the calculation result of the sensitivity adaptation module 42 is subtracted from log (1000), so that the image data is inverted and shifted to the appropriate density region (# 12).

  With the above processing, the image data (low-resolution image data) from the digital camera can be processed by the density correction unit 40C in which the density correction algorithm designed for photographic film is mounted, and is sent to the density correction unit 40C. And is used for correction calculation based on the density correction algorithm (# 13). When the density correction unit 40C completes the correction calculation, the density correction LUT 44 is set based on the calculation result (# 14).

When the photographic recording medium is the film 2a, when the film 2a is loaded into the film scanner 20 (# 04), the film scanner 20 is driven in the pre-scan mode (# 05), and the shot frame image is transferred from the film 2a. After being read at a low resolution and log-converted by the log converter 31a (# 06), it is transferred to the memory 30 as low-resolution image data (# 07). The low-resolution image data from the photographic film is naturally used for the density correction calculation in the density correction unit 40C without being subjected to the preprocessing by the adaptation unit 40B (# 13).

  In the density correction unit 40C, when the density correction LUT 44 is set, if the photo recording medium is the film 2a, only low-resolution image data is captured by pre-scanning. (# 15), the captured frame image is read from the film 2a with high resolution, and is developed in the memory 30 as high resolution image data (# 16). This is because the film scanner 20 needs to return and transport the film 2a from the pre-scan to the main scan, and the return and transport time can be used effectively.

  In any case, once the density correction LUT 44 is set, the high-resolution image data used for photographic print output is corrected using the density correction LUT 44 (# 17). The high-resolution image data corrected by the density correction unit 40C is almost sufficient for outputting an appropriate photographic print, but for manual check by the operator, special image processing, or a special print size or number of prints. Then, a well-known pre-judge operation is performed (# 18). When various correction settings and print number settings for each captured frame image are completed in this pre-judge operation, the corresponding high-resolution image data is subjected to image processing based on the settings by the image processing unit 52 (# 19). ) Is further sent to the print data generation unit 34 and converted into print data (# 20). This print data is transferred to the print exposure unit 14 of the print station 1B, and based on this, the print exposure unit 14 is controlled to emit light, whereby a photographic print is output (# 21).

  The present invention is widely applicable for correcting the density of image data acquired by a digital camera with an image processing apparatus equipped with a density correction algorithm for correcting the density of image data from a photographic film acquired through a film scanner. is there.

External view of photographic print system employing image processing technology according to the present invention Schematic diagram schematically showing the configuration of the print station of the photo print system Functional block diagram explaining functional elements built in the controller of the photo print system A flowchart showing a typical flow when image correction processing is performed on image data of an inputted photographed frame image

Explanation of symbols

20: Film scanner 30: Memory 40: Basic image processing unit 40A: Image size conversion unit 40B: Adaptation unit 40C: Density correction unit 41: Gradation degree adaptation module 42: Sensitivity adaptation module 43: Reference density area adaptation module 44: Density correction LUT
50: Main image processing unit

Claims (4)

In an image processing method for correcting the density of image data acquired by a digital camera in an image processing apparatus having a density correction algorithm for correcting the density of image data from a photographic film acquired via a film scanner,
Adapting the density characteristics of the image data from the digital camera to match the density characteristics of the image data from the photographic film;
Correcting the density of the image data from the adapted digital camera using the density correction algorithm;
Tona is,
The adaptation step includes a gradation adaptation step for adapting the gradation of the image data from the digital camera to the gradation of the image data from the photographic film, and the difference between the photographic film sensitivity and the imaging device sensitivity of the digital camera. A sensitivity adaptation step for reducing the density value of the image data from the digital camera to compensate for the image, and a reference density area adaptation for shifting the density area of the image data from the digital camera to the reference density area of the photographic film image processing method characterized by comprising the steps, a. The adaptation step is performed by the following transformation:

The image processing method according to claim 1 . In order to correct the density of image data acquired by a digital camera in a photographic image processing apparatus equipped with a density correction algorithm for correcting the density of image data from a photographic film acquired via a film scanner,
An adaptation function for adapting density characteristics of image data from the digital camera to density characteristics of image data from the photographic film;
A function of correcting the density of the image data from the adapted digital camera using the density correction algorithm;
An image processing program causing a computer to execute the,
The adaptation function is a gradation adjustment function that adjusts the gradation of the image data from the digital camera to the gradation of the image data from the photographic film, and the difference between the photographic film sensitivity and the imaging device sensitivity of the digital camera. Sensitivity adaptation function for reducing the density value of image data from the digital camera to compensate for, and reference density area adaptation for shifting the density area of image data from the digital camera to the reference density area of the photographic film And an image processing program. In an image processing apparatus provided with a density correction algorithm for correcting the density of image data from a photographic film obtained through a film scanner,
An image input unit for capturing an image data acquired by the digital camera,
An adapting unit for adapting density characteristics of image data from the digital camera to density characteristics of image data from the photographic film;
A density correction unit that performs density correction on the image data from the adapted digital camera using the density correction algorithm;
Tona is,
The adaptation unit adjusts the gradation level of the image data from the digital camera to the gradation level of the image data from the photographic film, and the difference between the photographic film sensitivity and the imaging device sensitivity of the digital camera A sensitivity adaptation module for reducing the density value of the image data from the digital camera to compensate for the image, and a reference density area adaptation for shifting the density area of the image data from the digital camera to the reference density area of the photographic film An image processing apparatus comprising: a module .

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