JP2000115509A - Image processing method and image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output an image with high image quality without distortion and color slurring by applying scaling processing to aberration correction parameter based on at least one of an electronic magnification, number of input pixels, a size of an input image and a size of an output image and using the aberration correction parameter that is scaling-processed for the parameter corresponding to a pixel unit of output image data to correction an aberration of the image resulting from a lens used to photograph an image. SOLUTION: A correction parameter supply section 74 stores an aberration correction parameter of an image corresponding to various lens types at an image forming plane. A correction parameter supply section 74 selects a aberration correction parameter corresponding to a lens type used to photograph the image and gives the parameter to a correction parameter conversion section 75. The correction parameter conversion section 75 applies scaling processing to the aberration correction parameter and gives it to an aberration correction section 72 as the aberration correction parameter in the unit of pixels of the output image. The aberration correction section 72 uses the aberration correction parameter received from the correction parameter conversion section 75 to correct a distortion and a magnification chromatic aberration of the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a digital image processing method and a digital image processing apparatus. More specifically, the present invention relates to a digital image processing apparatus for reading a film image photoelectrically and obtaining a print (photograph) in which the image is reproduced. In a photo printer or the like, it is possible to obtain a high-quality image without deterioration in image quality due to lens aberration, even if the image is taken with a lens with a low performance such as a film with a lens, an inexpensive compact camera or a digital camera. The present invention relates to a possible image processing method and an image processing apparatus.

[0002]

2. Description of the Related Art At present, printing of an image photographed on a photographic film (hereinafter, referred to as a film) such as a negative film or a reversal film onto a photosensitive material (photographic paper) involves exposing the photosensitive material by projection light of the film. The so-called direct exposure (analog exposure) is the mainstream.

On the other hand, in recent years, a printing apparatus utilizing digital exposure, that is, an image recorded on a film is photoelectrically read, and the read image is converted into a digital signal, and then subjected to various image processings and recorded. 2. Description of the Related Art Digital photo printers have been put to practical use in which a photosensitive material is scanned and exposed with recording light modulated in accordance with the image data to record and print an image (latent image).

In a digital photo printer, exposure conditions at the time of printing can be determined by image data processing using an image as digital image data, so that image skipping and blurring caused by backlight, strobe photography, and the like can be corrected, and sharpness can be reduced. By suitably performing (sharpening) processing or the like, a high-quality print that cannot be obtained by conventional direct exposure can be obtained. In addition, the composition of images and characters can be performed by image data processing, and prints that have been freely edited / processed according to the intended use can be output.

Further, according to the digital photo printer, in addition to the image photographed on the film, an image photographed by a digital camera or an image processed by a computer can be printed and output. Since the data can be supplied to a computer or the like or can be stored in a recording medium such as a floppy disk, the image data can be used for various purposes other than a photograph.

[0006] Such a digital photo printer basically includes a scanner (image reading device) that photoelectrically reads an image recorded on a film by inputting reading light to the film and reading the projected light. An image processing apparatus that performs predetermined image processing on image data read by a scanner or image data supplied from a digital camera or the like and sets image data for image recording, that is, an exposure condition, and an image output from the image processing apparatus. According to the image data, a printer (image recording device) that scans and exposes the photosensitive material by, for example, light beam scanning to record a latent image, and develops the photosensitive material exposed by the printer to reproduce an image A processor (developing device) for printing.

[0007]

One of the causes of image quality deterioration when an image photographed on a film is reproduced on a print is image quality deterioration due to so-called lens aberration caused by camera lens performance.

For example, even with one lens, R
The (red) light, G (green) light, and B (blue) light have different refractive indexes. Therefore, even at the same position in the scene, the so-called chromatic aberration of magnification occurs at the same position on the film between the R light, the G light, and the B light. Deviation occurs. Also,
In order to obtain an appropriate captured image, a plane perpendicular to the optical axis in the scene needs to be formed on the same plane perpendicular to the optical axis. However, with a normal lens, the image plane shifts in the direction of the optical axis, so-called distortion occurs, and the formed image is distorted. When an image captured on a film is reproduced, the obtained image has distortion. Would. Furthermore, the image quality is also degraded due to a decrease in the amount of peripheral light, which causes the image to be darker in the peripheral part than in the central part, and out-of-focus caused by the focus position being different in the plane direction of the film, which occurs depending on the performance of the lens. Is the cause.

For a camera such as a single-lens reflex camera, which can incur a certain amount of cost, a high-precision lens is used, and a combination of a plurality of lenses is used to correct various aberrations so that the film can be properly adjusted. Images can be taken. However, in a camera that is required to be inexpensive, such as a film with a lens and a compact camera, the cost of the lens cannot be increased, so that an aberration occurs in an image photographed on the film. As a result, an image reproduced as a print has color misregistration and distortion.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. Even if an image is taken by a film with a lens, an inexpensive compact camera, or an inexpensive digital camera, the lens can be processed by image processing. Digital image processing method and image that corrects image aberrations (image quality deterioration due to lens aberrations) due to the performance of the image and enables to output high-quality images without distortion, color shift, etc. An object of the present invention is to provide a processing device.

