JPH07203467A - Image pickup device - Google Patents

Abstract

PURPOSE:To facilitate the white balance adjustment by inserting plural filter sections into an optical path of an emitted light whose light trasmissivity differs with respect to color temperature and moving the filter member in a prescribed direction in crossing with the optical axis. CONSTITUTION:A color temperature conversion filter 119 is provided on a side of a light source section 1 and a filter drive section 111 drives the filter 119 based on a color slip signal detected by a white balance circuit 6 as a basis of white balance adjustment. The filter 119 is made up of a blue side emphasis filter, an ND filter and a red side emphasis filter and the drive section 111 moves the filters in the arrangement direction. When the light collected by a condenser lens 113 is projected to the ND filter, the intensity of the red light is increased and the intensity of the blue color is decreased, and when the light enters the blue side emphasis filter, the intensity distribution is uniformized and when the light enters the red side emphasis filter, the R intensity is decreased and the B intensity is increased conversely to move the filter 119 thereby controlling the light from the light source as a basis on white balance adjustment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device, and more particularly to an image pickup device for improving S / N characteristics of color signals.

[0002]

2. Description of the Related Art For example, in a color image pickup device with a light source such as a film scanner, R (red), G (green),
Conventionally, white balance (WB) adjustment for adjusting the spectral characteristic of B (blue) is generally performed on the side of an image pickup circuit that processes an image signal obtained by an image pickup element or on the side of an optical system. Target.

FIG. 14 shows a configuration example of such a conventional image pickup apparatus. In the light source unit 1, the light from the lamp 112 which is turned on by the lamp power supply 10 under the control of the CPU 9 is condensed on the light emitting side by the condenser mirror 111, and the condenser lens 11
Focus at 3. The light condensed by the condenser lens 113 is cut by the heat ray cut filter 114 to prevent heat damage to the film, then diffused by the diffusion lens 115 and sandwiched between the diffusion plates 116 and 117 to randomly scatter the light. Light is projected through a reflection box 118 having a reflecting mirror surface.

The projection light from the light source unit 1 is applied to the surface of the film 2, and the light passing through the film 2 is imaged on the image pickup device 4 via the imaging lens 3. The image signal converted into an electric signal by the image pickup device 4 is sampled and held by the first image pickup circuit 5, the gain is adjusted, and the white balance circuit 6 is supplied. In the white balance circuit 6, white balance adjustment is performed to make the input spectral distribution to the image pickup device uniform, and the output is output to the second image pickup circuit 7. The second image pickup circuit 7 converts the output signal from the white balance circuit 6 into a signal form suitable for the output form and outputs the signal form. This conversion is conversion to NTSC signals if the output monitor is a home-use television, and conversion to R, G, B signals if it is a personal computer monitor. The timing generator 8 outputs the timing signal of the image signal processing system under the control of the CPU 9.

FIG. 15 shows a diagram for explaining the white balance adjustment. FIG. 15A shows the input spectral distribution characteristics to the image sensor when using a halogen lamp, for example, from the long wavelength R (red) region to the G (green) region, B
The light intensity decreases as the wavelength decreases to the (blue) region. Further, as shown in FIG. 3B, the spectral distribution of each color filter of the image sensor also has the highest transmittance in the R region, the second highest in the G region, and the lowest in the B region. Therefore, the signal levels of the R, G, and B colors are, as shown in FIG. 7C, the R signal is high, the G signal is the next highest, and the B signal is the lowest. The color cannot be reproduced. Therefore, white balance adjustment is a process for adjusting the R, G, and B signal levels to the same level. For example, as shown in FIG. 15D, the levels indicated by the dotted lines of R, G, and B are adjusted to be the solid line levels.

[0006]

As described above, in the conventional image pickup apparatus, the white balance adjustment is performed on the image pickup circuit side. However, for example, the level adjustment for white balance adjustment as shown in FIG.
Since the gain is increased for the signal and the G signal, the noise component indicated by the shaded area in the figure is also increased, and as a result, S /
N will be deteriorated.

On the other hand, on the optical system side, there is also a device for changing the correction amount by replacing the filter with a monochromatic filter to adjust the white balance, but in this device, the replacement must be performed manually, and the operability is poor. Not only that, but the correction amount becomes discrete, and there is a problem in terms of accuracy.

