JPH1132349A - Color printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output a photograph photographed by a conventional digital camera without any special function efficiently as a high image quality color print. SOLUTION: A printer uses an image data reception means 1 from a digital camera 10, an interpolation magnification means 2 interpolates image data to have a pixel number suitable for resolution of the printer and converts the color by a color conversion means 3 so that an impression of the color at photographing is equal to an impression of a color of a color print 9. Furthermore, after gradation conversion by a gradation conversion means 4 and correction by an image correction means 5 are conducted, a print mount is exposed by a laser printer 6 to produce the color print 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printer for outputting a photographic image taken by a digital camera as a color print.

[0002]

2. Description of the Related Art In general, the quality of a photograph, particularly the finish of a color photograph, greatly varies depending on exposure conditions.
Therefore, a conventional camera using a film is usually equipped with an AE mechanism for setting an appropriate exposure amount in accordance with the brightness at the time of shooting and the luminance distribution of a subject.

[0003] However, in the case of a digital camera, it is often impossible to perform very sophisticated processing on the camera side due to restrictions on cost and calculation time. In the case of a digital camera, an image acquired without using a photo store is often used as it is, so a monitor display with a relatively wide image quality tolerance, such as an image displayed on a CRT monitor or an LCD monitor attached to the camera, is used. If the image is an image that can withstand observation, it is considered that the image quality is sufficient, and there is a case where a very high-performance AE mechanism is not mounted.

Therefore, when a photographic print is created from digital image data captured by a digital camera, high-quality prints cannot be obtained only by performing the same processing as when acquiring image data from film. For this reason, with respect to image data taken in from a digital camera, image processing and test printing are individually repeated until a satisfactory image quality is obtained, thereby producing a print.

[0005]

However, in recent years,
2. Description of the Related Art Digital cameras are attracting attention not only to PC users but also to more general users, and there is an increasing need to print photographs taken by digital cameras. Therefore, as described above, the fact that the printing process takes time and costs is not preferable for providing a prompt service.

On the other hand, Japanese Patent Application No. 8-279205 discloses a digital camera that stores shooting conditions such as a light source and brightness at the time of shooting together with image data, and captures the shooting conditions together with the image data to suit the shooting conditions. An image reproducing apparatus that creates a high-quality print by performing image processing has been proposed. However, this method is based on the premise that the digital camera has the above functions, and is not effective in the case of an ordinary digital camera.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a color printer having an image processing function and a printing function for image data taken from a general digital camera having no special function. .

[0008]

SUMMARY OF THE INVENTION A color printer according to the present invention is a color printer for outputting a photographic image taken by a digital camera as a color print, and is recorded from a recording medium for a digital camera on the recording medium. Image data capturing means for capturing image data, enlargement / reduction means for expanding or reducing the captured image data so that the number of pixels of the image data is the number of pixels required for the print size, Color conversion means for performing color conversion so that colors are the same between the RGB primary colors of the digital camera and the RGB primary colors of the color printer; and a preferable gradation of the color print for the image data. Gradation conversion means for performing gradation conversion so that the image is processed by the enlargement / reduction means, color conversion means, and gradation conversion means. Image correction means for determining the color tone and / or density balance of the data and performing necessary correction processing on the image data based on the result of the determination; and recording the image data after the correction processing on a print mount. And a printing means for generating the color print.

Here, the recording medium for the digital camera is, specifically, a built-in memory or an IC of the digital camera.
It is a memory card or the like, and the image data capturing means is a connection cable to a digital camera, a card reader, or the like. Also, the format of image data recorded on the recording medium of a digital camera depends on the camera model.
Alternatively, since the image data differs depending on the mode setting, when the image data is taken in, it is necessary to develop such data in a format that can be handled by the printer. However, software for performing such processing is included in the image data taking-in means.

The scaling means changes the number of pixels of image data by a known interpolation method such as linear interpolation or spline interpolation. Image data obtained by photographing with a digital camera is usually recorded as image data of about 480 pixels × 640 pixels, while 1000 pixels × 1
Since about 500 pixels are required, generally, the number of pixels may be increased by interpolation. Specifically, for example, it is desirable to perform interpolation so that the resolution of the printer is set to (dpi) and the number of pixels is suitable.

Further, the color conversion is performed by using a digital camera.
For example, a matrix for converting GB into R'G'B 'of laser light when exposing by a laser printer is obtained in advance, and the RGB values of each pixel of the captured image data may be converted by this matrix. One matrix may be prepared for a standard digital camera, or several matrices may be prepared and used for each digital camera model. As a color conversion method, for example, a method described in JP-A-2-192968, Japanese Patent Application No. 9-176809, or the like can be used.