[0011]

That is, the image processing method of the present invention performs image processing on input image data obtained from an optically captured image to obtain output image data for output. Aberration correction parameters on the image forming surface of the image of the lens that captured the image set in advance, the electronic magnification for obtaining the output image data, the number of input pixels of the input image data, the size of the input image, And scaling processing by at least one of the sizes of the output image to obtain an aberration correction parameter corresponding to a pixel unit of the output image data, and using the aberration correction parameter in the pixel unit, an image caused by a lens that has captured the image. An image processing method characterized by correcting aberrations of

An image processing apparatus according to the present invention is an image processing apparatus that performs image processing on input image data obtained from an optically captured image to obtain output image data for output. Acquiring means for acquiring identification information for identifying a lens that has captured an image; storage means for storing an aberration correction parameter for correcting a lens aberration on an image forming surface of a lens for capturing an image; Selecting means for selecting an aberration correction parameter on the imaging surface of the corresponding lens from the storage means, an electronic magnification for obtaining the output image data, the number of input pixels of the input image data, the size of the input image, And at least one of the size of the output image and scaling processing of the aberration correction parameter on the image plane selected by the selection unit, A conversion unit that converts the image data into an aberration correction parameter corresponding to a pixel unit, and an aberration correction parameter corresponding to the pixel unit converted by the conversion unit, using the aberration correction parameter corresponding to the pixel unit to correct the aberration of the image caused by the lens that captured the image. There is provided an image processing apparatus having a correction unit for performing correction.

In the present invention, the image is:
Preferably, the size of the input image is an image taken on a photographic film, and the size of the input image is a reading size of the image from the photographic film, and the aberration is chromatic aberration of magnification, distortion, defocus, and peripheral light amount. Preferably at least one of the reductions.

Further, the correcting means calculates a shift amount of an image position of another color from a reference color of the three primary colors caused by the chromatic aberration of magnification, using the aberration correction parameter and information on the image position. Using the shift amount caused by this chromatic aberration of magnification and the shift amount of the image position of the reference color caused by the distortion, an appropriate position of each image corrected for the distortion and the chromatic aberration of magnification is calculated. It is preferable to correct distortion and chromatic aberration of magnification using an appropriate position, or to perform electronic scaling processing using the appropriate position.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image processing method and an image processing apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram showing an example of a digital photo printer using the image processing method and the image processing apparatus of the present invention. The 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 captured on a film F, and read image data ( An image processing device 14 that performs image processing of image information and the entire operation and control of the photo printer 10, and images a photosensitive material (photographic paper) with a light beam modulated according to image data output from the image processing device 14. And a printer 16 for performing exposure, development, and output as a print (photograph). The image processing apparatus 14 includes an operation system 18 having a keyboard 18a and a mouse 18b for inputting (setting) various conditions, selecting and instructing processing, and instructions for color / density correction, and the like. A display 20 for displaying an image read at 12, various operation instructions, a condition setting / registration screen, and the like is connected.

The scanner 12 is a device for photoelectrically reading an image photographed on a film F or the like one frame at a time.
A variable aperture 24, a diffusion box 28 for making the reading light incident on the film F uniform in the surface direction of the film F, an imaging lens unit 32, R (red), G (green), and B
An image sensor 34 having a line CCD sensor corresponding to each image reading of (blue), an amplifier 36,
An A / D (analog / digital) converter 38 is provided.

In the photo printer 10, the type and size of a film such as a new photographic system (Advanced Photo System) or a 135-size negative (or reversal) film, the form of the film such as strips and slides, and the like are determined. In addition, a dedicated carrier that can be mounted on the main body of the scanner 12 is prepared, and by changing the carrier, it is possible to cope with various films and processes. An image (frame) photographed on a film and provided for printing is conveyed to a predetermined reading position by this carrier.

When the scanner 12 reads an image photographed on the film F, the image is emitted from the light source 22.
The reading light, the light amount of which is adjusted by the variable aperture 24, is transmitted to the film F positioned at a predetermined reading position by the carrier 30.
, And is transmitted therethrough to obtain projection light carrying an image photographed on the film F.

As shown in FIG. 2A, the carrier 30 holds the film F at a predetermined reading position, and has a sub-scanning direction orthogonal to the extending direction (main scanning direction) of the line CCD sensor of the image sensor 34. A pair of transport rollers 30a and 30b arranged so as to sandwich the reading position in the sub-scanning direction and convey the film F in the scanning direction and the longitudinal direction of the film F, and regulate the projection light of the film F into a predetermined slit shape; Slit 40 extending in the main scanning direction located corresponding to the reading position
a having a. The film F receives the reading light while being transported in the sub-scanning direction while being positioned at the reading position by the carrier 30. As a result, as a result, the film 40 has the slit 40 extending in the main scanning direction.
The two-dimensional slit scan is performed by a, and the image of each frame captured on the film F is read.

As is well known, a magnetic recording medium is formed on the film of the new photographic system, and a carrier 30 corresponding to the film (cartridge) of the new photographic system has information recorded on the magnetic recording medium. And a magnetic head 42 for recording necessary information. The information recorded on the magnetic recording medium of the film F is
The data is read by the magnetic head 42 and sent from the main body of the scanner 12 to a necessary portion such as the image processing device 14, or
Various kinds of information are recorded on the magnetic recording medium of the film F by the magnetic head 42. Reference numeral 44 in the figure denotes a DX code optically recorded on the film, an extended DX code,
A sensor for reading a bar code such as an FNS code, various information optically recorded on a film, an image photographing area in a frame, and the like. To a predetermined site.

