JP4848748B2 - Imaging device - Google Patents

Description

The present invention relates to an imaging equipment such as digital cameras.

2. Description of the Related Art Some imaging devices such as digital cameras have a function of displaying a luminance distribution of a subject image, commonly referred to as a “histogram”, on a liquid crystal display device (LCD).
2. Description of the Related Art Conventionally, there has been known an imaging apparatus that can divide a subject image into a plurality of areas and display a histogram for each of these areas (see, for example, Patent Document 1). It is possible to grasp the distribution state of the brightness in more detail.

  However, the composition of the subject and the purpose of the photographer are not uniform, and it is not always good if there is no bias in the distribution of luminance. Adjustment of the exposure condition requires experience, and this is the same for the above-described divided and displayed histogram.

In addition, since the LCD provided in a normal camera has a smaller number of pixels than the image sensor, it is difficult to determine the in-focus state from the subject image displayed on the LCD.
For this reason, it has been desired to be able to determine from the subject image displayed on the LCD whether or not the desired position of the subject is correctly focused (in focus).
JP 2003-333378 A

The first object of the present invention is to provide an imaging equipment having a display function of luminance distribution can be accurately evaluated the exposure state of the photographic image.
A second object of the present invention is to provide an imaging equipment which can easily determine the quality of the focus state with respect to the subject by the image displayed on the display unit.

The present invention solves the above problems by the following means.
According to the first aspect of the present invention, an imaging unit that acquires a subject image, an image processing unit that generates image data based on an output of the imaging unit, and a plurality of luminance data corresponding to pixel positions of the image data are generated. And a display unit that displays the plurality of pieces of luminance data in a state of being arranged corresponding to the related pixel positions, and the display unit transmits the luminance data during shooting. An image pickup apparatus that displays an image or a photographed image in an overlapping manner .

According to a second aspect of the present invention, in the imaging apparatus according to the first aspect, the display unit performs a three-dimensional display representing the luminance data in an axial direction orthogonal to a two-dimensional region formed by the image data. This is an imaging apparatus.
According to a third aspect of the present invention, in the imaging device according to the first or second aspect, the luminance data generation unit divides the image data into a plurality of regions according to the pixel positions, and An imaging apparatus characterized by generating luminance data.
According to a fourth aspect of the present invention, in the imaging apparatus according to the third aspect, the luminance data generation unit uses the luminance data as data regarding the number of pixels included in the region and having a luminance equal to or higher than a predetermined value. An imaging device characterized by the above.

According to a fifth aspect of the present invention, in the imaging apparatus according to any one of the first to fourth aspects, the display unit can select a region for spot metering or a region for focusing. An imaging apparatus characterized by displaying an area selection display.
The invention according to claim 6 is the imaging apparatus characterized in that the luminance data generation unit can select a size of an area on the image data corresponding to each of the luminance data .

As described above, the present invention has the following effects.
(1) Since a plurality of luminance data generated corresponding to the pixel position of the image data is displayed on the display unit in a state corresponding to the related pixel position, the distribution of the luminance data of the subject image is grasped for each pixel position. And the exposure condition of the photographed image can be accurately evaluated.
(2) Since the luminance data is three-dimensionally displayed, the level of luminance of each pixel can be visually grasped, and the distribution of luminance data can be easily grasped.
(3) Since the image data is divided into a plurality of regions according to the pixel positions and the luminance data is generated for each region, even if the number of pixels of the display unit included in the imaging device is smaller than the number of pixels of the imaging device, The luminance distribution of the entire subject image can be displayed.

(4) Since the luminance data is displayed together with the subject image, the distribution of the luminance data and the subject image can be compared, and the exposure condition can be adjusted more easily.
(5) Since the area for spot metering or focusing can be selected while checking the luminance distribution in the subject image, these areas can be selected accurately.
(6) Since the contrast data generated in correspondence with the pixel position of the image data is displayed on the display unit in a state corresponding to the related pixel position, the contrast data for each pixel position in the subject image is individually grasped. It is possible to easily confirm which part of the subject image is in focus (whether it is in focus).

