JPH06113193A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain an image pickup device capable of executing always the appropriate adjustment of exposure for various kinds of subjects. CONSTITUTION:This image pickup device is constituted of a lens optical system 1, a light quantity control device 31 to transmit light emitted from the lens optical system every area divided into N rows in a horizontal direction and M lines in a vertical direction, an image pickup element 32 to convert an optical image transmitted through the light quantity control device 31 into an electric signal, an average value per area detection circuit 200 to detect the average value of the signal obtained from the image pickup element 32 at every area divided in the light quantity control device 31, and a transmittivity control circuit 40 to control the transmittivity of the light quantity control device 31 in accordance with output from the average value per area detection circuit 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to improvement of the dynamic range of the image pickup apparatus.

[0002]

2. Description of the Related Art FIG. 19 shows, for example, Japanese Patent Application No. 03-17566.
It is a block diagram which shows the structure of the conventional imaging device shown by the 0 publication, 1 is a lens, 2 is the diaphragm mechanism which controls the light quantity, 23 is a half mirror which divides incident light into two systems, 3a Is an image pickup device for picking up the light of the first system among the lights split by the half mirror 23, 4a is a preamplifier, 6a is a detection circuit for detecting the average luminance level of the output of the preamplifier 4a, and 7 is a detection circuit 6a. A diaphragm drive circuit for driving the diaphragm mechanism 2 according to the output level, 24a
Is a first Y / C separation circuit for separating the output signal of the preamplifier 4a into a luminance signal and a chrominance signal. Reference numeral 25 denotes the image sensor 3 among the luminance signals output from the Y / C separation circuit 24a.
A high-brightness detection circuit that detects a signal having a voltage equal to or higher than the brightness level at which a begins to be saturated, and 26 is a transmittance variable filter that controls the amount of light of the second system of the light split by the half mirror 23. Reference numeral 3b is an image pickup element for picking up the light transmitted through the variable transmittance filter 26, 4b is a preamplifier, 6b is a detection circuit for detecting the peak level of the output of the preamplifier 4b, and 27 is a variable transmission filter according to the output of the detection circuit 6b. A transmittance control circuit for controlling the transmittance of 26,
24b is a Y / C separation circuit that separates the signal output from the preamplifier 4b into a luminance signal and a chrominance signal, 28 is a gain control circuit, and 29 is the transmittance of the variable transmittance filter 26 based on the output of the detection circuit 6b. A control circuit for controlling the gain of the gain control circuit 28 so as to obtain a corresponding gain, 30 is a Y / C separation circuit 24 based on the detection result of the high brightness detection circuit 25.
a switch for selecting one of the first luminance signal and color signal output from a and the second luminance signal and color signal output from the gain control circuit 28, and 16 is a process such as gamma correction and white balance A camera signal processing circuit for
Reference numeral 17 denotes a video signal output terminal for outputting a video signal obtained by the camera signal processing circuit.

Next, the operation will be described. The light from the subject is condensed by the lens 1, and the amount of light is limited by the diaphragm mechanism 2. This light passes through the half mirror 23, forms an image on the image pickup device 3a, is converted into an electric signal, and is amplified to an appropriate size by the preamplifier 4a. The output of the preamplifier 4a is detected by the detection circuit 6a, and its output is input to the diaphragm drive circuit 7 to drive the diaphragm mechanism 2 so that the output of the preamplifier 4a becomes constant.

At this time, if the detection characteristic of the detection circuit 6a is set to the average value detection characteristic such that the average brightness is constant in the central area of the screen as shown in FIG. The main subject that seems to be present has an appropriate exposure.
However, the light or bright sky around the main subject is saturated beyond the dynamic range of the image sensor 3a, and so-called whiteout occurs.

For example, when a light amount of 400% of the reference input is incident on the image pickup device 3a as shown in FIG. 21A, the output of the image pickup device 3a is as shown in FIG. 21B. If saturation starts from 250%, it will be completely saturated at 300%. That is, the input signal is 250%
Between ~ 400%, it becomes overexposed.

The output of the preamplifier 4a is also input to the Y / C separation circuit 24a, separated into the luminance signal Y1 and the color signal C1 and input to the switch 30. And the luminance signal Y
1 is also input to the high brightness detection circuit 25, and this brightness signal Y1
However, the signal of a positive logic value (H) is high when the preset specific voltage corresponding to the brightness level at which the image pickup device 3a starts to be saturated is exceeded, and the signal of a negative logic value (L) is high when it is equal to or lower than the specific voltage. It is output from the brightness detection circuit 25. In the example shown above, the luminance signal output Y1 of the Y / C separation circuit 24a is as shown in FIG. 21C, and if the specific voltage is set to a voltage corresponding to 250% of the reference signal level, high luminance is obtained. The output of the detection circuit 25 is as shown in FIG.

