JPH10221593A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bring an object into good focus regardless of degree of contrast even if number of dots for displaying contrast is fewer. SOLUTION: An integrator 8A determines contrast value for each frame and an integrator 8B determines brightness value for each frame, and a RAM 16 stores the contrast value and the brightness value for plural frames. A CPU 9 checks the change of brightness, when the change of brightness shows possibility of displaying increase/decrease of contrast, judges the increase/decrease trend based on the stored contrast values, and controls a finder 15 so that the finder displays the judged consequence.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a digital camera, and more particularly to a CCD (Charge Couple).
The present invention relates to a digital camera that inputs image data obtained by imaging a subject using a solid-state imaging device such as an imaging device.

[0002]

2. Description of the Related Art In a digital camera of this type, focusing is usually performed by an automatic focus adjustment (hereinafter, referred to as an autofocus) function at the time of imaging. This autofocus function requires a mechanism dedicated to autofocus, such as a lens drive motor, which increases the size of the entire apparatus and makes it difficult to focus on a desired subject.

For this reason, conventionally, the auto-focus function itself has been omitted from the photographing function of the digital camera, or the auto-focus function has been canceled and manual focusing has been performed to focus on the desired subject within the screen. Was focused.

However, when focusing is performed manually, the operation is performed while checking the image displayed on the display screen of a viewfinder or the like with the naked eye.
It was difficult to find the optimum focus position.

Therefore, in recent years, as disclosed in Japanese Patent Application Laid-Open No. 6-113184, it has been proposed to display an image of a subject on a display screen and to display a state transition of an in-focus state in a graph with contrast.

[0006]

As described in the above publication, in the digital camera according to the conventional example, the degree of focus is visually confirmed by graphing the contrast, so that the in-focus state can be determined for any subject. In order to display a graph, it is necessary to increase the number of displayed contrasts.

That is, in the focusing detection based on the contrast, the size of the contrast data at the time of focusing can be determined only at the time of focusing. Therefore, the graph display range is prepared from the minimum value to the maximum value at which the contrast data can be output. However, as the graph display resolution, for example, it is necessary to be able to determine the in-focus state even for a subject with a small change in contrast. For this reason, when the number of displayed contrasts is small, if the contrast of the subject is reduced, there is no change in the graph display of the in-focus time and the out-of-focus time, and accurate focusing may not be performed.

However, with the size of the display screen given to the digital camera, the number of displayed contrasts is limited, and it is impossible to increase the number of displayed images to the number necessary for optimal focusing. Was.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital camera capable of performing good focusing regardless of the level of contrast even if the number of displayed contrasts is small, in order to solve the above-described problem of the conventional example. I do.

[0010]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, a digital camera according to the first aspect of the present invention is a digital camera that adjusts a focus at the time of imaging according to a manual operation, wherein an imaging unit that captures an image of a subject to obtain digitized image data; A contrast detection unit that detects a contrast value of the subject based on image data obtained by the imaging unit; and an increase / decrease tendency determination unit that determines an increase / decrease tendency of contrast based on the contrast value detected by the contrast detection unit. Display means for displaying a display indicating the contrast increase / decrease tendency determined by the increase / decrease tendency determination means.

According to the first aspect of the present invention, the contrast value of the subject is detected, the contrast increase / decrease tendency is determined based on the contrast value, and a display indicating the determined contrast increase / decrease tendency is performed. As a result, the number of displayed contrasts is reduced, whereby good focusing can be performed regardless of the level of contrast.

A digital camera according to a second aspect of the present invention has a fixed focus and a variable focus, and adjusts the focus at the time of imaging according to a manual operation. Imaging means for obtaining the obtained image data; contrast detection means for detecting the contrast value of the subject based on the image data obtained by the imaging means; and determining whether the focus at the time of imaging is a fixed focus or a variable focus. Focus determining means; increasing / decreasing tendency determining means for determining an increasing / decreasing tendency of contrast based on a contrast value detected by the contrast detecting means only when a result of determination of variable focus is obtained by the focus determining means; Display means for displaying a display indicating the contrast increasing / decreasing tendency determined by the tendency determining means;
It is characterized by having.

According to the second aspect of the invention, only when the focus is a variable focus, the contrast increase / decrease tendency is determined based on the contrast value, and a display indicating the determined contrast increase / decrease tendency is performed. As a result, the contrast increase / decrease display does not need to be performed at the time of the fixed focus, thereby preventing erroneous display. Also, at the time of the variable focus, the number of contrast displays in the contrast increase / decrease display is reduced, so that it is good regardless of the contrast level. It is possible to perform focusing.

