JP2008147749A - Color camera device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color camera device capable of reducing the shift and color phase irregularity of an image and photographing a fast and smooth moving picture. <P>SOLUTION: A liquid crystal color filter is used as a color filter 20 capable of varying transmission wavelength of light by varying an applied voltage, and a CMOS image sensor is used as an image sensor 40. A control circuit 1209 controls a voltage applied to the color filter 20 so that the wavelength of light transmitted through the color filter 20 continuously varies within a fixed wavelength range and the variation periodically repeats, and also controls the operation of the image sensor 40 in each timing when light beams with three reference wavelengths needed to obtain a color image are transmitted through the color filter 20 in each period of the variation in transmission wavelength, thereby acquiring image data of the three reference wavelengths as color image data of one picture on a time-division basis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a color camera device that acquires a color image using an image sensor.

  FIG. 8A is a schematic configuration diagram of a color camera device as a first conventional example, and FIG. 8B is a schematic block diagram of the color camera device. As shown in FIG. 8, a color camera device as a first conventional example includes a red filter 220a, a green filter 220b, a blue filter 220c, three image sensors 240a, 240b, 240c, and three AD converters 250a. , 250b, 250c, three image memories 270a, 270b, 270c, an image processing device 280, and a control circuit 290.

  In such a color camera device, filters 220a, 220b, and 220c are installed in the three image sensors 240a, 240b, and 240c, respectively. Each filter 220a, 220b, 220c transmits light of a predetermined color among incident light. Thereby, light of each color can be taken into a predetermined image sensor, and a color image can be obtained. Specifically, the red wavelength optical image transmitted through the red filter 220a is captured by the image sensor 240a and converted into an electrical signal. The converted electrical signal is digitized by the AD converter 250a to obtain red image data. Similarly, an optical image having a green wavelength transmitted through the green filter 220b is taken into the image sensor 240b and converted into an electric signal, and then the converted electric signal is converted into green image data by the AD converter 250b. The blue wavelength optical image transmitted through the blue filter 220c is taken into the image sensor 240c and converted into an electric signal, and then the converted electric signal is converted into blue image data by the AD converter 250c. Here, the operations of the image sensors 240a, 240b, 240c and the AD converters 250a, 250b, 250c are controlled by the control circuit 290. For example, 8-bit binary data per pixel is used as the image data for each color. The red image data, green image data, and blue image data thus obtained are stored in the image memories 270a, 270b, and 270c, respectively.

  The image processing device 280 combines the image data of each color stored in the three image memories 270a, 270b, and 270c to generate 24-bit color image data per pixel. Specifically, when one screen is composed of 400 pixels in the vertical direction and 600 pixels in the horizontal direction, a total of 400 × 600 × 3 = 720000 photoelectric conversion elements constituting the three image sensors 240a, 240b, and 240c. I need. Since the data amount of the color image data is 24 bits per pixel, it is 720000 × 24 bits = 17280000 bits = 21600000 bytes = 2.16 megabytes. The image processing device 280 performs image processing such as image compression and color correction on the color image data.

By the way, in a color camera device, it is necessary to form an image sensor in a limited size due to limitations in optical design. For example, when the area of the three image sensors 240a, 240b, and 240c is 24 cm ² , the size of one pixel is about 0.33 × 10 ⁻⁴ cm ² . The resolution of color camera devices tends to be further increased in the future, but for this purpose, it is necessary to reduce the size of the photoelectric conversion elements and increase the degree of integration. However, this reduces the light receiving area, which may cause adverse effects such as a decrease in light receiving sensitivity and a decrease in response speed. As described above, in the conventional color camera device, it is very difficult to simultaneously realize high resolution, high sensitivity, high response, high color gradation, miniaturization, and the like.

  In order to solve the above-described problems, a color camera apparatus that recently applied a method of providing a transmission wavelength variable color filter on the front surface of an image sensor and capturing image data of three primary colors while sequentially changing the transmission wavelength. Has been devised (see, for example, Patent Document 1). Here, this color camera device is a second conventional example. FIG. 9A is a schematic configuration diagram of a color camera device as a second conventional example, and FIG. 9B is a schematic block diagram of the color camera device. As shown in FIG. 9, a color camera device as a second conventional example includes a color filter 320, a driver circuit 330, an image sensor 340, an AD converter 350, three registers 360a, 360b, 360c, Two image memories 370a, 370b, and 370c, an image processing device 380, and a control circuit 390 are provided.

  The color filter 320 selects light having a specific wavelength from incident light and guides it to the image sensor 340. By varying the voltage applied to the color filter 320, the wavelength of light transmitted through the color filter 320 can be varied. The driver circuit 330 applies a voltage to the color filter 320. The control circuit 390 controls the voltage applied to the color filter 320 via the driver circuit 330, sets the transmission wavelengths of the color filter 320 to the wavelengths of the three primary colors, and controls the operations of the image sensor 340 and the AD converter 350. .

  Next, the operation of the color camera device as the second conventional example will be described. FIG. 10A is a diagram for explaining a waveform of a voltage applied to the color filter 320 in the color camera device, and FIG. 10B is a color filter when the voltage of FIG. 10A is applied to the color filter 320. It is a figure for demonstrating the change of the transmission wavelength of 320. FIG. Here, in FIG. 10A, the vertical axis represents the applied voltage, and the horizontal axis represents time. In FIG. 10B, the vertical axis represents the transmission wavelength, and the horizontal axis represents time.

As shown in FIG. 10, at time _{t 0,} the color filter 320 the control circuit 390 through a driver circuit 330, when a predetermined voltage is applied to _{V R,} after the predetermined response time _{T 0} has passed, the color filter 320 the transmissive wavelength reaches the red wavelength lambda _R. In general, the response time T ₀ from when a voltage is applied to the electrode of the color filter until the transmission wavelength of the color filter starts changing requires about 10 ms. Then, the control circuit 390 by controlling the operation of the image sensor 340 at a timing when the transmission wavelength of the color filter 320 has reached the red wavelength lambda _R, the optical image of the red wavelength lambda _R transmitted through the color filter 320 is an image sensor 340 Is converted into an electrical signal. The converted electrical signal is digitized by the AD converter 350 to obtain red image data. On the other hand, when the optical image of the red wavelength lambda _R is incorporated into the image sensor 340, the control circuit 390 turns off the voltage to be immediately applied to the color filter 320.

Thus, when the response time T ₀ elapses after the applied voltage is turned off, the transmission wavelength of the color filter 320 returns to the initial state. The control circuit 390 applies a predetermined voltage V _G to the color filter 320 at the timing when the transmission wavelength of the color filter 320 returns to the initial state. Then, after the response time T ₀ has elapsed, the transmission wavelength of the color filter 320 reaches the green wavelength λ _G. Then, the control circuit 390 by controlling the operation of the image sensor 340 at a timing when the transmission wavelength of the color filter 320 reaches the green wavelength lambda _G, an optical image of the green wavelength lambda _G that passes through the color filter 320 is an image sensor 340 Is converted into an electrical signal. The converted electrical signal is digitized by the AD converter 350 to obtain green image data. On the other hand, when the optical image of the green wavelength lambda _G is taken into the image sensor 340, the control circuit 390 turns off the voltage to be immediately applied to the color filter 320.

When the response time T ₀ elapses after the applied voltage is turned off, the transmission wavelength of the color filter 320 returns to the initial state again. The control circuit 390 applies a predetermined voltage V _B to the color filter 320 at the timing when the transmission wavelength of the color filter 320 returns to the initial state. Then, after the response time T ₀ has elapsed, the transmission wavelength of the color filter 320 reaches the blue wavelength λ _B. Then, the control circuit by controlling the operation of the image sensor 340 at 390 the timing of the transmission wavelength of the color filter 320 reaches the blue wavelength lambda _B, the optical image of the blue wavelength lambda _B transmitted through the color filter 320 is an image sensor 340 Is converted into an electrical signal. The converted electrical signal is digitized by the AD converter 350 to obtain blue image data. On the other hand, when the optical image having the blue wavelength λ _B is captured by the image sensor 340, the control circuit 390 immediately turns off the voltage applied to the color filter 320.

  The red image data, green image data, and blue image data thus obtained are stored in the image memories 370a, 370b, and 370c via the registers 360a, 360b, and 360c, respectively. The image processing device 380 generates color image data by combining the image data of each color stored in the three image memories 370a, 370b, and 370c, and performs predetermined image processing on the generated color image data. Apply.

  As described above, in the color camera device of the second conventional example, one color filter 320 is used, and the transmission wavelength of the color filter 320 is sequentially changed to a red wavelength, a green wavelength, and a blue wavelength, and one image sensor 340 is used. The image data for each color is imported. Thus, in the second conventional example, it is not necessary to provide an image sensor for each of the three primary colors, so that the size per pixel of the image sensor can be made wider than in the first conventional example. Therefore, even if the size of the photoelectric conversion element is reduced in order to increase the resolution, the light receiving sensitivity does not decrease so much.

Japanese Patent Laid-Open No. 11-205807

  However, in the second conventional example described above, the voltage of the color filter is applied after the voltage is applied to the electrode of the color filter until the transmission wavelength of the color filter starts to change, or after the voltage applied to the color filter is turned off. A predetermined response time, for example, about 10 ms is required until the transmission wavelength returns to the initial state. Specifically, in the example of FIG. 10, it takes about 20 ms from capturing red image data to capturing green image data, and approximately 20 ms from capturing green image data to capturing blue image data. For this reason, since it takes about 40 ms from taking in the red image data to taking in the blue image data, there is a problem in that when a moving subject is photographed, an image shift or color unevenness occurs in the color image. is there. In addition, in the example of FIG. 10, the cycle of capturing a color image for one screen is about 60 ms, and the maximum number of moving images that can be captured at about 16 screens / second is the limit. For this reason, with the color camera device of the second conventional example, it is difficult to perform high-speed and smooth moving image shooting.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide a color camera device that can reduce the occurrence of image shift and color unevenness and enables high-speed and smooth video shooting. Is.

