JP2001245204A - Imaging device and luminance distribution display method - Google Patents

Abstract

(57) [Problem] To facilitate exposure (brightness) adjustment work while observing a luminance distribution of a captured image in an electronic still camera or the like, and improve visibility of the luminance distribution of the captured image. SOLUTION: When the EV value is shifted (SA2
YES), the luminance level is counted for each pixel from the captured image (SA6), and display data of a histogram of the luminance distribution is generated (SA7). If the EV value is not the upper or lower limit of the adjustment range (NO in SA8), the display color is combined with the through image as white (SA9), and the through image on which the white histogram is superimposed is displayed (SA11). If the EV value is the upper or lower limit of the adjustment range (YES in SA8),
The display color is set to red and synthesized with the through image (SA10),
A through image on which the red histogram is superimposed is displayed (SA11). In addition, the display color of the histogram is changed according to the bias state of the luminance distribution, or the histogram is displayed in a gradation pattern in the direction of the set axis of the luminance level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image pickup apparatus and a luminance distribution display method suitable for use in an electronic still camera.

[0002]

2. Description of the Related Art Conventionally, in an electronic still camera equipped with a solid-state image pickup device such as a CCD, when a photographing mode is set and a photographing preparation state is established, a subject image is sequentially taken in regardless of a shutter operation, and a through image is taken. In many cases, the image is displayed on a liquid crystal monitor so that the liquid crystal monitor also has a finder function. Such an electronic still camera generally has an automatic exposure control (AE control or program AE control) function so that an appropriate exposure can always be obtained at the time of shooting. However, an appropriate exposure is always set in an unexpected shooting environment. Since it is extremely difficult to obtain and adjust the exposure according to the preferences of all photographers, generally, the exposure value (EV) as a control target can be adjusted (corrected).

Further, as an auxiliary function for the above adjustment,
By counting the luminance level for each pixel from the image captured by the solid-state imaging device and displaying a histogram indicating the luminance distribution on the liquid crystal monitor, it is possible to confirm whether the exposure is appropriate at the time of imaging from the histogram. (See JP-A-7-38801).

[0004]

However, as described above, even in an electronic still camera that displays the histogram, it is possible to confirm whether or not the exposure is appropriate from the histogram.
In spite of the fact that it has reached the upper limit or the lower limit of the adjustment range, useless adjustment operations may be repeated. For this reason, usability at the time of exposure adjustment was not satisfactory.

[0005] Further, for example, a user who is not accustomed to the above-mentioned adjustment is difficult to understand the degree of change when the exposure adjustment is performed, just by looking at the histogram. In addition, since the display area of the histogram must be small, it is not possible to provide detailed information such as the frequency of the luminance level and the frequency of the luminance level which is low, and the state of the luminance distribution cannot be provided. Was confusing. Therefore, it is not always easy to adjust the exposure while observing the luminance distribution of the captured image.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and makes it easy to adjust the exposure (brightness) while observing the luminance distribution of a captured image and to improve the visibility of the luminance distribution of the captured image. It is an object of the present invention to provide an imaging device and a brightness distribution display method that can be improved.

[0007]

According to a first aspect of the present invention, there is provided an image pickup means for picking up an image of a subject, and an exposure at the time of image pickup by the image pickup means is adjusted according to a user operation. Exposure adjusting means, generating means for generating display data of a graph showing a luminance distribution of an image captured by the imaging means, display means for displaying a graph based on the display data generated by the generating means, Display color control means for changing the display color of the graph in accordance with the state of adjustment by the exposure adjustment means.
In such a configuration, when performing exposure adjustment during imaging,
The display of a graph showing the luminance distribution of the image being picked up not only informs the degree of exposure adjustment, but also simultaneously changes the display color of the graph, thereby improving the visibility of the luminance distribution of the picked-up image and making it easier to understand. Can be done.

Further, in the invention according to claim 2, the display color control means displays the display color of the graph at an upper limit or a lower limit of the adjustment range by the exposure adjusting means at a position other than the upper limit or the lower limit of the adjustment range. It was changed to a color different from the color. In such a configuration, when performing exposure adjustment at the time of imaging, it is possible to immediately notify that the exposure adjustment range has reached the upper limit or the lower limit by changing the display color of the graph.