An object of the present invention is to provide an image pickup apparatus and an image reproduction apparatus having a luminance distribution display function capable of accurately evaluating the exposure condition of a captured image. This is realized by displaying a correspondingly arranged three-dimensional graph on the LCD.
Another object of the present invention is to provide an image pickup apparatus and an image reproduction apparatus that can easily determine whether or not a subject is in focus based on an image displayed on a display unit. This is realized by generating contrast data in accordance with the luminance difference from the image data adjacent to the image data, and displaying the contrast data on the LCD in correspondence with the relevant pixel position.

A digital still camera (hereinafter simply referred to as “camera”) that is an embodiment of an imaging apparatus of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating the camera of the embodiment. 2 is a diagram illustrating an example of a subject image acquired by the camera of FIG. 1. FIG. 2A illustrates a subject image displayed on the LCD, and FIG. 2B illustrates a plurality of subject images of FIG. The state divided into areas is shown.
The camera 1 of this embodiment has a function of displaying the luminance distribution of the subject image 10 by a three-dimensional graph and a function of displaying the distribution state of the contrast of the subject image. The camera lens group L, the CCD 2, An image processing unit 3, a luminance data generation unit 4, a contrast data generation unit 5, an operation unit 6, a recording unit 7, an LCD 8, and an ECU 9 are provided.

The photographing lens group L is an optical system that forms a subject image, and includes a plurality of lenses arranged on substantially the same optical axis I. Each lens included in the lens moves in the direction of the optical axis I by focusing, zooming, or the like, for example.
The CCD 2 is an imaging unit that acquires a subject image formed by the photographing lens group L, and includes a plurality of light receiving elements (not shown) that convert subject image light into electrical signals. The data is output to the image processing unit 3.
The image processing unit 3 is a part that generates image data based on the captured image signal output from the CCD 2. This image data includes information regarding the pixel position of each pixel, information regarding luminance, and the like.

The luminance data generation unit 4 and the contrast data generation unit 5 are portions that generate luminance data and contrast data, respectively, based on the image data output from the image processing unit 3. The luminance data generation unit 4 and the contrast data generation unit 5 will be described in detail later.
The operation unit 6 is connected to an ECU 9 which will be described later, and allows the photographer to perform various operations such as a release operation and display / non-display selection of a three-dimensional histogram and a contrast distribution diagram, both of which will be described later. In addition, the operation unit 6 includes a pointing device for operating an area selection display 21 described later displayed on the LCD 8.
The recording unit 7 is a part for recording image data output from the image processing unit 3, and includes a drive device that reads and writes information from and on a recording medium such as a detachable flash memory card.

The LCD 8 is provided, for example, on the back side (photographer side) of the camera 1 and reproduces and displays a captured image held by the recording unit 7 and an image (through image) output in real time by the CCD 2 during framing. To display. The LCD 8 is a display unit that displays a three-dimensional histogram and a contrast distribution diagram.
The ECU 9 is an information processing unit including a CPU that comprehensively controls the above-described elements such as the image processing unit 3, the luminance data generation unit 4, the contrast data generation unit 5, the recording unit 7, and the LCD 8.

  In the present embodiment, an example in which the camera 1 is photographed with the two trees 11 taken as a subject at a normal photographing position (a position where the longitudinal direction of the CCD 2 having a rectangular imaging surface is substantially horizontal) will be described. (See FIG. 2 (a)). In addition to the tree 11, the subject image 10 includes a sun 12 and a shadow 13 of the tree 11.

Next, the luminance data generation unit 4 and the three-dimensional histogram 20 will be described.
As shown in FIG. 2B, the luminance data generation unit 4 generates luminance data for each of a plurality of areas (hereinafter referred to as “luminance data generation areas”) set by dividing the imaging surface of the CCD 2 into a matrix. It is designed to generate.
In this embodiment, for easy understanding, for example, the imaging surface of the CCD 2 (subject image 10) is divided into 24 equal parts in the horizontal direction and 18 equal parts in the vertical direction to generate a total of 432 luminance data. Although the area is provided, the size of the brightness data generation area (the number of divisions of the CCD 2) is not limited to this, and an area smaller than the above example can be selected according to the type of the subject. Can grasp the luminance distribution state in more detail.
Here, “luminance data” is a parameter relating to the luminance of the pixels included in each luminance data generation region. Specifically, the luminance of the pixels included in the luminance data generation region is based on the output of the image processing unit 3. And the total number of pixels having a luminance equal to or higher than a predetermined threshold.