As described above, at a predetermined reading position, the reading light is transmitted through the film F held by the carrier 30 and becomes projection light for carrying an image. An image is formed on the light receiving surface of the sensor 34. As shown in FIG. 2B, the image sensor 34 includes a line CCD sensor 34R for reading an R image, a line CCD sensor 34G for reading a G image,
And a line CCD sensor 34B having a line CCD sensor 34B for reading the B image. Each line CCD sensor extends in the main scanning direction as described above. The projection light of the film F is transmitted to the image sensor 3
4, the light is separated into three primary colors of R, G and B and read photoelectrically. The output signal of the image sensor 34 is
The signal is amplified by the amplifier 36, converted into a digital signal by the A / D converter 38, and sent to the image processing device 14.

The scanner 12 reads an image photographed on the film F by two image readings: a pre-scan for reading at a low resolution and a main scan for obtaining image data of an output image. The pre-scan is performed under pre-scan reading conditions set in advance so that the image of all the films targeted by the scanner 12 can be read without saturation of the image sensor 34. On the other hand, the main scan is performed under the main scan reading conditions set for each frame so that the image sensor 34 is saturated at a density slightly lower than the minimum density of the image (frame) from the prescan data. Therefore, the output signals of the pre-scan and the main scan are basically the same except that the resolution and the output level are different.

In the present invention, the scanner is not limited to the one using the slit scanning, but uses a surface exposure that reads the entire surface of one frame at a time using an area CCD sensor. You may. In addition to the scanner 12 that photoelectrically reads an image captured on a film such as a negative or a reversal, the photo printer 10 also includes an image reading device that reads an image of a reflection original, an imaging device such as a digital camera or a digital video camera, Image data can be received from various sources such as a communication means such as a computer communication or a recording medium such as an MO (magneto-optical recording medium) and a print can be created. That is,
The present invention can also be suitably used for images (image data) optically captured by an imaging device such as a digital camera.

As described above, the output signal (image data) from the scanner 12 is output to the image processing device 14.
FIG. 3 shows a block diagram of an image processing device (hereinafter, referred to as a processing device 14). The processing device 14 includes a data processing unit 50,
It includes a Log converter 52, a pre-scan memory 54, a main scan memory 56, a pre-scan processing unit 58, a main scan processing unit 60, and a condition setting unit 62.
FIG. 3 mainly shows parts related to image processing.
The processing device 14 further includes a CPU that controls and manages the entire photo printer 10 including the processing device 14, a memory that stores information necessary for the operation of the photo printer 10, and the like. The operation system 18 and the display 2
0 is connected to each part via the CPU or the like (CPU bus).

The R, G and B digital signals output from the scanner 12 are converted by the data processing section 50 into D
After performing predetermined data processing such as C offset correction, dark time correction, and shading correction, the data is converted by the Log converter 52 into digital image (density) data, and the prescan (image) data is stored in the prescan memory 54. The main scan (image) data is stored in the main scan memory 56. The pre-scan data and the main scan data are basically the same data except that the resolution (pixel density) and the signal level are different.

The pre-scan data stored in the pre-scan memory 54 is processed in the pre-scan processing section 58, and the main scan data stored in the main scan memory 56 is processed in the main scan processing section 60. The pre-scan processing unit 58 includes an image processing unit 64 and a data conversion unit 66. On the other hand, the main scan processing unit 60 includes an image processing unit 68, a data conversion unit 70, a correction parameter supply unit 74, and a correction parameter conversion unit 75.
Is configured.

The image processing section 64 of the prescan processing section 58
And the image processing unit 68 of the main scan processing unit 60
It is a part that performs predetermined image processing on an image (image data) read by the scanner 12 according to an image processing condition set by a condition setting unit 62 described later. Image processing unit 6
4 and 68 basically perform the same processing except that the pixel density of the image data to be processed is different, and the image processing unit 64 does not have the aberration correction unit 72. The image processing unit 68 of the unit 60 is performed as a representative example. In the present invention, the image processing unit 64 of the prescan processing unit 58 is also provided with an aberration correction unit,
If necessary, the prescanned image may be subjected to aberration correction described later.

The LUT of the image processing unit 68 (64) is LU
This is a portion for performing color balance adjustment, contrast adjustment (gradation processing), and brightness adjustment (density adjustment) of an image by using a T (lookup table). Also, MTX
Is a part for adjusting the saturation of an image by a matrix operation.

The image processing section 68 of the main scan processing section 60 includes between the MTX and the block 68A correction of distortion and chromatic aberration of magnification caused by the lens characteristics of the camera that has captured the image, and electronic zooming processing. Perform aberration correction unit 7
2 are arranged. In addition, a correction parameter supply unit 74 and a correction parameter conversion unit 75 are connected to the aberration correction unit 72.

