JP2003259387A - Image display device, digital camera, and image processing circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image splay technology for quickly performing color matching correction corresponding to characteristics of a display device in the case of reproducing and displaying a recorded image without increasing the circuit scale. <P>SOLUTION: A digital camera 1 is provided with an image processing circuit GP for correcting color matching with respect to display characteristics of the display devices 10, 20. In the case of reproducing and displaying recorded image data recorded on a memory card 8 on the display devices, the image processing circuit GP applies color matching correction to the data corresponding to the characteristics of the display device designated by a user and then the resulting data are displayed. In the reproduction and display, selection of a linear matrix 209, a gamma table 211 and a color difference matrix 213 set at live view display or image recording applies optimum correction to the recording image data. Thus, in the case of reproducing and displaying the recorded image, color matching correction corresponding to the characteristics of the display device can quickly be performed without increasing the circuit scale. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display technique for displaying based on recorded image data.

[0002]

2. Description of the Related Art A digital camera is equipped with an image processing circuit for performing color matching correction in order to improve color reproducibility in a display device when live view displaying an image acquired by an image sensor such as a CCD. There is. This image processing circuit is a dedicated hardware circuit, and the processing speed is increased.

FIG. 10 shows a digital camera 7 according to a conventional example.
6 is a diagram for explaining color matching correction of FIG.

The digital camera 7 has a plurality of display devices, specifically, the LCD 10 and the EVF 20, and also has an image processing circuit GP (208, 210, 212) capable of performing color matching correction corresponding to their display characteristics. is doing. This image processing circuit GP enables live view display with good color reproducibility.

Also, when an image acquired by the image sensor 303 is recorded, after the image processing circuit GP uniformly performs color matching correction based on, for example, sRGB which is an international color reproduction standard, , Resizer 219
The image is resized to the display size of the display device to generate a recording image for display (hereinafter referred to as "screen nail"), and the screen nail is compressed and recorded in the memory card 8. As a result, when the recorded image is reproduced, the image can be quickly displayed by transmitting the screen nail recorded in the memory card 8 to the display device.

[0006]

However, in the above digital camera 7, when the screen nail recorded in the memory card 8 is reproduced and displayed on the LCD 10 of the digital camera, it is adapted to the characteristics of the display device used for the reproduction display. If the image is recorded without the color matching correction described above, it is difficult to display an image with good color reproducibility.

In this case, in order to quickly reproduce and display the screen nail on the display device with good color reproducibility, a dedicated correction circuit for each display device corresponds to the characteristics of the display device before the display. The color matching correction described above may be performed, but on the other hand, the circuit scale in the digital camera increases due to this dedicated correction circuit, leading to an increase in cost.

According to the present invention, when reproducing and displaying a recorded image,
An object of the present invention is to provide an image display technique capable of quickly performing color matching correction corresponding to the characteristics of a display device without increasing the circuit scale.

[0009]

In order to solve the above-mentioned problems, the invention of claim 1 is an image display device capable of displaying based on image data in a display means, wherein (a) the image data: A processing circuit capable of color matching correction according to display characteristics, (b) an input unit for inputting the image data, and (c) a predetermined display by the processing circuit with respect to the image data input by the input unit. After performing color matching correction corresponding to the characteristics, recording control means for recording in the storage means, (d) reading means for reading the image data recorded in the storage means, and (e) reading by the reading means Display control means for displaying on the display means, after performing color matching correction on the display characteristics of the display means by the processing circuit on the generated image data.

According to a second aspect of the present invention, in the image display device according to the first aspect of the present invention, the display means has a plurality of display portions, and in the color matching correction, at least γ correction is performed on the image data. Is performed, the image display device, (f) from the plurality of display units,
(G) holding means for holding a plurality of γ correction information usable in the γ correction, and (h)
Extraction means for extracting one γ correction information corresponding to the display characteristic of the one display section from the plurality of γ correction information, further comprising: (e-1) the reading means. Display control means for displaying the read image data on the display unit after performing the γ correction based on the first γ correction.

According to a third aspect of the present invention, there is provided a digital camera capable of displaying on the display means based on image data, and (a) a processing circuit capable of performing color matching correction on the image data according to display characteristics. And (b) image pickup means for obtaining the image data of the subject, and (c) color matching correction corresponding to a predetermined display characteristic is performed by the processing circuit for the image data obtained by the image pickup means. After that, with respect to the recording control means for recording in the storage means, (d) the reading means for reading the image data recorded in the storage means, and (e) the image data read by the reading means, the processing circuit And a display control unit for displaying on the display unit after performing color matching correction on the display characteristic of the display unit.