FIG. 3 is a diagram showing a three-dimensional histogram displayed on the LCD.
The ECU 9 forms a two-dimensional area in which the luminance data generation area is arranged in correspondence with the pixel position based on data relating to the pixel position of each image data included in the luminance data generation area in which a plurality of pixels are collected. And displayed on the LCD 8.
The three-dimensional histogram 20 is a three-dimensional graph representing the size of luminance data for each luminance data generation region in a direction orthogonal to the two-dimensional region. Here, the “three-dimensional graph” is a perspective view of a space formed by three axes orthogonal to each other (for example, the X axis, the Y axis, and the Z axis), and is formed by, for example, two axes of X and Y. Numerical data at a predetermined position (X, Y) in the plane area is expressed in the Z-axis direction.
In FIG. 3, the luminance data of the background portion other than the two trees 11, the sun 12, and the shadow 13 included in the subject image are distributed substantially uniformly, so that it is easy to understand here. In order to do this, the display is omitted.

As described above, the luminance data is the number of pixels having a luminance equal to or higher than the threshold value in the luminance data generation region. It is displayed larger than other parts (tree 11 etc.).
When luminance data larger than a preset value is included, the ECU 9 displays a warning display on the LCD 8 to alert the photographer, for example. This set value can be arbitrarily set, and the photographer can select ON / OFF of the warning display function. In addition, for example, a warning sound (buzzer or the like) may be transmitted from a warning output unit (not shown).

The three-dimensional histogram 20 is displayed on the LCD 8 together with the through image displayed on the LCD 8 at the time of photographing or together with this image when the subject image recorded on the recording unit 7 is reproduced. When displaying the three-dimensional histogram 20 during image reproduction, the camera 1 functions as an image reproduction device.
At this time, the two-dimensional region formed by the image data of the three-dimensional histogram 20 is displayed so as to be superimposed on the through image or the reproduced image, and the photographer can specify in which part of the subject image the luminance is high or low. Can be confirmed.

The LCD 8 displays a region selection display 21 (see FIG. 3).
The area selection display 21 is a cursor displayed, for example, by imitating a symbol “+”, and is displayed on the LCD 8 together with the three-dimensional histogram 20. The photographer refers to the operation unit 6 while referring to the three-dimensional histogram 20. An area where spot metering is performed or an area where focusing is performed can be selected by operating the pointing device. The area for spot metering or the area for focusing is determined by operating a button (not shown) provided on the operation unit 6.

Here, the process performed by the ECU 9 when generating the three-dimensional histogram 20 will be described with reference to the flowchart shown in FIG.
(Step S01: Image data generation)
First, the ECU 9 causes the image processing unit 3 to generate image data for each pixel based on the subject image acquired by the CCD 2. In this specification, “image data” means both image data included in a captured image held by the recording unit 7 and image data included in a through image.
(Step S02: Select luminance data generation area)
Next, the ECU 9 displays a selection menu (not shown) on the LCD 8, and determines whether or not to provide a luminance data generation area from this selection menu, and when providing the luminance data generation area, this size (included in each luminance data generation area) The number of pixels to be determined).
For example, the photographer decides whether or not to provide a luminance data generation area according to the type and composition of the subject and the purpose of the shooting, and if the luminance data generation area is provided, selects the size and selects these items. Is input to the ECU 9 via the operation unit 6.
Here, when the luminance data generation area is provided and the luminance data is displayed for each luminance data generation area, the process proceeds to step S03. On the other hand, when the luminance is displayed for each pixel without providing the luminance data generation area, the process proceeds to step S04.