On the other hand, the second separated by the half mirror 23
The light amount of the system is again limited by the variable transmittance filter 26, is imaged on the image sensor 3b, is converted into an electric signal, and is amplified to an appropriate size by the preamplifier 4b.
The output of the preamplifier 4b is detected by the detection circuit 6b, and its output is input to the transmittance control circuit 27 so that the output of the preamplifier 4b becomes constant.
To drive.

At this time, if the detection characteristic of the detection circuit 6b is set to a so-called peak detection so that the brightest part of the entire screen, that is, the high-brightness part is properly exposed, the light around the main subject and Proper exposure will be obtained in a bright sky, etc., but the main subject will be underexposed.

The output of the detection circuit 6b is the control circuit 2
9 is also input to control the gain of the gain control circuit 28 according to the transmittance of the variable transmittance filter 26. For example, when the transmittance of the variable transmittance filter 26 is 50%, the gain of the gain control circuit 28 is doubled. Considering the above example, the amount of light incident on the image sensor 3b is as shown in FIG.
The output of the image sensor 3b is as shown in FIG.
It becomes like (f).

The output of the preamplifier 4b is also input to the Y / C separation circuit 24b and separated into a luminance signal Y2 and a color signal C2. The luminance signal Y2 and the chrominance signal C2 are input to the gain control circuit 28, and the gain control as described above is performed so that the luminance signal Y1 and the chrominance signal C1 become the signals of the levels corresponding to the levels of the switch. It is input to 30. In the above example, the luminance signal Y2 output from the Y / C separation circuit 24b is as shown in FIG.

The switch 30 operates when the output of the high-brightness detection circuit 25 is L, that is, when the light quantity of the object is the image pickup device 3a.
If it is within the dynamic range of, the luminance signal Y1 and the color signal C1 are selected, and if it is H, that is, the light amount of the object exceeds the dynamic range of the image sensor 3a, and the output of the Y / C separation circuit 24a is In the case where overexposure occurs, the luminance signal Y2 and the color signal C2 output from the gain control circuit 28 which is exposed in the high luminance portion are selected. In the case like the previous example, the switch 30
The output of is as shown in FIG.

As described above, the luminance signal and the color signal without overexposure and underexposure selected by the switch 30 are processed by the camera signal processing circuit 16 such as gamma correction and white balance. After that, video signal output terminal 1
It is output from 7.

[0013]

The image pickup apparatus according to the conventional invention is constructed as described above, and it is necessary to switch between two kinds of luminance signal and color signal according to the brightness of the subject. The two-plate type was required to obtain various kinds of signals, and the circuit scale was large. In addition, there is a problem that the diaphragm mechanism of the lens optical system and the variable transmittance filter must be used together in order to control the light amount of the subject.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an image pickup apparatus capable of always properly adjusting exposure for various subjects.

[0015]

According to a first aspect of the present invention, there is provided an image pickup apparatus, wherein a lens optical system and an amount of light incident from the lens optical system are divided into N columns in the horizontal direction and M rows in the vertical direction. Control means, an image sensor for converting an optical image transmitted through the light quantity control means into an electric signal, and an average value detection for each area for detecting an average value of a signal obtained from the image sensor for each area divided by the light quantity control means A circuit and a transmittance control circuit for controlling the transmittance of the light amount control means according to the output from the area-based average value detection circuit are provided.

An image pickup apparatus according to the invention of claim 2 is a lens optical system and R, G, B incident light from the lens optical system.
A color separation optical system for separating into three color lights, three light amount control means for transmitting the R, G, and B color lights separated by the color separation optical system, and an optical image transmitted through each of the light amount control means. Three image pickup elements for converting into electric signals, an average value detection circuit for detecting the average value of the signal obtained from the image pickup element for each screen, a color temperature detection circuit for detecting the color temperature of the subject,
A transmittance control circuit for controlling the transmittance of the three light amount control means according to the outputs of the average value detection circuit and the color temperature detection circuit is provided.