According to a third aspect of the present invention, there is provided a digital camera for adjusting a focus at the time of image capturing in accordance with a manual operation, wherein an image capturing means for capturing an image of a subject to obtain digitized image data; A contrast detection unit that detects a contrast value of the subject based on image data obtained by the imaging unit; a brightness detection unit that detects a brightness value of the subject based on image data obtained by the imaging unit; Judgment means for judging whether the contrast can be increased or decreased based on the luminance value detected by the luminance detection means, and detection by the contrast detection means only when the judgment result indicates that the contrast can be increased or decreased. An increase / decrease tendency determining means for determining a contrast increase / decrease tendency based on the obtained contrast value; Display means for displaying the effect that represents the determined contrast decrease tendency by increasing or decreasing tendency determination means, characterized by comprising a.

According to the third aspect of the present invention, it is determined whether the contrast can be increased or decreased according to the brightness of the subject, and only when the display can be increased or decreased, the contrast is increased or decreased based on the contrast value. Therefore, since the display indicating the determined contrast increasing / decreasing tendency is performed, the contrast increasing / decreasing display does not need to be performed at the time of an unreliable inappropriate luminance value, thereby preventing erroneous display. When an appropriate luminance value is obtained, the number of displayed contrasts in the contrast increase / decrease display is reduced, so that good focusing can be performed regardless of the contrast level.

According to a fourth aspect of the present invention, there is provided a digital camera for adjusting a focus at the time of image capturing in accordance with a manual operation, wherein an image capturing means for capturing a subject and obtaining digitized image data; A contrast detection unit that detects a contrast value of the subject based on image data obtained by an imaging unit; a contrast storage unit that stores, for a plurality of frames, a contrast value for each frame detected by the contrast detection unit; An increasing / decreasing tendency determining means for determining an increasing / decreasing tendency of the contrast based on the contrast values for a plurality of frames stored in the storage means; and a displaying means for displaying a display indicating the contrast increasing / decreasing tendency determined by the increasing / decreasing tendency determining means. , Is provided.

According to the present invention, the contrast value of the object is detected for each frame, the contrast value is stored, and the increase / decrease tendency of the contrast is determined based on the stored contrast value. Since the display indicating the contrast increase / decrease tendency obtained by the determination is performed, the display can be held by storing the data, and the number of displayed contrasts can be reduced. Focusing can be performed irrespective of the height of the image.

According to a fifth aspect of the present invention, there is provided a digital camera for adjusting a focus at the time of image capturing in accordance with a manual operation, wherein an image capturing means for capturing an image of a subject to obtain digitized image data; Contrast detecting means for detecting a contrast value of the subject for each frame based on image data obtained by an imaging means, and contrast storing means for storing a plurality of frames of the contrast value detected for each frame detected by the contrast detecting means. And determining means for determining whether or not to increase or decrease the contrast based on the contrast values for a plurality of frames stored in the contrast storage means, and when the determination means has determined that the increase or decrease of the contrast is possible. Only based on the contrast value stored in the storage means. An increasing / decreasing tendency judging means for judging the increasing / decreasing tendency of the trust, a display means for displaying a display indicating the contrast increasing / decreasing tendency judged by the increasing / decreasing tendency judging means, and a judgment result that the increase / decrease of the contrast cannot be displayed is obtained by the judging means. Display holding means for holding the previous display state of the display means when the display is given.

According to the fifth aspect of the invention, the contrast value of the subject is detected for each frame, and the contrast value is stored. When the contrast can be increased or decreased based on the contrast value, the stored contrast value is stored. The contrast increasing / decreasing tendency is determined based on the contrast value, and a display indicating the contrast increasing / decreasing tendency obtained by the determination is performed. When the contrast increasing / decreasing display is impossible, the previous display state is held. Therefore, it is possible to avoid an erroneous display due to an increase or decrease in a contrast value caused by noise or camera shake due to a tendency to increase or decrease the contrast, and in a normal contrast increase / decrease display, the number of displayed contrasts is reduced. Focusing can be performed irrespective of the height of the image.

According to a sixth aspect of the present invention, there is provided a digital camera for adjusting a focus at the time of image capturing in accordance with a manual operation, wherein an image capturing means for capturing a subject to obtain digitized image data; A contrast detection unit that detects a contrast value of the subject for each frame based on image data obtained by the imaging unit, and a brightness value of the subject that is detected for each frame based on the image data obtained by the imaging unit Brightness detection means, storage means for storing contrast values for a plurality of frames detected by the contrast detection means and brightness values for a plurality of frames detected by the brightness detection means, and a plurality of storage values stored in the storage means Judging means for judging whether or not to display an increase or decrease in contrast in accordance with an amount of change between luminance values for frames; An increase / decrease tendency judging means for judging an increase / decrease tendency of a contrast based on a contrast value stored in the storage means only when a judgment result that a contrast increase / decrease display is possible is obtained by the disconnection means, And display means for displaying a display indicating the contrast increase / decrease tendency.