Preferably, the color conversion is performed so that the color recorded by the digital camera as gray on the recording medium is reproduced as gray on the color print. Specifically, when R = G = B = k (where k is an arbitrary constant), R ′, G ′, and B ′ after color conversion are R ′
= G '= B' = k '.

Further, it is desirable that the gradation conversion be performed using a table whose characteristics improve the skipping of the highlight portion and the collapse of the shadow portion.

The image correcting means may be a means for automatically judging color and the like and automatically performing a correcting process. For example, the corrected result is displayed on a monitor attached to the printer to confirm the operator's confirmation. The user may be prompted to perform a correction process based on an instruction from the operator. A photograph or the like that has become black due to shooting against backlight can be corrected by this processing. For example, Japanese Patent Application No. 9-837
The correction described in No. 92 may be performed.

Here, the color conversion, gradation conversion, and image correction processing may be performed stepwise on the image data. However, a conversion table having three functions is created in advance and imported. After scaling the image data,
Batch conversion may be performed using the table.

In the present invention, the type of printing means is not particularly limited, but it is preferable that a printing board made of a photosensitive member such as a laser printer is exposed to light of an amount corresponding to each pixel value of the image data. Preferably, the image data is recorded on the print mount.

[0017]

Since the color printer of the present invention has an image capturing means for capturing image data directly from the memory for the digital camera in the main body, there is no need to transfer the data to an FD or the like and then bring it to a service shop. . The captured image data is subjected to pixel number conversion so that the number of pixels is sufficient for print output by the enlargement / reduction unit, and then by the color conversion unit, the gradation conversion unit, and the image correction unit.
Since the necessary color, gradation conversion, and correction processing are performed on the assumption that sufficient exposure control has not been performed on the camera side, shooting was performed with a low-cost digital camera that does not have an AE mechanism or white balance mechanism Even a photo can be output as a high-quality photo print, similar to a photo read by a film scanner.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color printer according to the present invention will be described below with reference to the drawings. FIG.
FIG. 1 is a diagram showing a configuration of a color printer of the present invention. As shown in the figure, the color printer of the present invention includes a card reader 1a and a cable interface 1b as image capturing means for capturing an image from a digital camera, and further includes an interpolation enlargement means 2, a color conversion means 3, a gradation conversion means. 4, an image correcting means 5, and a laser printer 6. However, FIG.
Are not intended to limit the present invention. For example, the enlargement process may be performed by the interpolation enlargement unit 2 after performing the color conversion by the color conversion unit 3.

The card reader 1a is a digital camera 10a that records a photographed image on a removable memory card 11.
This is for taking in image data from. PCMCIA, as a memory card 11 used for a digital camera,
Several types are known, such as SSFDC and compact flash. It is desirable to provide a plurality of card readers 1a for each type of card so as to be compatible with all types of digital cameras.

In the case of the digital camera 11b that records a photographed picture in a built-in memory, image data is captured by connecting a dedicated cable to the cable interface 1b. Also in this case, it is desirable to prepare several types of cables according to the camera model.

The format of the image data recorded in the memory card 11 or the internal memory of the digital camera may differ depending on the manufacturer of the digital camera. Even when the same digital camera is used for shooting, the format of the image data to be recorded changes depending on the mode settings such as a mode with a small number of pixels, a mode with a large number of pixels, and a compression mode (for example, JPEG). Therefore, the above card reader 1a and cable interface
When the image data is taken in via 1b, the image data is developed into a standard format that can be handled by the printer by software (not shown) for performing a predetermined format conversion. Image data 7 captured as described above
Is, for example, 480 for a photo taken in the standard mode.
It has about 640 pixels.

This image data 7 is then enlarged by the interpolation enlargement means 2 to become, for example, print image data 8 of about 1000 × 1500 pixels. Conversely, when a small-sized print such as an ID photo is created, the size is reduced. The image data 8 for printing is adjusted to the resolution of the color printer,
If the resolution is 0 dpi, the resolution of the print image data 8 is also 6
Interpolated to be 00 dpi.