According to a fourth aspect of the present invention, there is provided an image processing circuit capable of inputting image data, wherein the input image data is subjected to color matching correction for a predetermined display characteristic before being recorded in a storage means. The processing means includes means for performing color matching correction for display characteristics of the display means before displaying the image data read from the storage means on the display means.

According to a fifth aspect of the present invention, in the image processing circuit according to the fourth aspect of the invention, the display means has a plurality of display sections, and in the color matching correction, Before performing γ correction based on at least predetermined γ correction information, the processing means displays the image data read from the storage means on one display unit selected from the plurality of display units. In addition, there is provided a means for extracting one γ correction information corresponding to the display characteristic of the one display unit from a plurality of γ correction information and performing the γ correction based on the one γ correction information.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION <Structure of Main Parts of Digital Camera> FIGS. 1, 2 and 3 are views showing the structure of main parts of a digital camera 1 according to an embodiment of the present invention. FIG. ,
2 corresponds to a top view and FIG. 3 corresponds to a rear view. These drawings are not necessarily based on the trigonometry, and the main purpose is to conceptually exemplify the main configuration of the digital camera 1.

As shown in FIG. 2, the digital camera 1
The imaging unit 3 includes a lens group with macro function (hereinafter, also simply referred to as “lens”) 30 that is a photographing lens. Further, the digital camera 1 has a zoom function, and the photographing magnification can be changed by rotating the zoom ring 33 or the like. Furthermore, the digital camera 1 is provided with a macro switching lever 34, and can switch between macro shooting and normal shooting. Also,
A shutter button 9 is provided on the upper surface of the digital camera 1.

Further, on the upper surface of the digital camera 1, there is provided a mode switching dial 14 for switching and setting among "shooting mode", "reproduction mode" and "communication mode".
The photographing mode is a mode for taking a photograph, and the reproduction mode is a mode for reproducing and displaying the photographed image data recorded in the memory card 8 on the rear LCD 10 or the like. The communication mode is a mode in which data is transferred to an external personal computer 225 or the like via a USB terminal 226 provided on the side surface of the digital camera 1. A data panel 36 is further provided on the upper surface of the digital camera 1, and the setting states of various modes are displayed on the data panel 36.

As shown in FIG. 3, on the left side of the rear surface of the digital camera 1, a liquid crystal display (rear surface) for performing live view display for displaying a subject in a moving image mode and reproduction display of recorded images before the main photographing is performed. An LCD) 10 and an electronic viewfinder (EVF) 20 are provided. Each of the rear LCD 10 and the EVF 20 has a display size of 320 × 240, and an image is displayed in color.

A control button 35 including cursor buttons (cross keys) U, D, L, R, and an execution button 32 is provided on the right side of the rear surface of the digital camera 1,
Various operations are performed using the control button 35. A menu button 37 is provided on the back surface of the digital camera 1. When the menu button 37 is pressed, various menus are displayed on the rear LCD 10.
Is displayed in.

On the back surface of the digital camera 1, a video output terminal 222 and a display switching lever 31 are provided. The video output terminal 222 is connected to the external monitor 2
23 (FIG. 4) and a terminal for connecting via a communication line. The display switching lever 31 is provided on the rear LCD 10,
A lever for switching the display of the EVF 20 and the external monitor 223.

On the side surface of the digital camera 1, a memory slot 8 into which a memory card 8 functioning as a storage means can be mounted.
1 is provided.

<Functional Block of Digital Camera 1> FIG. 4
FIG. 3 is a diagram showing functional blocks of the digital camera 1.
Below, the functional blocks of the digital camera 1 will be described along the flow of signals. The digital camera 1 is different from the conventional digital camera 7 (FIG. 10) in that a path Fw for inputting image data in the memory card 8 to the spectral correction circuit 208 is added.

The digital camera 1 is provided with an image sensor (CCD) 303 behind the lens group 30. The imaging sensor 303 functions as an imaging unit that acquires image data of a subject, is an area sensor in which RGB primary color transmission filters are arranged in a checkered pattern in pixel units, and is an all-pixel reading type.

The image signal photoelectrically converted by the image sensor 303 is A / D converted by the A / D converter 205 and then converted into WB.
The RBG is normalized by the multiplier 206. And
Interpolation circuit 207 performs RGB pixel interpolation to generate RGB 3-channel data.

