JP3785234B2 - Image processing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to a technical field of an image processing apparatus that photoelectrically reads an image of a film original and performs image processing for obtaining an output image in which the image is reproduced.
[0002]
[Prior art]
Currently, printing of images taken on photographic films (hereinafter referred to as films) such as negative films and reversal films onto photosensitive materials (printing paper) is performed by projecting the film images onto photosensitive materials and exposing the photosensitive materials to surface exposure. This is done by so-called direct exposure.
[0003]
On the other hand, in recent years, a printing apparatus using digital exposure, that is, an image recorded on a film is photoelectrically read, and the read image is converted into a digital signal. Digital photo printers that print image data (latent images) by scanning and exposing a photosensitive material with recording light modulated in accordance with the image data and printing are put into practical use.
[0004]
In a digital photo printer, a film is read photoelectrically, color density correction is performed by signal processing, and exposure conditions are determined. Therefore, it is not necessary to determine the exposure conditions by the operator at the time of exposure, and to adjust the filter, aperture, etc., the exposure time per image is short, and the exposure time is also constant according to the image size. Therefore, it is possible to perform printing more quickly than conventional surface exposure.
In addition, you can freely edit print images such as combining multiple images and dividing images, and perform various image processing such as color / density adjustment and edge enhancement, and output finished prints that are freely processed according to the application. it can. Further, since the image of the finished print is handled as image data, the image data can be supplied to a computer or the like, and can be stored in a recording medium such as a floppy disk.
In addition, conventional direct exposure printing cannot reproduce all images recorded on film etc. in terms of resolution, color / density reproducibility, etc., but it is recorded on film by a digital photo printer. A print that reproduces almost 100% of the existing image (density information) can be output.
[0005]
Such a digital photo printer basically has a scanner (image reading device) that photoelectrically reads an image recorded on a film, and performs image processing (setup) for determining an exposure condition for image recording by processing the read image. ) Apparatus and a printer (image recording apparatus) that scans and exposes the photosensitive material in accordance with the determined exposure conditions and performs development processing.
[0006]
In a scanner, reading light emitted from a light source is incident on a film to obtain projection light carrying an image photographed on the film, and this projection light is imaged on an image sensor such as a CCD sensor by an imaging lens. Then, the image is read by photoelectric conversion, subjected to various image processing as required, and then sent to the image processing apparatus as film image data (image data signal).
The image processing apparatus sets image processing conditions from pre-scan image data, performs image processing according to the set conditions on the main scan image data, and outputs a printer as output image data (exposure conditions) for image recording. Send to.
In a printer, for example, if the apparatus uses light beam scanning exposure, the light beam is modulated in accordance with image data sent from the image processing apparatus, and the light beam is deflected in the main scanning direction. By transporting the photosensitive material in the sub-scanning direction perpendicular to the direction, the photosensitive material is exposed (baked) with a light beam carrying an image to form a latent image, and then subjected to development processing or the like according to the photosensitive material. Thus, a finished print (photograph) in which an image photographed on the film is reproduced.
[0007]
[Problems to be solved by the invention]
By the way, there are various requirements such as human skin finish and green and sky background finish as important requirements that influence the finish (image quality) of the finished print, but one of the important requirements is highlight That is, reproduction with good white color can be mentioned.
[0008]
In a high-quality image, white is required to have no color (saturation) and bright (high brightness). However, in the conventional digital color printer as well as the above-mentioned digital photo printer, the white color of the reproduced image is bluish, and the color balance in the highlight and its vicinity is poor, so that the overall image quality is improved. There is also a problem that it decreases.
[0009]
An object of the present invention is to solve the above-mentioned problems of the prior art, and when obtaining a visible image reproduced on a print or display from an image recorded on a film, highlights, that is, white and its neighboring images. Can reproduce a high-quality visible image with good reproduction, and also reproduce images brighter than white recorded on film, making full use of the recording area (color reproduction area) of the film Another object of the present invention is to provide an image processing apparatus capable of reproducing a visible image.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present inventor has conducted studies and has obtained the following knowledge.
