JPH0865690A - Color still picture photographing device - Google Patents

Abstract

PURPOSE: To generate the color video signal of a still object while using a single monochromatic video camera by fetching the output video signals of a video camera in the case of emitting light in the respective colors of a light source, synthesizing those signals and forming the color video signal. CONSTITUTION: Corresponding to the control from a stroboscope control circuit 12, a stroboscope 10 successively emits the light in red (R), blue (B) and green (G) of which the luminance is almost equal. This light illuminates a photographic object 22. Besides, a monochromatic video camera 14 photographs the photographic object 22 through a lens. Each time a photographic switch 20 is turned on, an image fetching/synthesizing circuit 16 emits the stroboscope 10 to the stroboscope control circuit 12, fetches the video signal from the monochromatic video camera 14, synthesizes three monochromatic video signals in the case of emitting the light in R, B and G and outputs the synthesized signal to a utilizing circuit 18 such as a printer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color still image capturing apparatus for generating a still image color video signal using a single monochrome video camera.

[0002]

2. Description of the Related Art Generally, a color image
A video camera is used. The color video camera has a single plate type in which one image pickup device (for example, CCD) is commonly used for the three primary color lights of red, blue and green, and a three plate type in which dedicated image pickup devices are used for each of the three primary color lights. There is. The single plate type has an advantage that the structure is simple and inexpensive, but has a drawback that it is difficult to increase the resolution. on the other hand,
Although the three-plate type has high resolution, it has a drawback that it is expensive because it has a high mounting accuracy and a complicated structure, and that adjustment for matching the characteristics of the three image pickup elements is troublesome.

Images input by a video camera for printing or the like are still images, but high resolution is required. Therefore, it has been conventionally practiced to take a color still image using a monochrome video camera. In this case, in front of the lens of the monochrome video camera,
Red, blue and green color filters of three primary colors are sequentially arranged, the red component, the blue component and the green component of the color image are sequentially photographed, and the three monochrome video signals thus photographed are combined,
Color video signal. Although the red component, the blue component, and the green component of the color image are deviated at the time of photographing, since the object to be photographed is a still image, there is no change in the image over time, so there is no problem at the time of photographing. On the other hand, since a single monochrome video camera is sufficient, the structure is simple and the cost is low, and the resolution is high as in the three-plate type.

[0004]

In a conventional color still image photographing apparatus using a monochrome video camera, red,
Three types of color filters, blue and green, were attached to the disc, and the disc was rotated by a step motor to switch the color filters. That is, since the filter is mechanically switched in front of the monochrome video camera, vibration may occur during the switching, which may affect the placement of the video camera. Therefore, the relative position between the object to be photographed and the video camera may change with the passage of time. In this case, even if the image is a still image, the relative position between the video camera and the object to be photographed may change
Color shift occurs. This has a greater effect as the resolution is higher.

In front of the monochrome video camera,
The applicant of the present application is also studying a method of removing an influence of vibration by providing an electronic filter and electrically changing the characteristics of the electronic filter. However, in this method, the electronic filters have unequal transmissivities when passing red, blue, and green light, and the output video signal of the video camera depends on the optical transmissivity of each light component of the electronic filter. Had to be corrected.

Therefore, an object of the present invention is to
It is an object of the present invention to provide a color still image capturing apparatus capable of generating a color video signal of a stationary object using a single monochrome video camera without providing a filter in front of the video camera. It is another object of the present invention to provide a color still image capturing device that does not require correction of the output video signal level of a monochrome video camera for each of the three primary colors of light.

[0007]

The color still image pickup device of the present invention comprises a monochrome video camera, a light source for emitting red, blue and green light, and red, blue and green light from the light source. A control circuit that controls to sequentially emit light and a capture and synthesis circuit that sequentially captures the output video signals of the video camera when the light source emits red, blue, and green light and synthesizes them to produce a color video signal. It has. Since no filter is provided in front of the monochrome video camera, the vibration caused by mechanical switching of the filter does not affect the video camera. Also, the red light emitted from the light source,
Equalizing the blue and green light intensities can be easily achieved by adjusting the emission intensity of the light emitting element.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of the present invention. The strobe 10, which is a light source, sequentially emits red (R), blue (B), and green (G) lights having substantially the same brightness under the control of the strobe control circuit 12. This light is the object 22 to be photographed.
Illuminate. In addition, the monochrome video camera 14
The subject 22 is photographed through the lens. Image capture /
Whenever the photographing switch 20 is turned on, the synthesizing circuit 16
The strobe control circuit 12 causes the strobe 10 to emit light, the video signal from the monochrome video camera 14 is taken in, the three monochrome video signals when red, blue, and green lights are emitted are combined, and the printer or the like Output to the utilization circuit 18 of. It is preferable that the light source (strobe) 10, the video camera 14 and the object to be photographed 22 are arranged in a closed dark room, but it may be a room where strong external light does not enter.