(Step S03: Brightness data generation)
In response to an input from the operation unit 6, the ECU 9 causes the luminance data generation unit 4 to generate luminance data for each selected luminance data generation region, and detects this.
(Step S04: Detection of luminance)
Based on the output from the image processing unit 3, the ECU 9 detects the luminance of each pixel included in the image data as luminance data.
(Step S05: 3D histogram display)
The ECU 9 generates a three-dimensional histogram on which the luminance data is displayed and displays it on the LCD 8. Here, when the luminance data generation area is provided and the luminance data is displayed, the three-dimensional histogram 20 can be displayed as a three-dimensional bar graph as shown in FIG.
On the other hand, when the luminance is displayed for each pixel without providing the luminance data generation region, the three-dimensional histogram can be displayed in a so-called three-dimensional contour graph (not shown). Note that the three-dimensional histogram displaying the luminance for each pixel can also be displayed on the LCD 8 with the subject image together with the through image or the reproduced image, as in the case where the luminance data generation area is provided.
Thereafter, the photographer evaluates the exposure state of the subject image based on these three-dimensional histograms 20, and determines the optimal exposure condition.

Next, the contrast data generation unit 5 and the contrast distribution diagram 30 will be described.
Similar to the luminance data generation unit 4 described above, the contrast data generation unit 5 provides a contrast data generation region set by dividing the imaging surface of the CCD 2 into a plurality of regions.
Further, the contrast data generation unit 5 contrasts according to the luminance difference (contrast) between a certain contrast data generation region and the other four contrast data generation regions adjacent to the contrast data generation region in the vertical and horizontal directions. Generate data.
Here, “contrast data” is information that makes it possible to identify whether or not the contrast difference includes a value that exceeds a predetermined threshold. The ECU 9 is based on the output of the contrast data generation unit 5. Thus, for example, a contrast distribution diagram 30 is displayed in which a contrast data generation area having contrast data exceeding a threshold value is displayed in a color different from other contrast data generation areas.

FIG. 5 is a contrast distribution diagram displayed on the LCD.
The subject image 10 shown in FIG. 2 (a) is substantially focused on the subject (tree 11), and the contrast at the boundary (edge) portion between the tree 11 and the background portion is large. Shows the boundary between the tree 11 and its background. In the subject image 10, the depth of field extends to the sun 12 and the shadow 13 of the tree 11, and is substantially focused on the sun 12 and the shadow 13. For this reason, the boundary between the sun 12 and the shadow 13 is also displayed in the contrast distribution diagram 20.
Further, the trunk and leaf portions of the tree 11, the portion inside the boundary between the sun 12 and the shadow 13, and the background portion of the subject are not displayed because the contrast is small (the luminance is almost uniform), and the contrast distribution diagram. As shown in FIG. 5, only the outlines of the tree 11, the sun 12, and the shadow 13 are extracted and displayed 30. The contrast threshold is set so that the outline of the subject is not displayed when the subject is not in focus.

Thus, since the contour of the contrast distribution diagram 30 is extracted and displayed from the subject image, the contrast data generation region is provided more than the above-described luminance data generation region (subject image is finely divided). ) Is preferable because the contour of the subject image can be reproduced in more detail.
Similarly to the three-dimensional histogram 20, this contrast distribution diagram 30 is also displayed on the LCD 8 together with a through image displayed on the LCD 8 at the time of photographing or together with this image when reproducing a subject image recorded on the recording unit 7. When displayed and the contrast distribution map 30 is displayed during image reproduction, the camera 1 functions as an image reproduction apparatus.

As described above, according to the camera 1 of the embodiment, the following effects can be obtained.
(1) Since the luminance data generated corresponding to the pixel position of the image data is displayed corresponding to the pixel position, the distribution of the luminance data of the subject image 10 can be grasped for each pixel position, and the captured image The exposure conditions can be accurately evaluated.
As a result, the photographer can set the luminance level at a position where the luminance of the subject image 10 is expected to be high (or low) in advance to correspond to the luminance level in these portions displayed on the three-dimensional histogram 20. What is necessary is just to adjust exposure conditions.
Specifically, since the portion of the sun 12 in the subject image 10 is expected to have a higher brightness than the other portions, the brightness level expected in this portion and the three-dimensional histogram 20 are displayed. It is only necessary to adjust the exposure conditions so as to correspond to the brightness level. Even a photographer with little experience can adjust the exposure conditions accurately.