As is well known, in human vision, a slight bluish color that can be felt brighter rather than a pure achromatic color is judged as the preferred brightest color, and this is usually the image color. Recognize as highlight or white. Here, since it is difficult to reproduce white with a dye in a color printer, the color of the photosensitive material (base density) is usually the brightest color. Therefore, the color of the photosensitive material is slightly It is white with a blue tint.
[0011]
In an analog (direct exposure) printer that exposes a photosensitive material by reflecting or projecting light from an original to obtain a visible image, the photosensitive material is also exposed in the white part of the image, and color balance is achieved under these conditions. The white is not bluish, and a high-quality image in which a preferred white is reproduced can be reproduced.
[0012]
On the other hand, in a digital color printer, analog image data output from an image sensor such as a CCD sensor is converted into digital image data, and then black (shadow) and white of an image recorded on a film are detected from the digital image data. Judging from this, white to black is determined as a color reproduction region in the visible image, and white is reproduced without exposing the photosensitive material to obtain a brighter image.
However, as described above, the photosensitive material is slightly bluish in order to reproduce bright colors that humans feel desirable. For example, Fuji Color laser paper manufactured by Fujifilm is a CIE (International Commission on Illumination) L ^* a ^* b ^* uniform color space, a ^* = 0, b ^* = − 1.3 (the negative direction of b ^* is (Blue direction)
For this reason, in a digital color printer, the reproduced image is bluish in white, and the color balance of the colors in the vicinity thereof is out of order, resulting in a decrease in image quality. Moreover, in the case of a photo printer, an image that is photographed on film and brighter than white cannot be reproduced.
[0013]
The present invention has been made on the basis of such knowledge. First image processing means for converting digital image data into image data in a first color space, and image data in the first color space, Second image processing means for converting into image data of a second color space that defines color reproduction of a visible image to be reproduced on a print or monitor , wherein the second image processing means converts the white color in the visible image. The image is defined as an image having a higher density than the brightest color in the visible image, and the white color image data is set to the inner side of the maximum value or the minimum value of the image data in the second color space. The image data in the space includes image data that is brighter than white , and further converts the image data in the first color space in a direction to increase the white chromaticity value b ^* in the visible image. Characterized as spatial image data An image processing apparatus is provided.
[0014]
In such an image processing apparatus of the present invention, a reading means for photoelectrically reading an image recorded on a film document, and image data output from the reading means are A / D converted into digital image data. Preferably, the first image processing means converts the digital image data output from the A / D conversion means into image data of a first color space.
[0015]
In the image processing apparatus of the present invention, the visible image is an image reproduced on a print, and the chromaticity value b ^* of the brightest color of the print on which the visible image is reproduced is negative. Preferably, the first color space is a color space that defines the color reproduction of the film.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image processing apparatus of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
[0017]
FIG. 1 is a block diagram showing an example of a digital photo printer using the image processing apparatus of the present invention.
A digital photo printer (hereinafter referred to as a photo printer 10) shown in FIG. 1 basically includes a scanner (image reading device) 12 that photoelectrically reads an image taken on a film F, and read image data ( (Image information) image processing and selection / setting / change of image processing conditions, operation and control of the entire photo printer 10 and the like, and modulation according to image data processed by the image processing device 14 The image forming apparatus includes a printer (image recording apparatus) 16 that exposes an image of the photosensitive material A with a light beam, develops it, and outputs it as a finished print P.
Further, the image processing apparatus 14 includes an operation system 18 having a keyboard 18a and a mouse 18b for inputting various settings (settings), processing selection and instructions, instructions for color / density correction, and the like, and a scanner. The display 20 is connected to display the image read in step 1, various operation instructions, various condition setting / registration screens, and the like.
[0018]
The scanner 12 is a device that photoelectrically reads an image shot on a film F or the like one frame at a time. The light source 22, a variable aperture 24, and three primary colors of R (red), G (green), and B (blue). A color filter plate 26 that has three color filters R, G, and B to be decomposed and rotates to act on the optical path of the arbitrary color filter, and the reading light incident on the film F is the surface of the film F A diffusion box 28 that is uniform in the direction, an imaging lens unit 32, a CCD sensor 34 that is an area sensor that reads an image of one frame of a film, and an amplifier 36 are configured.