According to a third aspect of the present invention, there is provided an image pickup means for picking up an image of a subject, a generating means for generating display data of a graph showing a luminance distribution of an image picked up by the image pickup means, and this generating means. Display means for displaying a graph based on the display data generated by the method, determining means for determining the luminance distribution state in the graph, and changing the display color of the graph according to the luminance distribution state determined by the determining means. And display color control means.
In such a configuration, when performing exposure adjustment during imaging,
By changing the display color of the graph showing the luminance distribution of the captured image according to the luminance distribution state, the visibility of the luminance distribution state of the captured image is improved, and the degree of change when the adjustment is performed can be understood. It can be easily informed.

According to a fourth aspect of the present invention, there is provided an image pickup means for picking up an image of a subject, a generation means for generating display data of a graph showing a luminance distribution of an image picked up by the image pickup means, and this generation means. Display means for displaying a graph based on the display data generated by
A display color control means for displaying the graph in a gradation pattern in which the display color gradually changes in accordance with the change in the luminance level along the direction of the luminance level setting axis. In such a configuration, when performing exposure adjustment at the time of imaging, the graph pattern showing the luminance distribution of the image being captured makes it possible to sense how much the frequency of the luminance level is high and how low the frequency of the luminance level is low. You can let them know.

According to a fifth aspect of the present invention, the display means further has a finder function of displaying a through image of the subject imaged by the imaging means, and the graph is superimposed on the through image. Was displayed.

According to a sixth aspect of the present invention, there is provided a brightness distribution display method for displaying a graph showing the brightness distribution of an image in an environment in which the brightness of the image to be displayed is adjustable.
The brightness adjustment state by the user operation is determined, and the display color of the graph is changed according to the determination result. In such a method, when adjusting the brightness of the image to be displayed, by displaying a graph showing the brightness distribution of the image,
In addition to notifying the degree of the exposure adjustment, the visibility of the luminance distribution of the captured image can be improved and easily understood by the change in the display color of the graph at the same time.

According to a seventh aspect of the present invention, in the luminance distribution display method for displaying a graph showing the luminance distribution of an image, a state of the luminance distribution in the graph is determined, and the state of the graph is determined according to the determination result. Changed display color. In such a method, the visibility of the brightness distribution of the captured image can be improved by changing the display color of the graph simultaneously with the brightness distribution of the image, and the degree of change in the brightness distribution when the brightness is adjusted can be determined. It can be easily informed.

According to the invention of claim 8, in the brightness distribution display method for displaying a graph showing the brightness distribution of an image, the graph is adapted to correspond to a change in the brightness level along the direction of the brightness level setting axis. Then, the display color is gradually changed to display a gradation pattern. In such a method, the luminance distribution of the image can be intuitively notified by the pattern of the graph as to how much the luminance level is high and how low the luminance level is.

According to the ninth aspect of the present invention, the graph is displayed so as to be superimposed on the image.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG.
FIG. 2 is a block diagram of the electronic still camera 1 according to the present invention.

The electronic still camera 1 has a lens 2
And a diaphragm device 3 for adjusting the amount of light of the subject image incident through the lens 2 and an image pickup device 4 composed of a CCD are sequentially arranged along the optical axis. The aperture device 3 is variably set in the aperture amount and is connected to an aperture control circuit 5, and the solid-state imaging device 4 is connected to a signal processing circuit 6.
The CPU 7 operates on the basis of the program to control each part constituting the electronic still camera. In automatic exposure control (AE control), the CPU 7 calculates an exposure value according to the light amount of the subject and outputs the calculated calculation result to the calculation result. An aperture value and a shutter speed are determined by controlling the aperture control circuit 5 based on this. Further, in the present embodiment, even in the AE mode in which the automatic exposure control is performed, an EV shift operation for increasing or decreasing the calculated exposure value within a predetermined range (exposure correction) is possible. Further, a manual exposure mode is provided in which only the aperture value can be adjusted while the shutter speed is fixed at a predetermined speed (for example, 1/125).

The CPU 7 includes the above-described image pickup device 4,
The aperture control circuit 5 and the signal processing circuit 6 are connected, and the ROM 8, the working RAM 9, and the recording memory 1
0, key input unit 11, external I / F control unit 12, display R
AM 13 and a histogram calculation circuit 14 are connected. The ROM 8 stores an operation program of the CPU 7 and the like, and the CPU 7 operates based on the operation program and controls each unit. The work RAM 9 is used as a work area of the CPU 7.