  In order to achieve the above object, a color camera device according to the first aspect of the present invention includes a color filter capable of changing a transmission wavelength of light by changing an applied voltage, and a specific wavelength transmitted through the color filter. An image sensor that obtains image data of the specific wavelength by converting the image information of the light into an electrical signal, and the wavelength of the light transmitted through the color filter continuously changes within a certain wavelength range and the change The voltage applied to the color filter is controlled to repeat periodically, and light of three reference wavelengths necessary for obtaining a color image is transmitted through the color filter in each period of change in the transmission wavelength. By controlling the operation of the image sensor at each timing, the image data of the three reference wavelengths is converted into color image data for one screen. It is characterized in that it comprises a control means for acquiring the time division to.

  According to a second aspect of the present invention, in the color camera device according to the first aspect, the control means is configured such that the transmission wavelength of the color filter is substantially linear or stepwise from a maximum wavelength to a minimum wavelength within the certain wavelength range. A period including a first period that changes to a second period in which the transmission wavelength of the color filter is maintained at the maximum wavelength is a period of a change in the transmission wavelength of the color filter. The voltage applied to the color filter is controlled.

  According to a third aspect of the present invention, in the color camera device according to the first aspect, the control means is configured such that the transmission wavelength of the color filter is substantially linear or stepwise from a maximum wavelength to a minimum wavelength within the fixed wavelength range. And a second period in which the transmission wavelength of the color filter changes substantially linearly or stepwise from the minimum wavelength to the maximum wavelength is a transmission wavelength of the color filter. The voltage applied to the color filter is controlled so as to be one cycle of the change.

  According to a fourth aspect of the present invention, in the color camera device according to the first, second, or third aspect, the control means transmits the light of the three reference wavelengths through the color filter in each period of a change in transmission wavelength. In addition to controlling the operation of the image sensor at each timing, the operation of the image sensor is controlled at each timing at which one or a plurality of light of a predetermined wavelength passes through the color filter in addition to the light of the three reference wavelengths. By doing so, the image data of the three reference wavelengths and the image data of the one or more predetermined wavelengths are acquired in a time division manner.

  In the first aspect of the present invention, the control means applies to the color filter so that the wavelength of the light transmitted through the color filter continuously changes within a certain wavelength range and the change of the transmission wavelength repeats periodically. By controlling the voltage and controlling the operation of the image sensor at each timing when light of three reference wavelengths necessary for obtaining a color image is transmitted through the color filter in each period of the change in the transmission wavelength, The image data of the three reference wavelengths are acquired in a time division manner as color image data for one screen. Here, when the transmission wavelength of the color filter continuously changes within a certain wavelength range, the time required to change from one wavelength to another within the wavelength range is very short. As a result, the image data of the three reference wavelengths can be obtained within a short period in which the transmission wavelength continuously changes. For these three reference image data, the remaining two after the first image data is acquired. The waiting time until one image data is acquired becomes very short. For this reason, it is possible to sufficiently reduce the occurrence of image shift and color unevenness among the image data of each reference wavelength constituting the color image data for one screen, and also enables high-speed and smooth shooting. . Therefore, with the color camera device of the present invention, it is possible to obtain a high-quality and high-resolution image at high speed.

  In addition, by handling the image data of the three reference wavelengths constituting the color image data for one screen in a time-sharing manner, the image data of each reference wavelength may be data having a smaller amount of data than in the past. When image processing is performed, image data with a small amount of data only needs to be processed for each reference wavelength, so that the amount of calculation for image processing can be reduced and the processing speed can be improved.

  In the invention according to claim 2, the control means includes a first period in which the transmission wavelength of the color filter changes substantially linearly or stepwise from the maximum wavelength to the minimum wavelength within a certain wavelength range, and then the color filter. The voltage applied to the color filter is controlled so that the period including the second period in which the transmission wavelength is the maximum wavelength is one cycle of the change in the transmission wavelength of the color filter. As a result, the transmission wavelength of the color filter changes substantially linearly or stepwise within the first period, so the control means manages the elapsed time from a certain point in time and operates the image sensor based on the elapsed time. Each timing to be performed can be easily determined.

  In the invention according to claim 3, the control means includes a first period in which the transmission wavelength of the color filter changes substantially linearly or stepwise from the maximum wavelength to the minimum wavelength within a fixed wavelength range, and thereafter the color filter The voltage applied to the color filter is set so that the period including the second period in which the transmission wavelength changes approximately linearly or stepwise from the minimum wavelength to the maximum wavelength is one cycle of the change in the transmission wavelength of the color filter. Control. As a result, the image data of each reference wavelength is acquired not only in the first period but also in the second period, and color image data for two screens is acquired during one cycle of the change in the transmission wavelength of the color filter. Therefore, it is possible to realize a color camera device capable of higher-speed shooting.

  In the invention according to claim 4, the control means not only controls the operation of the image sensor at each timing when the light of the three reference wavelengths transmits through the color filter in each cycle of the change of the transmission wavelength, but also controls the three references. By controlling the operation of the image sensor at each timing when light of one or a plurality of predetermined wavelengths passes through the color filter in addition to the light of the wavelengths, the image data of the three reference wavelengths and the one or more of the predetermined wavelengths Acquire image data in time division. As a result, more color information can be obtained, so that an image with higher quality and good color reproducibility can be obtained.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  First, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a schematic configuration diagram of a color camera apparatus according to the first embodiment of the present invention, and FIG. 1B is a schematic block diagram of the color camera apparatus. As shown in FIG. 1, the color camera device of the first embodiment includes a lens 10, a color filter 20, a driver circuit 30, an image sensor 40, an AD converter 50, a control signal generation circuit 60, and three Image memories 71, 72, 73, an image processing device 110, and a control circuit 120 are provided. Hereinafter, a case where a color image of the subject A is continuously captured using such a color camera device will be described.

  The lens 10 forms light on the photoelectric surface of the image sensor 40 as an optical image (optical image information) from the subject A. When photographing, it is necessary to adjust the positional relationship between the lens 10 and the image sensor 40 by moving the lens 10 so that an image of the subject A is formed on the photocathode of the image sensor 40.

  The color filter 20 is provided between the lens 10 and the image sensor 40. The color filter 20 selects light of a specific wavelength from light incident through the lens 10 and guides it to the image sensor 40. In the first embodiment, the color filter 20 that can change the transmission wavelength of light by changing the applied voltage is used. Specific examples of the color filter 20 include a liquid crystal color filter manufactured using liquid crystal and an organic color filter manufactured using organic electrochromic. Here, a case where a liquid crystal color filter is used as the color filter 20 will be described.

  The liquid crystal color filter has a structure in which a number of liquid crystal filters and deflection filters are combined. When a predetermined voltage is applied to the electrodes of the liquid crystal filter, the alignment of the liquid crystal material is aligned in the voltage (current) direction, and the light transmittance through the liquid crystal filter changes. In the liquid crystal color filter, since the liquid crystal filter and the deflection filter are combined, only light having a specific wavelength can be transmitted by the liquid crystal lattice effect when a voltage is applied. Thus, the applied voltage and the transmission wavelength of the liquid crystal color filter have a one-to-one correspondence. In addition, the liquid crystal color filter exhibits a gradual response characteristic with respect to a change in applied voltage. For this reason, if the voltage applied to the liquid crystal color filter is appropriately controlled, the wavelength of light transmitted through the liquid crystal color filter can be continuously changed. In the first embodiment, the control circuit 120 controls the voltage applied to the color filter 20 via the driver circuit 30.

  The driver circuit 30 applies a voltage to the color filter 20, and includes a power supply unit 31, a variable resistor 32, and an amplifier 33 as shown in FIG. The power supply unit 31 generates a voltage to be applied to the color filter 20. The variable resistor 32 adjusts the applied voltage, and the amplifier 33 amplifies the applied voltage. Here, the driver circuit 30 outputs a voltage having a substantially sawtooth waveform as shown in FIG. The driver circuit 30 is controlled by the control circuit 120.

  The image sensor 40 obtains image data (luminance data) of a specific wavelength by converting image information of light of a specific wavelength transmitted through the color filter 20 into an electrical signal. The operation of the image sensor 40 is controlled based on a signal from the control signal generation circuit 60. The image sensor 40 is composed of a large number of photoelectric conversion elements. Here, one photoelectric conversion element is used for one pixel. Specifically, when obtaining an image of 400 pixels in the vertical direction and 600 pixels in the horizontal direction, the number of photoelectric conversion elements used in one screen is 240000 (= 400 × 600). That is, in the first embodiment, as will be described later, since the image data of each wavelength of the three primary colors is acquired in a time-sharing manner, even when shooting a color image, the photoelectric required for shooting a monochrome image is obtained. It is only necessary to use an image sensor composed of the same number of photoelectric conversion elements as the number of conversion elements.

  As the image sensor 40, it is desirable to use a high-sensitivity image sensor that can be exposed at a shutter speed of, for example, about 200 μs, specifically, a CMOS image sensor, a CCD image sensor, an electronic image pickup tube, or the like. In particular, in the first embodiment, a CMOS image sensor is used as the image sensor 40. Since the CMOS image sensor has a built-in shutter (electronic shutter) in the chip, there is no need to provide a mechanical shutter, and there is an advantage that control is easy. On the other hand, when a CCD image sensor is used as the image sensor 40, it is difficult to manufacture an electronic shutter in the chip in the manufacturing process, and therefore it is necessary to provide a mechanical shutter.

