JP2003008987A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device with a high dynamic range without underexposure and overexposure even under a backlight condition and an excessive front light, with excellent S/N, and less image deterioration by reflecting an object image in a very small mirror of an array form whose reflection light quantity is changed with each pixel and receiving the image with an image pickup element. SOLUTION: A mirror control section 6 controls a very small mirror (2) to lead information of an object image on a reflection means to an image pickup element 4 by changing the lightness for each very small mirror (2). For example, the object image is formed on and reflected in a mirror device 1 via a photographing lens 1, an aperture 7 and a prism 9, and the object image is again formed on the image pickup element 4 via the prism 9 and a relay lens 3. A signal processing circuit 5 processes the photoelectric converted signal and part of information is fed to the mirror control section 6 and an aperture control section 8.

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 for an electronic camera using an image pickup element which serves as an image input means of information equipment such as a digital still camera, a movie, a surveillance camera, a mobile phone and a terminal information equipment (PDA). It is a thing.

[0002]

2. Description of the Related Art In recent years, one of the problems in the field of electronic cameras is the lack of image information due to overexposure and underexposure due to lack of the dynamic range of the camera under the conditions of backlight and over-exposure. Particularly in a surveillance camera, it is important that the visibility is required and the image information is not crushed, and there is a strong demand for improvement in response to the lack of the dynamic range.

Conventionally, as a method for expanding the dynamic range, for example, in Japanese Unexamined Patent Publication No. 10-23324, there are two kinds of conditions, an exposure condition for extracting information with overexposure and underexposure and an exposure condition for extracting normal image information. A method has been proposed in which is switched in a short time by using an electronic shutter of an image sensor, and the two types of image information are combined to obtain a high dynamic range in appearance.

[0004]

However, in the image pickup apparatus proposed in Japanese Patent Laid-Open No. 10-23324, a plurality of images having different exposure conditions are used, but each image has a constant exposure condition on the entire screen. Therefore, it is difficult to make the exposure conditions appropriate for the details of the image. Further, it is difficult to set conditions for cutting out each image and conditions for combining images, and when combining images having a particularly short exposure time, an image with poor S / N results. Furthermore, since a plurality of images are extracted at different timings in time, the resolution of the images deteriorates when the moving object is photographed or camera shake occurs.

The present invention has been made in order to solve these problems. By reflecting an object image with an array of microscopic mirrors whose reflection amount can be changed for each pixel and receiving the image by an image pickup device. It is an object of the present invention to provide an image pickup apparatus that has a high dynamic range with no blackouts and whiteouts even under backlight conditions or overexposure, has a good S / N, and has little image deterioration.

[0006]

In order to achieve the above object, a first image pickup device of the present invention is arranged on a first lens for forming an image of a subject and on an image forming surface of the first lens. A reflecting means having a structure in which minute mirrors are two-dimensionally arranged, and a second means for photographing the subject image reflected by the reflecting means.
An image sensor for converting the subject image captured by the lens and the second lens into an electric signal, a signal processing means for forming a video signal, which is video information from the electric signal photoelectrically converted by the image sensor, and the reflecting means. Of the image pickup device including a mirror control unit for individually controlling the micro mirrors, wherein the mirror control unit controls the micro mirrors so that the information of the object image on the reflecting means is displayed for each of the micro mirrors. Is changed to lead to the image pickup device.

Next, a second image pickup device of the present invention comprises a first lens for forming a subject image and a diaphragm for adjusting the amount of light incident on the first lens, which is incorporated in or close to the first lens. And a reflecting means having a structure in which minute mirrors are arranged two-dimensionally on the image forming surface of the first lens, a second lens for photographing the subject image reflected by the reflecting means, and the second lens An image pickup device for converting the subject image photographed by an electric signal into an electric signal; a signal processing unit for forming a video signal which is video information from the electric signal photoelectrically converted by the image pickup device; and the minute mirror of the reflecting unit. An image pickup apparatus comprising a mirror control unit for individually controlling and an aperture control unit for controlling the aperture, wherein the aperture control unit adjusts the brightness of a subject image formed on the reflecting means, The control unit and wherein the directing changing the brightness information of the object image on the reflection means by controlling the micromirrors in each of the micromirrors on the imaging device.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the image pickup device of the present invention,
The minute mirror on the image forming surface of the first lens can change the reflection direction of the subject image formed on the image forming surface for each minute mirror, so that the amount of light incident on the second lens can be changed for each minute mirror. The image of the subject that can be controlled and is re-formed on the image sensor is controlled to an appropriate amount of light that does not exceed the saturation of the image sensor for each resolution of the minute mirror. Video information can be obtained.