The aperture control circuit 5 drives the aperture device 3 based on the aperture value determined by the CPU 7. Image sensor 4
Is controlled in accordance with the shutter speed instructed by the CPU 7, thereby realizing an electronic shutter. The signal processing circuit 6 includes the imaging device 4
It performs gain adjustment of the analog image signal output from the CPU, color signal processing for the signal, and conversion to a digital signal. One frame of image data converted into a digital signal is sent to the display RAM 13, and a video signal is generated by the display circuit 15 based on the image data. Thus, when the REC through mode is set in the standby state during shooting, the captured subject image is displayed as a through image on the display element 16 including an LCD. At the time of a shooting instruction when the shutter key is pressed, the image data for one frame is recorded in the recording memory 10. The key input unit 11 includes the shutter key, a key for switching between the REC through mode and the PLAY mode, and the like.

The external I / F controller 12 controls the input and output of data to and from an external device such as a personal computer connected to the electronic still camera 1. The histogram calculation circuit 14 calculates the 1 generated by the signal processing circuit 6.
From the luminance data included in the image data of the frame, the luminance levels (256 levels from “0” to “255” in this embodiment) of each pixel are checked according to the image size at the time of recording, and each luminance level is checked. Is calculated, and the calculation result is C
Send to PU7.

In this embodiment having the above configuration, when the REC through mode is selected, the operation is performed as shown in the flowchart of FIG.

That is, in the REC through mode, when the AE mode is set (step S
A1 and SA2 are NO), an appropriate exposure corresponding to the amount of light of the subject is calculated according to a predetermined exposure control program, and exposure control for adjusting the shutter speed, aperture, etc. is performed accordingly (step SA3), and FIG. As shown in (a), a normal through image A in which a focus frame F is displayed on a subject is displayed (step SA11). On the other hand, even when the AE mode is set, when the EV shift is performed by operating the key input unit 11 (YES in step SA2), the exposure control based on the appropriate exposure according to the light amount of the subject is performed. At the same time, after performing exposure control for increasing or decreasing the appropriate exposure by an amount corresponding to the EV shift operation (step SA4), and when the exposure is completely manual control (YES in step SA1), the shutter speed is set to a predetermined speed, After performing the exposure control to set the aperture value to the value selected by the user (step SA
5) Perform the following operation.

First, the histogram calculation circuit 14 obtains luminance data for each pixel in one imaged frame and counts the number of pixels corresponding to each luminance level (step SA6). Is generated (step SA7). Next, whether the exposure set at that time is the upper limit or the lower limit of the adjustable (correctable) range, that is, if the EV shift operation has been performed by the key input unit 11, the shift is performed. Exposure value (EV
Value) is the upper limit value or the lower limit value, and if manual control has been performed, it is determined whether the aperture value is the maximum value or the upper limit value. If the result of this determination is NO and not the upper limit or the lower limit (NO in step SA8), the display color of the histogram is set to "white" and combined with a through image (step SA9), and then shown in FIG. Thus, the through image B on which the histogram H is superimposed is displayed (step SA1).
1). When the histogram H is combined with the through-the-lens image, the graph display area a is set at a predetermined position (the lower center in the present embodiment) of the through-the-lens image, and the brightness in the area is reduced by a predetermined amount. X in H
The bar graph is overwritten with the axis (luminance level setting axis) and the Y axis (frequency setting axis). That is, the histogram H is synthesized so that the graph display area a is in a semi-transparent state.

On the other hand, if the decision result in the step SA8 is YES.
And when the exposure adjustment is the upper limit or the lower limit,
Set the display color of the histogram to "red"
After combining with the through image in the same manner as described above (step SA10), the through image on which the histogram H is superimposed as shown in FIGS. 4B and 4C is displayed (step SA11). Thereafter, the above operation is repeated.

Thus, when the user is adjusting the exposure value of the image pickup screen by, for example, the EV shift, FIG.
As shown in (a) to (c), not only the luminance distribution is displayed, but also when the EV-shifted exposure value reaches the upper limit or the lower limit, that is, the exposure value cannot be changed any more by the EV shift operation. Sometimes, the color of the bar graph can be immediately notified by a change in color from "white" to "red". Therefore, for the user,
Useless operation such as repeating the EV shift operation despite the fact that the EV-shifted exposure value has reached the upper limit or the lower limit is eliminated, and usability is improved.

In this embodiment, manual exposure control is performed in which the shutter speed is set to a predetermined speed and the aperture value is selected by the user.
The aperture value may be set to a predetermined value, and the shutter speed may be set to a value selected by the user, or the manual exposure control may be performed by combining the shutter speed, the aperture, the signal gain, and the like as in the case of setting the AE mode.