In the image pickup device according to the invention of claim 3, the lens optical system and the incident light from the lens optical system are R, G, B.
And a three-color separation optical system that separates the color lights of R, G, and B separated by the color separation optical system into N columns in the horizontal direction and M rows in the vertical direction. Light amount control means, three image pickup elements for converting the three color lights transmitted through the respective light amount control means into electric signals, and an average value of signals obtained from the three image pickup elements for each region divided by the light amount control means. Area average value detection circuit, a color temperature detection circuit that detects the color temperature of a subject, and three light amount controls according to the output from the area average value detection circuit and the output from the color temperature detection circuit And a transmittance control circuit for controlling the transmittance of the means for each region.

[0018]

In the image pickup device according to the first aspect of the present invention, the transmittance control circuit controls the transmittance of the light amount control means to limit the amount of light emitted from the lens optical system for each region.

In the image pickup device according to the second aspect of the present invention, the transmittance control circuit controls the transmittances of the three light quantity control means,
The amount of R, G, B three-color light emitted from the color separation optical system is limited.

In the image pickup device according to the invention of claim 3, the transmittance control circuit controls the transmittances of the three light quantity control means,
The amount of R, G, B three-color light emitted from the color separation optical system is limited for each region.

[0021]

EXAMPLES Example 1. 1 is a block diagram showing the arrangement of an image pickup apparatus according to an embodiment of the present invention. In the figure, 1 is a lens optical system, 31 is a light amount control device for transmitting light emitted from the lens optical system for each region divided into N columns in the horizontal direction and M rows in the vertical direction, and 32 is the light amount control device 31. An image sensor for converting the optical image into an electric signal, 200 is an average value detection circuit for each area for detecting the average value of the signal from the image sensor 32 for each area divided by the light amount control device 31, and 40 is an average value for each area It is a transmittance control circuit that controls the transmittance of the light amount control device 31 for each region according to the output from the detection circuit 200.

FIG. 2 is a block diagram showing the structure of the area-specific average value detection circuit 200. Reference numeral 33 is an integrating circuit that integrates a signal obtained from the image sensor 32 at intervals divided by the light amount control device 31, 34 is a first comparing circuit that compares the output of the integrating circuit 33 with a first reference level, and 35 is A second comparison circuit that compares the output of the integration circuit 33 with a second reference level, 36 is a third comparison circuit that compares the output of the integration circuit 33 with a third reference level, 37 is a comparison circuit 34,
A data conversion circuit for converting a signal of a positive logical value (hereinafter, referred to as H) or a negative logical value (hereinafter, referred to as L) output from 35 and 36 into data according to a comparison result, 3
Reference numeral 8 is a storage circuit for storing the data from the data conversion circuit 37, and 39 is an addition circuit for adding the next data sent to the same area as the data stored in the storage circuit 38.

Next, the operation will be described. The subject image passes through the lens optical system 1 and the light amount control device 31, and is formed on the image pickup surface of the image pickup device 32. Light control device 3
Reference numeral 1 is, for example, a liquid crystal or the like, and as shown in FIG.
The area is divided into columns and M rows in the vertical direction. Image sensor 3
The signal obtained from 2 is integrated by the integrating circuit 33 at intervals divided into regions in the light quantity control device 31. The integrated output is compared with each reference level by comparison circuits 34, 35 and 36. As the reference level, for example, as shown in FIG. 4, a level in a relatively high luminance range is set as a first reference level (TH1), and a level for determining whether it is higher or lower than the vicinity of the center of the signal is a second reference level. (TH2), and a level in a relatively low luminance range is set as a third reference level (TH3). If the integrated output voltage exceeds each reference level, the comparator circuits 34, 35 and 36 output an "H" signal, and if not, an "L" signal is output. The signals output from the comparison circuits 34, 35 and 36 are input to the data conversion circuit 37.

