JP2004260572A - Digital camera and control method thereof - Google Patents

Abstract

When directly printing an image of a digital camera, a color space of a photographed image does not match a color space of a direct printer, and an image is not printed in a correct color.
A printer compatible with a first color space that can be directly connected to a digital camera, and a digital camera capable of capturing an image in a second color space wider than the first color space, An image captured in the second color space is output to the printer after performing image processing for converting the image into the first color space.
[Selection] Fig. 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a digital camera capable of directly outputting image data to a printer.
[0002]
[Prior art]
In digital cameras, the sRGB color space is used as a standard color space. However, cameras that can use an extended color space such as Adobe RGB color space, which has a color space wider than the sRGB color space, are increasing, mainly for single-lens reflex digital cameras.
[0003]
In addition, a direct print method in which a digital camera is directly connected to a printer by a cable and an image taken by the digital camera is directly printed out has begun to spread. Among the direct printing methods, those which do not have a built-in image processing function circuit on the printer side or are very simplified, and which are small and excellent in portability, have begun to spread. This type of direct printer does not include a color space conversion process or the like, and can generally use an sRGB color space which is a standard color space of a digital camera.
[0004]
[Patent Document 1]
JP 2001-195208A
[0005]
[Problems to be solved by the invention]
However, conventionally, color space conversion has not been performed, and the camera must be photographed in accordance with the color space of the printer. In a direct printer having only the sRGB color space, when directly printing an image of a digital camera photographed in the Adobe RGB color space, the color space of the photographed image does not match the color space of the direct printer, and the image is displayed in correct colors. Is not printed.
[0006]
[Means for Solving the Problems]
The present invention relates to a printer corresponding to a first color space that can be directly connected to a digital camera, and a digital camera capable of capturing an image in a second color space wider than the first color space. An image captured in the second color space is a digital camera compatible with direct printing, which performs image processing for converting the image into the first color space and then outputs the image to the printer.
[0007]
In the digital camera supporting direct printing according to the present invention, the first color space is an sRGB color space.
[0008]
In the digital camera supporting direct printing according to the present invention, the second color space is an Adobe RGB color space.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
An embodiment according to the present invention will be described below with reference to the drawings.
[0010]
FIG. 1 is a block diagram showing a schematic configuration of the digital camera 100, and 101 is an operation mode selection unit. The selectable operation modes include a photographing mode for photographing, a reproduction mode for reproducing a photographed image, a print mode for printing, and the like. The operation mode selection unit 101 is not particularly limited, such as a mode dial and a mode determination switch.
[0011]
Reference numeral 102 denotes an imaging unit including a photographic lens, an imaging element and its driving circuit, an A / D converter, and the like. The optical image formed by the taking lens is converted into an electric signal by the image pickup device, and the output signal is converted into a digital signal by the A / D converter. The digital camera control circuit 103 includes an imaging unit 102, and a memory 104, a recording medium 105, an image processing circuit 106, a JPEG encoding circuit 107, a color space conversion unit 108, an image display unit 109, a transfer control unit 110, and a format conversion, which will be described later. Control of each block such as the unit 115 and a data bus between the blocks are included. The memory 104 has a capacity capable of storing a plurality of pieces of image data for one screen read from the image sensor of the image capturing unit 102 as one unit. The digital signal output from the imaging unit 102 is recorded in the memory 104 from the digital camera control circuit 103. The capacity of the memory 104 is set large so that the continuous shooting operation in which a plurality of shooting operations are performed in a short time is not limited by the speed of the subsequent processing (format conversion, compression encoding, recording on a recording medium). You.
[0012]
The recording medium 105 is preferably a removable medium such as a semiconductor memory card. The image processing circuit 106 performs white balance adjustment, pixel interpolation processing, gradation processing, color conversion processing, and the like. The JPEG encoding circuit 107 is a circuit for compressing and decompressing image data according to the baseline JPEG method, and includes a well-known DCT, a quantization circuit, a Huffman code / composite circuit, and the like (not shown).
[0013]
The color space conversion unit 108 is a block for converting image data to be printed into an sRGB color space when an image photographed in the Adobe RGB color space is directly printed by the direct printer 120. More specifically, it includes a block for converting the Adobe RGB color space to the standard color space XYZ and a block for converting the standard color space XYZ to the sRGB color space. The image display unit 109 is configured by a liquid crystal display or the like, and is used for displaying a reproduced image recorded on the recording medium 105, selecting a print image described later, and the like. The transfer control unit 110 connects the digital camera 100 and the direct printer 120 directly with the cable 121, and when the image captured by the digital camera 100 is directly printed by the direct printer 120, the image data to be printed is transmitted to the direct printer 120. Control the transfer.