  Here, the circuit configuration of the photoelectric conversion element and the shutter in the CMOS image sensor 40 will be described. FIG. 2 is a diagram for explaining the circuit configuration of the photoelectric conversion element and the shutter in the CMOS image sensor 40. The circuit shown in FIG. 2 includes a photoelectric conversion element 41, a capacitor 42, and four transistors 43, 44, 45, and 46. When light of a specific wavelength that has passed through the color filter 20 enters the photoelectric conversion element 41, photoelectric charges corresponding to the intensity of the light are generated in the photoelectric conversion element 41. The transistor 43 corresponds to a shutter. That is, when the transistor 43 is turned on, the shutter is opened, and when the transistor 43 is turned off, the shutter is closed. When the shutter is opened, the photoelectric charge generated in the photoelectric conversion element 41 is stored in the capacitor 42. By taking out the photoelectric charge stored in the capacitor 42, the light intensity at that time can be read. Transistors 44 and 45 are used to extract such photocharges. These transistors 44 and 45 correspond to amplifiers. When the transistor 45 is turned on, an electrical signal corresponding to the photocharge stored in the capacitor 42 is output from the line 47, whereby the light intensity is read. The transistor 46 is a so-called resetting transistor that erases the electric charge stored in the capacitor 42. After the light intensity is read as described above, the transistor 46 is turned on to immediately erase the photocharge stored in the capacitor 42 and set the photoelectric conversion element 41 to the initial state. This prepares for the next reading operation. Such a reading operation is performed on each photoelectric conversion element, and a light intensity signal for each pixel is obtained. The entire light intensity signal for each pixel is image data of the specific wavelength. As described above, in a CMOS image sensor incorporating an electronic shutter, the photoelectric conversion element and the electronic shutter can be individually controlled to operate them accurately and at high speed. Therefore, it can be said that the CMOS image sensor is an effective means for high-speed shooting as compared with a CCD image sensor in which a mechanical shutter needs to be provided.

  The AD converter 50 converts luminance data obtained by the image sensor 40 into digital image data. The operation of the AD converter 50 is controlled based on a signal from the control signal generation circuit 60. In the first embodiment, binary data of 8 bits per pixel is used as digital image data. This 8-bit data can express the light intensity up to 256 gradations. Since the bit length can be easily increased, a desired bit length corresponding to the desired image quality may be determined as the bit length of the digital image data per pixel. For example, in response to a request for high image quality, the bit length is set to 16 bits or 24 bits.

  The control signal generation circuit 60 generates a control signal (read signal) for the image sensor 40 at a predetermined timing based on the timing signal sent from the control circuit 120 and sends the control signal to the image sensor 40. When the image sensor 40 receives the control signal (reading signal), the image sensor 40 performs an image reading operation at the received timing. Further, the control signal generation circuit 60 generates a control signal (start signal) for the AD converter 50 at a predetermined timing based on the timing signal, and sends it to the AD converter 50. When receiving the control signal (start signal), the AD converter 50 starts the conversion process.

The control circuit 120 controls the overall operation of each unit in order to obtain a color image. To obtain a color image, light of three reference wavelengths, for example, light of a red wavelength λ _R (for example, 700 nm), light of three primary colors, light of a green wavelength λ _G (for example, 546.1 nm), and blue wavelength λ _B (for example, 435.8 nm) is taken into the image sensor 40 and image data of each reference wavelength needs to be acquired. The image data of these three reference wavelengths constitute color image data for one screen. In the first embodiment, when imaging the subject A, the control circuit 120 continuously changes the wavelength of light transmitted through the color filter 20 within a certain wavelength range and periodically repeats the change. The voltage applied to the color filter 20 is controlled, and the operation of the image sensor 40 is controlled at each timing when light of three reference wavelengths is transmitted through the color filter 20 in each period of change in the transmission wavelength. That is, the image data of the three reference wavelengths necessary to obtain a color image are obtained by releasing the shutter of the image sensor 40 only three times within a period in which the transmission wavelength of the color filter 20 changes in each cycle. It is acquired in the division.

  As described above, in the first embodiment, a liquid crystal color filter is used as the color filter 20. This liquid crystal color filter has the following response characteristics. That is, the response time of the liquid crystal color filter is generally about 20 ms, and is about 8 ms even in the case of a high-speed response product. It is well known that the response time of the liquid crystal color filter is slow. Here, the response time of the liquid crystal color filter is the time from when the voltage is applied to the liquid crystal color filter until the liquid crystal color filter starts a response to the voltage application (change in transmission wavelength). Say. In addition, as a result of investigations by the present inventors, when the transmission wavelength of the liquid crystal color filter changes within a certain wavelength range, it takes a very short time to change from one wavelength to another within the wavelength range. I understood. This is presumably because the amount of movement of particles inside the filter is proportional to time. For this reason, if the transmission wavelength of the liquid crystal color filter is kept at a predetermined wavelength in advance, and then the transmission wavelength of the liquid crystal color filter is continuously changed within a certain wavelength range from the predetermined wavelength, During the change period, the liquid crystal color filter operates at high speed. In the first embodiment, this fact is used to acquire image data of three reference wavelengths within a period in which the transmission wavelength of the liquid crystal color filter is changing. As a result, color imaging for one screen can be completed in a very short time, and a color image free from image displacement and color unevenness can be obtained. That is, in the color camera device of the first embodiment, as in the second conventional example described above, in the color photographing for one screen, the transmission wavelength of the liquid crystal color filter is initialized every time image data of each reference wavelength is acquired. It does not return to the state. Further, in order to perform shooting while the liquid crystal color filter is operated at high speed in this way, a CMOS image sensor capable of high-speed shooting is used as the image sensor 40.

  Now, the applied voltage of the color filter 20 and the change in the transmission wavelength of the color filter 20 according to the applied voltage will be described in detail. 3A is a diagram for explaining a waveform of a voltage applied to the color filter 20 in the color camera device of the first embodiment, and FIG. 3B is a diagram in which the voltage of FIG. 3A is applied to the color filter 20. It is a figure for demonstrating the change of the transmission wavelength of the color filter 20 at the time. Here, in FIG. 3A, the vertical axis represents the applied voltage, and the horizontal axis represents time. In FIG. 3B, the vertical axis represents the transmission wavelength, and the horizontal axis represents time.

In the first embodiment, a substantially sawtooth voltage as shown in FIG. 3A is periodically applied to the color filter 20. Specifically, this applied voltage continuously changes from voltage V ₁ to voltage V ₂ during time T ₁₁ and is then held at that voltage V ₁ during time T ₁₂ . Thereafter, the applied voltage repeats the same change. Here, the voltage V ₁ is a set value of the applied voltage when the transmission wavelength of the color filter 20 becomes the predetermined wavelength λ ₁ near the red wavelength λ _R , and the voltage V ₂ is the transmission wavelength of the color filter 20 is blue. This is the set value of the applied voltage when the predetermined wavelength λ ₂ is near the wavelength λ _B. In practice, the wavelength λ ₁ is set to a wavelength slightly longer than 700 nm, for example, and the wavelength λ ₂ is set to a wavelength slightly shorter than 435.8 nm, for example. That is, the blue wavelength λ _B , the green wavelength λ _G , and the red wavelength λ _R are included in the range from the wavelength λ ₂ to the wavelength λ ₁ . Also, setting the time _{T 12} to the filter response time _{T 0.}

When a substantially sawtooth voltage shown in FIG. 3A is periodically applied to the color filter 20, the transmission wavelength of the color filter 20 continuously changes following the voltage change as shown in FIG. 3B. Indicates. Specifically, it is assumed that the applied voltage starts changing from the voltage V ₁ to the voltage V ₂ at time t ₀ . After the filter response time T ₀ (= T ₁₂ ) has elapsed from time t _0, the transmission wavelength of the color filter 20 starts changing from the wavelength λ ₁ to the wavelength λ ₂ . Here, in the first embodiment, the control circuit 120 adjusts the value of the variable resistor 32 of the driver circuit 30 in advance, and the transmission wavelength of the color filter 20 changes from the wavelength λ ₁ to the wavelength λ _{2 over} time. The applied voltage is controlled so as to change substantially linearly. For example, the time from the time t _{0 +} T ₀ start changes in certain T _1R has elapsed, the transmission wavelength of the color filter 20 reaches the red wavelength lambda _R, then the predetermined time T _1G has elapsed, the transmission wavelength of the color filter 20 There reached green wavelength lambda _G, then further predetermined time T _1B has elapsed, the transmission wavelength of the color filter 20 reaches the blue wavelength lambda _B. Then, when time T ₁₁ has elapsed from time t ₀ + T ₀ , the transmission wavelength of the color filter 20 reaches the wavelength λ ₂ . Immediately thereafter, the transmission wavelength of the color filter 20 changes rapidly from the wavelength λ ₂ to the wavelength λ ₁ in response to the applied voltage dropping from the voltage V ₂ to the voltage V ₁ at time t ₀ + T ₁₁ . The state in which the transmission wavelength of the color filter 20 is the wavelength λ ₁ is maintained for a time T ₁₂ (= T ₀ ). As described above, the transmission wavelength of the color filter 20 maintains the state in which the transmission wavelength is the wavelength λ ₁ after the first period T _{11 in} which the transmission wavelength changes substantially linearly from the wavelength λ ₁ to the wavelength λ _2. the period of the combination of the second time period T ₁₂ for performing a change to one period. Therefore, the use of color filters 20 of the first embodiment, in the first period T _11, it is possible to realize the sweep changes in spectrum light.

Here, as described above, the control circuit 120 adjusts the value of the variable resistor 32 of the driver circuit 30 in advance and applies the transmission wavelength of the color filter 20 so as to change substantially linearly with the passage of time. The voltage is controlled. However, for example, even if the voltage applied to the color filter 20 is changed linearly, the transmission wavelength of the color filter 20 does not necessarily change linearly. Actually, the value of the applied voltage for setting the transmission wavelength of the color filter 20 to a predetermined wavelength may be slightly different for each color filter, and the behavior when the transmission wavelength of the color filter 20 changes. May vary with temperature. That is, in general, the liquid crystal response time and the transmission wavelength vary depending on individual differences of the filters, the environment in which they are used (use temperature, operation time, etc.), and the like. Therefore, the control circuit 120 needs to determine the voltage to be applied to the color filter 20 in consideration of factors such as individual differences of the color filters 20 and operating temperatures. In the FIG. 3 (a), shows how the change in the applied voltage from the voltages V ₁ to the voltage V ₂ by a straight line, as can be seen from the above, necessarily state of change is not a straight line is not.