The color data of the interpolated and enlarged image data 8 is converted by the color conversion means 3 so that the RGB primary colors (or CMY primary colors) of the digital camera and the RGB primary colors of the printer match. At this time, the value of each pixel of the image data recorded by the digital camera is set to (R, G,
B), and the value of each pixel of the image data to be recorded on the print board is (R ′, G ′, B ′), and the pixel value represented by R = G = B = k is R ′ = B ′ = It is preferable that the pixel values are converted into pixel values having a relationship of G '= k'. In other words, this means that gray is reproduced as gray, and that gray is not yellowish or bluish.

This color conversion can be expressed as a matrix as shown in FIG.
By setting the coefficients related to the terms of G, GB, BR, R ² , G ² , and B ² to other than 0, it is also possible to perform correction such as saturation. In this case, by setting the sum of the rows of each matrix (for example, the sum of k11 to k19) to 1, the color saturation can be increased while maintaining the gray reproducibility.

Next, the processing by the gradation conversion means 4 will be described. For example, when outdoor photography is performed using a digital camera, photography is performed under relatively high illuminance. On the other hand, photographic prints are often viewed under room light, and the presence of flare such as surface reflection on the print mount cannot be ignored, so when printing out image data recorded with a digital camera, Appropriate gradation correction is required. As a method of gradation conversion, for example, a scene having a reflectivity of 20% can be used even if the reflectivity of the scene is 20%.
For example, there is a method of performing conversion using an S-characteristic conversion table (FIG. 2) that becomes%.

The image correcting means 5 is a means for performing correction for backlight correction or the like. For example, there is a method in which a histogram is obtained with an average value of each pixel, and correction is performed by changing all the pixels so that the number of brightest pixels occupies a predetermined ratio in the total number of pixels. In addition, a well-known correction process performed when printing image data captured by a film scanner may be performed. The correction of the image may be performed automatically, as in the above-described method of obtaining the histogram, or the image data may be temporarily displayed on a monitor attached to the printer, and an instruction from the operator may be received, and based on the instruction, May go.

The color conversion and the gradation conversion may be realized in a form of batch conversion using one predefined LUT. If the operator does not particularly intervene in the image correction, the image correction processing can be included in the same LUT.

The corrected image data is output as a photographic print 9 by the laser printer 6. That is, for example, a print mount (photosensitive member) using silver halide,
The print mount is exposed by irradiating an amount of laser light corresponding to the image data and developed, thereby reproducing a photographic image on the mount. As the printing means, any printer other than a laser printer, such as an ink jet printer and a sublimation printer, can be applied.

According to the above-described color printer, even with a digital camera that is currently in widespread use and has only a very standard function, the camera body or memory card is brought to a service shop and the image capture unit of the printer is taken. , A high quality color print can be obtained as in the case of film.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a color printer of the present invention.

FIG. 2 is a diagram illustrating an example of a gradation conversion characteristic.

[Explanation of symbols]

 7 Image data 8 Image data for printing 9 Color print 10 Digital camera 11 Memory card

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/765 H04N 5/781 510C 5/781

Claims (6)

[Claims] 1. A color printer for outputting a photographic image captured by a digital camera as a color print, comprising: image data capturing means for capturing image data recorded on a recording medium from a recording medium for the digital camera; Means for enlarging or reducing the fetched image data so that the number of pixels of the image data becomes the number of pixels required for the print size; and the RGB primary colors of the digital camera and the color printer for the image data. Color conversion means for performing color conversion so that the colors become the same among the RGB primary colors, and gradation conversion for performing gradation conversion on the image data so that the gradation of the color print becomes a preferable gradation. Means, and the color and / or density balun of the image data processed by the scaling means, color conversion means and gradation conversion means. Image correction means for performing necessary correction processing on the image data based on the result of the determination, and printing means for generating the color print by recording the image data after the correction processing on a print mount. And a color printer comprising: 2. The color conversion according to claim 1, wherein the color conversion is such that a color recorded as gray by the digital camera on the recording medium is reproduced as gray on the color print. Color printer. 3. The color printer according to claim 1, wherein the characteristic of the gradation conversion is a characteristic that reproduces a highlight part and / or a shadow part in detail. 4. The printing device according to claim 1, wherein the printing unit exposes a printing board made of a photosensitive member with an amount of light corresponding to each pixel value of the image data, thereby recording the image data on the printing board. The color printer according to any one of claims 1 to 3, wherein: 5. The color conversion means and the gradation conversion means,
The color printer according to claim 1, wherein the color printer is implemented as one conversion table. 6. The color printer according to claim 5, wherein said conversion table further has a function of a correction process by said image correction means.