According to the present invention, the contrast value and the brightness value of the subject are detected for each frame, and the contrast value and the brightness value are stored, and the contrast can be increased or decreased according to the amount of change between the brightness values. In such a case, the contrast increasing / decreasing tendency is determined based on the stored contrast value, and a display indicating the determined contrast increasing / decreasing tendency is performed. In addition to avoiding erroneous display, the number of displayed contrasts is reduced in normal contrast increase / decrease display, whereby good focusing can be performed regardless of the contrast level.

A digital camera according to a seventh aspect of the present invention is a digital camera that adjusts the focus at the time of imaging according to a manual operation, wherein the imaging means obtains digitized image data by imaging a subject. A contrast detection unit that detects a contrast value of the subject for each frame based on image data obtained by the imaging unit, and a brightness value of the subject that is detected for each frame based on the image data obtained by the imaging unit Brightness detection means, storage means for storing contrast values for a plurality of frames detected by the contrast detection means and brightness values for a plurality of frames detected by the brightness detection means, and a plurality of storage values stored in the storage means Judging means for judging whether or not to display an increase or decrease in contrast in accordance with an amount of change between luminance values for frames; Correction means for correcting the contrast value stored in the storage means by using the luminance value stored in the storage means when the result of the determination that the increase or decrease of the contrast cannot be displayed is obtained by the disconnection means; After the determination result that the increase / decrease display is possible is obtained or after the correction by the correction unit, the increase / decrease tendency determination unit that determines the increase / decrease tendency of the contrast based on the contrast value stored in the storage unit; Display means for displaying a display indicating the contrast increasing / decreasing tendency determined by the means.

According to the seventh aspect, the contrast value and the brightness value of the subject are detected for each frame, and the contrast value and the brightness value are stored, and the contrast cannot be increased or decreased according to the amount of change between the brightness values. In this case, the contrast value is corrected based on the luminance value, and then the contrast increase / decrease tendency is determined, and a display indicating the determined contrast increase / decrease trend is performed. It is possible to avoid erroneous display of the trend and reduce the number of displayed contrasts in the normal contrast increase / decrease display,
It is possible to perform good focusing regardless of the level of contrast.

According to the invention of claim 8, according to claim 1,
In the invention according to any one of the first to seventh aspects, the contrast detection means has a plurality of bandpass filter means, and detects a contrast value after filtering by each of the bandpass filter means.

According to the eighth aspect of the present invention, since the contrast value after the filtering by the plurality of band-pass filters is detected, it is possible to improve the accuracy of determining the increase or decrease of the contrast.

[0026]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an internal configuration of a digital camera according to Embodiment 1 of the present invention. As shown in FIG. 1, this digital camera has a lens system 1 as a photographing optical system, a manual autofocus mechanism 2, an image sensor CCD 3, an operational amplifier 4, an A / D converter 5, an image signal processing circuit 6, a band A pass filter (hereinafter referred to as a BPF) 7, an integrator 8A as a contrast detecting means, an integrator 8B as a luminance detecting means, a CPU 9,
Operation switch 10, image memory 11, storage device 12, D
A / A converter 13, an encoder 14, an electronic viewfinder (hereinafter referred to as a finder) 15 as a means for displaying a contrast increasing / decreasing tendency, a RAM 16 for storing contrast and brightness as data, a potentiometer 17 as a photographing area detecting means, and the like. ing.

The lens system 1 is set to be movable along its optical axis by a manual focus mechanism 2 composed of a focusing ring or the like. A CCD 3 is provided on the optical axis of the lens system 1, and is set so that a photographed image of a subject is formed on the imaging surface of the CCD 3 via the lens system 1. The imaging operation of the CCD 3 is controlled in accordance with a pulse output from a timing generator (not shown).

An analog image signal obtained by the imaging of the CCD 3 is output to the operational amplifier 4 and amplified to a predetermined level. The analog image signal amplified by the operational amplifier 4 is A / D-converted by a subsequent A / D converter 5 and output as a digital image signal to an image signal processing circuit 6.

In the image signal processing circuit 6, a luminance signal YH and a color difference signal (CR,
CB) is extracted. Note that CR is obtained by RY, and CB is obtained by BY. The above luminance signal Y
The H data is output to the BPF 7, and only a predetermined band component of the luminance signal YH is supplied to the integrators 8A and 8B.

Specifically, the BPF 7 has two types of filters having different bands, and obtains two types of outputs.