Further, by increasing the gradient of the change in applied voltage or the amount of change (voltage difference) in the applied voltage, the transmission wavelength change speed of the color filter 20 can be increased. In fact, in the first embodiment, the control circuit 120 is to precondition the value of the variable resistor 32 of the driver circuit 30, a first period T ₁₁ in each cycle of change in the transmission wavelength of the color filter 20 is about 2ms Thus, the applied voltage is controlled. Further, in the example of FIG. 3, the second time period _{T 12} is about 8 ms. Accordingly, the period T ₁₁ + T ₁₂ of the change in the transmission wavelength of the color filter 20 is about 10 ms.

Further, the control circuit 120, for example, the time T _1G until the transmission wavelength of the color filter 20 changes from the red wavelength λ _R to the green wavelength λ _G and the time until the transmission wavelength changes from the green wavelength λ _G to the blue wavelength λ _B. It is also possible to control the applied voltage so that T _1B is substantially the same. The time required for such a change is preferably set according to the characteristics of the image sensor 40.

Next, the operation timing of the image sensor 40 will be described. The image sensor 40 is within the first time period T ₁₁ in each cycle of change in the transmission wavelength of the color filter 20, at the timing when the read signal is sent from the control signal generating circuit 60, performs an operation of reading the image. The control signal generation circuit 60 can determine the timing for sending the read signal based on the elapsed time from the time when the applied voltage of the color filter 20 starts to change. From the time when the applied voltage of the color filter 20 starts to change from the voltages V ₁ to the voltage V _2, the transmission wavelength is a red wavelength lambda _R of the color filter _20, a green wavelength lambda _G, until it reaches the respective wavelength of the blue wavelength lambda _B This is because the time is constant.

Specifically, the control circuit 120 outputs a timing signal to the control signal generation circuit 60 at a timing when the applied voltage of the color filter 20 starts to change from the voltage V ₁ to the voltage V ₂ . The control signal generation circuit 60 manages the elapsed time from the time when the timing signal is sent from the control circuit 120. When the control signal generation circuit 60 determines that the elapsed time has reached the time T ₀ + T _1R , it sends a read signal to the image sensor 40. As a result, the shutter of the image sensor 40 is opened at the timing when the read signal is sent, and the image sensor 40 reads red wavelength image data (R image data). Next, when the control signal generation circuit 60 determines that the elapsed time has reached the time T ₀ + T _1R + T _1G , it sends a read signal to the image sensor 40. As a result, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads green wavelength image data (G image data). Thereafter, when the control signal generation circuit 60 determines that the elapsed time has reached the time T ₀ + T _1R + T _1G + T _1B , it sends a read signal to the image sensor 40. As a result, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads blue wavelength image data (B image data). In this way, during each period T ₁₁ + T ₁₂ of the change in the transmission wavelength of the color filter 20, the image data of the three reference wavelengths is acquired by the image sensor 40 in a time division manner and sequentially output to the AD converter 50. . Here, since the acquired image data of the three reference wavelengths is color image data for one screen, the period for photographing the color image for one screen is the same as the period of change in the transmission wavelength of the color filter 20. It is. Specifically, since the period is about 10 ms, when the color camera device of the first embodiment is used, about 100 screens (frames) are obtained per second, and smooth shooting is possible.

Here, although the first period T ₁₁ as described above is about 2 ms, in the first embodiment, as the image sensor 40, the use of the high-sensitivity CMOS image sensors can be exposed at a shutter speed of approximately 200μs , to cut three times the shutter of the image sensor 40 between the first period T ₁₁ is sufficiently possible.

  In order to more accurately determine the timing at which the control signal generation circuit 60 sends the read signal, the following method may be used. That is, an optical filter in which the transmission wavelength is fixed to the red wavelength, an optical filter in which the transmission wavelength is fixed to the green wavelength, and an optical filter in which the transmission wavelength is fixed to the blue wavelength are installed in a part of the image sensor 40, and those optical For each filter, detection means for detecting light transmitted through the optical filter is provided. When the control signal generation circuit 60 receives the detection signal from each detection unit, the control signal generation circuit 60 recognizes that the transmission wavelength of the color filter 20 has reached the wavelength of the light detected by the detection unit, and outputs the read signal to the image sensor 40. Can be sent to.

  Each image memory 71, 72, 73 stores digital image data output from the AD converter 50. The color image data for one screen is composed of R image data, G image data, and B image data, and these image data are finally converted into a first image memory 71, a second image memory 72, It is stored in the third image memory 73. Specifically, when the AD converter 50 outputs R image data, the R image data is first temporarily stored in the third image memory 73. Next, when the AD converter 50 outputs G image data, the R image data stored in the third image memory 73 is transferred to the second image memory 72, and the G image data is transferred to the third image memory 72. Stored in the memory 73. When the AD converter 50 outputs B image data, the R image data stored in the second image memory 72 is transferred to the first image memory 71 and stored in the third image memory 73. The image data is transferred to the second image memory 72 and the B image data is stored in the first image memory 73. Thus, the R image data, G image data, and B image data are stored in the first image memory 71, the second image memory 72, and the third image memory 73, respectively.

  As shown in FIG. 1B, the image processing apparatus 110 includes three image processing circuits 111, 112, and 113. The first image processing circuit 111 performs predetermined image processing on the R image data stored in the first image memory 71, and the second image processing circuit 112 is stored in the second image memory 72. The third image processing circuit 113 performs predetermined image processing on the B image data stored in the third image memory 73. Thus, image processing is performed for each image data of each reference wavelength. Specifically, the contents of the image processing performed in each of the image processing circuits 111, 112, and 113 include image compression processing and color correction processing. Each image processing circuit 111, 112, 113 starts processing based on a signal from the control circuit 120.

  The image compression process is a process for reducing the amount of data to be handled by comparing the previous and subsequent images with respect to the temporal change for the same wavelength color image, obtaining the difference, and converting the subsequent image into data. For example, as this compression method, there are a method in which only a portion having a luminance change between subsequent images is converted into data in a subsequent image, and a portion in which no luminance change is converted into data, or a method of handling pixel data as a large block image is there. Actually, there are various standardized formats (for example, JPEG) for the compression method, and the image processing circuits 111, 112, and 113 may perform calculations according to a predetermined format. Since a known technique can be used as the compression method, detailed description thereof is omitted here.

  The color correction process is a process for correcting a color, such as enhancing the color, for an image having the same wavelength color. Since a known technique can be used as the color correction method, a detailed description thereof is omitted here.

  By the way, in the conventional color camera device, data of 24 bits per pixel is used as color image data. For this reason, in the image compression processing, when comparing the previous and subsequent images, the amount of calculation becomes enormous, and the processing cannot be performed quickly. In contrast, in the first embodiment, image data of three reference wavelengths constituting color image data for one screen is handled in a time-sharing manner, and 8-bit data per pixel is used as image data of each reference wavelength. . Then, the image processing apparatus 110 performs processing independently on the image data of each reference wavelength, thereby reducing the amount of calculation in the image compression processing and increasing the processing speed.

  In the conventional color camera device, when color correction is performed on a specific pixel, it is necessary to use 24-bit data as the correction color for the 24-bit original data. For this reason, even in the color correction processing, the calculation processing is complicated, and there is a problem that the processing speed cannot keep up and a circuit scale is increased. Now, a calculation example for conventional color correction will be described in detail. Specifically, consider a case where correction for emphasizing color is performed on R image data of a certain pixel. The 24-bit original data (color image data) is assumed to be (331188). Here, this data notation (000000) is a hexadecimal notation. Of the data, the first two digits represent R image data, the next two digits represent G image data, and the last two digits represent B image data. First, in order to extract R image data, the logical product (AND) of the original data (331188) and (FF0000) is taken (step 1). Thereby, R image data (330000) is obtained. Next, a process of shifting the R image data to the right is performed to convert the R image data into data (000033) (step 2). Thereafter, a correction calculation is performed to add a predetermined correction value, for example, (000001) to the data (000033) (step 3). As a result, data (000034) is obtained. Next, a process for shifting the data to the left is performed, and the data is converted into data (340000) (step 4). Finally, a process for writing the data (340000) into the original data is performed, and corrected color image data (341188) is obtained (step 5). As described above, conventionally, there are many calculation steps in the color correction process.

  On the other hand, in the first embodiment, the image processing apparatus 110 handles the image data of each reference wavelength with respect to the image data of each reference wavelength by handling the image data of the three reference wavelengths constituting the color image data for one screen in a time division manner. Since each calculation is performed independently, the calculation amount in the color correction processing can be reduced and the processing speed can be increased. Specifically, similarly to the above example, a case will be described in which correction for emphasizing color is performed on R image data of a certain pixel. In the first embodiment, 8-bit data per pixel is used as image data for each reference wavelength. The original R image data is now (33). Here, the data notation (00) is a hexadecimal notation. In this case, the corrected R image data (34) is obtained simply by adding a predetermined correction value, for example, (01) to the original data (33). As described above, in the first embodiment, the calculation step in the color correction process can be reduced by about 80% compared to the conventional case, so that the image quality correction can be easily performed.

The image data of each reference wavelength processed by each image processing circuit 111, 112, 113 is output in a time division manner. That is, R image data, G image data, and B image data processed by the image processing apparatus 110 are sequentially output in that order. Here, the time required for outputting the data is, for example, 10 μs or less, which is very short compared to the filter response time T ₀ (= 8 ms). Therefore, it is possible to secure a sufficient time for image processing in the image processing apparatus 110. The shooting performance is not degraded.

  Next, in the color camera device of the first embodiment, a procedure of processing for photographing the subject A and acquiring the color image data will be described.

First, the positional relationship between the lens 10 and the image sensor 40 is adjusted so that an image of the subject A can be formed on the photocathode of the image sensor 40. Next, the control circuit 120 controls the driver circuit 30 to apply a periodic voltage shown in FIG. At this time, the control circuit 120 at the timing of the change from the first voltages V ₁ to the second voltage V ₂ is started in each period of the applied voltage, and outputs a timing signal to the control signal generating circuit 60.

The control signal generation circuit 60 sends a read signal to the image sensor 40 and a start signal to the AD converter 50 when a predetermined time T ₀ + T _1R elapses from when the timing signal is received. As a result, the image sensor 40 releases the shutter, acquires the R image data, and then outputs the R image data to the AD converter 50. The AD converter 50 converts the R image data sent from the image sensor 40 into digital R image data. Thereafter, the R image data converted by the AD converter 50 is stored in the third image memory 73.