The correction parameter supply unit 74 corrects the image aberration on the image forming surface of the image, that is, on the light receiving surface of an image sensor such as a digital camera or the like, corresponding to various kinds of lenses for photographing the image. An aberration correction parameter for correcting image quality deterioration caused by the aberration characteristic of the lens is stored. In the illustrated example, an aberration correction parameter for correcting chromatic aberration of magnification, corresponding to various lens types,
Further, aberration correction parameters for correcting distortion are stored. The correction parameter supply unit 74 obtains the lens type determination information, determines the lens type that has captured the image on the film F or the like, searches the stored aberration correction parameters, and determines the aberration correction parameters of the determined lens. And supplies it to the correction parameter converter 75.

It should be noted that the present invention is not limited to the case where all the images are subjected to the aberration correction. The image taken by a camera having a high-performance lens such as a single-lens reflex camera has no or very little lens aberration. There is no need to apply aberration correction to the image. The necessity / absence of aberration correction may be determined according to, for example, the type of lens (camera model) that captured the image, or the lens parameters of the type of lens that captured the image are stored in the correction parameter supply unit 74. It may be determined based on whether or not it has been performed.

There is no particular limitation on the discrimination information for discriminating the type of the lens that has captured the image on the film F or the like, and there are no particular limitations on the means for obtaining the information, and various methods can be used. Normally, the lens type can be determined if the model of the camera is known. For example, in the case of a camera of a new photo system, the camera type and the lens type are magnetically recorded on the film F, and the scanner 12 (carrier 30) is used at the time of printing. , And using this, the model of the camera, that is, the lens type can be determined. Alternatively, information of the lens type (model of the camera) may be optically printed on the film F by the camera, and the information may be read by the sensor 44 of the carrier 30. In the case of a film with a lens, such information may be magnetically recorded or printed at the time of manufacture, and this may be used to determine the type of lens. Alternatively, in the case of an imaging device such as a digital camera, the camera model and lens type may be recorded in the header of the image data (data file). Further, at the time of reception, the model of the camera is asked to the customer and recorded.
The lens type may be discriminated by inputting at 8a or the like.

As described above, the correction parameter supply unit 74
Selects an aberration correction parameter corresponding to the lens type that has captured the image, and supplies the selected parameter to the correction parameter conversion unit 75. Here, the aberration correction parameters stored in the correction parameter supply unit 74 correspond to the correction of the aberration on the image forming plane of the camera that has captured the image.
This is a parameter in mm unit corresponding to the position on the image plane. The correction parameter conversion unit 75 converts the aberration correction parameter on the image forming surface into an electronic scaling factor of the image, the number of input pixels (that is, the number of pixels before the electronic scaling process, or the number of pixels captured by the processing device 14), a scanner, and the like. 12, a scaling process is performed on at least one of the read size (input image size) of the film F and the output image size (the number of output pixels) to obtain an aberration correction parameter for each pixel of the output image. 72.

When reproducing an image optically photographed on a film or the like into a print, the aberration of the image due to the lens differs depending on input / output conditions such as the output print size (ie, the number of output pixels). Therefore, in order to properly correct the aberration, it is necessary to change the correction parameter according to the print size or the like. However, in order to have a correction parameter corresponding to all of various conditions such as a print size that may be output corresponding to a large number of lens types, a large capacity memory is required, and efficiency and cost are reduced. Disadvantageous in that. On the other hand, in the present invention, aberration correction parameters for correcting aberrations on the image forming surface are stored in correspondence with various lenses, and these are stored in an electronic magnification, the number of input pixels, the film reading size, and the output. By performing scaling processing by at least one of the image sizes and setting aberration correction parameters corresponding to pixel units of the output image, in the image processing of correcting aberration of the image caused by the lens, the above-described disadvantage is solved. It is possible to realize an efficient image processing device.

Whether the scaling process is performed using the electronic scaling factor, the number of input pixels, the film reading size, or the output image size may be appropriately selected and set according to the system configuration of the photo printer 10. For example,
When the reading size of the film and the output area (input image size) from the image sensor are fixed and the output image size is variable, the scaling process may be performed only with the electronic magnification and the number of input pixels. The output image size is unnecessary because it is determined by the electronic scaling factor and the number of input pixels.

On the other hand, if the input image size and the output image size are both variable in a photo printer,
The scaling process is performed according to the electronic magnification, the number of input pixels, and the film reading size. In a scanner that photoelectrically reads an image on the film F, in order to obtain more preferable image information, the print size to be output, for example, 1
35 film panorama size and L size, new photo system C type, H type and P type film F
Many devices change the reading size of a document. In a normal lens, the aberration varies depending on the position on the film surface, and therefore, the aberration characteristic varies depending on the read size of the film F. Therefore, when such a scanner is used, the scaling process is performed in consideration of the read size of the film F in addition to the electronic magnification and the number of input pixels.
In the case of a digital camera, the output area of the image sensor is similarly taken into account.

If the number of input pixels is fixed, if either the electronic magnification or the output image size is used,
A scaling process can be performed. However, even if the number of input pixels is fixed, if the input image size (shape and the like) is different, it is necessary to add the input image size as described above. If the output image size is a fixed system, scaling processing can be performed according to either the number of input pixels or the electronic scaling factor, or similarly, the input image size.