The operation of the embodiment shown in FIG. 1 will be further described. First, when the operator turns on the switch 20, a light emission instruction signal is sent from the image capturing / combining circuit 16 to the flash control circuit 1.
2, which emits red light. Then, the red light is emitted to the countermeasure object 22, and only the red portion of the object 22 is
It reflects this red light. Monochrome video camera 14
Captures the light reflected by the object 22, thus producing a monochrome video signal corresponding to the red portion of the object. The image capturing / combining circuit 16 captures a monochrome video signal at the time when the switch 20 is turned on, that is, the red portion of the object output by the video camera 14,
Accumulate in red memory.

When the operator turns on the switch 20 again, a light emission instruction signal is supplied from the image capturing / combining circuit 16 to the strobe control circuit 12 to emit blue light. Due to this light emission, only the blue part of the object 22 reflects this blue light. The monochrome video camera 14 generates a monochrome video signal corresponding to the blue portion of the object 22, and the image capturing / combining circuit 16 captures the monochrome video signal of this blue portion and stores it in the blue memory. To do. Similarly, when the operator turns on the switch 20 for the third time, the strobe 10 emits green light in response to a light emission instruction signal from the image capturing / combining circuit 16 to the strobe control circuit 12. The monochrome video camera 14 generates a monochrome video signal corresponding to the green portion of the object 22, and the image capturing / combining circuit 16 captures the monochrome video signal of this green portion and stores it in the green memory. To do.

The image capturing / combining circuit 16 captures the video signals corresponding to the three primary colors of light in the memories of red, blue and green, and simultaneously reads out the video signals stored in the respective memories to synthesize them. -Generate a video signal. Although the time points at which the image capturing / combining circuit 16 captures the video signals of the three primary colors are different from each other, this time difference is not a problem because the object 22 to be photographed is stationary. The combined color video signal is supplied to the utilization circuit 18 and processed according to the purpose of the utilization circuit. As an example, utilization circuit 18 is a color video printer and a color image printout of object 22 is obtained. It should be noted that when the switch 20 is turned on once, red, blue, and green lights are sequentially emitted automatically to capture images of the respective images.
Alternatively, the synthesizing circuit 16 may sequentially and automatically take in the data.

FIG. 2 is a diagram showing a first specific example of the light source 10. In this specific example, a dichroic prism is used. The same strobes 200 and 20 which are light emitting elements
2 and 204 are placed opposite one surface of prisms 206, 208 and 210, respectively. The strobe 20
Each of 0, 202 and 204 is white light including red, blue and green light. Also, the prisms 206 and 210 have three
The prism 208 is a prism and the prism 208 is a quadrangular prism, and is arranged as illustrated. Red reflective dichroic film 2
12 is provided on the contact surfaces of the prisms 208 and 210, and the blue reflection dichroic film 214 is provided on the prism 210 side of the prism 206. Further, in order to totally reflect the light, an air gap with a minute interval is provided between the prisms 206 and 210.

When the strobe 200 emits light, the light is
The blue reflection dichroic film 2 which passes through the inclined surface to the right of the prism 206 and totally reflects on the vertical surface and the blue reflection dichroic film 2 on the inclined surface to the right
Only blue light is reflected at 14 and is output to the outside. Also,
When the strobe 202 emits light, the light is emitted from the prism 20.
Red reflective dichroic film 212 passing through the vertical plane of 8
Then, only the red component is reflected, and the remaining blue and green components pass through the red reflection dichroic film 212. Further, the blue component is reflected by the blue reflection dichroic film 214, and only the green component is output to the outside. Further, when the strobe 204 emits light, the light passes through the horizontal plane of the prism 210 and is totally reflected by the air gap, and only the red component is reflected by the red reflection dichroic film 212 and passes through the prisms 210 and 206. Output to the outside. Therefore, strobe 2
00 controls the generation of blue light, the strobe 202 controls the generation of green light, and the strobe 204 controls the generation of red light.