FIG. 5 is a state diagram showing the input / output states of the data conversion circuit 37. In the figure, symbols A, B and C represent inputs to the data conversion circuit 37, that is, comparison circuits 34, 35 and 3.
6 represents the results compared in 6. The symbols D1 and D2 represent the output of the data conversion circuit 37, and are 2-bit data with D1 as the lower order. 6 is a block diagram showing the configuration of the data conversion circuit 37. Three inverter circuits 100, 101, 102 and three AND circuits 41, 4 are shown.
2, 43 and two OR circuits 44, 45. 5 and 6, for example, if the output (S) of the integrating circuit 33 exceeds the first reference level (TH1), the outputs A, B and C of the comparing circuits 34, 35 and 36 are all "H". Signal is output and input to the data conversion circuit 37. The AND circuit 41 receives the A signal (L after the inversion) and the B and C signals (both H) inverted by the inverter circuit 100, and outputs the “L” signal. A
The ND circuit 42 has the same signal for all A, B, and C (all H).
Is input and a “H” signal is output. AND circuit 4
The signals A and B (L after inversion) and the signal C (H) that are inverted by the inverter circuits 101 and 102 are input to the inverter 3, and the signal “L” is output. Then, the outputs of the AND circuits 41, 42 and 43 are connected to OR circuits 44 and 45, respectively.
When input to, the OR circuit 44 obtains a signal of "H", that is, the output D2, and the OR circuit 45 obtains a signal of "H", that is, the output D1 (3 in decimal).
become). In addition, for example, when the output (S) of the integration circuit 33 is lower than the first reference level (TH1) but exceeds the second reference level (TH2), the output A of the comparison circuit 34 is " The L "signal is output, and the comparison circuits 35 and 36
Outputs B and C of "H" are output. When this signal is input to the data conversion circuit 37, a signal "H" is output from the output D2 and a signal "L" is output from the output D1 (1
It becomes 2 when expressed in a decimal number). As shown in FIG. 5, the comparison circuits 34, 35, 3 according to the voltage value of the output of the integration circuit 33.
6 outputs the comparison result of H or L, and is converted into 2-bit data by the data conversion circuit 37.

The data output from the data conversion circuit 37 is stored in the storage circuit 38. The storage area of the storage circuit 38 is equal to the area divided by the light amount control device 31. FIG. 7 is a diagram illustrating an example of a method of storing data in the storage circuit 38. In the figure, (a) shows a case where data corresponding to the first scanning line is stored.
In the region (N1, M1), the integrated output of the integrating circuit 33 is lower than the first reference level (TH1) and the second reference level (T1).
The data when it is higher than H2) (2 in decimal) is stored. The data stored in the memory circuit 38 is added by the adder circuit 39 to the data in the same area sent next, and the result is stored. The number of times of addition is the same as the number of lines included in the area.
For example, in the memory circuit 38, the area of the second line (N1, M
When data (1 in decimal notation) corresponding to 1) is sent, the previously stored data (2 in decimal notation) and the next data (2 in decimal notation) as shown in FIG. 10
The addition circuit 39 adds 1) expressed in a decimal number, and the total (3 expressed in a decimal number) is stored.

The data read from the memory circuit 38 is input to the transmittance control circuit 40, and the transmittance of the light quantity control device 31 is changed for each region according to the data. For example, assuming that the storage circuit 38 outputs the addition total for five lines in one area, the result is as shown in FIG. The sum total data of each area read from the storage circuit 38 is set to 10
In the range of 4 to 11 when expressed in a decimal number, the light quantity control device 31 is controlled to maintain the transmittance as it is, and when the data of the addition total is expressed in a decimal number, 0 to
When it is within the range of 3, the transmittance is controlled to be increased. Then, when the addition total data is represented by a decimal number, 11 to 1
When it is within the range of 5, the transmittance is controlled to be lowered.

Example 2. FIG. 9 is a block diagram showing the arrangement of an image pickup apparatus according to the second embodiment of the invention. In the figure, 1 is a lens optical system, 46 is a color separation optical system that separates the incident light from the lens optical system 1 into three color lights of R, G and B, and 47, 48 and 49 are color separation optical systems 46. Quantity control device for transmitting the separated R, G, B color lights, 5
Reference numerals 0, 51, and 52 denote image pickup elements that convert the light images transmitted through the light amount control devices 47, 48, and 49 into electric signals, and 201 detects an average value of signals obtained from the image pickup elements 50, 51, and 52 for each screen. An average value detection circuit, 65 is a color temperature detection circuit that detects the color temperature of the object, and 66 is a transmission of the light amount control devices 47, 48, 49 according to the output of the average value detection circuit 201 and the output of the color temperature detection circuit 65. It is a transmittance control circuit for controlling the rate.