Further, it may be possible to easily determine that the EV shift is not performed by changing the display color in the state where the EV shift operation is not performed (the state of the proper exposure).

Further, in the present embodiment, in the REC through mode, that is, in the shooting standby state, the histogram is always superimposed and displayed on the through image. However, display / non-display of the histogram can be selected according to a predetermined operation. By doing so, the entire image of the subject can be easily checked even when the EV shift or the like is performed. Also, the histogram is configured to be superimposed and displayed on the through image.
The histogram H and the through-the-lens image may be displayed independently, and if the display color can be changed, a configuration may be provided in which a display means dedicated to the histogram, such as an LED, is provided. Also, the case where the present invention is applied to the electronic still camera 1 has been described. However, other than this, a video camera that shoots a moving image, an image scanner And other imaging devices.

In this embodiment, the case where the adjustment limit is notified at the time of adjusting the exposure of a captured image has been described. However, the present invention is not limited to this. When the recorded image is displayed in the PLAY mode, it can also be used for notifying the adjustment limit when adjusting the brightness of the displayed image. In this case, there is no needless operation of repeating the adjustment operation despite the brightness adjustment reaching the upper limit or the lower limit, and the usability is improved.
Further, the method is not limited to electronic still cameras, devices that can adjust the brightness of images, for example, when processing moving images and still images in a personal computer, and when adjusting the brightness in a general television receiver, It can also be used as a method of indicating the adjustment limit.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings. This embodiment has the same configuration as that shown in FIG.
The present invention relates to an electronic still camera that displays a histogram using a display method different from that described above. In the present embodiment, there is no complete manual exposure mode in which only the aperture value can be adjusted while the shutter speed is fixed at a predetermined speed.

Hereinafter, in such an electronic still camera, R
The operation when the EC through mode is selected will be described with reference to the flowchart of FIG. That is, also in the present embodiment, in the REC through mode, when the AE mode is set (step SB1 is N
O) After calculating an appropriate exposure according to the amount of light of the subject in accordance with a predetermined exposure control program, performing exposure control for adjusting the shutter speed, aperture, and the like accordingly (step SB2), and then proceeds to step SB4.

If the EV shift has been performed (YES in step SB1), the exposure control is performed based on the proper exposure corresponding to the light amount of the subject, and the appropriate exposure is increased or decreased by the amount corresponding to the EV shift operation. Is performed (step SB3), the process proceeds to step SB4, and the following operation is performed. First, the histogram calculation circuit 14 obtains luminance data for each pixel in one captured frame, counts the number of pixels corresponding to each luminance level (step SB4), and displays a histogram indicating a luminance distribution based on the count result. After generating the display data (step SB5), a state of uneven brightness is determined (step SB6). Here, the determination means determines whether the bias state is “bright tendency” largely biased toward the bright side with high luminance, “dark tendency” largely biased toward the dark side with low luminance, or “normal” without particularly large bias. It is determined according to a predetermined criterion whether the condition is satisfied. For example, a luminance level at which the cumulative frequency from the higher luminance level becomes a predetermined ratio (for example, 80%) of all pixels is calculated, and the calculated luminance level is a limit reference level on the high luminance side (for example, “200”) ), The brightness is determined to be “bright tendency”, and the cumulative frequency from the lower luminance level and the luminance level at a predetermined ratio (for example, 80%) of all pixels are calculated. When it is lower than the limit reference level (for example, “50”), “dark tendency” is set, and when neither “bright tendency” nor “dark tendency” is satisfied, “normal” is set.

When the result of determination at step SB6 is "bright tendency", the display color of the histogram is changed to that shown in FIG.
As shown in (a), the color is set to “white” and combined with a through image (step SB7).
After the display color of the histogram is set to “gray” as shown in FIG. 6B and combined with the through image (step SB)
8) If it is “dark tendency”, the display color of the histogram is set to “black” as shown in FIG. 6C and the histogram H is superimposed after being synthesized with the through image (step SB9). Display a through image (step SB1)
0). In other words, the histogram H depends on the bias state of the luminance.
Is changed to three colors, and thereafter, the above-described operation is repeated.

Therefore, in the present embodiment, when the user adjusts (corrects) the exposure value of the imaging screen by the EV shift, the exposure value is largely overexposed due to the change in the display color of the histogram H. When it becomes less or under-appears, it can be reliably and easily notified.

Further, since the histogram is displayed even when only the AE control is being performed, a change in the photographing environment can be easily known from a change in the color of the histogram.