In the illustrated photo printer 10, the type and size of a film such as a new photo system (Advanced Photo System) or a 135-size negative film, the form of a film such as strips or slides, the type of processing such as trimming, etc. Accordingly, a dedicated carrier that can be mounted on the main body of the scanner 12 is prepared, and various films and processes can be handled by replacing the carrier.
[0019]
In such a scanner 12, the reading light emitted from the light source 22, adjusted in light quantity by the variable diaphragm 24, adjusted in color through the color filter plate 26, and diffused in the diffusion box 28 enters the film F. , The projection light carrying the image of the frame photographed on the film F is obtained.
The projection light of the film F is imaged on the light receiving surface of the CCD sensor 34 by the imaging lens unit 32, is read photoelectrically by the CCD sensor 34, and the output signal is amplified by the amplifier 36 to the image processing device 14. Sent.
The CCD sensor 34 is an area CCD sensor of 1380 × 920 pixels, for example. Further, in the illustrated apparatus, the CCD sensor 34 is configured to be two-dimensionally movable in the pixel arrangement direction by an amount corresponding to a half pixel, whereby the number of read pixels is apparently increased to four times. Can do.
[0020]
In the scanner 12, such image reading is performed three times by sequentially inserting each color filter of the color filter plate 26, thereby separating and reading one frame image into the three primary colors of R, G, and B.
Here, in the photo printer 10, prior to image reading (main scan) for outputting the finished print P, a pre-scan for reading an image at a low resolution is performed in order to determine image processing conditions and the like. Therefore, a total of six image readings are performed in one frame.
[0021]
As described above, the output signal (image data) from the scanner 12 is output to the image processing device 14.
As shown in the block diagram of FIG. 2, the image processing apparatus 14 includes an A / D converter 38, a Log converter 40, a prescan (frame) memory 42, a main scan (frame) memory 44, and an image processing condition setting apparatus. 46 (hereinafter referred to as setting device 46) and image data processing device 48 (hereinafter referred to as data processing device 48).
FIG. 2 mainly shows image processing-related parts. In addition to this, the image processing apparatus 14 includes a CPU for controlling and managing the entire photo printer 10, operation of the entire photo printer 10, and the like. A memory for storing necessary information, a means for determining the aperture value of the variable aperture 24, and the like are disposed. The operation system 18 and the display 20 are connected to each part via the CPU or the like (CPU bus). .
[0022]
The R, G, and B output signals output from the scanner 12 are converted into digital data by the A / D converter 38 and are subjected to Log conversion by the Log converter 40 to be image data indicating the image density of the film F. The prescan image data is stored (stored) in the prescan memory 42 and the main scan image data is stored in the main scan memory 44, respectively.
Note that various corrections such as DC offset correction, dark correction, and shading correction may be applied to the image data as needed between the A / D converter 38 and both memories.
[0023]
The setting device 46 calculates and sets various image processing conditions in the data processing device 48.
When the image data is stored in the pre-scan memory 42, the setting device 46 reads the image data from the pre-scan memory 42, creates a density histogram, and further features image features (average density, maximum / minimum density, etc.). Is calculated.
[0024]
The setting device 46 determines white (highlight) and black (shadow) in the image (image taken on the film F) from the density histogram and the image feature amount, and the information amount (gradation resolution) of the image data. Accordingly, white and black image data are set, film image data is allocated and standardized accordingly, and an LUT (Look Up Table) for correcting the image data is created.
[0025]
Here, in the conventional apparatus, for example, when the information amount of the image data is 8 bits and the larger the image data is, the lower the density (there may be the opposite case), the white image data is the maximum value of 255, black Is set to 0 as the minimum value, and the image data is standardized as image data of 256 gradations by assigning between the two. That is, the white color is not exposed, and image data outside the white color is discarded (not reproduced).
