JPH071886Y2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a camera such as a video camera or an electronic still camera.

(B) Conventional technology For example, in Japanese Unexamined Patent Publication No. 62-84660 (H04N5 / 232), during autofocus control, it is determined whether or not the focus state is achieved based on necessary AF information, and the focus state is determined. There is proposed a method of turning on the light emitting element when it is determined that the user is informed that the in-focus point is reached even during the manual focus control.

(C) Problems to be solved by the invention By the way, generally, in a camera, in order to know the depth of field, the subject is first focused, and then the eye is once removed from the viewfinder and calibrated on the lens barrel. It was necessary to check the depth of field range.

When focusing on a subject in this way, the depth of field changes greatly depending on the aperture, subject distance, focal length of the lens, etc., but it may be necessary to look away from the viewfinder to find out the depth of field. It is very inconvenient.

Therefore, the present invention seeks to overcome such drawbacks.

(D) Means for Solving the Problems In order to solve the above problems, the camera of the present invention includes an image sensor,
It is obtained from a first sampling area provided at the center of the image pickup surface of the image pickup device, a second sampling area provided around the first sampling area, and the first and second sampling areas. Of the signal components,
A first bandpass filter that permits passage of a signal component in a first frequency band, and a second frequency wider than the first frequency band among signal components obtained from the first and second sampling areas. A second bandpass filter that permits passage of a band signal component, a selection unit that selects outputs of the first and second bandpass filters, and the first of the signals obtained from the first sampling area. A first value, which is the ratio of the signal that has passed through the bandpass filter and the signal that has passed through the second bandpass filter, and the signal obtained from the second sampling area that has passed through the first bandpass filter. Calculated by the depth-of-field calculation means for calculating the ratio of the second value, which is the ratio of the signal that has passed through the second band-pass filter, and the depth-of-field calculation means. A configuration in which a means for displaying the depth of field in the viewfinder.

(E) Operation According to the above configuration, the depth of field can be displayed on the viewfinder.

(F) Embodiment An embodiment of the camera of the present invention will be described below with reference to FIGS.

FIG. 1 shows a block diagram of a main part of a camera of the present invention. (1) is an image pickup optical system such as a lens, (2) is an image pickup device such as CCD, and (3) is FIG. 2 (a). A first BPF (bandpass filter) having a pass band as shown in FIG. 3, (3 ′) is a second BPF having a pass band as shown in FIG. 2 (b), (4)
Is a sync separation circuit for extracting a sync signal from an image signal obtained from the image pickup device (2), (5) is a timing pulse generator for receiving various sync signals from the sync separation circuit (4), and generating various timing pulses. (6) receives the timing pulse from the timing pulse generator (5) and receives the first and second bandpass filters (3) and (3 ').
Selection switch that selects the output of each 1V (vertical period),
(7) is an amplifier, (8) is a detection circuit, (9) is an A / D converter, (10) receives a timing pulse from the timing pulse generator (5), and a first sampling area described later or A gate switch for passing a signal corresponding to the second sampling area, (11) a digital integrator for obtaining integrated data for each field, (12) a microcomputer, (13) a viewfinder, etc. It is an indicator.

The video signal output from the image sensor (2) is selected by the first and second band pass filters (3) and (3 ') for each 1V, and the amplifier (7), the detection circuit (8), and the A / D are selected. Converter (9)
After that, it is supplied to the gate switch (10). In this gate switch (10), the screen (1
5) The digital video signal corresponding to the inside of the first sampling area (A) provided in the central part of 5) is added to the digital integrator (11), and the microcomputer (12) obtains the first bandpass filter ( The ratio between the output data of 3) and the output data of the second bandpass filter (3 '), that is, the relative ratio data (a) of the first sampling area (A) is calculated.

Next, the gate switch (10) digitally integrates the digital video signal obtained from the second sampling area (B) provided around the first sampling area (A) of the screen (15) shown in FIG. In addition to the device (11), the microcomputer (12) has a ratio of the output data of the first band pass filter (3) and the output data of the second band pass filter (3 ') obtained at this time, that is, the second Relative ratio data (b) of the sampling area (B) is calculated.

In this way, the relative ratio in each sampling area (A) and (B) is calculated every 2V period. Since each of the relative ratios (a) and (b) is affected by only the focused state of the focus, regardless of the subject, when b / a is calculated, the blurring degree of the background around the screen with respect to the subject at the center of the screen is a numerical value. Can be recognized by. That is, the closer the ratio value b / a is to 1,
The depth of field is deep, and the closer it is to 0, the shallower the depth of field.

Therefore, the microcomputer (12) calculates b / a and displays it on the display (13) provided in the finder. If the viewfinder is of electronic type, b / a
The value of may be superimposed.

(G) Effect of the Invention According to the present invention as described above, it is very convenient to know the depth of field without having to look away from the viewfinder, and the usability of the camera is improved.

[Brief description of drawings]

FIG. 1 is a block diagram of essential parts showing an embodiment of a camera of the present invention, FIG. 2 is a characteristic diagram of a bandpass filter used therein, and FIG. 3 is a diagram showing a sampling area. (1) ... Solid-state image sensor, (A) ... First sampling area, (B) ... Second sampling area,
(3) …… First bandpass filter, (3 ′) …… Second
Band pass filter of (6) …… Selection switch, (1
2) …… Microcomputer, (13) …… Display (viewfinder).

Claims (1)

[Scope of utility model registration request] 1. An image sensor, a first sampling area provided in a central portion of an image pickup surface of the image sensor, a second sampling area provided around the first sampling area, and the first sampling area. Of the signal components obtained from the second sampling area, a first bandpass filter that allows passage of signal components in the first frequency band, and among the signal components obtained from the first and second sampling areas A second bandpass filter that allows passage of a signal component in a second frequency band wider than the first frequency band; a selection unit that selects outputs of the first and second bandpass filters; A first value that is a ratio of a signal that has passed through the first bandpass filter and a signal that has passed through the second bandpass filter among signals obtained from one sampling area; Field that calculates a ratio of a second value, which is a ratio of the signal that has passed the first bandpass filter and the signal that has passed the second bandpass filter, of the signals obtained from the sampling area A camera comprising: depth calculation means; and means for displaying the depth of field calculated by the depth of field calculation means on a viewfinder.