Further, by incorporating a diaphragm for adjusting the amount of light incident on the first lens into or close to the first lens, the diaphragm control and the mirror control are interlocked with each other, and image information with a higher dynamic range can be obtained. it can.

Further, by arranging the second lens and the image pickup device so as to maintain the focused image forming relationship with respect to the plane of the reflecting means, it is possible to improve the focus over the entire screen. .

Further, a prism is arranged between the first lens and the reflecting means and between the reflecting means and the second lens, and the reflected light from the reflecting means is totally reflected by the prism and is incident on the second lens. Since the lens, the reflecting means, and the second lens can be placed close to each other, the size of the entire imaging device can be reduced.

Further, the signal processing means transforms the image information so as to correct the change in the perspective generated in the image on the subject and the image pickup device, so that the image due to the arrangement of the reflecting means and the image pickup device is covered. The deformation can be corrected.

Further, a prism is arranged between the first lens and the reflecting means and between the reflecting means and the second lens, and the reflected light from the reflecting means is totally reflected by the prism and is incident on the second lens. Since the lens, the reflecting means, and the second lens can be placed close to each other, the size of the entire imaging device can be reduced.

Further, the mirror control section individually controls the minute mirrors based on the information on the brightness of the image calculated by the signal processing means, and the exposure amount is adjusted so that an appropriate light amount enters the image pickup element. Furthermore, by sending individual control amounts for controlling individual micro mirrors to the signal processing means and correcting the corresponding video signals, the dynamic range within a certain range is suppressed at the output stage of the image sensor, and signal processing is performed. The signal can be restored based on the control amount of each mirror, and a high dynamic range image can be obtained by a simpler method.

Further, the mirror control unit arranges the mirrors in the ON state in which the object image is incident on the second lens for each of the minute mirrors and the object image is not incident on the second lens OF.
By switching the arrangement of the mirrors in the F state and changing the time during which the ON state continues for a certain period of time, it is possible to perform highly accurate exposure control without making the spatial resolution of the mirror control fine. It is possible to provide an imaging device that does not have a burden on the configuration.

Further, the signal processing means adjusts the brightness of the entire image by using the electronic shutter of the image pickup device based on the information on the brightness of the image calculated in the signal processing means, Since the aperture control can be omitted or the exposure control with less burden on the aperture can be performed, an inexpensive imaging device can be provided.

An embodiment of the image pickup apparatus of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows an image pickup apparatus according to the first embodiment. A photographing lens 1, a mirror device 2, a relay lens 3, and an image sensor 4 are arranged from the subject side in correspondence with the flow of image information, and thereafter, a signal processing circuit 5 and a mirror control unit 6 are connected as a flow of electric signals. The output of the mirror control unit 6 is connected to the mirror device 2.

The mirror device 2 is a so-called DMD (digital micromirror device), which has recently attracted attention as a reflective display panel. As shown in FIG. 2, the surface is divided into a plurality of pixels, and each pixel has a square shape. The microscopic mirrors are arranged, and each mirror has a structure in which it rotates about two diagonals A and B as a fulcrum and tilts about ± 10 ° for each pixel. The function to change the direction of the incident light ray for each pixel have. The mirror device 2 is arranged at an image forming position of a subject photographed by the photographing lens 1, and the subject image is relayed by the relay lens 3
Reflect on. For example, when the mirror of each pixel of the mirror device 2 is ON at + 10 °, the reflected light is reflected by the relay lens 3
Is controlled so that the reflected light does not enter the relay lens 3 in the OFF state at -10 °. The relay lens 3 is an optical system that forms a subject image on the mirror device 2 on the image sensor 4. In addition, since the reflected image is kept in focus on the image sensor 4,
The relay lens 3 and the image pickup device 4 are arranged with respect to the mirror device 2 so as to follow the so-called Scheimpflug's law. The image pickup device 4 photoelectrically converts the reflected image of the mirror device 2, and the converted electric signal is input to the signal processing circuit 5 and subjected to a certain signal processing based on the characteristics of the image pickup device 4 to perform TV display and memory recording. It is output as the video signal I converted into each possible format. On the other hand, the brightness information J1 of the entire screen and the brightness information J2 corresponding to each pixel of the mirror device 2 are extracted by the signal processing circuit 5 and output to the mirror control unit 6. The mirror control unit 6 uses the brightness information J1 of the entire screen and the brightness information J2 of each pixel so that the image pickup device does not saturate and the entire image becomes an image with appropriate exposure conditions.
To the relay lens 3 for each pixel of the mirror device 2
The amount of exposure is changed depending on the ON time of the light reflected on. For example, in the case of a backlit state, the exposure condition of the whole screen is set to a dark part which is not backlit, and a constant ON time is set, and the pixels of the part of the backlit condition are shorter than the exposure condition of the whole screen according to the brightness of the whole backlit part. Set to ON time. By controlling under the condition of over-forward light and under the condition of back light, it is possible to obtain image information with a high dynamic range without blackout or overexposure.

