JPH0575921A - Exposure control device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive exposure control device capable of partial exposure control. CONSTITUTION:The exposure control device consists of a spatial light modulator 6 having plural lenses 1 to 5 for forming an image of a subject, a photoelectric conversion element 9 for converting light obtained through the lenses 1 to 5 into an electric signal and plural controllable elements arranged like a face and the whole of image light arriving at the element 9 or a part of it can be controlled by the modulator 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control device having a lens diaphragm mechanism such as a video camera and an image projection device using a lens such as a video camera.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram of a lens diaphragm mechanism of a conventional exposure control apparatus. 601 is a diaphragm blade, 602 is a lens, 60
3 is a fixed pin, 604 is a drive pin, 605 is a drive rod, and 606 is a ring for transmitting the operation of the drive rod 605 to the drive pin 604. A plurality of diaphragm blades 601 are attached around the lens 602, but only one of them is shown for the sake of explanation.

By moving the drive rod 605, the ring 60
6 rotates, and the drive pin 604 fixed on the ring 606 rotates, so that the diaphragm blade 601 is fixed pin.
With 603 as the fulcrum, the size of the pupil is changed.

FIG. 10 is a block diagram showing a control mechanism of a conventional exposure control apparatus. In the figure, 701 is a lens and 70
2 is a diaphragm, 703 is an image sensor that converts an optical image into an electrical signal, 704 is a preamplifier that amplifies the output of the image sensor to an appropriate size, and 705 is a portion corresponding to the internal photometric area of the video signal output from the preamplifier 704. Photometric circuit to extract the
Reference numeral 706 is a detection circuit, 708 is a pulse generation circuit that controls the photometric circuit 705 from vertical and horizontal synchronizing pulses, and 707 is an aperture that feedback-controls the diaphragm 702 so that the output of the detection circuit 706 matches a predetermined reference voltage. It is a control circuit.

The light passing through the lens 701 is appropriately attenuated by the diaphragm 702 and forms an image on the image pickup device 703. Image sensor 703
Then, the formed optical image is converted into a video signal which is an electric signal, and is amplified by the preamplifier 704 to a size that can be easily processed later. With respect to this amplified video signal, only the signal in the photometric area is input to the detection circuit 706 by the photometric circuit 705 controlled by the pulse generation circuit 708. Detection circuit
At 706, the input signal is integrated into a photometric signal having a level corresponding to the average brightness of the photometric area of the video signal, and the photometric signal is input to the aperture control circuit 707. The aperture control circuit 707 performs feedback control of the aperture 702 so that this value matches a predetermined reference voltage.

However, the types of subjects to be imaged are unlimited and cannot be limited. Therefore, in the fixed photometric area, there are some subjects for which good images can be captured, and for some subjects (so-called poor subjects) for which normal images cannot be captured in this photometric region. For example, when there is a main subject in the center and most of the background has high brightness, there is high brightness that occupies most of the background in the photometry area during so-called backlighting. The subject appears to be closed, so the main subject becomes completely black (blackout).

On the other hand, when the background is mostly black, that is, when the subject is over-lit, the black background causes the diaphragm to open for the main subject, so that the main subject flies to white ( Whiteout).

Next, regarding the image projection apparatus, FIG. 11 shows an image projection apparatus such as a conventional video camera.
In FIG. 11- (a), the lens 710 is directed to the subject and an image is taken. At this time, since the reflecting mirror 711 is at the position of the broken line,
The subject is imaged on the image sensor 712 by the lens 710.
At the same time, if it is desired to magnify and project the image, the system is reassembled as shown in FIG. 11- (b). At this time, the reflecting mirror 711 is operated and tilted to the horizontal position indicated by the solid line. The image of the liquid crystal display 713 illuminated by the light source 714 is enlarged and displayed by the lens 710. As a conventional example, JP-A-2-13071
There is a camera-integrated video tape recorder disclosed in Japanese Patent Publication No.

In the conventional image projection apparatus configured as described above, since the system configuration changes at the time of image pickup and at the time of projection, it takes time and effort to change the configuration. In addition, since the optical path is moved in the middle, the image forming accuracy deteriorates.

[0010]

Since the conventional exposure control apparatus is constructed as described above, many mechanical operations are required to control the diaphragm, which slows the operation speed and lowers the reliability. There was a problem. Furthermore, the number of parts used is large, and the structure is complicated and expensive. Further, due to the structure that it is incorporated in the lens system, only exposure control for the entire light receiving element can be performed, and partial correction is impossible. Further, the conventional exposure control device has no additional function of performing image projection in addition to its own function.