By the way, the dichroic films 212 and 2
In the color separation by 14 only, when the color separation is incomplete, the color separation can be improved by using the trimming filter. In this case, the blue trimming filter 216 is provided between the strobe 200 and the prism 206, the green trimming filter 218 is provided between the strobe 202 and the prism 208, and the red trimming filter 220 is provided.
Between the strobe 204 and the prism 210. These trimming filters have the function of adjusting the spectral characteristics of each color, and the characteristics for the output light are as shown in FIG. As can be seen from the characteristic diagram of FIG. 3, since the characteristics of the lights of the respective colors emitted by the strobes are reliably separated, the blue (B), green (G), and red (R) color coding is clear. Therefore, the sharpness of the color of the image can be emphasized. Therefore, the color characteristics of the color video signal from the image capturing / combining circuit 16 are also clearly classified.

FIG. 4 shows a second specific example of the light source. In this specific example, a single strobe 10A is used as a light source and a liquid crystal shutter 10B is used as an electronic filter. Therefore, the control circuit 12 controls the light emission of the strobe 10A and the characteristics of the liquid crystal shutter 10B. That is, the electronic filter 10B is used as a red filter, a blue filter, and a green filter. In this case, the strobe 10A is caused to emit light after changing the characteristics of the electronic filter 10B. In addition, when the transmission characteristics of the electronic filter 10B differ depending on the color, the emission voltage of the strobe may be controlled by adjusting the supply voltage of the strobe according to the transmission characteristics.

Next, details of the electronic filter 10B will be described. FIG. 5 is an exploded perspective view of the electronic filter. In this electronic filter, the light from the strobe 10A is incident from the left side of the drawing, and the polarization filter 42, the liquid crystal cell 54 which is a variable optical delay device, the polarization filter 82, the liquid crystal cell 56 which is a variable optical delay device, and the polarization filter 44 are They are arranged in order. The polarization filter 42 has a vertical polarization axis that transmits red, green and blue light and a horizontal polarization axis 48 that transmits blue light. The polarization filter 82 has a vertical polarization axis 84 that transmits green light and a horizontal polarization axis 86 that transmits red, blue and green light. The polarization filter 44 has a vertical polarization axis 50 which transmits red light and a horizontal polarization axis 52 which transmits red, blue and green light.

The projection 62 of the optical axis on the light transmitting surfaces 64 and 66 of the liquid crystal cell 54 is orthogonal to the projection 68 of the optical axis on the light transmitting surfaces 70 and 72 of the liquid crystal cell 56, which projections are polarization filters. The polarization axes 42, 82 and 44 are arranged at an angle of 45 degrees. The liquid crystal cells 54 and 56 are connected to the liquid crystal control circuit 2 via the signal lines 58 and 60.
Depending on the control voltage from 4 or 36, there are "on" and "off" optical delay states. In the on-optical delay state, the plane of polarization of the incident light is allowed to pass without rotation. In the off optical delay state, the plane of polarization of incident light is
Rotate it 0 degrees and let it pass.

When the electronic filter is in the first state, the control circuit 12 brings both the liquid crystal cells 54 and 56 into the ON optical delay state and does not change the polarization direction of the incident light. Therefore, the light rays associated with the vertical polarization axis 46 and the horizontal polarization axis 48 of the polarization filter 42 are polarized in the vertical and horizontal directions, respectively, and the polarization directions do not change when passing through the liquid crystal cells 54 and 56.
Therefore, the red R, green G, and blue B rays do not pass through all of the vertical polarization axes of the polarization filters 42, 82, and 44, so that no light is output from the vertical polarization axis 50 of the polarization filter 44. However, the light of blue B is reflected by the polarization filter 4
It is output after passing through the horizontal polarization axes of 2, 82 and 44. That is, in this state, the electronic filter 14 passes blue light.