There is no particular limitation on the method of the scaling process, and the aberration correction parameter corresponding to the position on the image plane is converted into an output image in consideration of the electronic magnification and the number of input pixels according to the aberration correction parameter and the like. A scaling process for converting (converting) to the aberration correction parameter corresponding to the pixel of the above may be performed. The electronic magnification, the number of input pixels, the input image size, and the output image size can be specified by an operator such as input of an output print size, input of a film size (film type), or the like to the film of the above-described new photographic system. Can be obtained by magnetic recording, optical recording on a film, recording of image data on a header, and the like. In addition,
The film size is the carrier 3 mounted on the scanner 12.
It may be known by 0. Further, the focal length at the time of image capturing may be acquired from magnetic information or optical information recorded on the film F, and the aberration correction parameter may be corrected according to the focal length.

The aberration correction parameters are not particularly limited.
For example, a correction function or a correction coefficient for performing the aberration correction may be used, or a coefficient or a function that multiplies the correction function used for the aberration correction by the aberration correction unit 72 or corrects the correction function. In general, the characteristics of aberrations of a lens such as distortion and chromatic aberration of magnification are determined by the distance from the optical axis of the lens, that is, the center of an image captured on the film F (for example, x-
(indicated by y) as a parameter, which can be approximated to a certain extent, so that the cubic function itself may be used as an aberration correction parameter, or a coefficient that is applied to or corrects the cubic function, The function may be used as the aberration correction parameter.

The aberration corrector 72 corrects image distortion and chromatic aberration of magnification using the aberration correction parameters supplied from the correction parameter converter 75.
In the illustrated example, as preferable aspects, the aberration correction parameter and information on the position (pixel position) of image data,
For example, correction of distortion and chromatic aberration of magnification and electronic scaling processing are performed using a coordinate position (the number of pixels from the center pixel) from a center pixel (a pixel corresponding to the center of the optical axis of the photographing lens). . This coordinate is, for example, x-
The y-coordinate or the polar coordinate may be used, and various position information can be used as long as the position of the pixel can be relatively detected. For an image for which aberration correction is not performed, the aberration corrector 72 performs only electronic scaling processing.

When the center of an image cut out by a mask or the like is considered to be almost the center of the optical axis of the lens at the time of photographing, the center pixel of the cut out image is set as the center of the optical axis of the lens. Various aberrations (distortion, lateral chromatic aberration, peripheral light amount, image blur) may be corrected.

Here, if the correction of the chromatic aberration of magnification and the distortion is separately performed, it takes a long time to perform the calculation, and the interpolation calculation needs to be performed a plurality of times. Therefore, preferably, the image magnification of R and B is converted by using the aberration correction parameter and the pixel position with reference to the reference colors (usually G) of the three primary colors of R, G, and B to obtain R The chromatic aberration of magnification is corrected by matching the images of B and B to the G image, and then the distortion of the G image is corrected to correct the chromatic aberration of magnification and the distortion of the image.

That is, the appropriate position for each pixel is determined from the shift amount of the R and B pixel positions with respect to the reference color (G) caused by the chromatic aberration of magnification and the shift amount of the pixel position of the reference color caused by the distortion. By calculating and interpolating the image data of each pixel using the calculated information on the appropriate position of each pixel, image data obtained by correcting the chromatic aberration of magnification and the distortion of the image photographed on the film is obtained. Accordingly, since only the calculation for the G image needs to be performed for the distortion, the amount of calculation and interpolation calculation can be reduced, and more suitable correction can be performed.

Here, although the scaling processing is also affected, the image processing apparatus usually enlarges or reduces an image by image data processing, that is, performs an electronic scaling process to obtain an image (image data). Is output in a size corresponding to the output image. This electronic scaling process is usually performed by performing an interpolation operation on image data. However, since the interpolation calculation is necessary even in the correction of the chromatic aberration of magnification and the distortion, the result is that the interpolation is performed twice,
The image quality may deteriorate.

For this reason, it is more preferable that the image data is interpolated N times according to the electronic magnification using the information on the calculated appropriate position of each pixel, thereby simultaneously performing the electronic magnification processing of the image. In other words, the shift amount of the pixel position due to the chromatic aberration of magnification and the distortion aberration is calculated to find out where each pixel should be originally located, and the N-times interpolation calculation of the image data is performed according to the appropriate position. To perform the electronic scaling process. Thereby, the correction of the distortion and the chromatic aberration of magnification and the electronic scaling process can be performed by one interpolation operation.

The aberration corrector 72 in the illustrated example is a part for performing the above-described processing method. As shown in the conceptual diagram of FIG. 4, the aberration corrector 72 includes a coordinate conversion processor 72A and an enlargement / reduction processor 72B. Be composed. In FIG. 4, ir, ig
And ib represent the pixel position (address) of the image data (input image data) supplied from MTX, respectively;
r, Ig and Ib denote the pixel positions of the image data in which the chromatic aberration of magnification and the distortion have been corrected;
The shift amounts (that is, correction amounts) of the R and B pixel positions with respect to the G pixel position due to the chromatic aberration of magnification, respectively;
Indicates the amount of shift of the G pixel position due to distortion;

In the aberration corrector 72, when the image data is supplied from the MTX, the coordinate conversion processor 72A uses the aberration correction parameters (of the chromatic aberration of magnification) supplied from the correction parameter converter 75 to calculate R and R. The shift amounts Δr and Δb due to chromatic aberration of magnification with respect to the G image data ig at the pixel positions ir and ib of the B image data are calculated, and the aberration correction parameters (of distortion) supplied from the correction parameter conversion unit 75 are calculated. Is used to calculate the shift amount D of the G input image data ig due to distortion.