The present invention has been made to solve the above problems, and by using a spatial light modulator for exposure control, it is possible to reduce the mechanical operation portion and the number of constituent points. In addition, it is possible to obtain an inexpensive and highly reliable exposure control device that enables partial exposure control, and by using a spatial light modulator as an image generator, it can be used as a magnifying projector. It is intended to obtain additional functionality.

[0012]

In an exposure control apparatus according to claim 1 of the present invention, a lens, a photoelectric conversion element,
The spatial light modulator is arranged along each optical path, and the exposure control is performed by this spatial light modulator.

In the exposure control apparatus according to claim 2,
An exposure analyzing apparatus for monitoring an exposure state and a spatial light modulator control apparatus are provided in the system configured in claim 1.

In the exposure control apparatus according to claim 3,
The average brightness of the whole screen or a part of the screen is detected to control the whole or a part of the spatial light modulator.

In the exposure control apparatus according to claim 4,
The spatial light modulator of only the signal having the brightness level signal exceeding the threshold level is controlled.

In the image projection apparatus according to the fifth aspect,
An image is formed by the spatial light modulator used for exposure control, and the light emitted from the light source is reflected on the image surface to obtain the image light, pass through the lens system, and enlarge and project. is there.

[0017]

In the exposure control apparatus according to the first aspect of the present invention,
Exposure control by individually controlling a plurality of controllable elements arranged in a plane on the spatial light modulator to control the image formed by the lens, and controlling the amount of all or part of the image light reaching the photoelectric conversion element. I am trying to do.

In the exposure control apparatus according to the second aspect, the exposure analysis apparatus and the spatial light modulator control apparatus are provided to monitor and analyze the state of the image to control the exposure.

In the exposure control apparatus according to the third aspect, the exposure analysis apparatus analyzes the brightness level of the image and controls the spatial light modulator to perform the exposure control when the brightness level is high. ..

In the exposure control apparatus according to the fourth aspect, in the exposure analysis apparatus, a portion having a brightness level exceeding the threshold level is extracted and only the portion corresponding to the address is controlled by the spatial light modulator for exposure control. I am trying to do it.

In the image projecting device according to the fifth aspect, the image is displayed by the spatial light modulator used for the exposure control, so that the image light can be projected along the path opposite to that at the time of image pickup. There is.

[0022]

EXAMPLES Example 1. FIG. 1 is a block diagram of an exposure control apparatus using the spatial light modulator 6. The image light incident on the lens system 1 passes through the lens composed of the lens systems 2, 3, 4, 5 and reaches the spatial light modulator 6 through the optical path 7. In the lens system, for example, 1 is a focus unit, 2 is a variator, 3 is a compensator, 4 is a master lens, and 5 is an optical filter.

In this embodiment, the spatial light modulator 6 is of the type known as a deformable mirror device (DMD), which will be described later. If the individual light beams can be redirected fast enough,
Other spatial light modulators can also be used. The photoelectric conversion element 9 is of a type known as CCD. Other photoelectric conversion elements can be used as long as the image light can be photoelectrically converted at a sufficiently high speed.

The operation of the spatial light modulator 6 will be described in detail with reference to FIG. The mirror 20 is movable with respect to the vertical plane 30 about the axis 26 from a position shown by a dotted line 28 to a position shown by a dotted line 44. In the “on” position, the edge 30 of the mirror 26
Contacts the landing electrode 32. The mirror 20 is moved to the "on" position by applying the appropriate voltage to the control electrode 34. The voltage on this electrode is applied to the positive electrode 38 and, via the inverter 39, to the negative electrode 40. A differential bias is applied to mirror 20 via electrode 42. At the position shown by the broken line 28, the mirror 20 guides part or all of the image light from the first optical path along the second optical path.

In the "off" state, the mirror 20 is rotated to the position shown by the broken line 44 by applying a negative voltage to the vertical surface 30 or the electrode 34 so that the image light is not guided to the second optical path. Let

In the spatial light modulator 6, a plurality of the mirrors 20 are arranged in a matrix and arranged in a plane, and each mirror can be controlled individually or simultaneously.