[0026]
On the other hand, in the photo printer 10 according to the image processing apparatus of the present invention, the setting device 46 displays the determined white color on the inner side (higher than the brightest color of the image to be reproduced (that is, the maximum (minimum) value of image data)). The image data is converted in a direction to reduce bluishness, that is, to increase b ^* of the chromaticity value . For example, when the obtained density histogram is shown in FIG. 3 and the black (D _max ) and white (D _w ) of the image are determined as illustrated, if the image data is 8 bits, Black is set as image data 0, and white is set as predetermined image data 240, for example.
Next, using black = image data 0 and white = image data 240, the image data of the film is allocated to 0 to 255 and normalized as 256 gradation image data, and an LUT that corrects the image data, that is, a gradation correction table is prepared. It is created and set in the data processing device 48. Therefore, the image data exceeding 240 corrected by this gradation table is image data brighter than white.
[0027]
Therefore, according to the image processing apparatus of the present invention, since white is not the unexposed photosensitive material A, by appropriately setting an exposure amount according to image data in the printer 16 to be described later, white and the vicinity thereof are blue. It is possible to obtain a high-quality reproduced image in which this region is appropriately reproduced without taste.
Further, since the image brighter than white photographed on the film F, which has been thrown away in the past, can be reproduced up to D _min which is the standardized brightest part (minimum density), the film F is reproduced more suitably. Finished prints can be obtained.
[0028]
In the image processing apparatus of the present invention, there is no particular limitation on how much of the maximum value (or minimum value) of the image data is the white image data, but it is preferable that the print density is 0.02 to 0.02. What is necessary is just to set inside the image data equivalent to about 0.1.
[0029]
Further, in the illustrated example, the setting device 46 determines the electronic scaling (enlargement / reduction) rate, dynamic range compression and / or expansion (the dodging effect by image processing, etc.) from the above-described density histogram and image feature amount. Processing), sharpness processing (sharpening processing) conditions, and the like are calculated and set in the data processing device 48.
[0030]
When the setting of the image processing conditions by the setting device 46 is completed, the image data is read from the pre-scan memory 42 as necessary, and the pre-scan image processed according to the image processing conditions is displayed on the display 20. As necessary, verification, color / density adjustment, gradation adjustment, and the like are performed, and the image processing conditions are corrected.
In general, the brightest color of the display is bluish for the same reason. However, by displaying the image data on the display 20 after processing the image data by the image processing apparatus of the present invention, white and the vicinity thereof are displayed. It is possible to output a high-quality reproduced image in which this area is appropriately reproduced without being bluish.
[0031]
When the image processing conditions are determined, the main scanning image data is read from the main scanning memory 44 by the data processing device 48, and includes electronic scaling processing, dynamic range compression, and / or processing including the processing based on the gradation correction table described above. Various image processing such as expansion and sharpness is performed and output to the printer 16 as output image data.
[0032]
FIG. 4 shows a schematic diagram of the printer 16.
The printer 16 includes a driver 50, an exposure unit 52, and a development unit 54. The printer 16 pulses the light beam L according to image data sent from the image processing device 14 (data processing device 48), for example. The width is modulated and the photosensitive material A is exposed.
[0033]
Image data from the image processing device 14 is sent to the driver 50.
The driver 50 converts the image data sent from the image processing device 14 (data processing device 48) into a pulse width modulation drive signal of the AOM 56 corresponding to the recorded image (exposure amount), and drives each AOM 56.
Here, the conversion table from the image data to the drive signal of the AOM 56 is set so that the recorded image in the white image data (the image data 240 in the above example) is appropriate white. That is, since the photosensitive material A usually has a slight bluish color, R exposure, G exposure, and B exposure are performed so that the photosensitive material A is slightly colored in the white image data 240 in order to reproduce an appropriate white color. A driving signal (exposure amount by each light beam L) of each AOM 56 is set. Therefore, in the image data 240 or more, the exposure amount gradually decreases to become brighter than white, and the image data 255 is not exposed. The conversion from the image data to the drive signal of the AOM 56 may be the same as that of a normal image exposure apparatus except for this.