FIG. 10 is a block diagram showing the structure of the average value detection circuit 201. Reference numeral 53 is an integrating circuit that integrates the R component signal obtained from the image sensor 50 for each screen, 54 is an integrating circuit that integrates the G component signal obtained from the image sensor 51 for each screen, and 55 is the image sensor 52 An integrating circuit that integrates the obtained B component signal for each screen, 56 is a first comparing circuit that compares the output of the integrating circuit 53 with a first reference level, and 57 is an output of the integrating circuit 53 that is a second reference level. A second comparing circuit for comparing with the level, 58 is a first comparing circuit for comparing the output of the integrating circuit 54 with the first reference level, and 59 is a second comparing circuit for comparing the output of the integrating circuit 54 with the second reference level. , 60 is a first comparison circuit that compares the output of the integration circuit 55 with a first reference level, 61 is a second comparison circuit that compares the output of the integration circuit 55 with a second reference level, and 62 is The light output of the comparison results of the comparison circuits 56 and 57 is determined. A light amount determination circuit for converting into a signal, 63 is a light amount determination circuit for converting the comparison results of the comparison circuits 58 and 59 into light amount determination signals, and 64 is a light amount determination circuit for converting the comparison results of the comparison circuits 60 and 61 into light amount determination signals. is there.

FIG. 11 is a block diagram showing the structure of the color temperature detecting circuit 65, for example. In the figure, 67 is a photoelectric conversion element mainly having red sensitivity (hereinafter referred to as R sensor), 68 is a photoelectric conversion element having mainly green sensitivity (hereinafter referred to as G sensor), and 69 is mainly. A photoelectric conversion element (hereinafter, referred to as a B sensor) 70 having sensitivity to blue is a green component (hereinafter, referred to as Gs) obtained from the G sensor 68 and a red component (hereinafter, referred to as R sensor) obtained from the R sensor 67.
A division circuit for calculating and outputting a ratio of (s) (denoted as s), 71 is a blue component obtained from the B sensor 69 (hereinafter referred to as Bs)
And a division circuit for calculating and outputting the ratio of the green component (Gs) obtained from the G sensor 68.

Next, the operation will be described. The light of the subject is collected by the lens optical system 1 and is converted into R by the color separation optical system 46.
It is decomposed into three color lights of G and B. Color separated R, G, B
The color light of (1) passes through the light amount control devices 47, 48, 49 and is converted into electric signals by the image pickup devices 47, 48, 49. The respective signals photoelectrically converted by the image pickup devices 47, 48 and 49 are integrated for each screen by the integrating circuits 53, 54 and 55.
The outputs integrated by the integrating circuit 53 are compared with respective reference levels by comparing circuits 56 and 57. The outputs integrated by the integrating circuit 54 are compared with respective reference levels by comparing circuits 58 and 59. Then, the outputs integrated by the integration circuit 55 are compared with the reference levels by the comparison circuits 60 and 61.

Comparing circuits 56, 57, 58, 59, 60,
The reference level of 61 is, for example, as shown in FIG. 12, the level in the range of relatively high brightness is the first reference level (K1).
And the level in the range of relatively low luminance is the second reference level (K2). If the integrated output voltage exceeds each reference level, the comparison circuits 56, 57, 58, 5
Signals of positive logic value (H) are output from 9, 60, and 61. Each comparison circuit 56, 57, 58, 59, 60, 61
The signals output from are input to the light amount determination circuits 62, 63, 64. The light amount determination circuits 62, 63, 64 issue a light amount promotion signal for instructing to increase the transmittance of the light amount control devices 47, 48, 49, a light amount maintaining signal for instructing to maintain the transmittance, and an instruction for decreasing the transmittance. Are converted into three types of signals of the light amount limiting signal.

Comparison results (signals of positive logic value (H) or negative logic value (L) from the comparison circuits 56, 57, 58, 59, 60, 61 input to the light amount determination circuits 62, 63, 64) ) Is determined as shown in FIG. In the figure,
The symbol A1 represents the result of comparison by the comparison circuits 56, 58 and 60, and the symbol B1 represents the result of comparison by the comparison circuits 57, 59 and 61. The symbol X indicates the light amount determination circuit 6
It represents the outputs of 2, 63 and 64. For example, the image sensor 50
For example, if the output (RS1) of the integration circuit 53 exceeds the first reference level (K1), the output (A1), (B1) of the comparison circuits 56, 57 is H level. The signal is output. In this case, the light amount determination circuit 62
Outputs a light amount limiting signal. The output (A1) of the comparison circuit 56 is an L signal, and the output (B1) of the comparison circuit 57.
When a signal of H is output, the light amount determination circuit 62 outputs a light amount maintenance signal. When both the output (A1) of the comparison circuit 56 and the output (B1) of the comparison circuit 57 are L signals, the light amount determination circuit 62 outputs a light amount promotion signal.