The light beam passing through the lens system and reaching the spatial light modulator 6 from the optical path 7 which is the first optical path,
By controlling the controllable element of the spatial light modulator 6, it is guided to the photoelectric conversion element 9 along the optical path 8 which is the second optical path. The photoelectric conversion element 9 converts the incident light into an electric signal. When the controllable element is controlled by the electric signal and the amount of light incident on the photoelectric conversion element 9 is changed, the spatial light modulator 6 functions as a diaphragm of an optical system.

Example 2. In the first embodiment, by converting and analyzing the signal output from the photoelectric conversion device 9 and feeding back the information to the spatial light modulator 6, it is possible to perform aperture adjustment in real time.

In FIG. 1, the electric signals converted from the image light by the photoelectric conversion element are as described in the first embodiment. The converted electric signal is sent to the camera signal processing device 11 via the transmission line 10. The camera signal processing device 11 converts the sent electrical signal into an image signal. The image signal is sent to the exposure analysis device 13 via the transmission line 12. The exposure analysis device 13
From the image signal, for example, the luminance level of the entire screen, the presence / absence of pixels that have reached the saturation level in terms of luminance, the address thereof, and the like are analyzed. Next, how to control the spatial light modulator 6 is processed based on the analyzed data, and the signal is sent to the spatial light modulator controller 15 via the transmission line 14. The spatial light modulator control device 15 moves the controllable element of the spatial light modulator 6 by the received signal to reduce the ratio of the image light of the whole screen or a part of the screen to the second optical path.

Example 3. The exposure analyzer 13 can utilize the spatial light modulator 6 as various optical diaphragms depending on the internal processing method.

A block diagram of the exposure analyzer is shown in FIG.
The signal sent from the photoelectric conversion element is converted into an image signal by the camera signal processing device 50. The image signal is
It is sent to the A / D converter 53 inside the exposure analysis apparatus 51 via the transmission line 52, and is subjected to analog / digital conversion.
The converted signal is sent to the adder 55 via the transmission path 54.

S built in the camera signal processing device 50
The sync signal output from the SG is sent to the timing generator 60 and the CPU 57 via the transmission line 62. The timing generator 60 uses the synchronization signal sent to the adder
Make 55 timings. The adder 55 adds the signals sent from the transmission line 54 based on the signals sent from the timing generator 60. The added value is proportional to the brightness of the image when sampled. This value is sent to the CPU 57 via the transmission line 56. The CPU 57 compares the result with a predetermined specified value and sends a signal corresponding to the result to the level modulator 64 via the transmission line 63. The specified value is
It can be set externally through the transmission line 65. Details of the processing performed by the CPU 57 will be described later.

The level modulator 64 judges from the signal sent from the CPU 57 how much the spatial light modulator 6 sends the image light to the photoelectric conversion element 9, and transmits the data signal. Spatial light modulator controller via path 66
Send to 67. The level converter 64 can also be incorporated in the CPU 57.

FIG. 4 is a flow chart showing the flow of image signals in the system in which the level converter is incorporated in the CPU. The signal output from the photoelectric conversion element 70 passes through the camera signal processing device 71, the A / D converter 72, and the adder 73, is processed, and is input to the CPU 74. In CPU74,
First, at 75, it is checked whether or not the memory 76 is cleared. Since it was cleared at the beginning, it becomes Y and proceeds to 77 below. At 77, it is checked whether the signal sent from the adder 73 is larger than the designated value of the designated brightness. Now, if it is below the specified value, the result is Y, and no instruction is given to the spatial light control device 78.

If it is larger than the specified value, the value of the signal is stored in the memory 76, the level conversion value is changed, and the spatial light modulator control device 78 is operated. When the spatial light modulator control device 78 is operated, the photoelectric conversion element 70 is naturally used.
The amount of light received at changes. The signal is a signal processor
When it is input to the CPU 74 again through 71, 72, 73, 75
At, since the memory is not cleared, the route of N is traced. Next, at 79, it is determined if there was a sudden change in the value of the signal. A sudden change means that the image has changed to a different one. Now, if it has not changed suddenly, it will become N and proceed to 80 below. At 80, it is determined whether the value in the memory has fallen to the specified value.

If it has not fallen, it becomes N, the level conversion value is further changed, and the spatial light modulator control device 78 operates. Next, at 80, if the value in the memory has fallen to the specified value, the result is Y and the process proceeds to 82. At 82, the current level conversion value is held and the spatial light modulator control device continues to operate as it is.