Next, when a predetermined time T ₀ + T _1R + T _1G elapses after receiving the timing signal, the control signal generation circuit 60 sends a read signal to the image sensor 40 and sends a start signal to the AD converter 50. To do. As a result, the image sensor 40 releases the shutter, acquires the G image data, and then outputs the G image data to the AD converter 50. The AD converter 50 converts the G image data sent from the image sensor 40 into digital G image data. Thereafter, the R image data already stored in the third image memory 73 is transferred to the second image memory 72, and the G image data converted by the AD converter 50 this time is transferred to the third image memory 73. Is remembered.

Next, when a predetermined time T ₀ + T _1R + T _1G + T _1B elapses from when the control signal generation circuit 60 receives the timing signal, the control signal generation circuit 60 sends a read signal to the image sensor 40 and sends a start signal to the AD converter 50. To send. As a result, the image sensor 40 releases the shutter, acquires the B image data, and then outputs the B image data to the AD converter 50. The AD converter 50 converts the B image data sent from the image sensor 40 into digital B image data. The R image data already stored in the second image memory 72 is transferred to the first image memory 71, and the G image data already stored in the third image memory 73 is transferred to the second image memory 71. The B image data that is transferred to the memory 72 and converted at this time by the AD converter 50 is stored in the third image memory 73.

  Thus, when image data of three reference wavelengths (R image data, G image data, and B image data) constituting color image data for one screen are respectively stored in predetermined image memories 71, 72, and 73, control is performed. The circuit 120 sends a predetermined signal to each image processing circuit 111, 112, 113. When each of the image processing circuits 111, 112, and 113 receives a signal from the control circuit 120, it starts predetermined image processing. Specifically, the first image processing circuit 111 performs image compression processing and color correction processing on the R image data stored in the first image memory 71. The second image processing circuit 112 performs image compression processing and color correction processing on the G image data stored in the second image memory 72, and the third image processing circuit 113 Image compression processing and color correction processing are performed on the B image data stored in the image memory 73. Thus, when the image processing for each of the image data of the three reference wavelengths is completed, the image data of the three reference wavelengths is output in a time division manner. By repeating the above processing, a color image of the subject A is continuously taken.

  In the color camera device of the first embodiment, the control circuit uses the color filter so that the wavelength of the light transmitted through the color filter continuously changes within a certain wavelength range and the change in the transmission wavelength is repeated periodically. Controlling the voltage applied, and controlling the operation of the image sensor at each timing at which light of three reference wavelengths necessary for obtaining a color image passes through the color filter in each cycle of the change in transmission wavelength. Thus, the image data of the three reference wavelengths are acquired in time division as color image data for one screen. As a result, the image data of the three reference wavelengths can be obtained within a short period in which the transmission wavelength continuously changes. For these three reference image data, the remaining two after the first image data is acquired. The waiting time until one image data is acquired becomes very short. For this reason, it is possible to sufficiently reduce the occurrence of image shift and color unevenness among the image data of each reference wavelength constituting the color image data for one screen, and also enables high-speed and smooth shooting. . Therefore, in the color camera device of the first embodiment, it is possible to obtain a high-quality and high-resolution image at high speed.

  In the first embodiment, the image data of the three reference wavelengths constituting the color image data for one screen is handled in a time-sharing manner, so that the image data of each reference wavelength is data having a smaller data amount than conventional. In addition, when image processing is performed, image data with a small amount of data only needs to be processed for each reference wavelength, so that the amount of calculation for image processing is reduced and the processing speed is improved. be able to.

  Here, the image data used in the first embodiment is independent for each reference wavelength, but the image data of each reference wavelength can be easily combined with conventional 24-bit color image data. For example, 24-bit color image data can be easily obtained by aligning 8-bit image data of each reference wavelength in the bit length direction according to a certain rule calculation. Thus, it is very versatile to handle the image data of the three reference wavelengths constituting the color image data for one screen in a time division manner.

  In the first embodiment, the data length of the image data of each reference wavelength can be freely changed by handling the image data of the three reference wavelengths constituting the color image data for one screen in a time division manner. It is. This is because when processing image data of three reference wavelengths in a time-sharing manner, the processing side can recognize the separation of the image data of each reference wavelength, so there is no limit to the data length of the image data of each reference wavelength. Is not imposed. Therefore, for example, even if the data lengths of the image data of the three reference wavelengths are 8 bits, 16 bits, and 24 bits, respectively, the processing side recognizes which wavelength the image data to be processed is image data. It is possible to respond immediately.

  Further, in the color camera device of the first embodiment, three image sensors as shown in FIG. 8 are prepared, and the incident light is divided into red, green, and blue light, and these lights are respectively image sensors. Compared to the first prior art example, the image sensor needs to be provided with only one image sensor, so there is an advantage that the apparatus can be downsized. Further, since only one image sensor is provided, if the area of the image sensor is increased, the sensitivity can be increased as compared with the color camera device of the first conventional example shown in FIG.

  An efficient image system can be constructed by using the color camera device of the first embodiment and image data of each reference wavelength obtained by time division with the color camera device. Specifically, in this image system, the color camera device of the first embodiment is connected to a commercially available image display device that can use time-division data of each of the three primary colors as input data. In such an image display device, spectrum display is performed in a time division manner on image data of each reference wavelength, and a color image is displayed. As a result, since all data can be handled in a spectrum expression during image capture, image processing, image display, etc., an image with high color purity and excellent color reproducibility can be displayed.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4A is a schematic configuration diagram of a color camera apparatus according to the second embodiment of the present invention, and FIG. 4B is a schematic block diagram of the color camera apparatus. In the second embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the color camera device according to the second embodiment includes a lens 10, a color filter 20, a driver circuit 30a, an image sensor 40, an AD converter 50, a control signal generation circuit 60a, Image memories 71, 72, 73, a selector circuit 80, an image processing device 110, and a control circuit 120 are provided.

  The driver circuit 30a applies a voltage to the color filter 20, and includes a power supply unit 31a, a variable resistor 32, and an amplifier 33 as shown in FIG. The power supply unit 31 a generates a voltage to be applied to the color filter 20. The driver circuit 30a outputs a substantially sawtooth waveform voltage as shown in FIG. That is, the driver circuit 30a and the driver circuit 30 of the first embodiment differ only in the voltage output waveform.

  The control signal generation circuit 60a generates a control signal (read signal) for the image sensor 40 at a predetermined timing based on the timing signal sent from the control circuit 120, and sends the control signal to the image sensor 40. Based on the above, a control signal (start signal) for the AD converter 50 is generated at a predetermined timing and sent to the AD converter 50. As will be described later, the control signal generation circuit 60a performs the first implementation in that the control signal is transmitted four times to the image sensor 40 and the AD converter 50 in one cycle of the change in the transmission wavelength of the color filter 20, respectively. This is different from the control signal generation circuit 60 of the embodiment.

  The color camera device of the second embodiment and the color camera device of the first embodiment are mainly different in how the transmission wavelength of the color filter 20 changes. Now, the applied voltage of the color filter 20 and the change in the transmission wavelength of the color filter 20 according to the applied voltage in the second embodiment will be described in detail. FIG. 5A is a diagram for explaining a waveform of a voltage applied to the color filter 20 in the color camera device of the second embodiment, and FIG. 5B is a diagram in which the voltage of FIG. 5A is applied to the color filter 20. It is a figure for demonstrating the change of the transmission wavelength of a color filter at the time. Here, in FIG. 5A, the vertical axis represents the applied voltage, and the horizontal axis represents time. In FIG. 5B, the vertical axis represents the transmission wavelength, and the horizontal axis represents time.

In the second embodiment, a substantially sawtooth voltage as shown in FIG. 5A is periodically applied to the color filter 20. Specifically, the applied voltage is continuously changed from the voltage V _R to the voltage V _B during the time T _21, continuously changes therefrom, from the voltage V _B during the time T ₂₂ until the voltage V _R To do. Thereafter, the applied voltage repeats the same change. Here, the voltage V _R is a value of an applied voltage when the transmission wavelength of the color filter 20 becomes the red wavelength λ _R , and the voltage V _B is a value when the transmission wavelength of the color filter 20 becomes the blue wavelength λ _B. This is the value of the applied voltage.

When a substantially sawtooth voltage shown in FIG. 5 (a) is periodically applied to the color filter 20, the transmission wavelength of the color filter 20 continuously changes following the voltage change as shown in FIG. 5 (b). Indicates. Specifically, the applied voltage at time t ₀ is assumed to initiate a change to the voltage V _B from the voltage V _R. After the filter response time T ₀ has elapsed from time t _0, the transmission wavelength of the color filter 20 starts to change from the red wavelength λ _R to the blue wavelength λ _B. In the second embodiment, the control circuit 120 adjusts the value of the variable resistor 32 of the driver circuit 30a in advance, and the transmission wavelength of the color filter 20 is substantially reduced from the red wavelength λ _R to the blue wavelength λ _{B over} time. The applied voltage is controlled so as to change linearly. For example, when a predetermined time T _21G elapses from the change start time t ₀ + T _0, the transmission wavelength of the color filter 20 reaches the green wavelength λ _G, and when the predetermined time T _21B elapses _thereafter , the transmission wavelength of the color filter 20 Reaches the blue wavelength λ _B. Here, T _21G + T _21B = T ₂₁ . Thereafter, the transmission wavelength of the color filter 20 starts to change from the blue wavelength λ _B to the red wavelength λ _R. In the second embodiment, the control circuit 120 adjusts the value of the variable resistor 32 of the driver circuit 30a in advance, and the transmission wavelength of the color filter 20 is substantially reduced from the blue wavelength λ _B to the red wavelength λ _{R over} time. The applied voltage is controlled so as to change linearly. For example, when a predetermined time T _22G elapses from the change start time t ₀ + T ₀ + T ₂₁ , the transmission wavelength of the color filter 20 reaches the green wavelength λ _G , and then when the predetermined time T _22R elapses, transmission wavelength reaches the red wavelength lambda _R. Here, T _22G + T _22R = T ₂₂ . Thus, the transmission wavelength of the color filter 20 includes a first time period T ₂₁ in which the transmission wavelength varies substantially linearly from the red wavelength lambda _R until blue wavelength lambda _B, then the transmission wavelength from the blue wavelength lambda _B performing a change to one period of time in conjunction with the second period T ₂₂ which varies substantially linearly to red wavelength lambda _R.

