JPH02181578A - Video camera automatic aperture device - Google Patents

Abstract

PURPOSE:To attain appropriate automatic stop down adjustment under a counter light state by detecting the first and second areas in the video period of an image pickup element and controlling incident light quantity to the image pickup element in a diaphragm control part. CONSTITUTION:It is decided whether a beam state is a normal light state or the counter light state by comparing signal based on the first and second areas in the video period of the image pickup element with each other, and respective control parts 24-26 determine the gains of respective gain control parts 20-22 according to the decided beam state. The signals of the respective areas extracted from the output signals of the image pickup element through respective gate parts 10-12 are amplified in the respective gain control parts 20-22 according to the beam state at that time and after that synthesize in an adding part 23, and a signal corrected according to the beam state is obtained for the output of the adding part 23. A stop down control part 4 determines a proper stop down value based on a signal obtained by controlling the signal of the adding part 23 based on a signal detected in a detection part 3 and correcting the controlled signal based on the beam state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic aperture device in a video camera device.

2. Description of the Related Art A conventional automatic diaphragm device is constructed as shown in FIG. The imaging device 1 includes an optical lens system, an aperture mechanism, and
It is composed of these optical lens systems and an image sensor disposed at a position where the light passing through the aperture mechanism forms an image, and the image signal is photoelectrically converted and read out by the image sensor. The signal photoelectrically converted and read out by the image sensor is also input to the detection unit 3 via the amplification unit 2, and the aperture control unit operates based on the output signal obtained by detecting the signal in the detection unit 3. 4 determines an appropriate aperture value, and an aperture control section 4 adjusts the aperture mechanism of the imaging device to the appropriate aperture value. The above control loop consisting of the imaging device 1, the detection section 3, and the aperture control section 4 alone cannot perform appropriate automatic aperture adjustment when shooting in backlit conditions. When photographing in a backlit situation, the user manually applies a switching signal 6 to the switching device 5, and changes the quantitative value preset in the setting device 7 to the aperture control section 4 instead of the output signal of the detection section 3.
input to adjust the aperture mechanism of the imaging device.

Problems to be Solved by the Invention In such a conventional configuration, when photographing in a backlit situation, the user manually applies a switching signal 6 to the switching device 5 to adjust the aperture mechanism. If you switch to the setting device 7 side, you may not be able to perform backlight compensation and adjust the aperture appropriately when shooting in front light conditions, or forget to manually operate backlight compensation when shooting in backlight conditions and adjust the aperture appropriately. There is a problem that it cannot be done.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic aperture device that can automatically correct backlight and adjust the aperture without manually instructing backlight correction.

Means for Solving the Problems The automatic aperture device of the present invention includes a first detection means for detecting a first region of a video period of an output signal of an image sensor, and a second detection means for detecting a first region of a video period of an output signal of an image sensor. a second detection means for detecting the area; The first detection means amplifies the output signal of the second detection means at respective amplification degrees. a second amplification section; a comparator that compares the levels of the output signal of the first amplification section and the output signal of the second amplification section; and a video period of the output signal of the image sensor that is divided into a plurality of regions; a plurality of gate sections that extract signals from each of the divided regions, a plurality of gain control sections that vary the gain of the output signal of each of the gate sections, and each of the gain control sections according to the level judgment output of the comparator. a plurality of control units for instructing the gains of the gain control units; an addition unit for adding the output signals of the gain control units; and a detection unit for detecting the output signals of the addition units;
An aperture control section that determines an aperture value according to an output signal of the detection section is provided, and an aperture mechanism that adjusts the amount of light incident on the image sensor is controlled by a signal from the aperture control section.

According to this configuration, the comparator compares the signals based on the first region and the second region of the video period of the output signal of the image sensor to determine whether the light beam condition is front lighting or back lighting. . Each control section determines the gain of each gain control section according to the determined light beam state. The signals of each region extracted from the output signal of the image sensor through each gate section are amplified in each gain control section at an amplification degree corresponding to the light beam state at that time, and then combined in an addition section. A signal corrected according to the state of the light beam is obtained from the output of the adder. The diaphragm control section that controls the diaphragm mechanism is controlled based on a signal obtained by detecting the signal from the addition section via the detection section, and the diaphragm control section adjusts the appropriate aperture value based on the signal corrected according to the light beam condition. decide.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4. Components having the same functions as those in FIG. 5 showing the conventional example will be described with the same reference numerals.

FIG. 1 shows an automatic diaphragm according to the invention. The output signal of the imaging device 1 is the first one. The second detection means 8, 9 and the first detection means 8,9. Second.
It is applied to the input of the third gate section 10.11.12. FIG. 2 shows the imaging screen of the imaging device 1, and the first detection means 8 includes a gate 13 for extracting the signal in the central first region T1 from the output signal of the imaging device 1,
and a first detection section 14 that detects the output signal of No. 13. The second detection means 9 includes a gate [5] that extracts a signal in a second area T2 around the first area T1 from the output signal of the imaging device 1, and a second detection unit that detects the output signal of the gate 15. It consists of a section 16. First detection section 1
The output signal of No. 4 is the first amplification section 17, and the set amplification degree m
The output signal {circle around (2)} of the second detection section 16 is amplified by n times the set amplification degree in the second amplification section 18 . The output signal (I・m) of the first amplification section 17 and the output signal (■・n) of the second amplification section 18 are compared by the comparator 1B, and when (I'm)≧(■・n), is in front light condition (■・m)<
When (II·n), it is determined that the situation is backlit.