The integrator 8A integrates the data of the input luminance signal YH, and converts a DC voltage proportional to the contrast of a captured image into a contrast voltage (contrast value).
And supplies this to the CPU 9. In this case, B
Since two types of outputs are obtained from the PF 7, two types of contrast values are obtained.

On the other hand, the integrator 8B integrates the data of the input luminance signal YH, obtains a DC voltage proportional to the luminance of the photographed image as a luminance voltage (luminance value), and supplies this to the CPU 9. .

The operation switch 10 includes a shutter release button, an exposure compensation button, and the like, and supplies an input signal detected by operating each switch or button to the CPU 9. The CPU 9 stores two types of contrast values and luminance values supplied from the integrators 8A and 8B, respectively, in a RAM.
16 and performs a predetermined calculation. Based on the calculation result, a contrast increase / decrease display, which will be described later, is controlled, and various controls are executed in accordance with an input signal from the operation switch 10.

The RAM 16 includes RAMs 16A and 16B for storing two types of contrast values, ie, contrast a data and contrast b data, and a RAM 16C for storing luminance data.

The image memory 11 stores the above-mentioned luminance signal YH and color difference signals (CR, C) obtained by the image signal processing circuit 6.
B), the recording device 12 has a storage memory such as a magnetic disk, and the luminance signal YH and the color difference signal (C) stored in the image memory 11 under the control of the CPU 9.
R, CB).

The luminance signal YH and the color difference signals (CR, CB) stored in the image memory 11 or the recording device 12 for outputting a display image to the viewfinder 15, that is, for performing, for example, a contrast increase / decrease display described later. D
The signal is converted into an analog signal by the / A converter 13, and the image is output to the finder 15 through the control of the encoder 14. The encoder 14 can also output an external image via an external terminal (not shown).

The finder 15 reproduces an image based on the video output output from the encoder 14. The finder 15 is constituted by, for example, a liquid crystal display device.

Further, the manual focus mechanism 2 has an R
The focusing operation is performed by manually receiving an operation from the user according to a contrast increase / decrease display described later obtained from the two types of contrast values and luminance values stored in the AM 16.

Next, the operation will be described. FIG. 2 is a flowchart illustrating a contrast increase / decrease display process, and FIG.
FIG. 4 is a diagram illustrating an integration operation at the time of contrast increase / decrease display processing, FIG. 4 is a diagram illustrating a guidance display example at the time of contrast increase / decrease processing, and FIGS. 5 to 8 are diagrams illustrating processing data at the time of contrast increase / decrease display. This contrast increase / decrease display processing is performed by the CPU 9 in the ROM built in the CPU 9.
(Not shown).

When the contrast increasing / decreasing display process is started, it is assumed that the arrows of "+" and "-" shown in FIG.

In this contrast image increase / decrease display, as shown in FIG. 3, after this program is started, two types of contrast values (contrast data a) are sequentially provided from the first frame (1/30 second per frame). , B) and a luminance value (luminance data) are obtained by integration. In addition,
The interval for taking in each data may be the above-mentioned one-frame interval, two-frame interval or more.

In FIG. 3, “mf_data_a” means contrast a data for manual focus, “mf_data_b” means contrast b data for manual focus, and “ae_d”.
“ata” means luminance data.

In the contrast increasing / decreasing display processing, first, in step S1, "mf_di" is displayed on the finder 15.
sp = MF_READY ”is displayed.
The contrast a data, contrast b data, and luminance data stored in M16A, 16B, and 16C, respectively, are cleared for three frames. RAM 16A, 16B
16C can hold data of at least three frames.

As a result, as shown in FIG. 5, the contrast a data, contrast b data, and luminance data for three frames (indicated by [1], [2], and [3] in the figure) are all “0”. Set as a value.

In the following step S2, a photographing area is detected. In this case, the imaging area currently set by the potentiometer 17 is detected by the voltage. Based on the voltage value, it is determined whether the shooting area is the standard shooting area or the close-up shooting area. The standard photographing area has a fixed focus and can be set mechanically by the manual focus mechanism 2. According to this fixed focus, 0.6m
Focuses from to infinity depending on the depth of the subject. The close-up shooting area has a variable focus.

If it is determined in step S2 that the area is the standard photographing area, the process returns to step S1. If the result of determination is that the area is a close-up photographing area requiring contrast increase / decrease display, the process proceeds to step S3.

In step S3, the contrast a data, contrast b data, and luminance data acquired in accordance with the image pickup are stored in the RAM 16 for three frames each.
A, 16B and 16C.

As a result, as shown in FIG. 6, contrast a data, contrast b data, and luminance data for three frames (indicated by [1], [2], and [3] in the figure) are set.