In this embodiment, the distribution state of the histogram H is determined by dividing it into three tendencies, and the display color is changed to three colors. However, the distribution state to be determined and the display color corresponding thereto are determined. By increasing the number, the change in the luminance distribution can be easily understood, and even an inexperienced person can easily perform exposure adjustment and the like.

In the present embodiment, the display color is monotone, but the display color may be changed using a color such as red, blue, or green.

Further, by using a specific display color in the case of the proper exposure, it may be possible to easily determine that the state is the proper exposure.

Further, similarly to the first embodiment, the display / non-display of the histogram may be selected according to a predetermined operation. Further, a configuration in which the histogram H and the through image are displayed independently, or a configuration in which a display unit dedicated to the histogram is provided may be employed. Further, the present invention can be applied to the above-described other imaging devices other than the electronic still camera 1.

Although the present embodiment has been described with reference to the case where a histogram is displayed in the REC through mode, the method of the present invention is not limited to this. An image recorded in the recording memory 10 of the camera 1 is played.
When displaying in the mode, the histogram may be displayed in a color corresponding to the luminance distribution of the display image.

The method of displaying a histogram according to the present embodiment is not limited to an electronic still camera, but may be a video camera or a personal computer.
It can also be used when reproducing or processing a still image, or when adjusting luminance in a general television receiver.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings. This embodiment has the same configuration as that shown in FIG.
The present invention relates to an electronic still camera that displays a histogram using a display method different from that described above. The present embodiment also does not have a manual exposure mode in which only the aperture value can be adjusted while the shutter speed is fixed at a predetermined speed.

Hereinafter, in such an electronic still camera, R
The operation when the EC through mode is selected will be described with reference to the flowchart of FIG. That is, also in the present embodiment, in the REC through mode, when the AE mode is set (step SC1 is N
O) After calculating an appropriate exposure according to the amount of light of the subject in accordance with a predetermined exposure control program and performing exposure control for adjusting the shutter speed, aperture, and the like (step SC2), the process proceeds to step SC4.

If the EV shift has been performed (YES in step SC1), the exposure control based on the proper exposure according to the light amount of the subject is performed, and the proper exposure is increased or decreased by the amount corresponding to the EV shift operation. Is performed (step SC3), the process proceeds to step SC4, and the following operation is performed. First, the histogram calculation circuit 14 obtains luminance data for each pixel in one imaged frame, and counts the number of pixels corresponding to each luminance level (step SC4). Next, display data of a histogram showing a luminance distribution is generated based on the count result (step SC5), and a gradation pattern as shown in FIG. 8, that is, as shown in FIG. Along the X-axis (luminance level setting axis) from the large side to the small side of the luminance level in a stepless or stepwise (or two-step) manner from white to black, to the through image. Synthesis is performed (step SC6). Then, a through image on which the histogram H is superimposed is displayed (step SC7), and thereafter, the above-described operation is repeated.

Thus, in the present embodiment, E
When the exposure value of the imaging screen is adjusted (corrected) by the V shift, the histogram H (specifically, a bar graph portion)
Depending on the pattern, how many brightness levels are high,
It is possible to easily inform the user of how low the luminance level is. Therefore, the user can easily adjust the exposure value.

Also, in the present embodiment, the histogram is displayed even when only the AE control is performed, so that the change of the photographing environment can be easily known by the gradation display of the histogram. it can.

In the present embodiment, the display color of the histogram H is changed from white to black. However, the display color may be changed in accordance with the increase or decrease of the luminance level at the display location. For example, the color may be changed from white to red, or the luminance of a specific color may be changed.

Further, similarly to the second embodiment, display / non-display of the histogram may be selected according to a predetermined operation. Further, a configuration in which the histogram H and the through image are displayed independently, or a configuration in which a display unit dedicated to the histogram is provided may be employed. Further, the present invention can be applied to the above-described other imaging devices other than the electronic still camera 1.

Although the present embodiment has been described with reference to the case where a histogram is displayed in the REC through mode, the method of the present invention is not limited to this. An image recorded in the recording memory 10 of the camera 1 is played.
When displaying in a mode, a histogram corresponding to the luminance distribution of the display image may be displayed in gradation.

The method of displaying a histogram according to the present embodiment is not limited to an electronic still camera, but may be a video camera or a personal computer.
It can also be used when reproducing or processing a still image, or when adjusting luminance in a general television receiver.