On the other hand, in the color temperature detection circuit 65, the light of the subject is received by the R, G, and B sensors 67, 68, and 69 for each color component, and is proportional to the R component, G component, and B component of the incident light. Generate an output signal. R sensor 67 and G sensor 6
The signal from 8 is input to the division circuit 70 and outputs the ratio of the G component and the R component (Gs / Rs). The signals from the B sensor 69 and the G sensor 68 are input to the division circuit 71 and the ratio (Bs / Gs) of the B component and the G component is output.

The outputs from the light amount determination circuits 62, 63 and 64 and the signals divided by the color temperature detection circuit 65 are input to the transmittance control circuit 66. Control for controlling the transmittance of the light amount control devices 47, 48, 49 from the transmittance control circuit 66 based on the judgment signals from the light amount judgment circuits 62, 63, 64 and the signals from the division circuits 70, 71 of the color temperature detection circuit 65. Output a signal. The output control signal is sent to the respective light amount control devices 47, 48, 49, and the light amount is controlled so that the outputs of the corresponding image pickup devices 50, 51, 52 reach the optimum level with good S / N, and the screen is displayed. Change the overall brightness.

Example 3. FIG. 14 is a block diagram showing the arrangement of an image pickup apparatus according to the third embodiment of the invention. In the figure, 1 is a lens optical system, 46 is a color separation optical system for separating incident light from the lens optical system 1 into three color lights of R, G, B, and 72, 73 and 74 are emitted from the color separation optical system 46. R, G, and B three-color light in the horizontal direction in N columns and in the vertical direction in M
Light quantity control device for transmitting light in each area divided into rows, 5
Reference numerals 0, 51, and 52 denote image pickup devices that convert the light images transmitted through the light amount control devices 72, 73, and 74 into electric signals, respectively.
Reference numeral 202 denotes an area-specific average value detection circuit that detects the average value of the signals obtained from the image pickup devices 50, 51, and 52 for each area divided by each light amount control device, and 65 denotes color temperature detection that detects the color temperature of the subject. Circuit, 96 is an average value detection circuit 2 for each area
This is a transmittance control circuit that controls the transmittance of the light amount control devices 72, 73, and 74 for each region by the output from the output 02 and the output from the color temperature detection circuit 65.

FIG. 15 is a block diagram showing the configuration of the average value detection circuit 202 for each area. In the figure, 75, 76,
Reference numeral 77 is an integrating circuit for integrating the outputs from the image pickup devices 50, 51, 52 at time intervals divided by the light amount control devices 72, 73, 74, and 78, 81, 84 are integrating circuits 75, 7.
First comparator circuits 79, 82, 85 for comparing the outputs of 6, 77 with a first reference level are integrating circuits 75, 76, 77.
A second comparator circuit that compares the output of
Reference numerals 80, 83, 86 denote third comparing circuits for comparing the outputs of the integrating circuits 75, 76, 77 with a third reference level, 87, 8
8 and 89 are comparison circuits 78, 79, 80, 81, 82 and 8
Data conversion for converting a signal of a positive logical value (hereinafter, referred to as H) or a negative logical value (hereinafter, referred to as L) output from 3, 84, 85, and 86 into data according to a comparison result. Circuits 90, 91, 92 are data conversion circuits 87, 8
Memory circuit for storing data from 8, 89, 93, 9
Reference numerals 4 and 95 are addition circuits for adding the next data sent to the same area as the data stored in the storage circuits 90, 91 and 92, respectively.

Next, the operation will be described. The light of the subject is collected by the lens optical system 1 and is converted into R by the color separation optical system 46.
It is decomposed into three color lights of G and B. Color separated R, G, B
The colored light of is transmitted through the light amount control devices 72, 73, 74 divided into N columns in the horizontal direction and M rows in the vertical direction for each region, and is converted into electric signals by the image pickup devices 50, 51, 52.
The signals obtained from the image pickup devices 50, 51, and 52 are integrated by the integration circuit 75 at intervals divided into regions in the light amount control device.
It is integrated by 76 and 77. The output of the integrating circuit 75 is compared with each reference level by comparing circuits 78, 79 and 80.
The output of the integrating circuit 76 is compared with each reference level by comparing circuits 81, 82 and 83. Then, the output of the integrating circuit 77 is compared with each reference level by comparing circuits 84, 85 and 86. Each reference level is, for example, the level shown in FIG. 16, and the level in the high luminance range is set to the first reference level (T
1) The second reference level (T2) is the level for determining whether the signal is higher or lower than the vicinity of the center of the signal, and the level in the low luminance range is the third reference level (T3). Each comparison circuit 7
8, 79, 80, 81, 82, 83, 84, 85, 86
The result of the comparison is input to the data conversion circuits 87, 88, 89.