The RGB image data generated by the interpolation circuit 207 is an image processing circuit GP (spectral correction circuit 208, γ correction circuit 210 and color conversion circuit 21) which is a dedicated hardware circuit for color matching correction.
According to 2), variable color matching processing is performed according to the display characteristics of the display device. The details will be described below.

The spectral correction circuit 208 converts the RGB data generated by the interpolation circuit 207 into 3
The image sensor 303 by the × 3 linear matrix 209
The spectral correction calculation of is performed. After spectral correction calculation is performed, γ
In the correction circuit 210, the γ table 2 corresponding to the γ correction information
By 11, the gradation correction according to the display device or the like is performed on each of the RGB channels.

After the γ correction, the color conversion circuit 212 uses the color difference matrix 213 to convert RGB to YC.
The conversion to the r · Cb channel is performed, and the luminance signal Y and the color difference signals Cr and Cb are separated.

The luminance signal Y is frequency band separated by an HPF (High Pass Filter) 215 and an LPF (Low Pass Filter) 216 in the Y enhancer circuit 214. Then, for the high frequency side of the luminance signal Y, after the signal level adjustment by the amplifier unit 217 and the contour correction and noise suppression by the base clip processing by the base clip unit 218 are performed, the luminance signal Y from the LPF 216. Is output as a luminance signal Y.

The Y, Cr and Cb signals are sent to the resizer circuit 21.
In 9, the resizing of each channel is performed according to the display size, recording size, and recording format.

Display size of display device 320 × 240
The image data that has been resized to the rear LCD 10, the EVF 20, or the external monitor 2 is displayed via the display switching unit 235.
23 is displayed on each display device. Here, the display device is designated according to the setting state of the display switching lever 31. For example, when the rear LCD 10 is selected, an image will be displayed on the rear LCD 10.

When the shutter button 9 is released, image data is compressed and then written in the memory card 8. When writing to the memory card 8, the image data (screen nail) resized to the display size 320 × 240 of the display device is also compressed / recorded. Then, this screen nail will be used for reproduction display.

The operation section 250 is composed of various buttons and levers such as the shutter button 9, the display switching lever 31, and the control button 35 described above.

The overall control section 221 is a section that organically controls each section of the above-mentioned camera and totally controls the operation of the digital camera 1, and serves as a microcomputer.
ROM 22 having U and RAM 221a
1b and.

This ROM 221b stores a control program and also has a linear matrix 209 used in the spectral correction circuit 208, a γ table 211 used in the γ correction circuit 210, and a color difference matrix used in the color conversion circuit 212. 213 are stored. In particular,
As shown in FIG. 5, the linear matrix 208 holds five types of matrices 1-1 to 1-3, 2, and 3,
Regarding the γ table 211, seven types of γ tables 1-1
1 to 3 and 2, 3-1 to 3-3, and four types of matrix 1 for the color difference matrix 213.
It holds 2-1 to 2-3.

With respect to the digital camera 1 having the above configuration, the operation during live view display, the operation during image capture, and the operation during image reproduction will be described below.

<Operation during live view display> FIG. 6 is a diagram for explaining the operation during live view display in the digital camera 1.

During live view display, the signal flow shown by the solid line in FIG. 6 is formed in the digital camera 1, and the image of the subject is displayed on the display device designated by the display switching lever 31 before the main capture. Here, according to the display device, the linear matrix 209
Are switched by the matrices 1-1 to 1-3 (FIG. 5), and the γ table 211 is changed to γ1-1 to 1-3 (FIG. 5).
Can be switched with. For example, when the EVF 20 is set as the designated display device, the matrix 1-2 is set in the linear matrix 209, and
Γ1-2 is set in the table 211.

As a result, in live view display, optimum color matching correction can be performed for the selected display device, and different appearances between display devices can be canceled.

<Operation at the time of image capture> FIG. 7 is a diagram for explaining the operation at the time of image capture in the digital camera 1.

At the time of image capture (recording), the signal flow shown by the solid line in FIG. 7 is formed in the digital camera 1, and the image of the subject and the screen nail resized by the resizer 219 are stored in the memory card 8. Will be recorded.
Here, in the image processing circuit GP, the rear LCD 10
The color matching process is performed on a characteristic different from that of the display device, such as a display characteristic conforming to sRGB. That is, the matrix 2 (FIG. 5) is set in the linear matrix 209 of the spectral correction circuit 208, and
Γ2 (FIG. 5) is set in the table 211.

As a result, the image picked up by the image pickup sensor 303 can be recorded in the memory card 8 after being subjected to standard and appropriate color matching correction.

<Regarding Operation During Image Reproduction> FIG. 8 is a diagram for explaining the operation during image reproduction in the digital camera 1.