  In the color camera device of the second embodiment, the period of the voltage applied to the color filter 20, and thus the period of change in the transmission wavelength of the color filter 20, is set to an arbitrary time, for example, from 1 millisecond to several seconds. Is possible. In this case, the control circuit 120 applies a voltage to the color filter 20 at the set cycle.

Next, the operation timing of the image sensor 40 will be described. In the second embodiment, the control signal generation circuit 60a sends the read signal to the image sensor 40 four times in each cycle of the change in the transmission wavelength of the color filter 20. Specifically, the control circuit 120 outputs a timing signal at a timing applied voltage of the color filter 20 starts to change from the voltage V _R to the voltage V _B to the control signal generating circuit 60a. The control signal generation circuit 60 a manages the elapsed time from the time when the timing signal is sent from the control circuit 120. Then, the control signal generating circuit 60a determines that the elapsed time reaches the time T _0, sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the R image data. Next, when the control signal generation circuit 60a determines that the elapsed time has reached the time T ₀ + T _21G , it sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the G image data. Thereafter, when the control signal generation circuit 60 a determines that the elapsed time has reached the time T ₀ + T ₂₁ , the control signal generation circuit 60 a sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the B image data. Thereafter, when the control signal generation circuit 60a determines that the elapsed time has reached the time T ₀ + T ₂₁ + T _22G , it sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the G image data. In this way, R image data, G image data, B image data, and G image data are acquired in a time-division manner by the image sensor 40 during each period T ₂₁ + T ₂₂ of the change in the transmission wavelength of the color filter 20. The signals are sequentially output to the AD converter 50.

  Of the four image data obtained during one cycle in this way, the R image data obtained first, the G image data obtained second, and the B image data obtained third are one screen worth. The color image data is composed of the B image data obtained third and the G image data obtained fourth during the one cycle together with the R image data obtained first during the next cycle. Thus, color image data for one screen is constructed. That is, R image data or B image data is commonly used for color image data constituting two consecutive screens.

  As described above, in the second embodiment, the period for capturing a color image for one screen is half the period of change in the transmission wavelength of the color filter 20. In other words, since the period for keeping the transmission wavelength of the color filter at a constant wavelength is not required as in the first embodiment, by effectively using the period and acquiring the image data in that period, The color image data for two screens is acquired during one cycle of the change in the transmission wavelength of the color filter 20. For this reason, in the color camera device of the second embodiment, it is possible to obtain continuous images with a short imaging cycle.

  In the second embodiment, the red wavelength light and the blue wavelength light are each photographed once during one period of the change in the transmission wavelength of the color filter 20, whereas the green wavelength light is photographed twice. Shooting. This is because the human eye is sensitive to light having a wavelength near green and has high visual sensitivity to the light. That is, by acquiring more G image data than R image data and B image data, a very clear image with high visual sensitivity can be obtained. Actually, in the conventional general color CCD image sensor or color CMOS image sensor, the same number of red filters that transmit light of red wavelength and blue filters that transmit light of blue wavelength are used, and light of green wavelength is transmitted. A color filter using twice the number of green filters is provided on the front surface of a plurality of photoelectric conversion elements, thereby improving the green sensitivity. As can be seen from this, the method for reading image data of each color in the second embodiment is a very effective method in terms of increasing the sensitivity of green.

  By the way, in the first embodiment, the time required to obtain one screen (frame) is about 10 ms. That is, since about 100 screens can be obtained per second, smooth shooting is possible. The photographing speed has a sufficient margin even compared with the drawing standard for current television broadcasting (60 screens per second). However, in the first embodiment, the image data of the three reference wavelengths are captured during a short period (about 2 ms) in which the transmission wavelength of the color filter is changed. It is conceivable that the amount of light to be used is insufficient. On the other hand, in the method of reading image data of each color in the second embodiment, it is possible to increase the shooting sensitivity even when shooting at such low illuminance. That is, in the second embodiment, when shooting at low illuminance, the voltage applied to the color filter 20 is gradually changed, and the period of change in the transmission wavelength of the color filter 20 is compared with that in the first embodiment. The shutter speed of the image sensor 40 may be set slower than that of the first embodiment while being set longer. As a result, the amount of light reaching the image sensor 40 can be increased to improve the photographing sensitivity.

  The selector circuit 80 selects an image memory for storing each image data output from the AD converter 50 from among the three image memories 71, 72, 73 based on a signal from the control circuit 120. In the second embodiment, the image data of each color is output from the AD converter 50 in the order of R, G, B, G,..., And in the color image data constituting two continuous screens, the R image Since data or B image data is used redundantly, in order to efficiently perform image processing by the image processing apparatus 110, a storage area (image memory) for storing image data of each color output from the AD converter 50 is controlled. There is a need to.

  Specifically, when the AD converter 50 outputs R image data, the selector circuit 80 sends a signal to the first image memory 71 to release the storage area, and uses the R image data as the first image. Store in the memory 71. When the AD converter 50 outputs the G image data, the selector circuit 80 sends a signal for releasing the storage area to the second image memory 72 and stores the G image data in the second image memory 72. Let When the AD converter 50 outputs B image data, the selector circuit 80 sends a signal to the third image memory 73 to release the storage area, and the B image data is sent to the third image memory 73. Remember me.

  Next, in the second embodiment, the relationship between the output order of image data of each color from the image sensor 40 (AD converter 50) and the output order of image data of each color from the image processing apparatus 110 will be described.

Now, R image data D _R1 , G image data D _G11 , B image data D _B1 , G image data D _G12 , R image data D _R2 , G image data D _G21 , B image data D _B2 , G image data D _G22 , Are output from the AD converter 50 in that order. At the time when the B image data D _B1 is output, the R image data D _R1 , the G image data D _G11 , and the B image data D _B1 are respectively the first image memory 71, the second image memory 72, and the third image. Stored in the memory 73. Each of the image processing circuits 111, 112, and 113 reads the image data stored in the image memories 71, 72, and 73, and performs image processing on the image data. The R image data D _R1 , G image data D _G11 , and B image data D _B1 that have been subjected to the image processing in this way are output in time division in that order.

Next, when the G image data D _G12 is output from the AD converter 50, the selector circuit 80 stores the G image data D _G12 in the second image memory 72. Thereafter, when the R image data D _R2 is output from the AD converter 50, the selector circuit 80 stores the R image data D _R2 in the first image memory 71. At this time, the B image data D _B1 remains in the third image memory 73 without being erased. Each of the image processing circuits 111, 112, and 113 reads the image data stored in the image memories 71, 72, and 73, and performs image processing on the image data. The R image data D _R2 , G image data D _G12 , and B image data D _B1 that have been subjected to image processing in this way are output in a time-sharing manner in that order.

Next, when the G image data D _G21 is output from the AD converter 50, the selector circuit 80 stores the G image data D _G21 in the second image memory 72. Thereafter, when the B image data D _B2 is output from the AD converter 50, the selector circuit 80 stores the B image data D _B2 in the third image memory 73. Here, at this time, the first image memory 71 has remained intact without erasing the R image data D _R2. Each of the image processing circuits 111, 112, and 113 reads the image data stored in the image memories 71, 72, and 73, and performs image processing on the image data. The R image data D _R2 , the G image data D _G21 , and the B image data D _B2 that have been subjected to the image processing in this way are output in time division in that order.

Therefore, R image data D _R1 , G image data D _G11 , B image data D _B1 , G image data D _G12 , R image data D _R2 , G image data D _G21 , B image data D _B2 ,. Output from the AD converter 50, the image processing device 110 outputs R image data D _R1 , G image data D _G11 , B image data D _B1 , R image data D _R2 , G image data D _G12 , B Image data D _B1 , R image data D _R2 , G image data D _G21 , B image data D _B2 ,... _Are output in that order. That is, the output order of each image data from the image processing apparatus 110 is the order of R, G, B as in the first embodiment.

  The color camera device of the second embodiment also has the same operations and effects as the color camera device of the first embodiment. In particular, in the second embodiment, the control circuit includes a first period in which the transmission wavelength of the color filter changes substantially linearly from the maximum wavelength to the minimum wavelength within a certain wavelength range, and then the transmission wavelength of the color filter The voltage applied to the color filter is controlled so that the period including the second period that changes substantially linearly from the minimum wavelength to the maximum wavelength is one cycle of the change in the transmission wavelength of the color filter. As a result, the image data of each reference wavelength is acquired not only in the first period but also in the second period, and color image data for two screens is acquired during one cycle of the change in the transmission wavelength of the color filter. Therefore, the color camera device of the second embodiment can perform high-speed shooting as compared with the color camera device of the first embodiment.

  In the second embodiment, the period of change of the transmission wavelength of the color filter can be set to an arbitrary time, for example, from 1 millisecond to several seconds. For this reason, when the illuminance of the subject is sufficient, it is possible to cope with various shooting methods such as high-speed shooting and slow motion shooting. When the illuminance of the subject is low, the photographing sensitivity can be increased by setting the period of change of the transmission wavelength of the color filter to be long and setting the shutter speed of the image sensor to be slow. Thus, since the color camera device of the second embodiment is capable of high-speed shooting, slow motion shooting, and high-sensitivity shooting, it is suitable for continuous shooting such as high-quality video shooting and moving images, as well as medical, bio, It can be used for observation in various fields such as celestial bodies, geography, agriculture, and living things, photography for observation purposes, spectrum analysis, and the like.

  Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 6A is a schematic configuration diagram of a color camera device according to the third embodiment of the present invention, and FIG. 6B is a schematic block diagram of the color camera device. In the third embodiment, components having the same functions as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the color camera device of the third embodiment includes a lens 10, a color filter 20, a driver circuit 30b, an image sensor 40, an AD converter 50, a control signal generation circuit 60b, Image memories 71, 72, 73, a selector circuit 80, an image processing device 110, and a control circuit 120 are provided.