[0034]
The exposure unit 52 scans and exposes the photosensitive material A by light beam scanning and records an image of the image data on the photosensitive material A, and is formed on the photosensitive material A as conceptually shown in FIG. Each light of a light source 58R that emits a light beam in a narrow band wavelength range corresponding to the exposure of the R photosensitive layer, a light source 58G corresponding to the exposure of the G photosensitive layer, and a light source 58B corresponding to the exposure of the B photosensitive layer. AOMs 56R, 56G, and 56B that modulate the light source of each beam according to the recorded image, the polygon mirror 60 as an optical deflector, the fθ lens 62, and the sub-scan transport means for the photosensitive material A Have
[0035]
Each light beam emitted from the light source 58 (58R, 58G, 58B) and traveling at a different angle enters the corresponding AOM 56 (56R, 56G, 56B). Drive signals for R, G, and B corresponding to the recorded image from the driver 50, that is, the image data supplied from the image processing device 74, are transferred to each AOM 56, and the incident light beam is transmitted according to the recorded image. Modulate.
[0036]
Each light beam modulated by the AOM 56 is incident on and reflected by substantially the same point of the polygon mirror 60, deflected in the main scanning direction (arrow x direction in the figure), and then predetermined by the fθ lens 62 at a predetermined scanning position z. The light beam is adjusted so as to form an image with the beam shape, and enters the photosensitive material A. The exposure unit 52 may be provided with a light beam shaping means and a surface tilt correction optical system as necessary.
[0037]
On the other hand, the photosensitive material A is long and is wound in a roll shape and loaded into a predetermined position in a magazine state.
Such a photosensitive material A is pulled out by a drawing roller (not shown), and is held at the scanning position z by the conveying roller pairs 64a and 64b constituting the sub-scanning means arranged with the scanning position z interposed therebetween, in the main scanning direction. Is transported in the sub-scanning direction (arrow y direction in the figure) perpendicular to.
Since the light beam is deflected in the main scanning direction, the photosensitive material A conveyed in the sub-scanning direction is two-dimensionally scanned and exposed by the light beam and transferred to the photosensitive material A from the image processing apparatus 14. An image (latent image) of the image data is recorded.
[0038]
After the exposure, the photosensitive material A is carried into the developing unit 54 by the conveying roller pair 66 and is subjected to development processing to be a finished print P.
Here, for example, if the photosensitive material A is a silver salt photosensitive material, the developing unit 54 includes a color developing tank 68, a bleach-fixing tank 70, washing tanks 72a, 72b, 72c and 72d, a drying unit and a cutter (not shown). The photosensitive material A is subjected to predetermined processing in each processing tank, dried, and then cut into a predetermined length corresponding to one print by a cutter, and output as a finished print P.
[0039]
Hereinafter, the operation of the image processing apparatus of the present invention will be described together with the operation of the illustrated photo printer 10.
When producing the finished print P in the photo printer 10, the operator sets a carrier corresponding to the film F serving as a document in the scanner 12, and gives necessary instructions using the mouse 18b or the like.
On the other hand, when it is confirmed that the photo printer 10 is in a predetermined state such as the light amount of the light source 22 of the scanner 12, the operator sets the film F at a predetermined position of the scanner 12 (carrier) and the first frame is displayed. It is conveyed to a predetermined reading position.
[0040]
When an instruction to start reading is issued, the scanner 12 first starts pre-scanning.
When pre-scanning is started, the reading light emitted from the light source 22 is adjusted in light quantity by the variable diaphragm 24 and light-adjusted by a filter of the color filter plate 26 inserted in the optical path L, for example, a G filter, and the film F Projection light that is incident on and transmitted through the first frame and carries an image (G image) photographed in this frame is obtained.
This projection light is imaged in the effective pixel area of the CCD sensor 34 by the imaging lens unit 32, the G image of the film F is read, amplified by the amplifier 36, sent to the image processing device 14, and A / D The signal is A / D converted by the converter 38, converted by the Log converter 40, and stored in the prescan memory 42. When the reading of the G image ends, similarly, for example, the B image and then the R image are read and sequentially stored in the prescan memory 42, and the prescan ends.