(2) Since the luminance distribution diagram in the subject image is displayed by the three-dimensional histogram 20 in which the luminance data is shown in the height direction, the luminance level of each pixel can be visually grasped, and the luminance data distribution can be obtained. It can be easily grasped.
(3) Since the three-dimensional histogram 20 which is a three-dimensional bar graph displays luminance data for each luminance data generation region generated by dividing the subject image into a plurality of regions, even if the number of pixels of the LCD 8 is smaller than that of the CCD 2 The luminance distribution of the entire subject image can be displayed. In addition, since the luminance data is the number of pixels whose luminance is equal to or higher than the threshold value, the luminance data of the region including the high luminance pixel is larger than the region where the luminance data is not so, for example, compared to the case where the average luminance is displayed. These areas can be easily distinguished.
(4) Since the area for spot metering or focusing can be selected while confirming the three-dimensional histogram 20, the selection of these areas can be performed accurately.
(5) Since the contrast distribution diagram is obtained by extracting and displaying the contour of the subject image, it is not displayed on the LCD 8 when the focus state is poor (so-called out of focus). It is possible to easily determine whether or not the desired position is in focus.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) The image pickup apparatus of the embodiment is a digital camera, but the image pickup apparatus is not limited to this, and may be a movie camera for shooting a moving image. These cameras may be mobile communication terminals such as mobile phones, It may be used in a state incorporated in a device other than the camera.
(2) In the embodiment, the luminance distribution is displayed by a three-dimensional histogram. However, the luminance is not limited to this as long as the luminance data is arranged corresponding to the related pixel position. Alternatively, two-dimensional display may be performed by numerical values, color classification, and the like.
(3) The luminance data is not limited to that described in the embodiment, and may be an average value or a total value of luminance included in each luminance data generation region, for example.
(4) The display of the three-dimensional histogram is not limited to that shown in the embodiment, and for example, independent display may be performed for each RGB color.
(5) In the embodiment, the camera functions as an image reproducing device. However, the image reproducing device is not limited to this. For example, a general-purpose machine such as a computer device provided with software for image reproduction, an image display, and the like. It may be a storage device such as a portable hard disk drive provided with the device.

It is a block diagram which shows the camera of an Example. It is a figure which shows an example of the to-be-photographed image which the camera of FIG. 1 acquired. It is a figure which shows the three-dimensional histogram displayed on LCD. It is a flowchart which shows the process of ECU at the time of producing | generating a three-dimensional histogram. It is a contrast distribution map displayed on LCD.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera: 2 CCD: 3 Image processing part: 4 Luminance data generation part: 5 Contrast data generation part: 6 Operation part: 7 Recording part: 8 LCD: 9 ECU: 10 Subject image: 20 Three-dimensional histogram: 21 Area selection display : 30 Contrast distribution map

Claims (6)

An imaging unit for acquiring a subject image;
An image processing unit that generates image data based on the output of the imaging unit;
A luminance data generation unit that generates a plurality of luminance data respectively corresponding to pixel positions of the image data;
A display unit that displays the plurality of luminance data in a state of being arranged corresponding to the related pixel positions;
The image display apparatus, wherein the display unit displays the luminance data superimposed on a through image or a captured image at the time of shooting. The imaging device according to claim 1,
The image display apparatus, wherein the display unit performs three-dimensional display that represents the luminance data in an axial direction orthogonal to a two-dimensional region formed by the image data. In the imaging device according to claim 1 or 2,
The luminance data generation unit divides the image data into a plurality of regions according to the pixel positions, and generates the luminance data for each region. The imaging device according to claim 3.
The imaging apparatus according to claim 1, wherein the luminance data generation unit uses, as the luminance data, data relating to the number of pixels that are included in the region and whose luminance is a predetermined value or more. In the imaging device according to any one of claims 1 to 4,
The image display apparatus, wherein the display unit displays an area selection display that enables selection of an area for spot metering or an area for focusing. In the imaging device according to any one of claims 1 to 5,
The imaging apparatus, wherein the brightness data generation unit can select a size of an area on the image data corresponding to each of the brightness data .

Images