In the above-described first to third embodiments, a histogram indicating the luminance distribution of a captured image is simply displayed. A histogram indicating the luminance distribution may be displayed.

[0052]

As described above, in the present invention,
At the time of exposure adjustment and image brightness adjustment at the time of imaging, not only the degree of exposure adjustment and brightness adjustment is notified, but also the visibility of the brightness distribution of the captured image can be improved by changing the display color of the graph at the same time. Can be easily understood. In addition, the change in the display color of the graph allows the user to immediately know that the exposure adjustment range has reached the upper limit or the lower limit. Nevertheless, useless operations are not repeated despite the fact that it is used, and the usability is improved.

When adjusting the exposure and brightness of an image at the time of imaging, not only is the degree of exposure and brightness adjusted, but also the visibility of the brightness distribution of the image is improved by changing the display color of the graph. The degree of change at the time of adjustment can be notified in an easy-to-understand manner. As a result, even those who are unfamiliar with exposure adjustment and brightness adjustment work can easily perform exposure adjustment and the like.

Further, in exposure adjustment and image brightness adjustment at the time of image pickup, it is possible to intuitively notify the user of how much the brightness level is high and how low the brightness level is, depending on the pattern of the graph. Therefore, the user of the imaging device or the like can easily perform the exposure adjustment and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic still camera 1 according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation in a REC through mode in the embodiment.

FIG. 3 is a diagram showing a normal through image and a through image on which a histogram is superimposed.

FIG. 4 is an explanatory diagram showing a change in a display color of a histogram in the embodiment.

FIG. 5 is a flowchart illustrating an operation in a REC through mode according to the second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a change in a display color of a histogram in the embodiment.

FIG. 7 is a flowchart illustrating an operation in a REC through mode according to the third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a histogram superimposed on a through image in the embodiment.

[Explanation of symbols]

 Reference Signs List 3 aperture device 4 image sensor 5 aperture control circuit 6 signal processing circuit 7 CPU 8 ROM 11 key input unit 14 histogram calculation circuit 16 display element H histogram

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/243 H04N 5/243 // H04N 101: 00 101: 00

Claims (9)

[Claims] An imaging unit configured to image a subject; an exposure adjustment unit configured to adjust an exposure at the time of imaging by the imaging unit in accordance with a user operation; and a graph showing a luminance distribution of an image captured by the imaging unit. Generating means for generating display data; display means for displaying a graph based on the display data generated by the generating means; display color control means for changing a display color of the graph according to an adjustment state by the exposure adjusting means An imaging device comprising: 2. The display color control unit changes a display color of the graph at an upper limit or a lower limit of an adjustment range by the exposure adjusting unit to a color different from a display color other than the upper limit or the lower limit of the adjustment range. The imaging device according to claim 1. 3. An image pickup means for picking up an image of a subject, a generation means for generating display data of a graph showing a luminance distribution of an image taken by the image pickup means, and a graph based on the display data generated by the generation means. Display means for displaying; determining means for determining a luminance distribution state in the graph; and display color control means for changing a display color of the graph according to the luminance distribution state determined by the determining means. Characteristic imaging device. 4. An image pickup means for picking up an image of a subject, a generation means for generating display data of a graph showing a luminance distribution of an image picked up by the image pickup means, and a graph based on the display data generated by the generation means. Display means for displaying; and display color control means for displaying the graph in a gradation pattern in which the display color gradually changes in accordance with the change in the luminance level along the luminance level setting axis direction. An imaging device, comprising: 5. The display device according to claim 1, further comprising a finder function of displaying a through image of the subject imaged by the imaging device, wherein the graph is displayed so as to be superimposed on the through image. Item 5. The imaging device according to any one of Items 1 to 4. 6. A brightness distribution display method for displaying a graph showing a brightness distribution of an image to be displayed in an environment in which the brightness of the image to be displayed is adjustable. A display color of the graph by changing the display color of the graph. 7. A luminance distribution display method for displaying a graph showing a luminance distribution of an image, wherein a state of the luminance distribution in the graph is determined, and a display color of the graph is changed according to the determination result. Brightness distribution display method. 8. A brightness distribution display method for displaying a graph showing a brightness distribution of an image, wherein said graph is displayed in a gradation in which a display color gradually changes in accordance with a change in the brightness level along a direction of a brightness level setting axis. A brightness distribution display method characterized by displaying a pattern. 9. The brightness distribution display method according to claim 6, wherein the graph is displayed by being superimposed on the image.