[0041]
On the other hand, in the image processing device 14, the setting device 46 reads prescan image data from the prescan memory 42, creates a density histogram, calculates an image feature amount, and the like, and black (shadow) and white (high) in this image. Light), black image data is set to 0, white image data is set to a preset numerical value inside the maximum value, for example, 8-bit image data 240 as described above, and both are used to set the image data. Is assigned to 256 gradations and standardized to create a gradation correction table, which is set in the data processing device 48.
Further, the setting device 46 determines other electronic magnification and sharpness processing conditions and sets them in the data processing device 48.
If necessary, verification by the operator is performed to determine the image processing conditions.
[0042]
Thereafter, when the main scan is started, the G image, the B image, and the R image of the film document are sequentially read and sent to the image processing device 14 and stored in the main scan memory 44 as in the pre-scan. .
The image data stored in the main scan memory 44 is sequentially read out, subjected to image processing according to the set gradation correction table and various image processing conditions, and output to the printer 16 as output image data. .
When reading of the first frame (main scan) is completed, the film F is conveyed by one frame by the carrier, and the image of the next frame is read.
[0043]
The printer 16 scans and exposes the photosensitive material A drawn from the magazine with a light beam that is modulated in accordance with the image data sent from the image processing apparatus 14 and deflected in the main scanning direction while being conveyed in the sub scanning direction. To form a latent image. In the photo printer 10 according to the present invention, the white portion of the image photographed on the film F is also reproduced by exposing the photosensitive material A, so that the white image and the image in the vicinity thereof are suitable images without bluishness. While being reproduced, an image brighter than white photographed on the film F is also preferably reproduced.
The exposed photosensitive material A is subjected to color development, bleach-fixing, and water washing in the developing unit 54 in order, developed, dried, cut into prints, and finished prints P.
[0044]
The image processing apparatus according to the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the scope of the present invention. It is.
[0045]
【The invention's effect】
As described above in detail, according to the image processing apparatus of the present invention, a high-quality visible image in which highlights, that is, white and nearby images are well reproduced, is reproduced from an image recorded on a film. An image that is reproducible and brighter than white recorded on the film can also be reproduced, and a suitable visible image that makes full use of the recording area of the film can be reproduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of an example of a digital photo printer using an image processing apparatus of the present invention.
FIG. 2 is a block diagram of an example of an image processing apparatus of the digital photo printer shown in FIG.
FIG. 3 is an example of a density histogram for explaining an image processing apparatus of the present invention.
4 is a schematic diagram of an example of a printer of the digital photo printer shown in FIG.
[Explanation of symbols]
10 (digital) photo printer 12 scanner 14 image processing apparatus 16 printer 18 operation system 20 display 22 light source 24 variable aperture 26 color filter plate 28 diffusion box 32 imaging lens unit 34 CCD sensor 36 amplifier 38 A / D converter 40 log conversion Device 42 Pre-scan memory 44 Main scan memory 46 (Image processing condition) setting device 48 (Image) data processing device 50 Driver 52 Exposure unit 54 Development unit 56 AOM
58 Light source 60 Polygon mirrors 62 and 66 Conveying roller pair 68 Color developing tank 70 Bleach fixing tank 72 Flushing tank

Claims (4)

First image processing means for converting digital image data into image data of a first color space;
Second image processing means for converting the image data of the first color space into image data of a second color space that defines color reproduction of a visible image to be reproduced on a print or monitor ;
The second image processing means defines white in the visible image as an image having a higher density than the brightest color in the visible image, and uses the white image data as the maximum of the image data in the second color space. In the direction in which image data brighter than white exists in the image data in the second color space, and b ^* of the white chromaticity value in the visible image is increased. An image processing apparatus characterized by converting image data in the first color space into image data in the second color space .   Reading means for photoelectrically reading an image recorded on a film document; and A / D conversion means for converting the image data output from the reading means into digital image data by A / D conversion. The image processing apparatus according to claim 1, wherein the image processing unit converts the digital image data output from the A / D conversion unit into image data of a first color space. 3. The visible image is an image reproduced on a print, and b ^* of the chromaticity value of the brightest color of the print on which the visible image is reproduced is a negative value. Image processing apparatus. The image processing apparatus according to claim 2 , wherein the first color space is a color space that defines color reproduction of a film.

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