Next, in the photoelectric conversion element 70, when there is a rapid change in the value of the signal, the signal whose N is selected in 75 is 79
The value becomes Y and the value in the memory is cleared at 83. The value of the level conversion is returned to the original. This series of operations is repeated to perform aperture control.

Example 4. In the third embodiment, the spatial light modulator is operated according to the average brightness of all the image planes to function as a conventional diaphragm. However, in the present embodiment, the brightness is partially saturated, , An exposure analysis apparatus that suppresses the luminance only in the portion exceeding the threshold level will be described.

A block diagram of the exposure analyzer is shown in FIG.
Further, FIG. 6 shows an image forming surface of the photoelectric conversion element, a photometric area, an image input signal, and a signal after passing through the A / D converter.
Similar to the third embodiment, the image signal output from the camera signal processing device 90 is sent to the exposure analysis device 92 via the transmission line 91. The image signal sent to the exposure processing device 92 is sent to the A / D converter 93, where it is subjected to analog / digital conversion. The converted signal is sent to the peak detector 95 via the transmission line 94. The peak detector 95 is a CPU 100
The threshold level set in the above step is compared with the signal, and an over-level signal is sent to the CPU 100 via the transmission path 96.

To the CPU 100, the synchronization signal sent from the camera signal processing device 90 via the transmission path 99,
In addition, the clock signal sent from CLOCK98 via the transmission line 112 is also transmitted to the CL signal via the transmission line 101.
The distance measuring area signal sent from the distance measuring area timing generator 102 synchronized with the clock signal sent from the OCK 98 via the transmission path 103 is input. The ranging area timing generator 102 can change the ranging area via the transmission path 111.

The signal sent from the peak detector 95 is an address determined by the CPU 100 from the signal from the sync signal sent from the distance measuring area timing generator 102 and the camera signal processing device 90. It is recorded in the memory 105 via the bus 104 together with.
Further, in the CPU 100, the level signal corresponding to the overlevel portion of the signal sent from the peak detector 95 is sent to the level converter 108 via the transmission line 107, and the address of the pixel which is overleveled. The transmission line 11
3 to the spatial light modulator controller 110.

The level modulator 108 includes the CPU 100
From the signal sent from the spatial light modulator 6, the spatial light modulator 6 determines how much image light is sent to the photoelectric conversion element 9, and the data signal is transmitted via the transmission path 109 to the spatial light modulator control. Send to device 110. The level converter 108 includes the C
It can also be incorporated into the PU100.

FIG. 7 shows an example of the relationship between the output of the adder, the output of the level converter, and the "ON" period of the spatial light modulator. Now, if the summed output is small, the output of the level converter is large, that is, the "on" period of the spatial light modulator is long. Next, in the area on the right side of the dotted line on the left side, the CPU operates, the level conversion output decreases, and the “on” period of the spatial light modulator also decreases. When the added output further increases and exceeds the right dotted line, which is the threshold level, to the right, the level conversion output continues to maintain the minimum value. The amount of change in the area between the two dotted lines, which is the section in which the level conversion output changes, can be set to a desired amount of change and may be continuous or discrete.

Example 5. FIG. 8 shows an embodiment of an exposure control device having the function of an image projector. Regarding the exposure control, the first embodiment and the second embodiment shown in FIG.
Is the street. In this embodiment, the image projection function will be described.

In FIG. 8, the light emitted from the light source 120 is condensed by the reflecting mirror 121, passes through the optical path 133 and the lens 122.
Be led to. The lenses 122, 123, and 124 have an optical path 133.
It forms a beam columnator that acts so that the light that has passed through becomes a light flux as shown in optical path 125. The light beam is guided to the spatial light modulator 6 through the optical path 125 which is a fourth optical path. The spatial light modulator 6 is in the "off" state at the time of exposure control and is in the "on" state, that is, when a negative voltage is input to the control input 34, it is "on".

The storage medium 127 stores image signals sent from the camera signal processing device 11 via the transmission path 129 and the transmission path 13
The image signal from the outside sent from 0 can be stored. The image signal is sent to the image projection CPU 128 via the transmission line 131. The image projection CPU 12
It is also possible for 8 to directly input an image signal via the transmission path 134.

The image projection CPU 128 converts the input image signal into data for displaying an image on the spatial light modulator, and the spatial light modulator control device via the transmission line 132.
15 to control the spatial light modulator 6. The spatial light modulator 6 controls the individual controllable elements by the data sent via the transmission line 16, and forms an image on the controllable element surface.