At the time of image reproduction, the signal flow shown by the solid line in FIG. 8 is formed in the digital camera 1. Here, the image of the screen nail stored in the memory card 8 is read out and expanded. However, the screen nail is not directly transferred to the display device and displayed, but before being input to the designated display device. The image processing circuit GP performs color matching correction on the display characteristics of this display device.

In this color matching correction, the linear matrix 209, the γ table 211 and the color difference matrix 213, which are different from those in the live view display and the image capture, are switched so that the optimum color reproduction can be performed on the selected display device. . This process will be described in detail below.

The screen nail Y, Cr, and Cb signal data recorded in the memory card 8 is input to the spectral correction circuit 208 through the path Fw and set in the linear matrix 3 (FIG. 5). 208 by Y
-The Cr / Cb channel is converted to the RGB channel.

The screen nail converted into the RGB channels has three γ tables 3-1 to 3-3.
From (FIG. 5), the γ table corresponding to the one display device designated by the display switching lever 31 is extracted and set by the γ correction circuit 210. On the other hand, optimum γ correction is performed. In addition, these γ tables 3-1 to 3-3 (FIG. 5) are tables in which the input and output of the γ table 2 (FIG. 5) used when the screen nail is generated are reversed, and the γ table of each display device. It is a combination of 1-1 to 1-3 (Fig. 5).

After the γ correction in the γ correction circuit 210, the screen nail has color difference circuits 2-1 to 2-3 (FIG. 5) set in accordance with the designated display device.
12, the correction calculation for optimizing the color reproduction characteristics for each display device is performed, and the RGB to Y
・ Convert to Cr / Cb channel. That is, the color conversion circuit 212 simultaneously executes the processing performed by the spectral correction circuit 208 and the processing performed by the color conversion circuit 212 in the live view display. The Y, Cr, Cb signals converted by the color conversion circuit 212 are processed by the Y enhancer circuit 2 which has already been processed at the time of image recording.
14 and the resizer 219 are passed through and the display switching unit 2
35 is input. The input screen nail is displayed on the rear LCD 10 designated by the display switching lever 31.
Is displayed on the display device such as.

By the reproducing operation of the digital camera 1 described above, the image processing circuit uses the image processing circuit to perform variable color matching correction according to the display device. Since it is also used for the circuit used for color matching correction of
It is possible to quickly perform display with good color reproducibility on each display device without increasing the circuit scale and reducing the display speed. Further, with respect to image data taken by a digital camera other than the digital camera 1, if the color matching processing for the display device is performed in consideration of the color matching correction (correction regarding sRGB etc.) performed at the time of recording, the same effect can be obtained. Will be obtained.

<Modification> ◎ Regarding the γ correction in the above embodiment, it is not essential to perform the processing based on the γ table, and when the display characteristics can be approximated by one γ value, the processing is performed based on this γ value. You may go.

Regarding the playback display of the digital camera in the above embodiment, it is not essential to display based on the recorded image for display (screen nail) corresponding to the display size, but the recorded image corresponding to the image size of the image sensor. You may make it display based on. In this case, it is displayed after being resized to the display size of the designated display device through the color matching correction.

◎ It is not essential that the digital camera of the above embodiment is provided with a plurality of display devices.
It may have one display device. Also in this case, it is possible to perform display with better color reproducibility than directly displaying the recorded image on the display device.

The present invention can be applied not only to a digital camera but also to the following image display device having no image sensor such as CCD.

FIG. 9 is a diagram for explaining the image display device 6 according to the modification.

The image display device 6 is configured as, for example, a personal computer, and has a display section 61 and a processing section 6.
2 and a digital camera 69 via a cable 68.
Is connected so that data can be transmitted.

The image display device 6 is provided with the image processing circuit GP (see FIG. 4) of the digital camera 1 described above in the processing section 62, and the image processing circuit GP is used by the digital camera 6 to operate.
It is possible to perform color mangle correction on image data input from the cable 9 through the cable 68.

In the image display device 6 described above, the color matching correction for the display characteristics of the display unit 61 can be performed when the recorded image recorded in the storage unit such as the hard disk of the processing unit 62 is reproduced. A quick display is possible without an increase.

[0056]

As described above, according to the first to third aspects of the present invention, the processing circuit for color matching correction includes the color matching correction before the image data is recorded in the storage means and the storage means. It is also used for both color matching correction when reading and displaying the image data from the display device, and in the latter case, the color matching correction according to the display characteristics of the display means used is a dedicated circuit for each display characteristic. It can be realized without providing. As a result, when reproducing and displaying the recorded image, color matching correction corresponding to the characteristics of the display device,
It can be done quickly without increasing the circuit scale.