In the following step S4, the RAM 16
A among the data stored in A, 16B and 16C, RAM
A process of comparing the value of the luminance data stored in 16C, that is, the measured luminance value, with a preset comparative luminance value in order to determine whether contrast increase / decrease detection is possible is executed.

If it is determined that the measured luminance value is lower than the comparative luminance value, it is determined that contrast increase / decrease cannot be detected, and the finder 15 informs the finder 15 in step S6 that the contrast increase / decrease cannot be detected. "Mf_disp = MF_NG" is displayed and output. Thereafter, the process returns to step S1.

If it is determined that the measured luminance value is equal to or greater than the comparative luminance value, the process proceeds to step S
The process proceeds to step 5 to determine the contrast. That is, among the data stored in the RAMs 16A, 16B, and 16C, the difference between the respective values of the contrast a data and the contrast b data stored in the RAMs 161 and 16B, that is, the measured contrast value, is determined between the frames (two or three frames). Then, a process of comparing the obtained difference with a preset contrast value for comparison to determine whether the contrast increase / decrease detection is possible is executed.

If it is determined that the measured contrast value is lower than the comparison contrast value,
It is determined that the contrast increase / decrease cannot be detected, and “mf_disp = MF_NG” indicating that the contrast increase / decrease cannot be detected is displayed on the finder 15 in step S6. Thereafter, the process returns to step S1.

If a determination result that the measured contrast value is equal to or greater than the comparison contrast value is obtained,
The process proceeds to step S7, and determines whether or not the change in luminance is equal to or greater than an allowable value. In this case, the luminance data stored in the RAM 16C is compared between the frames, and if the difference has changed by a predetermined allowable value or more, the process returns to step S1.

On the other hand, if the difference is less than the allowable value, the process proceeds to step S8, where the RAM 16A, 1
It is determined whether data for three frames has been stored in each of 6B and 16C. As a result, if data for three frames exists, the process further proceeds to step S9. If data for three frames does not exist, the process returns to step S2.

In step S9, first, the processing of judging the decreasing tendency of each of the contrast a and the contrast b by executing the (1) judgment of the decrease of the contrast a and the (2) judgment of the decrease of the contrast b shown in FIG. 7 is executed. Is done.
As a result, if both the contrasts a and b are decreasing, “mf_disp = MF_DOWN” indicating the decrease in contrast is displayed on the finder 15.

At this time, the "+" arrow being displayed on the viewfinder 15 flashes or is lit and displayed with emphasis more than the "-" arrow. After confirming the above guidance display, the user manually operates the contrast increasing operation. The adjustment may be made with.

In the following step S10, first, a process of judging the respective increasing tendency of the contrast a and the contrast b by (1) judging the increase of the contrast a and (2) judging the increase of the contrast b shown in FIG. Be executed.

As a result, if both the contrasts a and b are increasing, “mf_disp = MF_UP” indicating the increase in the contrast is displayed on the finder 15. At this time, the “−” arrow displayed on the viewfinder 15 blinks or is lit and displayed with emphasis more than the “+” arrow. After confirming the above guidance display, the user confirms
The contrast reduction operation may be adjusted manually.

As described above, according to the embodiment, the contrast value of the subject is detected, the contrast increase / decrease tendency is determined based on the contrast value, and the determined contrast increase / decrease tendency is indicated. Since the display is performed, the number of displayed contrasts is reduced, so that good focusing can be performed regardless of the contrast level.

Further, only when the focus is a variable focus, the contrast increasing / decreasing tendency is determined based on the contrast value, and a display indicating the determined contrast increasing / decreasing tendency is performed. You do n’t need to show the change,
Further, at the time of variable focus, since the number of displayed contrasts in the contrast increase / decrease display is small, it is possible to perform good focusing regardless of the contrast level.

Further, it is determined whether or not the display of the contrast can be increased or decreased according to the brightness of the subject, and only when the display of the increase or decrease can be performed, the tendency of the increase or decrease of the contrast is determined based on the contrast value. Since the display indicating the tendency is performed, it is not necessary to perform the contrast increase / decrease display in the case of an unreliable inappropriate luminance value, thereby preventing an erroneous display and obtaining a suitable luminance value. In this case, since the number of displayed contrasts is reduced in the contrast increase / decrease display, it is possible to perform good focusing regardless of the level of the contrast.

Further, the contrast value of the subject is detected for each frame, the contrast value is stored, and the contrast increasing / decreasing tendency is determined based on the stored contrast value. Is displayed so that the display can be retained by storing the data, and the number of displayed contrasts is reduced, thereby achieving good focusing regardless of the contrast level. It is possible to do.