FIG. 17 shows data conversion circuits 87, 88, 89.
It is a state diagram showing the state of the input and output of. The input / output states are converted in the same states as those shown in the first embodiment. In the figure, symbols H, I, and J are inputs to the data conversion circuits 87, 88, 89, that is, comparison circuits 78, 79, 80 ,. 81, 82,
83, 84, 85, 86 represent the results compared. The symbols DD1 and DD2 are data conversion circuits 87 and 88,
It represents the output of 89 and becomes 2-bit data with DD1 as the lower order. In FIG. 17, for example, if the output (S1) of the integrating circuit 75 exceeds the first reference level (T1), all the signals of "H" are output from the outputs H, I, J of the comparing circuits 78, 79, 80. Is output. When this signal is input to the data conversion circuit 37, "H" signals are obtained from the outputs DD1 and DD2 (3 in decimal). In addition, as shown in FIG. 17, integration circuits 75, 7
Comparing circuits 78, 79 according to the voltage values of the outputs of 6, 77,
80, 81, 82, 83, 84, 85, 86 output H or L comparison results, and data conversion circuits 87, 88,
Each is converted to 2-bit data by 89.

The data output from the data conversion circuits 87, 88, 89 are stored in the storage circuits 90, 91, 92. The storage areas of the storage circuits 90, 91 and 92 are equal to the areas divided by the light amount control devices 72, 73 and 74. The data stored in the memory circuits 90, 91, 92 are added by the adder circuits 93, 94, 95 with the data in the same area sent next, and the result is stored. The number of times of addition is the same as the number of lines included in the area.

On the other hand, in the color temperature detection circuit 65, the light of the subject is received by the R, G, and B sensors 67, 68, and 69 for each color component, and is proportional to the R component, G component, and B component of the incident light. Generate an output signal. R sensor 67 and G sensor 6
The signal from 8 is input to the division circuit 70 and outputs the ratio of the G component and the R component (Gs / Rs). B sensor 69 and G
The signal from the sensor 68 is input to the division circuit 71 and outputs the ratio (Bs / Gs) of the B component and the G component. Memory circuit path 9
The addition total output from 0, 91, and 92 and the output from the color temperature detection circuit are input to the transmittance control circuit 96, respectively. For example, as shown in FIG. 18, when the subject is backlit and the color temperature is high (when the B component is large and the R component is small relative to the G component), the transmittance control circuit 96 eliminates the difference in brightness between the main subject and the background. The light quantity control devices 72, 73,
The transmittance of 74 is controlled for each area. Since the color temperature is high, the light amount control device 72, that is, the transmittance of the light of the R component is entirely raised according to the signal from the color temperature detection circuit 65, and the light amount control device 74, that is, the light of the B component of the light is controlled. The transmittance is controlled to be lowered as a whole.

Example 4. Although the reference levels for comparison are set as shown in FIGS. 4, 12, and 17 in Examples 1, 2, and 3, the levels are not limited to these set levels,
For example, the setting may be arbitrarily changed from the outside.

Example 5. In the second and third embodiments, the external photometry method in which the R, G, and B sensors are provided to detect the color temperature of the subject is shown, but the photometry method is not limited to this, and the internal photometry is not limited. A method may be used to detect the color temperature of the subject.

[0043]

As described above, according to the first aspect of the present invention, a device capable of controlling the amount of light is provided between the lens optical system and the image pickup device to change the transmittance of the light incident on each region. Since it is configured, it is possible to obtain an image pickup apparatus capable of appropriately adjusting the exposure for each region for subjects under various conditions.

According to the second and third aspects of the present invention, a light quantity control device is provided between the color separation optical system and the three image pickup elements in the double plate system so that the transmittance of the incident light can be adjusted to the color temperature of the subject. Since it is configured to be changed correspondingly, it is possible to obtain an image pickup apparatus capable of appropriately adjusting the exposure of the entire screen and the area of the screen with respect to subjects under various conditions and capable of white balance adjustment. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image pickup apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a region-specific average value detection circuit according to an embodiment of the present invention.

FIG. 3 is a partial view showing an example in which the light amount control device in one embodiment of the invention of claim 1 is divided into regions.