Particularly, in the inventions of claims 2 and 5, of the plurality of γ correction information, one γ correction information corresponding to the display characteristic of the designated one display portion is extracted, and After the γ correction is performed based on the γ correction information, it is displayed on the display unit 1. As a result, since the γ correction information can be switched according to the display means, simple and appropriate color matching correction can be performed.

Further, according to the invention of claim 4, the image data read from the storage means by the processing means for performing color matching correction for a predetermined display characteristic before recording the input image data in the storage means. Regarding
Color matching correction is performed on the display characteristics of the display unit before displaying on the display unit. As a result, when reproducing and displaying the recorded image, color matching correction corresponding to the characteristics of the display device can be quickly performed without increasing the circuit scale.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of a digital camera 1 according to an embodiment of the present invention.

FIG. 2 is a diagram showing a main configuration of a digital camera 1.

FIG. 3 is a diagram showing a main configuration of a digital camera 1.

FIG. 4 is a diagram showing functional blocks of the digital camera 1.

5 is a diagram for explaining information stored in a ROM 211b of the overall control unit 221. FIG.

FIG. 6 is a diagram for explaining the operation of the digital camera 1 during live view display.

FIG. 7 is a diagram for explaining the operation of the digital camera 1 when capturing an image.

FIG. 8 is a diagram for explaining the operation of the digital camera 1 during image reproduction.

FIG. 9 is a diagram for explaining an image display device 6 according to a modified example of the present invention.

FIG. 10 is a diagram for explaining color matching correction of a digital camera 7 according to a conventional example.

[Explanation of symbols]

1,7,69 Digital Camera 6 Image display device 10 Rear LCD 20 EVF 31 Display switching lever 209 Linear Matrix 221 γ table 213 color difference matrix 221 Overall control unit 221b ROM 223 External monitor 235 Display switching unit GP image processing circuit

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Claims (5)

[Claims] 1. An image display device capable of displaying based on image data in a display means, comprising: (a) a processing circuit capable of performing color matching correction according to display characteristics of the image data; Input means for inputting image data, and (c) recording control for recording in the storage means after performing color matching correction corresponding to predetermined display characteristics by the processing circuit on the image data input by the input means. Means, (d) a reading means for reading the image data recorded in the storage means, and (e) a color for the display characteristic of the display means by the processing circuit with respect to the image data read by the reading means. An image display device, comprising: display control means for displaying on the display means after performing matching correction. 2. The image display device according to claim 1, wherein the display unit has a plurality of display units, and in the color matching correction, at least γ correction is performed on the image data, and the image display is performed. The apparatus comprises: (f) a designation unit that designates one display unit from the plurality of display units; (g) a holding unit that holds a plurality of γ correction information that can be used in the γ correction; Extracting means for extracting one piece of γ correction information corresponding to the display characteristic of the one display unit from a plurality of pieces of γ correction information;
Further comprising: (e-1) after performing the γ correction based on the γ correction of 1 on the image data read by the reading means,
An image display device, comprising: a display control unit configured to display on the first display unit. 3. A digital camera capable of displaying based on image data in a display means, comprising: (a) a processing circuit capable of performing color matching correction according to display characteristics of the image data; and (b) a subject. Image pickup means for obtaining the image data, and (c) the image data obtained by the image pickup means is subjected to color matching correction corresponding to a predetermined display characteristic by the processing circuit, and then recorded in the storage means. Recording control means, (d) reading means for reading the image data recorded in the storage means, and (e) display characteristics of the display means by the processing circuit for the image data read by the reading means. And a display control means for displaying on the display means after performing color matching correction for the digital camera. 4. An image processing circuit capable of inputting image data, comprising processing means for performing color matching correction on a predetermined display characteristic of the input image data before recording the image data in a storage means. The image processing means includes a means for performing color matching correction on the display characteristics of the display means before displaying the image data read from the storage means on the display means. circuit. 5. The image processing circuit according to claim 4, wherein the display unit has a plurality of display units, and the color matching correction is based on at least predetermined γ correction information for the image data. [gamma] correction is performed, and the processing unit, from the plurality of [gamma] correction information, displays the image data read from the storage unit before displaying the image data on one display unit selected from the plurality of display units. An image processing circuit, comprising: a unit that extracts one γ correction information corresponding to the display characteristic of the one display unit and performs the γ correction based on the one γ correction information.