  The driver circuit 30b applies a voltage to the color filter 20, and includes a power supply unit 31b, a variable resistor 32, and an amplifier 33 as shown in FIG. The power supply unit 31 b generates a voltage to be applied to the color filter 20. The driver circuit 30b outputs a voltage having a substantially sawtooth waveform as shown in FIG. That is, only the voltage output waveform is different between the driver circuit 30b and the driver circuit 30a of the second embodiment.

  The control signal generation circuit 60b generates a control signal (read signal) for the image sensor 40 at a predetermined timing based on the timing signal sent from the control circuit 120, and sends the control signal to the image sensor 40. Based on the above, a control signal (start signal) for the AD converter 50 is generated at a predetermined timing and sent to the AD converter 50. As will be described later, the control signal generation circuit 60b transmits the control signal six times to the image sensor 40 and the AD converter 50 in one cycle of the change in the transmission wavelength of the color filter 20, respectively. This is different from the control signal generation circuits 60 and 60a of the second embodiment.

  The color camera device according to the third embodiment and the color camera devices according to the first and second embodiments mainly differ in how the transmission wavelength of the color filter 20 changes. Now, the applied voltage of the color filter 20 and the change in the transmission wavelength of the color filter 20 according to the applied voltage in the third embodiment will be described in detail. FIG. 7A is a diagram for explaining a waveform of a voltage applied to the color filter 20 in the color camera device of the third embodiment, and FIG. 7B is a diagram in which the voltage of (a) is applied to the color filter 20. It is a figure for demonstrating the change of the transmission wavelength of a color filter at the time. Here, in FIG. 7A, the vertical axis represents the applied voltage, and the horizontal axis represents time. In FIG. 7B, the vertical axis represents the transmission wavelength, and the horizontal axis represents time.

In the third embodiment, a substantially sawtooth voltage as shown in FIG. 7A is periodically applied to the color filter 20. Specifically, the applied voltage varies continuously from voltages _{V 1} to a voltage _{V 2} between the time _{T 31,} then, during the time _{T 32,} is retained to the voltage _{V 2.} Thereafter, continuously changes from the voltage _{V 2} to the voltages _{V 1} during the time _{T 33,} then, during the time _{T 34,} is held in voltages _{V 1.} Thereafter, the applied voltage repeats the same change. Here, as described in the first embodiment, the voltage V ₁ is the value of the applied voltage when the transmission wavelength of the color filter 20 becomes the predetermined wavelength λ ₁ near the red wavelength λ _R , and the voltage V _2. Is a value of an applied voltage when the transmission wavelength of the color filter 20 becomes a predetermined wavelength λ ₂ near the blue wavelength λ _B.

When the substantially sawtooth voltage shown in FIG. 7A is periodically applied to the color filter 20, the transmission wavelength of the color filter 20 continuously changes following the voltage change, as shown in FIG. 7B. Indicates. Specifically, it is assumed that the applied voltage starts changing from the voltage V ₁ to the voltage V ₂ at time t ₀ . After the filter response time T ₀ has elapsed from time t _0, the transmission wavelength of the color filter 20 starts changing from the wavelength λ ₁ to the wavelength λ ₂ . In a third embodiment, the control circuit 120 in advance by adjusting the value of the variable resistor 32 of the driver circuit 30b, substantially linearly from the wavelength lambda ₁ to wavelength lambda ₂ transmission wavelengths of the color filter 20 with the passage of time The applied voltage is controlled so as to change to. For example, if the time _t 0 + _{T 0} start changes in the predetermined time _{T 31R} has elapsed, the transmission wavelength of the color filter 20 reaches the red wavelength lambda _R, then the predetermined time _{T 31G} has elapsed, the transmission wavelength of the color filter 20 There reached green wavelength lambda _G, then further predetermined time T _31B has elapsed, the transmission wavelength of the color filter 20 reaches the blue wavelength lambda _B. Then, when the time T ₃₁ has elapsed from the time t ₀ + T ₀ , the transmission wavelength of the color filter 20 reaches the wavelength λ ₂ . Thereafter, the state where the transmission wavelength of the color filter 20 is the wavelength λ ₂ is maintained for a time T ₃₂ .

Thereafter, the transmission wavelength of the color filter 20 starts changing from the wavelength λ ₂ to the wavelength λ ₁ . In the third embodiment, the control circuit 120 adjusts the value of the variable resistor 32 of the driver circuit 30b in advance, so that the transmission wavelength of the color filter 20 is substantially linear from the wavelength λ ₂ to the wavelength λ ₁ over time. The applied voltage is controlled so as to change to. For example, when a predetermined time T _33B elapses from the change start time t ₀ + T ₀ + T ₃₁ + T ₃₂ , the transmission wavelength of the color filter 20 reaches the blue wavelength λ _B, and when the predetermined time T _33G elapses _thereafter , the color filter When the transmission wavelength of 20 reaches the green wavelength λ _G and a predetermined time T _33R elapses _thereafter , the transmission wavelength of the color filter 20 reaches the red wavelength λ _R. Then, when the time T ₃₃ has elapsed from the time t ₀ + T ₀ + T ₃₁ + T ₃₂ , the transmission wavelength of the color filter 20 reaches the wavelength λ ₁ . Thereafter, the state where the transmission wavelength of the color filter 20 is the wavelength λ ₁ is maintained for a time T ₃₄ . As described above, the transmission wavelength of the color filter 20 maintains the state in which the transmission wavelength is the wavelength λ ₂ and the first period T _{31 in} which the transmission wavelength changes substantially linearly from the wavelength λ ₁ to the wavelength λ _2. The second period T ₃₂ , the third period T _{33 in} which the transmission wavelength changes substantially linearly from the wavelength λ ₂ to the wavelength λ _1, and the fourth period T _{34 in} which the transmission wavelength is maintained at the wavelength λ _1. The change which makes period which combined with one period is performed.

Next, the operation timing of the image sensor 40 will be described. In the third embodiment, the control signal generation circuit 60 b sends the read signal to the image sensor 40 six times in each cycle of the change in the transmission wavelength of the color filter 20. Specifically, the control circuit 120 outputs a timing signal at a timing applied voltage of the color filter 20 starts to change from the voltages V ₁ to the voltage V ₂ to the control signal generating circuit 60b. The control signal generation circuit 60b manages the elapsed time from the time when the timing signal is sent from the control circuit 120. When the control signal generation circuit 60b determines that the elapsed time has reached the time T ₀ + T _31R , it sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the R image data. Next, when it is determined that the elapsed time has reached the time T ₀ + T _31R + T _31G , the control signal generation circuit 60b sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the G image data. Thereafter, when the control signal generation circuit 60b determines that the elapsed time has reached the time T ₀ + T _31R + T _31G + T _31B , it sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the B image data.

Next, when it is determined that the elapsed time has reached the time T ₀ + T ₃₁ + T ₃₂ + T _33B , the control signal generation circuit 60b sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the B image data. Thereafter, when the control signal generation circuit 60b determines that the elapsed time has reached the time T ₀ + T ₃₁ + T ₃₂ + T _33B + T _33G , it sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the G image data. After that, when the control signal generation circuit 60b determines that the elapsed time has reached the time T ₀ + T ₃₁ + T ₃₂ + T _33B + T _33G + T _33R , it sends a read signal to the image sensor 40. Thereby, the shutter of the image sensor 40 opens at the timing when the read signal is sent, and the image sensor 40 reads the R image data. In this way, R image data, G image data, B image data, B image data, G image data, and R image during each period T ₃₁ + T ₃₂ + T ₃₃ + T ₃₄ of the change of the transmission wavelength of the color filter 20. Data is acquired by the image sensor 40 in a time division manner and sequentially output to the AD converter 50.

  Of the six image data obtained during one cycle in this way, the R image data obtained first, the G image data obtained second, and the B image data obtained third are color for one screen. The image data is configured, and the fourth obtained B image data, the fifth obtained G image data, and the sixth obtained R image data constitute color image data for one screen. As described above, in the third embodiment, the period for capturing a color image for one screen is half of the period of change in the transmission wavelength of the color filter 20.

  In addition, the change in the transmission wavelength of the color filter 20 in the third embodiment is an extra period for keeping the transmission wavelength constant in the change in the transmission wavelength of the color filter 20 in the second embodiment. . For this reason, the color camera device of the third embodiment is suitable for use when shooting with a longer cycle than that of the second embodiment or shooting with a slow shutter speed. However, in the third embodiment, unlike the second embodiment, the R image data or the B image data is not redundantly used in the color image data constituting two continuous screens. This is to prevent image quality such as color unevenness and the like from being deteriorated due to a shift in the image for each reference wavelength constituting one screen when the photographing cycle is lengthened.

  Next, in the third embodiment, the relationship between the output order of image data of each color from the image sensor 40 (AD converter 50) and the output order of image data of each color from the image processing apparatus 110 will be described.

Now, R image data D _R1 , G image data D _G1 , B image data D _B1 , B image data D _B2 , G image data D _G2 , R image data D _R2 , R image data D _R3 , G image data D _G3 , _Assume that B image data D _B3 ,... _Are output from the AD converter 50 in that order. When the R image data D _R1 is output from the AD converter 50, the selector circuit 80 stores the R image data D _R1 in the first image memory 71. Next, when the G image data D _G1 is output from the AD converter 50, the selector circuit 80 stores the G image data D _G1 in the second image memory 72. Thereafter, when the B image data D _B1 is output from the AD converter 50, the selector circuit 80 stores the B image data D _B1 in the third image memory 73. Each of the image processing circuits 111, 112, and 113 reads the image data stored in the image memories 71, 72, and 73, and performs image processing on the image data. The R image data D _R1 , G image data D _G1 , and B image data D _B1 that have been subjected to image processing in this manner are output in time division in that order.