[0014]
A data format conversion unit 115 converts RGB stored in the memory 114 into a data format compatible with the direct printer 120.
[0015]
Next, processing in the print mode will be described with reference to the flowchart of FIG.
[0016]
When the print mode is selected by the operation mode selection unit 101 (step S101), the digital camera control circuit 103 displays a print image selection screen on which the captured image is displayed on the image display unit 109, and displays the print image to the user. The user is selected (step S102). The method of selecting the print image is not limited to this, and is arbitrary.
[0017]
When the user instructs to start printing after the print image is selected (step S103), the digital camera control circuit 103 reads the image data of the print image from the recording medium 105 to the memory 104 (step S104). Next, the color space attached to the image data read into the memory 104 is detected (step S105). The detection of the color space is performed by a known method such as detection of a tag indicating the color space defined by EXIF. Next, it is determined whether or not the color space is the Adobe RGB color space (step S106). If the color space is the Adobe RGB color space, the process proceeds to image processing including the color space conversion process of step S107.
[0018]
FIG. 3 shows a detailed flowchart of step S107. The image read to the memory 104 is converted into YCbCr by JPEG expansion in the JPEG encoding circuit 107, and further converted from YCbCr to RGB (step S201). At this time, the color space of the image data is AdobeRGB having a wider color space than sRGB. Next, AdobeRGB is converted into the standard color space XYZ by the color space conversion unit 108 (step S202), and further converted from the standard color space XYZ into sRGB which is the color space of the direct printer 120 (step S203). Further, the sRGB is converted into a data format compatible with the direct printer 120 by the data format converter 115 (step S204). At this time, the image data whose data format has been converted is stored in another area of the memory 104. However, the image data whose data format has been converted may be sent to the sequential transfer control unit 110.
[0019]
If the color space of the image in the memory 104 is sRGB in step S106, the process proceeds to step S108. FIG. 4 shows a detailed flowchart of step S108. The image stored in the memory 104 is JPEG decompressed by the JPEG encoding circuit 107, converted into YCbCr, and further converted from YCbCr to RGB (step S301). The color space of the image data at this time is sRGB. The sRGB is converted by the data format converter 115 into a data format compatible with the direct printer 120 (step S302). The image data whose data format has been converted is stored in another area of the memory 104. However, the image data whose data format has been converted may be sent to the sequential transfer control unit 110.
[0020]
Returning to the flowchart of FIG. 2 again, the transfer control unit 110 outputs the image data whose data format has been converted to the direct printer 120 (step S109).
[0021]
As described above, when the color space of the image data is AdobeRGB, AdobeRGB is converted to sRGB which is the color space of the direct printer 120. This makes it possible to perform printing in accordance with the color space of the direct printer 120, even if the direct printer 120 does not have an image processing function.
[0022]
Next, it is determined whether or not printing of the image transferred to the direct printer 120 has been completed (step S110). If not completed, the process returns to step S109 to continue the transfer of the image data. When printing is completed, it is determined whether or not there is a next print image (step S111). If there is a next print image, the process returns to step S104, and the same processing is performed on the next print image. If there is no next print image, the print mode process ends.
[0023]
In the present embodiment, the color space conversion unit 108 performs conversion from the Adobe RGB color space to the sRGB color space via the standard color space XYZ, but instead of the standard color space XYZ, the color space conversion unit 108 performs a conversion from the Adobe RGB color space. A wide color space (for example, a Lab uniform color space or the like) may be used.
[0024]
In the present embodiment, the direct printer 120 is in the sRGB color space, and the digital camera 100 is in the Adobe RGB color space. However, the present invention is not limited to this. It is applied when it is wider than space.
[0025]
(Second embodiment)
In the second embodiment, a conversion from the Adobe RGB color space to the sRGB color space using a lookup table will be described. FIGS. 1 and 2 are common to the first embodiment, and therefore, detailed description is omitted here, and description will be made using the flowchart of FIG.
[0026]
FIG. 5 shows a detailed flowchart of step S107. The image read to the memory 104 is converted into YCbCr by JPEG expansion in the JPEG encoding circuit 107, and further converted from YCbCr to RGB (step S401). At this time, the color space of the image data is AdobeRGB having a wider color space than sRGB. Next, AdobeRGB refers to a look-up table in which the input color signal is AdobeRGB and the output color signal is sRGB, and converts it into sRGB (step S402). The sRGB is converted into a data format compatible with the direct printer by the data format conversion unit 115 (step S403). At this time, the image data whose data format has been converted is stored in another area of the memory 104. However, the image data whose data format has been converted may be sent to the sequential transfer control unit 110.