Next, Δr and D are added to each pixel position ir of the R input image data to calculate a pixel position Ir of the R image data in which the chromatic aberration of magnification and distortion have been corrected, and the B input image data B in which the chromatic aberration of magnification and the distortion have been corrected by adding Δb and D to each pixel position ib of
The pixel position Ib of the B image data corrected for the chromatic aberration of magnification and the distortion is calculated by adding the D to each pixel position ig of the G input image data.
b is calculated. That is, in this calculation, the chromatic aberration of magnification of the R image and the B image is corrected based on the G image,
The entire image is aligned with the G image, and the entire distortion is corrected using the shift amount D due to the distortion of the G image,
The pixel positions of the R, G, and B images in which the chromatic aberration of magnification and the distortion have been corrected are calculated.

Next, in the enlargement / reduction processing section 72B,
The pixel position I corrected for this chromatic aberration of magnification and distortion.
Using r, Ig, and Ib, the image is scaled by performing interpolation (N-fold interpolation) of the image data in accordance with the enlargement / reduction magnification, thereby correcting magnification chromatic aberration and distortion, and electronic scaling. As the processed image data,
Output to block 68A. There is no particular limitation on the method of the electronic scaling process, and various known methods can be used. Examples thereof include a method using bilinear interpolation and a method using spline interpolation.

When the distortion is corrected, the image in the reproduction area may be lost, that is, so-called vignetting may occur. Therefore, when the correction of the distortion is performed, it is 0.1% to 5% higher than usual. It is preferable to perform electronic scaling processing (interpolation) at a high scaling factor. Further, the electronic magnification at that time may be variously set according to the lens type. In addition, since the amount of distortion may differ between the vertical and horizontal directions of the image, the magnification of the electronic magnification processing may be changed between the vertical and horizontal directions.

In the illustrated example, both distortion and lateral chromatic aberration are corrected as a preferable mode, but only one of them may be performed. Also in this case, instead of separately performing the aberration correction and the electronic scaling process, the appropriate position of the image in which the amount of deviation caused by the aberration has been corrected is calculated in the same manner as described above, and the information on the appropriate position is calculated. It is preferable to perform the electronic scaling process by performing N-fold interpolation of the image data using

Further, in addition to the distortion and the chromatic aberration of magnification, an aberration correction parameter on the image forming surface for correcting aberrations such as a focus blur (PSF: Point Spread Function) and a decrease in peripheral light amount due to the lens is also included. In advance, the scaling processing is performed in the same manner as described above, and as an aberration correction parameter corresponding to the pixel of the output image,
In addition to or instead of the aberration correction, focus blur correction and peripheral light amount correction may be performed.

The MTX of the image processing section 64 and the image data processed by the aberration correction section 72 are then sent to block 6
Processed at 4A and 68A. Blocks 64A and 68A are portions for performing image processing other than the above-described various processing such as sharpness processing, dodging processing (compression of image dynamic range while maintaining intermediate gradation), and synthesis of characters and images.

The image data processed by the image processing units 64 and 68 are sent to the data conversion units 66 and 70.
The data conversion unit 66 of the pre-scan processing unit 58 converts the image data processed by the image processing unit 64 by using a 3D (three-dimensional) -LUT or the like to obtain image data corresponding to the display on the display 20. . If necessary, the data conversion unit 66 may perform an electronic scaling process. On the other hand, the data conversion unit 7 of the main scan processing unit 60
0 similarly converts the image data processed by the image processing unit 68 using the 3D-LUT, and converts the converted image data into image data corresponding to image recording by the printer 16.
To supply.

Various processing conditions by the prescan processing section 58 and the main scan processing section 60 are set by the condition setting section 62. The condition setting section 62 includes a setup section 72, a key correction section 78, and a parameter integration section 80.
Is configured.

The setup section 72 sets the reading conditions for the main scan using the pre-scan data, selects the image processing to be performed, and selects the image processing sections 64 and 6.
8 and the image processing conditions in the data conversion units 66 and 70 are set and supplied to the parameter integration unit 80. Specifically, the setup unit 76 calculates
It creates a density histogram, calculates image features such as average density, highlight (lowest density), shadow (highest density), etc. In addition, the main scan is performed according to an operator's instruction performed as necessary. Are set, and image processing conditions such as creation of an LUT for performing the above-described color balance adjustment and a matrix operation expression for performing the saturation adjustment are determined.