When the electronic filter is in the second state, the control circuit 12 puts the liquid crystal cell 54 into the ON optical delay state and puts the liquid crystal cell 56 into the OFF optical delay state. Therefore, the liquid crystal cell 5
4 does not change the polarization direction of the incident light, but the liquid layer cell 56
Changes the polarization direction of incident light clockwise by 90 degrees toward the output direction. The red, green and blue rays associated with the vertical polarization axis 46 of the polarization filter 48 pass through the liquid crystal cell 54 as they are, and the vertical polarization axis 84 of the polarization filter 82 blocks the red and blue rays from passing through the green color. Only the rays of light pass through. Then, this green ray changes its polarization direction by 90 degrees in the liquid crystal cell 72 and passes through the horizontal polarization axis 52 of the polarization filter 44. On the other hand, the blue ray that has passed through the horizontal polarization axis 48 of the polarization filter 42 is the horizontal polarization axis 8 of the polarization filter 82.
6, but the polarization direction is changed by 90 degrees in the liquid layer cell 56, and then the passage is blocked by the vertical polarization axis 50 of the polarization filter 44. That is, in this state, the electronic filter 1
4 passes the green light.

When the electronic filter is in the third state, the electronic filter control circuit 19 puts the liquid crystal cells 54 and 56 into the off optical delay state. Therefore, the liquid crystal cells 54 and 56 change the polarization direction of the incident light in the clockwise direction toward the output direction by 90 degrees.
Change once. The red, green, and blue rays incident on the vertical polarization axis 46 of the polarization filter 48 have their polarization directions changed by 90 degrees by the liquid crystal cell 54, and the horizontal polarization axis 86 of the polarization filter 82.
Then, the red, green and blue rays pass through as they are. And
These light rays have their polarization directions changed again by 90 degrees in the liquid crystal cell 72, and only the red light rays pass by the vertical polarization axis 50 of the polarization filter 44. On the other hand, the blue ray that has passed through the horizontal polarization axis 48 of the polarization filter 42 cannot pass through the vertical polarization axis 42 because the polarization direction of the liquid crystal cell 54 changes by 90 degrees. That is, in this state, the electronic filter 14
Passes red light.

FIG. 6 is a sectional view in which the liquid crystal cells 54 and 56 are enlarged in the thickness direction. In relation to FIG. 5, the vertical liquid crystal cell in FIG. 5 lies in the horizontal direction in FIG. The nematic liquid crystal material 106 is sandwiched between the transparent electrode structures 100 and 102 and the spacer 114. Each electrode structure is made of glass 10
8. Director oriented film layer 112 and conductive layer 110
Consists of The conductive layer 110 receives a control voltage from the liquid crystal control circuit 24 or 36 via the conductive wire 113.

FIG. 7 shows a conductive layer 11 of the liquid crystal cell shown in FIG.
It is explanatory drawing at the time of giving an electric potential difference between 0, adding an alternating electric field, and setting it as an ON optical delay state. Due to the alternating electric field E, the majority of the surface non-contact directors 120 in the liquid crystal substance 106 having a positive anisotropy connect their ends substantially along the direction 121 of the lines of electric force perpendicular to the surface of the electrode structure. To line up. Therefore, the light passing through the liquid crystal cell passes as it is. FIG. 8 is an explanatory diagram when the potential difference between the conductive layers 110 of the liquid crystal cell 54 shown in FIG. 6 is removed. Since the surface non-contact director 120 is oriented as illustrated, the light passing through the liquid crystal cell is rotated by 90 degrees. The liquid crystal that operates in this way is called a π-type liquid crystal cell. In the π-type liquid crystal cell,
Fast response (2ms due to no torque acting on the central molecule)
The following) is possible.

FIG. 9 shows a third specific example of the light source 10. A rotary plate 10C is provided on the entire surface of the strobe 10A, and red, blue and green filters are installed on the rotary disc 10C. Therefore, the red, blue, and green filters can be sequentially selected by rotating the rotary plate 10C. The rotation of the rotary plate 10C is controlled by the step motor 10E via the gear 10D. In addition, the light emission of the strobe 10A and the motor 10
The rotation of E is controlled by the strobe / motor control circuit 12. Also in this case, if the transmission characteristics of the filters are different, the intensity of the strobe light emission can be adjusted to make the intensity of each output light constant. In this case, the light source 10 vibrates due to the rotation of the rotating plate 10C when the color filters are switched, and
It should be noted that the relative position between the emitted light and the object to be photographed slightly fluctuates, but there is almost no influence of color shift or the like on the photographed image as compared with the case where the camera vibrates.