(Second Embodiment) FIG. 3 shows an image pickup apparatus according to the second embodiment. In the first embodiment, the mirror device 2 is configured to adjust the exposure of the entire screen.
In this case, the exposure time is very short for a bright subject, and the S / N may not be good in a place where the brightness of the screen is low, and the condition for flash photography may be the same for moving images. Then, by incorporating it in the shooting lens 1 or making it close to it, a normal camera, video camera,
A diaphragm 7 used in DSC or the like is arranged. The diaphragm 7 is controlled by the diaphragm controller 8.

The overall operation is similar to that of the first embodiment, but the way of handling the brightness information is different. In the second embodiment, the brightness information J of the entire screen extracted by the signal processing circuit 5
Brightness information J2 corresponding to each pixel of the aperture control unit 8 and the mirror device 2 is input to the mirror control unit 6, the exposure of the entire screen is adjusted by the aperture 7, and the subject under the condition of backlight or over-forward light Is the mirror control unit 6 and the mirror device 2
The ON time of the mirror of each pixel is adjusted according to the conditions. As a result, it is possible to obtain image information having a high S / N and a high dynamic range without blackout or whiteout.

(Third Embodiment) FIG. 4 shows an image pickup apparatus according to the third embodiment. Although the basic configuration is based on the second embodiment, the taking lens 1 and the mirror device 2
A prism 9 is inserted between the relay lens 3 and the relay lens 3 as shown in FIG. FIG. 5 shows a detailed state of the prism 9 and its surroundings. The light flux emitted from the taking lens 1 first passes through the prism block 91 and then the prism block 92.
A subject image is formed on the mirror device 2 after passing through.
The image reflected by the mirror device 2 is a prism block 9
The light is totally reflected by the reflecting surface M of No. 2, and thereafter reaches the image pickup device 4 via the relay lens 3. Here, the prism block 91 and the prism block 92 are configured and shaped such that the light paths passing through the prism have equivalent optical path lengths. Further, the reflecting surface M is tilted so as to satisfy the condition of total reflection with respect to the reflected light from the mirror device 2. As a result, the entire structure can be made more compact than when the reflected light is directly received by the relay lens 3.

(Fourth Embodiment) FIG. 6 shows the configuration of a signal processing circuit 5 of an image pickup apparatus according to the fourth embodiment. As shown in FIG. 7, the relay lens 3 and the image pickup device 4 need to be in a tilted relationship with the mirror device 2 in order to maintain a focused relationship. At this time, the image is deformed because P1, P2, ... Pn at equal intervals on the mirror device become coarser as they are closer to P'1 on the image sensor 4 and denser as they are closer to P'n. An image with a different so-called perspective is formed. Therefore, as shown in FIG. 6, a video signal processing circuit 51 for forming a video signal in the signal processing circuit 5
Thereafter, the perspective correction circuit 53 corrects the deformation based on the deformation information stored in the memory 52, and an image similar to the subject image can be obtained. Here, the perspective correction is performed based on the information in the memory 52, but it may be based on the calculation. Further, at the time of correction, a process that is generally used in video processing such as averaging or interpolation is used so that the image is in a good state.

(Fifth Embodiment) FIG. 8 shows an image pickup apparatus according to the fifth embodiment. The constituent elements are the same as those in the third and fourth embodiments. Mirror control amount, that is, mirror is ON
Is output to the signal processing circuit 5 as information J3, and the signal processing circuit 5 corrects the signal amount for each pixel based on J3. That is, 1 for the standard ON time of the mirror
If the time is / 2, the signal is doubled, and if the time is twice, the signal is halved. As a result, a signal with a high dynamic range can be taken out without being restricted by the bit length of the AD converter of the input of the signal processing circuit 5, and for example, the image of a portion desired to be viewed with good gradation can be processed and produced. it can. That is, it is possible for the operator to improve the gradation of the portion he wants to see.

(Sixth Embodiment) FIG. 9 shows an image pickup apparatus according to the sixth embodiment. The configuration is from the second embodiment.
An electronic shutter control unit 10 that uses an electronic shutter of an image sensor is provided in place of the diaphragm 7 and the diaphragm control unit 8 in any one of the image pickup devices of No. 5 and 5. The function is the same as that of the diaphragm 7, and an appropriate exposure condition is calculated as the exposure time of the electronic shutter from the brightness information J1 of the entire screen to control the exposure time of the image sensor. This makes it possible to use an inexpensive configuration for setting the exposure conditions for the entire screen.