The key correction section 78 responds to a correction instruction for brightness, color, gradation, saturation, etc., from the keyboard 18a or the like.
The correction amount of the image is calculated and supplied to the parameter integration unit 80. The parameter integration unit 80 receives the image processing conditions set by the setup unit 76, sets the supplied image processing conditions in predetermined portions of the pre-scan processing unit 58 and the main scan processing unit 60, and further sets the key correction unit 78 In accordance with the calculated correction amount, an LUT or the like for performing this correction is created and set for a predetermined part, and the image processing conditions set for each part are corrected.

Hereinafter, the operation of the scanner 12 and the processing device 14 will be described. After the operator loads the carrier 30 corresponding to the film F into the scanner 12, sets the film F (cartridge) at a predetermined position of the carrier 30, and inputs necessary instructions such as a print size to be created, and then instructs to start printing. I do. The print size information and the like are sent to the processing device 14, and the image processing unit 68 and the correction parameter conversion unit 75 obtain information on the electronic magnification, the number of input pixels, the film reading size, the output image size, and the like.

In response to the print start instruction, the aperture value of the variable aperture 24 of the scanner 12 and the storage time of the image sensor (line CCD sensor) 34 are set according to the prescan reading conditions. F is conveyed in the sub-scanning direction at a speed corresponding to the pre-scan, and the pre-scan is started. At the predetermined reading position, the film F is slit-scanned and the projection light forms an image on the image sensor 34 as described above. Thus, the image photographed on the film F is decomposed into R, G, and B and photoelectrically read.

When the film F is transported, information magnetically recorded on the film F is read by the magnetic head 42 of the carrier 30, and various information optically recorded by the sensor 44 are read. The necessary information is sent to a predetermined portion of the processing device 14 or the like. For example, the correction parameter supply unit 74 of the processing device 14 obtains identification information of the lens type. Note that the determination information and the like may be provided by various methods such as input by an operator, as described above.

The pre-scan and the main scan include
The prescan and the main scan may be performed one frame at a time, or continuously for all frames or for a predetermined plurality of frames. In the following example, one frame of image reading will be described as an example to simplify the description.

The output signal of the image sensor 34 due to the pre-scan is amplified by the amplifier 36 and is output from the A / D converter 3.
8, converted into a digital signal, transmitted to the processing device 14, subjected to data processing by the data processing unit 50, converted into digital image data by the Log converter 52, and stored in the prescan memory 54. Is done.

When the pre-scan data is stored in the pre-scan memory 54, the setup unit 76 of the condition setting unit 62 reads out the pre-scan data, creates a density histogram, and calculates image features such as highlights and shadows. The reading conditions for the main scan are set and supplied to the scanner 12,
Further, various image processing conditions such as gradation adjustment are set and supplied to the parameter integration unit 80. Parameter integration unit 76
Indicates the supplied image processing conditions to the pre-scan processing unit 5
6 and a predetermined portion (hardware) of the main scan processing section 58.

When performing a test, pre-scan data is read from the pre-scan memory 54 by the pre-scan processing unit 62, subjected to image processing under the image processing conditions set in the image processing unit 64, and further subjected to data conversion. Part 6
6 and displayed on the display 20 as a simulation image. The operator operates the display 20
, The image, that is, the processing result is confirmed (verified), and the color, density, gradation, and the like are corrected using the adjustment keys and the like set on the keyboard 18a as necessary. The input of this adjustment is sent to the key correction unit 78 and the key correction unit 7
8 calculates a correction amount according to the correction input, and sends it to the parameter integration unit 76. The parameter integration unit 76 sets a correction condition for executing the correction in accordance with the correction amount, and corrects the previously set image processing condition. Therefore, the image displayed on the display 20 also changes according to the correction, that is, the adjustment input by the operator.

When the operator determines that the image of this frame is proper (OK), the operator instructs a print output using the keyboard 18a or the like. As a result, the image processing conditions are fixed, the aperture value of the variable aperture 24 is set in the scanner 12 in accordance with the reading conditions of the main scan, and the carrier 30 moves the film F at a speed corresponding to the main scan. Then, the main scan is started. When the test is not performed, the parameter integration unit 80
When the setting of the image processing conditions in the main scan processing unit 60 is completed, the image processing conditions are determined, and the main scan is started. It is preferable that the presence or absence of such a test can be selected as a mode.

The main scan is performed in the same manner as the pre-scan except that the read conditions such as the aperture value of the variable aperture 24 are set for the main scan.
Is amplified by an amplifier 36, is converted into a digital signal by an A / D converter 38, is processed by a data processing unit 50 of the processing device 14, is converted into a main scan data by a Log converter 52, and is converted into a main scan data. The data is sent to the memory 56. When the main scan data is sent to the main scan memory 54, the main scan data is read out by the main scan processing unit 60 and
The gradation adjustment and the saturation adjustment are performed by the 8 LUTs and MTX, and then sent to the aberration corrector 72.

On the other hand, the correction parameter supply section 74 determines the lens type from the obtained determination information, reads out the aberration correction parameter of the corresponding lens type on the image plane, and sends it to the correction parameter conversion section 75. The correction parameter conversion unit 75 converts the supplied aberration correction parameter on the imaging plane into an electronic magnification, an input pixel number, a film reading size (input image size), and an output image size, which are found from input print size information and the like. The output image data is subjected to scaling processing to obtain an aberration correction parameter corresponding to a pixel unit of the output image data, which is sent to the aberration correction unit 72.