The first gate section IO extracts the signal of the region t1 shown in FIG. The third gate unit 13 extracts a signal in a region t3 outside the region t2 from the output signal of the imaging device 1.

Each output signal of the first to third gate sections 10, 11.12 is outputted from the first to third gate sections 10, 11.12. Second. The signals are input to the adder 23 via the third gain controllers 20, 21, and 22, and are added to combine the three signals into one. 1st゜2nd. Third gain control section 20.2
Each amplification degree of 1.22 is 1.22. Second. Third control unit 24
, 25, 26 as follows.

In the state that the comparator 13 determines as the front light state, the first.
Second. As shown in FIG. 4(a), the third control section 24, 25, 26 controls the first gain control section 20 at a gain of G10°, the second gain control section 21 at a gain of Gll, and the third gain control section 22 at a gain of G10. is set to gain G12. Here, GIO>Gll>G12, and the gain GIO is slightly larger than Gll and G12.

In a state where the comparator 19 determines that it is a backlit state, the first.
Second. The third control section 24, 25, 26 controls the first gain control section 20 to a gain of G20.2 as shown in FIG. 4(b). The second gain control unit 21 has a gain G21. The third gain control section 22 is set to gain G22. Here, the gain G20 is G20 > G21 > G22
is G21. It is much larger than G22.

Therefore, in a state where the comparator 1B determines the forward light state, the regions tl, t2 . The aperture mechanism of the imaging device is adjusted to an appropriate aperture value via the detection section 3 and the aperture control section 4 using a signal obtained by combining the signals at t3 by the addition section 23.

In a state where the comparator 19 determines that it is a backlit state, the gain G
20. G21. Region t amplified by G22
l, t2. A signal obtained by combining the signals at t3 in the adder 23,
The aperture mechanism of the imaging device 1 is adjusted to an appropriate aperture value via the detection section 3 and the aperture control section 4.

In this manner, the gain of the first gain control unit 20 for the region t1 is G20 in the backlit state,
Area t2. 2nd for t3. Third gain control section 21.
22 gain G21. The aperture mechanism of the imaging device 1 is automatically adjusted to an appropriate aperture value using a signal that is much larger than G22 and focuses on the central region t1.

In the above embodiment, the second region T2 does not include the first region T1 as shown in FIG. 2, but the second region T2 may include at least a part of the first region T1. The same is true.

In the above embodiment, the case where signals are extracted by dividing the first to third gate sections 10 to 12 into three regions t1 to t3 was explained as an example. The same applies when the area is divided into two or more areas and extracted.

Effects of the Invention As described above, according to the present invention, the first detection means detects the first region of the video period of the output signal of the image sensor, and the second region of the video period of the output signal of the image sensor detects the first region of the video period of the output signal of the image sensor. 2nd to detect
a detection means; a first detection means; The first detection means amplifies the output signal of the second detection means at respective amplification degrees. a second amplification section; a comparator that compares the levels of the output signal of the first amplification section and the output signal of the second amplification section; and a video period of the output signal of the image sensor that is divided into a plurality of regions; a plurality of gate sections that extract signals from each of the divided regions, a plurality of gain control sections that vary the gain of the output signal of each of the gate sections, and each of the gain control sections according to the level judgment output of the comparator. a plurality of control sections for instructing the gains of the respective gain control sections; an addition section for adding the output signals of the respective gain control sections; a detection section for detecting the output signals of the addition sections; an aperture control unit that determines an aperture value, and an aperture mechanism that adjusts the amount of light incident on the image sensor is controlled by a signal from the aperture control unit;
The comparator detects the backlight condition and automatically switches the gain of each gain control section to a value different from that in the frontlight condition, so even in the backlight condition, it is not necessary to perform quantitative correction manually as in the past. The aperture value can be adjusted automatically.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the automatic diaphragm device of the present invention, and FIG. The first wave extracted by the second detection means
．． An explanatory diagram of the second region, FIG. 3 is an explanatory diagram of each region extracted by the gate section of the same device, and FIG. 4 is an explanatory diagram of the gain change of the gain control section in the forward light state and backlight state of the same device. , 5th
The figure is a configuration diagram of a conventional automatic diaphragm device. DESCRIPTION OF SYMBOLS 1... Imaging device, 3... Detection part, 4... Aperture control part, 8.9... 1st. second detection means, 10, 11.
12... 1st ° 2nd. Third gate section, 17.18・
...First. Second amplification section, 19... comparator, 20.2
1.22... 1st. Second. third gain control section, 23.
...Addition section, 24, 25.28...1st. 2nd, 3rd
control unit, TI, T2--first. second region, tl,
t2. t3... area.

Claims (1)

[Claims] 1. Control the aperture mechanism according to the output signal of the image sensor,
An automatic aperture device that automatically adjusts the amount of light incident on an image sensor, the device comprising: a first detection means for detecting a first region of a video period of an output signal of the image sensor; a second detection means that detects the second region, first and second amplification sections that amplify the output signals of the first and second detection means at respective amplification degrees, and an output signal of the first amplification section. and second
a comparator that compares the level of the output signal of the amplification section; a plurality of gate sections that divide the video period of the output signal of the image sensor into a plurality of regions and extract signals from each of the divided regions; a plurality of gain control sections that vary the gain of the output signal of each gate section; a plurality of control sections that instruct the gain of each of the gain control sections according to the level judgment output of the comparator; and each of the gain control sections. an adding section for adding the output signals of the adding section, a detecting section for detecting the output signal of the adding section, and an aperture control section for determining the aperture value according to the output signal of the detecting section. An automatic aperture device that controls an aperture mechanism that adjusts the amount of incident light using a signal from the aperture control section.