FIG. 10 shows an embodiment of the color filter 11 in FIG. Here, adjustment of the amount of light passing through the filters of each color will be described. In this figure, a part of the color filter is shown enlarged. Enlargement parts 11a and 11b
As shown in FIGS. 6A and 6B, by printing a dot-like or net-like pattern on the color filter 11 with an opaque paint or ink, the amount of light passing through the filter can be adjusted. That is, the amount of light passing through is adjusted according to the non-transmissive area of light due to printing. Further, as shown in the enlarged portion 11c, dots and mesh patterns may be used in combination. Printing of these patterns can be easily performed by an inkjet printer, an electronic photograph (copy), or the like. This process is performed on each of the red, blue, and green filters in consideration of the corresponding light transmission amount. For example, if a personal computer and an inkjet printer are combined, a pattern according to a desired transmission amount can be printed and the transmission amount for each color can be changed. Furthermore, without printing the pattern on the red, blue, and green filters, print the pattern on a separately prepared transparent sheet, and use it by overlaying it on the filters of each color to allow the light passing through the red, blue, and green filters to pass through. May be adjusted.
In this case, if a plurality of transparent sheets having various light transmission amounts are prepared, the light transmission amount of each color can be quickly changed as needed.

Although the preferred embodiment of the present invention has been described above, various modifications and changes can be made without departing from the spirit of the present invention. For example, the image capturing / combining circuit 16 may be a Macintosh (trademark) personal computer manufactured by Apple. In this case, the captured data can be edited in various ways. The monochrome video 14 may use an image pickup tube other than the CCD as an image pickup element. Although the video camera is monochrome, a color video camera may be used in monochrome mode.

[0026]

As described above, according to the present invention, a color video signal of a stationary object is generated using a single monochrome video camera without providing a filter in front of the monochrome video camera. it can. Further, it becomes unnecessary to correct the output video signal level of the monochrome video camera for each of the three primary colors of light.

[Brief description of drawings]

FIG. 1 is a block diagram of a preferred embodiment of the present invention.

FIG. 2 is a diagram showing an example of a light source used in the present invention.

FIG. 3 is a diagram showing characteristics of the light source of FIG.

FIG. 4 is a diagram showing another example of a light source used in the present invention.

5 is an explanatory diagram of an electronic filter used in the light source of FIG.

6 is an explanatory diagram of a liquid crystal cell used in the electronic filter of FIG.

FIG. 7 is a diagram illustrating the operation of the liquid crystal cell of FIG.

FIG. 8 is a diagram illustrating the operation of the liquid crystal cell of FIG.

FIG. 9 is a diagram showing still another example of the light source used in the present invention.

FIG. 10 is a color filter in FIG. 9 and a partially enlarged view thereof.

[Explanation of symbols]

 10 Light Source 12 Control Circuit 14 Monochrome Video Camera 16 Capture / Composition Circuit 18 Utilization Circuit 20 Switch 22 Imaging Target

Claims (6)

[Claims] 1. A monochrome video camera, a light source that emits red, blue, and green light, a control circuit that controls the light source to sequentially emit red, blue, and green light; A color still image photographing device comprising a capturing / combining circuit that sequentially captures output video signals of the above video camera when emitting red, blue, and green light and synthesizes them to obtain a color video signal. 2. The light source comprises first, second and third light emitting elements, and a dichroic film which receives light from the first, second and third light emitting elements and reflects the first and second light. To extract the light of the first, second and third colors from the light from the first, second and third light emitting elements, and use the prism to extract the first and second light.
And a dichroic prism for matching the optical paths of the third light and the color still image pickup device according to claim 1. 3. The color still image pickup device according to claim 2, wherein the dichroic prism has a red trimming filter, a blue trimming filter, and a green trimming filter. 4. The light source includes a light emitting element, a polarization filter that receives light from the light emitting element, and a liquid crystal cell, and an electronic filter that sequentially passes blue, red, and green light from the light from the light source. The color still image capturing device according to claim 1, further comprising: 5. The electronic filter comprises: a first axis for selecting light of first, second, and third colors; and a first axis for selecting light of a third color and having a second axis perpendicular to the first axis. A polarizing filter, a first liquid crystal cell for selectively polarizing 90 degrees, a first axis for selecting the light of the second color, and light for the first, second and third colors. A second polarizing filter having a second axis perpendicular to the axis, a second liquid crystal cell for selectively polarizing 90 degrees, a first axis for selecting the light of the first color, and the first, second and 5. The color still image photographing device according to claim 4, wherein light of a third color is selected and a third polarizing filter having a second axis perpendicular to the first axis is sequentially arranged. 6. The color still image capturing apparatus according to claim 1, wherein the light source includes a light emitting element and a rotating plate which receives light from the light emitting element and has red, blue and green filters. .