The aberration correction unit 72 calculates the pixel positions Ir and Ig in which the chromatic aberration of magnification and the distortion have been corrected in the coordinate conversion processing unit 72A as described above, based on the supplied aberration correction parameters and the pixel positions of the image data. And Ib are calculated and sent to the scaling processor 72B. The enlargement / reduction processing section 72B performs electronic magnification of the image by performing N-times interpolation of the image data using the pixel positions Ir, Ig, and Ib, and blocks the image data as a result of the aberration correction and the electronic magnification processing. 68A. Note that an image for which aberration correction is not performed is not subjected to any processing in the coordinate conversion processing unit 72A, and is only subjected to electronic scaling processing in the scaling processing unit 72B.

The image data is further subjected to necessary image processing such as sharpness processing and dodging processing in block 68A, sent to the data conversion unit 70, and then sent to the image data conversion unit 70 for image recording by the printer 16. The image data is converted to corresponding image data and sent to the printer 16.

The printer 16 exposes a photosensitive material (printing paper) in accordance with image data to record a latent image, performs a developing process in accordance with the photosensitive material, and outputs a print (finished). For example, after the photosensitive material is cut into a predetermined length corresponding to the print, recording of the back print, red (R) exposure, green (G) exposure, and blue (B) according to the spectral sensitivity characteristics of the photosensitive material (photographic paper). 3) The three types of light beams of exposure G are modulated according to image data (recorded image), deflected in the main scanning direction, and conveyed in a sub-scanning direction orthogonal to the main scanning direction to form a latent image. After performing recording and the like, the photosensitive material on which the latent image has been recorded is subjected to predetermined wet development processing such as color development, bleach-fixing, and washing with water, dried, printed, sorted, and accumulated.

The image processing method and the image processing apparatus according to the present invention have been described above in detail. However, the present invention is not limited to the above embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Of course you can do it.

[0073]

As described above in detail, according to the present invention, even if an image is taken by an inexpensive compact camera or the like having a zoom function, it is possible to preferably correct aberrations such as distortion and chromatic aberration of magnification. Can be performed, and a print in which a high-quality image is reproduced can be output.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a digital photo printer using an image processing apparatus according to the present invention.

2A is a conceptual diagram of a carrier of the digital photo printer shown in FIG. 1, and FIG. 2B is a conceptual diagram of an image sensor of the digital photo printer shown in FIG.

FIG. 3 is a block diagram of an example of an image processing device of the digital photo printer shown in FIG.

4 is a conceptual diagram of an aberration correction unit of the image processing device shown in FIG.

[Explanation of symbols]

 10 (Digital) Photo Printer 12 Scanner 14 (Image) Processing Device 16 Printer 18 Operation System 20 Display 22 Light Source 24 Variable Aperture 28 Diffusion Box 32 Imaging Lens Unit 34 Image Sensor 36 Amplifier 38 A / D Converter 40 Mask 42 Magnetic Head 44 sensor 50 data processing unit 52 log converter 54 prescan memory 56 main scan memory 58 prescan processing unit 60 main scan processing unit 62 condition setting unit 64, 68 image processing unit 66, 70 data conversion unit 72 aberration correction unit 74 correction Parameter supply unit 75 Correction parameter conversion unit 76 Setup unit 78 Key correction unit 80 Parameter integration unit

Claims (4)

[Claims] 1. An image processing method for input image data obtained from an optically captured image to obtain output image data for output, wherein a predetermined image of the lens is used for capturing the image. By subjecting the aberration correction parameter on the image plane to scaling processing by at least one of an electronic scaling factor for obtaining the output image data, the number of input pixels of the input image data, the size of the input image, and the size of the output image. ,
An image processing method, wherein an aberration correction parameter corresponding to a pixel unit of the output image data is used, and using the aberration correction parameter in the pixel unit, an aberration of an image caused by a lens that has captured the image is corrected. 2. An image processing apparatus which performs image processing on input image data obtained from an optically captured image to obtain output image data for output, wherein a lens that has captured the image is determined. Acquisition means for acquiring the discrimination information, storage means for storing an aberration correction parameter for correcting a lens aberration on an image forming surface of a lens for photographing an image, and a correspondence from the storage means according to the discrimination information acquired by the acquisition means. Selecting means for selecting an aberration correction parameter on the image forming surface of the lens; at least one of an electronic magnification for obtaining the output image data, the number of input pixels of the input image data, the size of the input image, and the size of the output image The scaling processing is performed on the aberration correction parameter on the image plane selected by the selection unit, and the pixel data of the output image data is subjected to scaling processing. A conversion unit that converts the image into a corresponding aberration correction parameter; and a correction unit that uses the aberration correction parameter corresponding to a pixel unit converted by the conversion unit to correct the aberration of the image caused by the lens that captured the image. An image processing apparatus characterized by the above-mentioned. 3. The image processing apparatus according to claim 2, wherein the image is an image photographed on a photographic film, and the size of the input image is a read size of an image from the photographic film. 4. The image processing apparatus according to claim 2, wherein the aberration is at least one of chromatic aberration of magnification, distortion, out-of-focus, and reduction in peripheral light amount.