FIG. 4 is a diagram showing a reference level of a comparison circuit in an embodiment of the invention of claim 1;

FIG. 5 is a state diagram showing an input / output state of the data conversion circuit according to the embodiment of the invention of claim 1;

FIG. 6 is a block diagram showing a configuration of a data conversion circuit according to an embodiment of the invention of claim 1;

FIG. 7 is a diagram illustrating an example of a method of storing data in a storage circuit according to an embodiment of the invention of claim 1;

FIG. 8 is a diagram illustrating an example of control of a transmittance control circuit according to an embodiment of the invention of claim 1;

FIG. 9 is a block diagram showing a configuration of an image pickup apparatus according to an embodiment of the invention of claim 2;

FIG. 10 is a block diagram showing a configuration of an average value detection circuit according to an embodiment of the invention of claim 2;

FIG. 11 is a block diagram showing a configuration of a color temperature detection circuit according to an embodiment of the invention of claim 2;

FIG. 12 is a diagram showing a reference level of a comparison circuit according to an embodiment of the invention of claim 2;

FIG. 13 is a state diagram showing an input / output state of a light amount determination circuit according to an embodiment of the invention of claim 2;

FIG. 14 is a block diagram showing a configuration of an image pickup apparatus according to an embodiment of the invention of claim 3;

FIG. 15 is a block diagram showing a configuration of a region-based average value detection circuit according to an embodiment of the invention of claim 3;

FIG. 16 is a diagram showing a reference level of a comparison circuit in an embodiment of the invention of claim 3;

FIG. 17 is a state diagram showing an input / output state of a data conversion circuit according to an embodiment of the invention of claim 3;

FIG. 18 is a diagram showing an example of a subject for explaining an embodiment of the invention of claim 3;

FIG. 19 is a block diagram showing a configuration of a conventional imaging device.

FIG. 20 is a diagram showing a detection range of a detection circuit 6a in an example of a conventional image pickup apparatus.

FIG. 21 is a diagram showing signal amplitudes at respective points in an example of a conventional image pickup apparatus.

[Explanation of symbols]

 1 Lens Optical System 31, 47-49, 72-74 Light Quantity Control Device 32, 50-52 Imaging Element 33, 53-55, 75-77 Integration Circuit 34-36, 56-61, 78-86 Comparison Circuit 37, 87 -89 Data conversion circuit 38, 90-92 Storage circuit 39, 93-95 Addition circuit 40, 66, 98 Transmittance control circuit 100-102 Inverter circuit 41-43 AND circuit 44, 45 OR circuit 62-64 Light amount determination circuit 65 Color temperature detection circuit 67 R sensor 68 G sensor 69 B sensor 70, 71 Division circuit 200, 202 Region-specific average value detection circuit 201 Average value detection circuit

Claims (3)

[Claims] 1. A lens optical system, a light amount control means for transmitting light emitted from the lens optical system for each region divided into N columns in the horizontal direction and M rows in the vertical direction, and the light amount control means. An image sensor for converting an optical image into an electric signal,
A region-specific average value detection circuit that detects the average value of the signal obtained from the image pickup device for each region divided by the light-quantity control unit, and transmission of the light amount control unit according to the output from the region-specific average value detection circuit An image pickup device, comprising: a transmittance control circuit for controlling a rate. 2. A lens optical system, a color separation optical system for separating incident light from the lens optical system into three color lights of R, G, B, and R, G, which are color separated by the color separation optical system. The three light quantity control means for transmitting the B color light, the three image pickup elements for converting the three color light transmitted through the respective light quantity control means into electric signals respectively, and the average value of the signals obtained from the three image pickup elements are calculated. An average value detection circuit for detecting each one of the screens, a color temperature detection circuit for detecting the color temperature of the object, and transmission of three light amount control means according to the output of the average value detection circuit and the output of the color temperature detection circuit. An image pickup device, comprising: a transmittance control circuit for controlling a rate. 3. A lens optical system, a color separation optical system for separating incident light from the lens optical system into three color lights of R, G, B, and R, G, B color-separated by the color separation optical system. Three light amount control means for transmitting the colored light of N columns in the horizontal direction and M rows in the vertical direction for each region, and three image pickup devices for converting the three color lights transmitted through the respective light amount control means into electric signals, respectively. An average value detection circuit for each area that detects an average value of signals obtained from the three image pickup devices for each area divided by the light amount control means, a color temperature detection circuit that detects a color temperature of a subject, and the area An image pickup apparatus, comprising: a transmittance control circuit for controlling the transmittance of three light amount control means for each region according to the output from the separate average value detection circuit and the output from the color temperature detection circuit.