The contrast value of the subject is detected for each frame, and the contrast value is stored. When the contrast can be increased or decreased based on the contrast value, the contrast is increased or decreased based on the stored contrast value. Is determined, and a display indicating the determined contrast increase / decrease tendency is performed. When the contrast increase / decrease display is not possible, the previous display state is maintained.
It is possible to avoid an erroneous display due to an increase or decrease in the contrast value caused by noise or camera shake due to the tendency of the contrast to increase or decrease, and to reduce the number of displayed contrasts in a normal contrast increase / decrease display. Irrespective of this, good focusing can be achieved.

Further, the contrast value and the brightness value of the object are detected for each frame, and the contrast value and the brightness value are stored. When the contrast can be increased or decreased according to the change between the brightness values, the storage is performed. The contrast increasing / decreasing tendency is determined based on the determined contrast value, and a display indicating the determined contrast increasing / decreasing tendency is performed. Therefore, it is possible to avoid an erroneous display of the contrast increasing / decreasing tendency resulting from the luminance change. While it is possible, the number of displayed contrasts is reduced in the normal contrast increase / decrease display, whereby good focusing can be performed regardless of the contrast level.

Further, since the contrast value after filtering by the plurality of band-pass filters in the BPF 7 is detected, it is possible to improve the judgment accuracy of the increase or decrease of the contrast.

In the above-described embodiment, when the luminance change is equal to or larger than the allowable value, the RAMs 16A, 16B, 16C
Although the contrast a data, the contrast b data, and the luminance data stored in the respective sections are once cleared, the contrast increase / decrease display processing may be performed by correcting the luminance data.

With reference to FIGS. 9 and 10, only processing different from the above-described contrast increase / decrease display processing (see FIG. 2) will be described. FIG. 9 is a flowchart illustrating a contrast increase / decrease display process according to a modification.
FIG. 14 is a diagram showing processing data during contrast increase / decrease display according to a modification. Note that each of steps S21 to S21 shown in FIG.
The processing up to step S26 is performed at each step S shown in FIG.
The description is omitted because it is the same as the processing from 1 to step S6.

In the flow shown in FIG. 2, step S27
In step S, if the luminance change is equal to or greater than the allowable value,
Returning to 1, the data for three frames is cleared, but in this modified example, in step S27, a change in luminance is determined in the same manner as in step S7, and as a result, the change in luminance is equal to or greater than the allowable value. If it is determined that is, the process does not return to step S21 but shifts to step S28.

In this step S28, as shown in FIG. 10, the contrast a data and the contrast b data are each multiplied by the difference of the luminance data between the frames (multiplication), and the multiplication result is added to the new contrast a data and contrast data. An operation for b data is performed.

Thereafter, step S8 in FIG.
As in Step S10, the contrast increase / decrease determination and the result display are performed in the state where the contrast a data and the contrast b data of the third frame are corrected in the RAMs 16A and 16B, respectively.

As described above, according to the modification, the contrast value and the luminance value of the subject are detected for each frame, and the contrast value and the luminance value are stored, and the contrast value and the luminance value are stored in accordance with the amount of change between the luminance values. When the contrast increase / decrease display is not possible, the contrast value is corrected based on the luminance value, and then the contrast increase / decrease tendency is determined, and the display indicating the determined contrast increase / decrease tendency is performed.
It is possible to avoid erroneous display of the contrast increasing / decreasing tendency resulting from the change in luminance, and the number of displayed contrasts is reduced in normal contrast increasing / decreasing display. Thereby, it is possible to perform good focusing regardless of the level of contrast.

[0073]

As described above, according to the first aspect of the present invention, the contrast value of the subject is detected, and the contrast increasing / decreasing tendency is determined based on the contrast value. Is displayed, the number of displayed contrasts is reduced, thereby providing a digital camera capable of performing good focusing regardless of the level of contrast.

According to the second aspect of the present invention, only when the focus is a variable focus, the contrast increase / decrease tendency is determined based on the contrast value, and a display indicating the determined contrast increase / decrease tendency is displayed. As a result, the contrast increase / decrease display does not need to be performed at the time of the fixed focus, which prevents erroneous display.Also, the number of contrast displays in the contrast increase / decrease display at the time of the variable focus decreases, regardless of the contrast level. There is an effect that a digital camera capable of performing good focusing can be obtained.

Further, according to the third aspect of the present invention, it is determined whether or not the contrast can be increased or decreased according to the brightness of the subject.
Only when the increase / decrease display is permitted, the contrast increase / decrease tendency is determined based on the contrast value, and a display indicating the determined contrast increase / decrease tendency is performed. In this case, the contrast increase / decrease display does not need to be performed, which prevents erroneous display,
Also, when a suitable luminance value is obtained, the number of displayed contrasts in the contrast increase / decrease display is reduced, so that a digital camera capable of performing good focusing regardless of the contrast level can be obtained. To play.