Next, when the B image data D _B2 is output from the AD converter 50, the selector circuit 80 stores the B image data D _B2 in the third image memory 73. Thereafter, when the G image data D _G2 is output from the AD converter 50, the selector circuit 80 stores the G image data D _G2 in the second image memory 72. Thereafter, when the R image data D _R2 is output from the AD converter 50, the selector circuit 80 stores the R image data D _R2 in the first image memory 71. Each of the image processing circuits 111, 112, and 113 reads the image data stored in the image memories 71, 72, and 73, and performs image processing on the image data. The R image data D _R2 , the G image data D _G2 , and the B image data D _B2 that have been subjected to the image processing in this way are output in time division in that order.

Next, when the R image data D _R3 is output from the AD converter 50, the selector circuit 80 stores the R image data D _R3 in the first image memory 71. Thereafter, when the G image data D _G3 is output from the AD converter 50, the selector circuit 80 stores the G image data D _G3 in the second image memory 72. Thereafter, when the B image data D _B3 is output from the AD converter 50, the selector circuit 80 stores the B image data D _B3 in the third image memory 73. Each of the image processing circuits 111, 112, and 113 reads the image data stored in the image memories 71, 72, and 73, and performs image processing on the image data. The R image data D _R3 , G image data D _G3 , and B image data D _B3 that have been subjected to image processing in this way are output in a time-sharing manner in that order.

Therefore, R image data D _R1 , G image data D _G1 , B image data D _B1 , B image data D _B2 , G image data D _G2 , R image data D _R2 , R image data D _R3 , G image data D _G3 , When the B image data D _B3 ,... _Are output in that order from the AD converter 50, the image processing apparatus 110 outputs R image data D _R1 , G image data D _G1 , B image data D _B1 , R Image data D _R2 , G image data D _G2 , B image data D _B2 , R image data D _R3 , G image data D _G3 , B image data D _B3 ,... _Are output in that order. That is, the output order of each image data from the image processing apparatus 110 is the order of R, G, B as in the first or second embodiment.

  The color camera device of the third embodiment also has the same operations and effects as the color camera device of the first embodiment. In addition, since the change in the transmission wavelength of the color filter in the third embodiment is an extra period for keeping the transmission wavelength constant in the change in the transmission wavelength of the color filter in the second embodiment, The color camera device of the third embodiment is suitable for use when shooting with a longer period or shooting with a slow shutter speed than the color camera device of the second embodiment.

  By the way, even in the color camera device of the first embodiment, if the period during which the transmission wavelength of the color filter holds a constant wavelength is adjusted, the same photographing result as that obtained when the color camera device of the third embodiment is used is obtained. be able to. Regardless of which color camera device is used, optimum shooting performance can be obtained by appropriately selecting the output waveform of the applied voltage in accordance with the performance of the photoelectric conversion element and the amount of light from the subject to be shot.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist.

  For example, in each of the above embodiments, the control circuit is necessary to obtain a color image within a period in which the transmission wavelength of the color filter changes substantially linearly from the maximum wavelength to the minimum wavelength within a certain wavelength range. The control circuit controls the operation of the image sensor at each timing when light of three reference wavelengths passes through the color filter. However, the control circuit operates from the maximum wavelength to the minimum wavelength within the wavelength range where the transmission wavelength of the color filter is constant. The voltage applied to the color filter is controlled so as to change step by step, and within the period of change, the operation of the image sensor is controlled at each timing when light of three reference wavelengths passes through the color filter. Also good.

  In each of the above-described embodiments, the case where a moving image is shot using the color camera device of the present invention has been described. However, a still image can be shot using the color camera device of the present invention as a normal still camera. You can also. In this case, the transmission wavelength of the color filter is changed only over one period, and image data of three reference wavelengths may be acquired within a period in which the transmission wavelength is changing.

  In each of the above embodiments, the case where light of three primary colors (red, green, blue) is used as light of three reference wavelengths for obtaining a color image has been described. For example, light of three reference wavelengths is used. Alternatively, light of three primary colors (yellow, magenta, cyan) may be used.

  Further, in each of the above-described embodiments, the control circuit not only controls the operation of the image sensor at each timing when the light of the three reference wavelengths transmits through the color filter in each period of the change of the transmission wavelength, By controlling the operation of the image sensor at each timing when light of one or more predetermined wavelengths other than the light of the reference wavelength passes through the color filter, the image data of the three reference wavelengths and the one or more predetermined wavelengths are controlled. The image data may be acquired in a time division manner. As a result, more color information can be obtained, so that an image with higher quality and good color reproducibility can be obtained. In general, the control circuit may operate the image sensor a plurality of times within a period in which the transmission wavelength of the color filter continuously changes, and acquire image data of a plurality of arbitrary wavelengths in a time division manner. As a result, not only visible light imaging but also non-visible light imaging such as near-infrared imaging is possible, so the color camera device of the present invention should also be used for applications such as spectrum analysis, analysis, and observation. Can do.

  As described above, in the color camera device of the present invention, the control means is configured such that the wavelength of light transmitted through the color filter continuously changes within a certain wavelength range and the change in the transmission wavelength is repeated periodically. The operation of the image sensor is controlled at each timing when light of three reference wavelengths necessary for obtaining a color image is transmitted through the color filter in each period of the change in the transmission wavelength, and the voltage applied to the color filter is controlled. By controlling the above, image data of three reference wavelengths are acquired in a time-sharing manner as color image data for one screen. As a result, the image data of the three reference wavelengths can be obtained within a short period in which the transmission wavelength continuously changes. For these three reference image data, the remaining two after the first image data is acquired. The waiting time until one image data is acquired becomes very short. For this reason, it is possible to sufficiently reduce the occurrence of image shift and color unevenness among the image data of each reference wavelength constituting the color image data for one screen, and also enables high-speed and smooth shooting. . Therefore, the color camera device of the present invention is suitable for use as a high-quality color camera, but not only that, but also color inspection of products, surface inspection, chemical compounding inspection, food quality inspection, biological identification, etc. It can be used in a wide range such as in the field of inspection such as inspection and medical inspection, in-vehicle camera and security camera.

(A) is a schematic block diagram of the color camera apparatus which is 1st embodiment of this invention, (b) is a schematic block diagram of the color camera apparatus. It is a figure for demonstrating the circuit structure of the photoelectric conversion element and shutter in a CMOS image sensor. (A) is a figure for demonstrating the waveform of the voltage applied to a color filter in the color camera apparatus of 1st embodiment, (b) is permeation | transmission of a color filter when the voltage of (a) is applied to the color filter. It is a figure for demonstrating the change of a wavelength. (A) is a schematic block diagram of the color camera apparatus which is 2nd embodiment of this invention, (b) is a schematic block diagram of the color camera apparatus. (A) is a figure for demonstrating the waveform of the voltage applied to a color filter in the color camera apparatus of 2nd embodiment, (b) is permeation | transmission of a color filter when the voltage of (a) is applied to the color filter. It is a figure for demonstrating the change of a wavelength. (A) is a schematic block diagram of the color camera apparatus which is 3rd embodiment of this invention, (b) is a schematic block diagram of the color camera apparatus. (A) is a figure for demonstrating the waveform of the voltage applied to a color filter in the color camera apparatus of 3rd embodiment, (b) is permeation | transmission of a color filter when the voltage of (a) is applied to the color filter. It is a figure for demonstrating the change of a wavelength. (A) is a schematic block diagram of the color camera apparatus which is a 1st prior art example, (b) is a schematic block diagram of the color camera apparatus. (A) is a schematic block diagram of the color camera apparatus which is a 2nd prior art example, (b) is a schematic block diagram of the color camera apparatus. (A) is a figure for demonstrating the waveform of the voltage applied to a color filter in the color camera apparatus which is a 2nd prior art example, (b) is a color filter when the voltage of (a) is applied to the color filter It is a figure for demonstrating the change of the transmission wavelength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens 20 Color filter 30, 30a, 30b Driver circuit 31, 31a, 31b Power supply part 32 Variable resistance 33 Amplifier 40 Image sensor 41 Photoelectric conversion element 42 Capacitors 43, 44, 45, 46 Transistor 47 Line 50 AD converters 60, 60a, 60b control signal generation circuit 71 first image memory 72 second image memory 73 third image memory 80 selector circuit 110 image processing device 111 first image processing circuit 112 second image processing circuit 113 third image processing Circuit 120 control circuit

Claims (4)

A color filter that can vary the transmission wavelength of light by varying the applied voltage;
An image sensor for obtaining image data of the specific wavelength by converting image information of light of the specific wavelength transmitted through the color filter into an electrical signal;
The voltage applied to the color filter is controlled so that the wavelength of light transmitted through the color filter continuously changes within a certain wavelength range and the change repeats periodically, and the change in the transmission wavelength By controlling the operation of the image sensor at each timing when light of three reference wavelengths necessary for obtaining a color image passes through the color filter in each cycle, the image data of the three reference wavelengths is displayed on one screen. Control means for acquiring time-division as color image data for minutes,
A color camera device comprising:   The control means includes a first period in which the transmission wavelength of the color filter changes substantially linearly or stepwise from the maximum wavelength to the minimum wavelength within the fixed wavelength range, and then the transmission wavelength of the color filter is The voltage applied to the color filter is controlled so that a period including a second period in which the maximum wavelength state is maintained is one cycle of a change in the transmission wavelength of the color filter. The color camera device according to 1.   The control means includes a first period in which the transmission wavelength of the color filter changes substantially linearly or stepwise from the maximum wavelength to the minimum wavelength within the fixed wavelength range, and then the transmission wavelength of the color filter is The voltage applied to the color filter is set so that a period including a second period that changes substantially linearly or stepwise from the minimum wavelength to the maximum wavelength is one cycle of a change in the transmission wavelength of the color filter. The color camera device according to claim 1, wherein the color camera device is controlled.   The control means not only controls the operation of the image sensor at each timing when the light of the three reference wavelengths passes through the color filter in each cycle of the change of the transmission wavelength, but also controls the light of the three reference wavelengths. In addition, by controlling the operation of the image sensor at each timing when one or a plurality of light of a predetermined wavelength passes through the color filter, the image data of the three reference wavelengths and the one or a plurality of the predetermined wavelengths 4. The color camera device according to claim 1, wherein the image data is acquired in a time division manner.

Images