[0026]

As described above, according to the present invention, a subject image is reflected by an array of microscopic mirrors capable of changing the amount of reflected light for each pixel, and the image is received by an image pickup device, so that the backlight condition or the overshooting condition is exceeded. It is possible to provide an image pickup apparatus that has a high dynamic range with no blackouts and whiteouts even when exposed to light, has a good S / N, and has little image deterioration.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a mirror device showing the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an image pickup apparatus showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram of an image pickup apparatus showing a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a prism showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a signal processing circuit 5 showing a fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram of perspective change showing the fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of an image pickup apparatus showing a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram of an image pickup apparatus showing a sixth embodiment of the present invention.

[Explanation of symbols]

1 Shooting lens 2 Mirror device 3 relay lens 4 image sensor 5 Signal processing circuit 6 Mirror controller 7 aperture 8 Aperture controller 9 prism

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H002 CC00 CC21 HA01 JA07                 2H101 FF00                 5C022 AB03 AB12 AB43 AC51 AC56                       AC69

Claims (10)

[Claims] 1. A first lens for forming an image of a subject, a reflecting means having a structure in which microscopic mirrors are arranged two-dimensionally on the image forming surface of the first lens, and reflected by the reflecting means. A second lens that captures the subject image;
An image sensor for converting the subject image captured by a lens into an electric signal, a signal processing means for forming a video signal which is video information from the electric signal photoelectrically converted by the image sensor, and the microscopic mirror of the reflecting means. Is an image pickup apparatus including a mirror control unit for individually controlling each of the micro mirrors, the mirror control unit controlling the micro mirrors to change the brightness of information of a subject image on a reflecting unit for each of the micro mirrors. An image pickup device, characterized by being guided to an image pickup element. 2. A first lens that forms a subject image, a diaphragm that is incorporated in or close to the first lens and that adjusts the amount of light that enters the first lens, and a diaphragm that is disposed on the image forming surface of the first lens. The reflecting means having a structure in which the minute mirrors are two-dimensionally arranged, the second lens for photographing the subject image reflected by the reflecting means, and the subject image photographed by the second lens as an electric signal An image sensor for converting, a signal processing unit for forming a video signal which is video information from an electric signal photoelectrically converted by the image sensor, a mirror control unit for individually controlling the minute mirrors of the reflecting unit, and the diaphragm. An image pickup apparatus comprising an aperture control unit for controlling, wherein the aperture control unit adjusts the brightness of a subject image formed on the reflecting means, and the mirror control unit controls the minute mirror. Imaging apparatus characterized by guiding the imaging element by changing the brightness information of the object image for each of the micromirrors on the reflection means by. 3. The mirror control section adjusts the brightness of a subject image formed by the diaphragm on the reflecting means by the diaphragm control section,
The image pickup apparatus according to claim 2, wherein the minute mirror is controlled to adjust the exposure amount so that an appropriate amount of light enters the image pickup element. 4. The image pickup device according to claim 1, wherein the second lens and the image pickup device are arranged so as to hold an image-forming relationship in focus with respect to the plane of the reflecting means. apparatus. 5. A prism is disposed between the first lens and the reflecting means and between the reflecting means and the second lens, and the reflected light from the reflecting means is totally reflected by the prism and is incident on the second lens. The imaging device according to any one of 3 above. 6. The image pickup apparatus according to claim 4, wherein the signal processing means transforms the image information so as to correct the change in perspective generated in the image on the subject and the image pickup element. 7. The mirror control unit individually controls the minute mirrors based on the information on the brightness of the image calculated by the signal processing unit, and the exposure amount is adjusted so that an appropriate light amount enters the image pickup device. The image pickup apparatus according to claim 1. 8. The image pickup apparatus according to claim 7, wherein the mirror control section sends each control amount for controlling each micro mirror to the signal processing means to correct the corresponding video signal. 9. The mirror control unit switches between the arrangement of the mirrors in the ON state in which the subject image is incident on the second lens and the arrangement of the mirrors in the OFF state in which the subject image is not incident on the second lens, for each of the minute mirrors. 9. The image pickup apparatus according to claim 7, wherein the exposure amount to the image pickup element is changed by changing the time during which the ON state continues for a certain period of time. 10. The signal processing means adjusts the brightness of the entire image by using an electronic shutter of an image sensor based on the information on the brightness of the image calculated in the signal processing means. The imaging device according to any one of to 9.