According to the present invention, the contrast value of the subject is detected for each frame, the contrast value is stored, and the increase / decrease tendency of the contrast is determined based on the stored contrast value. Therefore, since the display indicating the determined contrast increasing / decreasing tendency is performed, the display can be held by storing the data, and the number of displayed contrasts can be reduced. There is an effect that a digital camera that can perform good focusing regardless of the height is obtained.

According to the fifth aspect of the present invention, the contrast value of the object is detected for each frame, and the contrast value is stored. When the contrast can be increased or decreased based on the contrast value, the stored contrast value is stored. The contrast increase / decrease tendency is determined based on the contrast value, and a display indicating that the determined contrast increase / decrease tendency is performed,
When the contrast increase / decrease display is not possible, the previous display state is retained, so it is possible to avoid erroneous display due to the increase / decrease of the contrast value caused by noise or camera shake due to the contrast increase / decrease trend and normal In such a contrast increasing / decreasing display, the number of displayed contrasts is reduced, thereby providing an effect of obtaining a digital camera capable of performing good focusing regardless of the level of contrast.

According to the present invention, the contrast value and the brightness value of the object are detected for each frame, and the contrast value and the brightness value are stored, and the contrast value and the brightness value are stored in accordance with the amount of change between the brightness values. When increase / decrease display is possible, a contrast increase / decrease tendency is determined based on the stored contrast value, and a display indicating the determined contrast increase / decrease trend is performed. A digital camera capable of avoiding erroneous display of the increase / decrease tendency and reducing the number of displayed contrasts in a normal contrast increase / decrease display, thereby enabling good focusing regardless of the contrast level. Is obtained.

According to the seventh aspect of the present invention, the contrast value and the brightness value of the object are detected for each frame, and the contrast value and the brightness value are stored, and the contrast value and the brightness value are stored in accordance with the amount of change between the brightness values. When the increase / decrease display is not possible, the contrast value is corrected based on the luminance value, and then the contrast increase / decrease tendency is determined, and the display indicating the determined contrast increase / decrease tendency is performed. It is possible to avoid the erroneous display of the contrast increasing / decreasing tendency that occurs, and reduce the number of displayed contrasts in the normal contrast increasing / decreasing display, thereby enabling good focusing regardless of the contrast level. This has the effect of obtaining a digital camera.

According to the invention of claim 8, according to claim 1,
In the invention described in any one of the above-described embodiments, since a contrast value after filtering by a plurality of band-pass filters is detected, a digital camera capable of improving the accuracy of determining a change in contrast can be obtained. It works.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an internal configuration of a digital camera according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart illustrating contrast increase / decrease display processing.

FIG. 3 is a diagram illustrating an integration operation during contrast increase / decrease display processing.

FIG. 4 is a diagram showing a guidance display example at the time of contrast increase / decrease processing.

FIG. 5 is a diagram showing processing data during contrast increase / decrease display.

FIG. 6 is a diagram showing processing data during contrast increase / decrease display.

FIG. 7 is a diagram showing processing data during contrast increase / decrease display.

FIG. 8 is a diagram showing processing data during contrast increase / decrease display.

FIG. 9 is a flowchart illustrating a contrast increase / decrease display process according to a modified example.

FIG. 10 is a diagram illustrating processing data during contrast increase / decrease display according to a modification.

[Explanation of symbols]

 Reference Signs List 1 lens system 2 manual autofocus mechanism 3 CCD 4 operational amplifier 5 A / D converter 6 image signal processing circuit 7 BPF 8A integrator 8B integrator 9 CPU 10 operation switch 11 image memory 12 storage device 13 D / A converter 14 encoder 15 finder 16 RAM 17 Potentiometer

Claims (8)