[0027]
If the color space of the image in the memory 104 is sRGB in step S106, the process proceeds to step S108. FIG. 4 shows a detailed flowchart of step S108. Here, FIG. 4 is common to the first embodiment, and therefore detailed description is omitted.
[0028]
As described above, when the color space of the image data is AdobeRGB, AdobeRGB is converted to sRGB which is the color space of the direct printer 120. This makes it possible to perform printing in accordance with the color space of the direct printer 120, even if the direct printer 120 does not have an image processing function.
[0029]
Although the input color signal of the lookup table used in the present embodiment is in the RGB format, the input color signal is not limited to the RGB format, and may be any format based on the Adobe RGB color space. For example, the input color signal may be YCrCb before being converted into RGB performed in step S201. Further, since the purpose of this embodiment is to convert the color space, it is assumed that the change in the luminance level is small, and it is possible to omit the calculation time by using only the above YCrCb to CrCb as input color signals.
[0030]
The output color signal of the look-up table used in the present embodiment is in the RGB format, but is not limited thereto, and may be based on the sRGB color space. The output color signal may be in the data format of the direct printer 120. In this case, it goes without saying that step S403 is omitted.
[0031]
In the present embodiment, the direct printer 120 is in the sRGB color space, and the digital camera 100 is in the Adobe RGB color space. However, the present invention is not limited to this. It is applied when it is wider than space.
[0032]
(Third embodiment)
In the third embodiment, a case where the direct printer 120 has a data format conversion function in a modification of the first and second embodiments will be described. The description will be given with reference to FIG. 6, but FIG. 6 is the same as FIG.
[0033]
Since FIG. 2 is common to the first embodiment, a detailed description thereof will be omitted here, and the description will be made with reference to the flowcharts of FIGS.
[0034]
FIG. 7 shows a detailed flowchart of step S107 of the third embodiment. The image read to the memory 104 is converted into YCbCr by JPEG expansion in the JPEG encoding circuit 107, and further converted from YCbCr to RGB (step S501). At this time, the color space of the image data is AdobeRGB having a wider color space than sRGB. Next, AdobeRGB is converted to a standard color space XYZ by the color space conversion unit 108 (step S502), and further converted from the standard color space XYZ to sRGB which is a color space of a direct printer (step S503). At this time, the image data converted to sRGB is stored in another area of the memory 104. However, the image data converted to sRGB may be sent to the sequential transfer control unit 110.
[0035]
If the color space of the image in the memory 104 is sRGB in step S106, the process proceeds to step S108. FIG. 4 shows a detailed flowchart of step S108. The image stored in the memory 104 is converted into JC-extended YCbCr by the JPEG encoding circuit 107, and further converted from YCbCr to RGB (step S601). The color space of the image data at this time is sRGB. The sRGB image data is stored in another area of the memory 104. However, the image data may be sent to the sequential transfer control unit 110.
[0036]
Returning to the flowchart of FIG. 2 again, the transfer control unit 110 transfers the image data converted to sRGB to the direct printer 120 (step S109).
[0037]
As described above, when the color space of the image data is AdobeRGB, AdobeRGB is converted to sRGB which is the color space of the direct printer 120. This makes it possible to perform printing in accordance with the color space of the direct printer 120, even if the direct printer 120 does not have an image processing function.
[0038]
In the present embodiment, the color space conversion unit 108 performs conversion from the Adobe RGB color space to the sRGB color space via the standard color space XYZ, but instead of the standard color space XYZ, the color space conversion unit 108 performs a conversion from the Adobe RGB color space. A wide color space (for example, a Lab uniform color space or the like) may be used.
[0039]
In the present embodiment, the direct printer 120 is in the sRGB color space, and the digital camera 100 is in the Adobe RGB color space. However, the present invention is not limited to this. It is applied when it is wider than space.
[0040]
Further, in the present embodiment, as a modification of the first embodiment, a method of converting into the standard color space XYZ has been described, but a look-up table may be used as in the second embodiment.
[0041]
Although the configuration for implementing the present invention is performed by a hardware configuration and a circuit in the digital camera, image processing such as color space conversion and each process related to data exchange with a printer are performed by a CPU in a digital camera control circuit. The scope of the present invention includes storing a program to be executed in an internal memory (for example, the memory 104 or the storage medium 105) and executing the present invention as software.