The light that has passed through the fourth optical path is incident on the spatial light modulator 6 that has formed this image, and the reflected image light passes through the optical path 7 that is the third optical path and passes through each lens. The image is enlarged and projected through the systems 5, 4, 3, 2, 1.

[0049]

As described above, by using the spatial light modulator (DMD) for the exposure control, the mechanical operation part is reduced, the mechanical part is simplified, and the partial exposure control is possible. There is an effect that an inexpensive and highly reliable exposure apparatus can be obtained. Further, there is an effect that an image can be projected by displaying an image on the spatial light modulator and applying light from the light source to reflect the light.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an exposure control apparatus.

FIG. 2 is a structural diagram of a spatial light modulator.

FIG. 3 is a block diagram of an exposure analysis apparatus according to a third embodiment.

FIG. 4 is a flow chart inside the CPU.

FIG. 5 is a block diagram of an exposure analysis apparatus according to a fourth embodiment.

FIG. 6 is a relationship diagram of a distance measuring area, an image signal, and an A / D conversion signal.

FIG. 7 is a relationship diagram of an addition output, a level conversion output, and an ON period of a spatial light modulator.

FIG. 8 is a configuration diagram of an exposure control apparatus having a magnifying projection function.

FIG. 9 is a configuration diagram of a conventional diaphragm.

FIG. 10 is a block diagram of a conventional exposure control apparatus.

FIG. 11 is a configuration diagram of a conventional magnifying projection device.

[Explanation of symbols]

 1, 2, 3, 4, 5 Lens system 6 Spatial light modulator 9 Photoelectric converter 20 Mirror 51 Exposure analysis device 74 CPU 92 Exposure analysis device 710 Lens 711 Reflection mirror 713 Liquid crystal display

Claims (5)

[Claims] 1. A lens for forming an image of an object, a photoelectric conversion element for converting light passing through the lens into an electric signal and outputting the electric signal, a first optical path passing through the lens, and the photoelectric conversion element. And a spatial light modulator having a plurality of controllable elements arranged in a plane along the incident second optical path, and the spatial light modulation by an output signal of the photoelectric conversion element. A first state for directing light from the first optical path to the second optical path and light from the first optical path by individually controlling a plurality of controllable elements disposed in the container. And a second state in which the second optical path is not guided to the second optical path. 2. A lens for forming an image of a subject, a photoelectric conversion element for converting light passing through the lens into an electric signal and outputting the electric signal, a first optical path passing through the lens, and the photoelectric conversion element A spatial light modulator having a plurality of controllable elements arranged in a plane along the incident second optical path, and exposure for analyzing the exposure level of the output signal of the photoelectric conversion element An analysis unit and a spatial light modulator control unit for controlling the spatial light modulator by a signal output from the exposure analysis unit are provided, and the spatial light modulator is arranged on the spatial light modulator based on the output of the exposure analysis unit. And controlling the plurality of controllable elements individually to guide the light from the first optical path to the second optical path and the light from the first optical path to the second state. The second state that does not lead to the optical path of An exposure control device characterized by the above. 3. The exposure control apparatus according to claim 2, wherein the exposure analysis unit detects an average luminance level of the entire screen or a part of the output signal of the photoelectric conversion element. .. 4. The exposure analysis means detects the signal portion of the entire screen or a part thereof which exceeds a predetermined luminance level, among the output signals of the photoelectric conversion element. Exposure control device. 5. A lens for forming an image of a subject, a photoelectric conversion element for converting light passing through the lens into an electric signal and outputting the electric signal, a first optical path passing through the lens, and the photoelectric conversion element A spatial light modulator having a plurality of controllable elements arranged in a plane along the incident second optical path; and a third spatial light modulator passing from the spatial light modulator to an imaging lens. And a light source arranged along a fourth optical path incident on the spatial light modulator, by individually controlling a plurality of controllable elements arranged on the spatial light modulator. A first mode in which the light from the first optical path is guided to the second optical path and a mode in which the light from the first optical path is not guided to the second optical path. It is possible to have two states, and as a second mode, pass through the fourth optical path. A third state in which the light from the light source is guided to the third optical path, and a fourth state in which the light from the light source that has passed through the fourth optical path is not guided to the third optical path. An exposure control device characterized in that