[Claims] 1. A digital camera which adjusts a focus at the time of imaging according to a manual operation, wherein: an imaging means for imaging a subject to obtain digitized image data; and Contrast detecting means for detecting a contrast value of the object; increasing / decreasing tendency determining means for determining a contrast increasing / decreasing tendency based on the contrast value detected by the contrast detecting means; contrast increasing / decreasing determined by the increasing / decreasing tendency determining means A digital camera, comprising: display means for displaying a display indicating a tendency. 2. A digital camera that has a fixed focus and a variable focus and adjusts a focus at the time of imaging in accordance with a manual operation, wherein: an imaging unit that captures an image of a subject to obtain digitized image data; Contrast detecting means for detecting the contrast value of the subject based on the image data obtained by the means, focus determining means for determining whether the focus at the time of imaging is a fixed focus or variable focus, and variable by the focus determining means An increase / decrease tendency judging means for judging an increase / decrease tendency of contrast based on a contrast value detected by the contrast detection means only when a judgment result of focus is obtained, and a contrast increase / decrease tendency judged by the increase / decrease tendency judgment means. A digital camera, comprising: display means for displaying an indication to indicate. 3. A digital camera for adjusting a focus at the time of image capturing according to a manual operation, wherein: an image capturing means for capturing an image of a subject to obtain digitized image data; A contrast detection unit that detects a contrast value of the subject, a brightness detection unit that detects a brightness value of the subject based on image data obtained by the imaging unit, and a brightness detection unit that detects a brightness value of the subject based on the brightness value detected by the brightness detection unit. Determining means for determining whether or not contrast increase / decrease display can be performed, and a contrast increase / decrease tendency based on a contrast value detected by the contrast detector only when a result of determination that contrast increase / decrease display is possible is obtained by the determination means. An increase / decrease trend determining means for determining A digital camera, comprising: display means for displaying a display indicating the last increase / decrease tendency. 4. A digital camera for adjusting a focus at the time of image capturing according to a manual operation, wherein: an image capturing means for capturing an image of a subject to obtain digitized image data; Contrast detecting means for detecting a contrast value of the subject; contrast storing means for storing a plurality of frames of contrast values for each frame detected by the contrast detecting means; and contrast for a plurality of frames stored in the storing means. A digital camera, comprising: an increase / decrease tendency determining means for determining a contrast increase / decrease tendency based on a value; and a display means for displaying a display indicating the contrast increase / decrease tendency determined by the increase / decrease tendency determination means. . 5. A digital camera for adjusting a focus at the time of image capturing according to a manual operation, wherein: an image capturing means for capturing an image of a subject to obtain digitized image data; and a digital camera based on the image data obtained by the image capturing means. Contrast detecting means for detecting a contrast value of the subject for each frame, contrast storing means for storing a plurality of frames of contrast values detected for each frame detected by the contrast detecting means, and a plurality of contrast values stored in the contrast storing means Determining means for determining whether or not to display an increase or decrease in contrast based on a contrast value for a frame; and determining the contrast value stored in the storage means only when a result of determining whether or not to display an increase or decrease in contrast is obtained by the determining means. An increase / decrease tendency judgment that determines the increase / decrease tendency of contrast based on Means, display means for displaying a display indicating the contrast increase / decrease tendency determined by the increase / decrease tendency determination means, and when the determination result that the contrast increase / decrease display is impossible is obtained by the determination means, A digital camera, comprising: a display holding unit that holds the display state of (1). 6. A digital camera for adjusting a focus at the time of image capturing according to a manual operation, wherein: an image capturing means for capturing an image of a subject to obtain digitized image data; and a digital camera based on the image data obtained by the image capturing means. A contrast detection unit that detects a contrast value of the subject for each frame; a brightness detection unit that detects a brightness value of the subject for each frame based on image data obtained by the imaging unit; Storage means for storing the detected contrast values for a plurality of frames and the brightness values for the plurality of frames detected by the brightness detection means, and according to a change amount between the brightness values for the plurality of frames stored in the storage means. Determining means for determining whether the contrast can be increased or decreased, and whether the contrast can be increased or decreased by the determining means. An increasing / decreasing tendency judging means for judging an increasing / decreasing tendency of the contrast based on the contrast value stored in the storage means only when the judgment result is obtained; and a statement indicating the contrast increasing / decreasing tendency judged by the increasing / decreasing tendency judging means. A digital camera, comprising: display means for displaying the image. 7. A digital camera for adjusting a focus at the time of image capturing according to a manual operation, wherein: an image capturing means for capturing an image of a subject to obtain digitized image data; and a digital camera based on the image data obtained by the image capturing means. A contrast detection unit that detects a contrast value of the subject for each frame; a brightness detection unit that detects a brightness value of the subject for each frame based on image data obtained by the imaging unit; Storage means for storing the detected contrast values for a plurality of frames and the brightness values for the plurality of frames detected by the brightness detection means, and according to a change amount between the brightness values for the plurality of frames stored in the storage means. Means for judging whether or not to increase or decrease the display of the contrast by the judgment means; Correction means for correcting the contrast value stored in the storage means using the luminance value stored in the storage means when the determination result is obtained, After being obtained or after correction by the correction means, an increase / decrease tendency determining means for determining an increase / decrease tendency of the contrast based on the contrast value stored in the storage means; and a contrast increase / decrease tendency determined by the increase / decrease tendency determination means. And a display means for displaying a display indicating the following. 8. The apparatus according to claim 1, wherein said contrast detection means has a plurality of bandpass filter means, and detects a contrast value after filtering by each of said bandpass filter means. Digital camera according to one of the above.