[0042]
The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.) or to an apparatus composed of one device (for example, a copying machine, a facsimile machine). You may.
[0043]
In order to operate various devices so as to realize the functions of the above-described embodiments, software programs for realizing the functions of the above-described embodiments are stored in a device or a computer in a system connected to the various devices. The present invention also includes those which are supplied and executed by operating the various devices according to a stored program in a computer (CPU or MPU) of the system or the apparatus.
[0044]
In this case, the program code of the software implements the functions of the above-described embodiment, and the program code itself and a unit for supplying the program code to the computer, for example, the program code is stored. The storage medium constitutes the present invention.
[0045]
As a storage medium for storing such a program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM, or the like can be used.
[0046]
When the computer executes the supplied program code, not only the functions of the above-described embodiments are realized, but also the program code is stored in an operating system (OS) running on the computer or another application. Needless to say, even when the functions of the above-described embodiments are realized in cooperation with software or the like, such program codes are included in the embodiments of the present invention.
[0047]
Further, the supplied program code is stored in a memory provided in a function expansion board of the computer or a function expansion unit connected to the computer, and then, based on an instruction of the program code, a CPU or the like provided in the function expansion board or the function storage unit. It is needless to say that the present invention includes a case where the functions of the above-described embodiments are implemented by performing a part or all of the actual processing.
[0048]
【The invention's effect】
As described above, according to the present invention, it is possible to capture an image in a printer compatible with a first color space that can be directly connected to a digital camera and in a second color space wider than the first color space. In a possible digital camera, an image captured in the second color space is output to the printer after performing image processing for converting to the first color space, and is output to the printer by a direct print-compatible digital camera. With this configuration, even when an image of a digital camera photographed in the Adobe RGB color space is printed by a direct printer compatible with the sRGB color space, color information can be transmitted correctly, and printing in a correct color can be performed.
[0049]
For example, while a digital camera can shoot in a wider color space, it is not necessary to shoot in accordance with a narrower color space of a printer, so that it is possible to fully utilize the imaging ability and print. Sometimes it is possible to transmit correct color information.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating first and second embodiments of the present invention.
FIG. 2 is a flowchart for explaining an embodiment of the present invention.
FIG. 3 is a flowchart for explaining a first embodiment of the present invention.
FIG. 4 is a flowchart for explaining an embodiment of the present invention.
FIG. 5 is a flowchart for explaining a second embodiment of the present invention.
FIG. 6 is a diagram illustrating a third embodiment of the present invention.
FIG. 7 is a flowchart for explaining a third embodiment of the present invention.
FIG. 8 is a flowchart for explaining a third embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 100 Digital camera 101 Operation mode selection unit 102 Imaging unit 103 Memory control circuit 104 Buffer memory 105 Storage medium 106 Image processing circuit 107 JPEG encoding circuit 108 Color space conversion unit 109 Image display unit 110 Transfer control unit 115 Data format conversion unit 120 Direct Printer

Claims (8)

In a printer corresponding to a first color space that can be directly connected to a digital camera, and in a digital camera capable of shooting an image in a second color space wider than the first color space,
A digital camera compatible with direct printing, wherein an image captured in the second color space is output to the printer after image processing for converting the image into a first color space. The digital camera according to claim 1, wherein the first color space is an sRGB color space. The digital camera according to claim 1, wherein the second color space is an Adobe RGB color space. The image processing for converting to the first color space converts an image captured in the second color space to a third color space that does not depend on a device, and converts the image that has been captured in the second color space into a third color space that does not depend on the device. 2. The digital camera according to claim 1, wherein the digital camera converts the color space into one color space. The image processing for converting to the first color space is performed by a lookup table including an input color signal based on the second color space and an output color signal based on the first color space. The digital camera according to 1. The digital camera according to claim 5, wherein the input color signal based on the second color space is RGB, YCbCr, or CbCr. The digital camera according to claim 5, wherein the output color signal based on the first color space is an RGB or an output format of the printer. A printer corresponding to a first color space that can be directly connected to a digital camera, and a control method of a digital camera capable of capturing an image in a second color space wider than the first color space,
An instruction step of instructing a print output of an image captured in the second color space,
An image processing step of performing image processing for converting to the first color space in response to the instruction being given in the instruction step;
A method for controlling a digital camera, comprising: outputting image data whose color space has been converted in the image processing step to the printer.

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