Therefore, an object of the present invention is to S / N the color signals.
An object of the present invention is to provide an image pickup apparatus which prevents deterioration of characteristics and has improved operability.

[0009]

In order to solve the above-mentioned problems, the image pickup apparatus according to the present invention intersects with the optical axis of the light path to be applied so that it is inserted in the optical path of the irradiation light. A filter member having a plurality of filter portions that are displaceable in a predetermined direction and have different light transmission characteristics with respect to color temperature; and a filter driving unit that drives the filter member in the predetermined direction. Composed.

[0010]

According to the present invention, a filter member, which is inserted in the optical path of irradiation light and has a plurality of filter portions having different light transmission characteristics with respect to color temperature, is provided so as to be displaceable in a predetermined direction intersecting the optical axis, This filter member is driven in a predetermined direction.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of an image pickup apparatus according to the present invention, and shows an application example to a film scanner. In FIG. 1, components designated by the same reference numerals as those in FIG. 14 indicate components having similar functions. In the present embodiment, a color temperature conversion filter 119 is provided on the light source unit 1 side, and the color temperature conversion filter 119 is used based on the color shift signal detected by the white balance circuit 6.
1 to drive the white balance adjustment.

As the color temperature conversion filter 119, for example, a color temperature conversion filter having the structure shown in FIGS. 2 to 4 is used. In the color temperature conversion filter shown in FIG. 2, a blue side emphasis filter, an ND filter, and a red side emphasis filter are arranged and integrated as shown in the figure, and are moved in the arrangement direction by the filter driving unit 11. In the color temperature conversion filter shown in FIG. 3, a red side emphasis filter, an ND filter, and a blue side emphasis filter are arranged in a circle (fan shape), and can be rotationally driven in both directions. The color temperature conversion filter shown in FIG.
It is a filter similar to that of FIG. 2, which is configured by only a blue side emphasis filter and a red side emphasis filter without using a D filter.

White balance adjustment using the color temperature conversion filter shown in FIG. 2 will be described with reference to FIG. Now, as shown in FIG. 5 (A1), the condenser lens 113
The spectral characteristics when the light condensed by (indicated by a circle) is projected on the ND filter are intensity distribution characteristics in which the R intensity is high and the B intensity is low, as shown in FIG. On the other hand, when the condensed light enters the blue side emphasis filter portion as shown in FIG. 11B1, the intensity distribution is made uniform as shown in FIG. As shown in FIG.
When the condensed light further enters the blue side emphasis filter, the intensity distribution is conversely low in R intensity and high in intensity. Therefore, move the color temperature conversion filter in the direction of the arrow in FIG.
It can control the light from the light source and can be the basis for white balance adjustment.

For example, a color temperature conversion filter is shown in FIG.
The spectral distribution obtained when the position 1) is set is shown in FIG.
FIG. 6B shows the signal levels of R, G, and B before white balance adjustment in FIG. Here, the B and R signal levels are substantially the same when considering the color filter characteristics shown in FIG. 15B, but the G signal level is low, so
The gain of the G signal is raised to the same level as shown in FIG. By doing so, only the G signal noise component indicated by the shaded area is increased, and the overall S / N deterioration can be avoided. At this time, since the color temperature conversion filter can be arranged in the light condensing unit, the size of the color temperature conversion filter can be small.

Another configuration example of the color temperature conversion filter is shown in FIG. In this example, as shown in the figure, a green filter is arranged in addition to the blue side enhancement filter and the red side enhancement filter. 8A, 8B and 8C show the spectral transmittance characteristics of the blue side emphasis filter, the red side emphasis filter and the green filter.

FIG. 9 shows the filter output light intensity distribution corresponding to the light position from the light source when the color temperature conversion filter shown in FIG. 7 is used. The intensity distribution at the position (A1) in the figure is (A2), the intensity distribution at the position (B1) is (B2), and the intensity distribution at the position (C1) is (C2), The intensity distribution at the (D1) position is shown in (D2). When the green filter has a light position, a characteristic that the G signal level rises is obtained.

10 (A) and 10 (B), FIG.
1) and (C2) and FIG. 9 (D1) and (D2), the respective color signal levels after the white balance adjustment are shown together with the noise component in the shaded area.

FIG. 11 shows still another embodiment of the image pickup device according to the present invention, in which RGB color filters are used instead of the color temperature conversion filters.
This is an example using the color liquid crystal 120. RGB color liquid crystal 120 installed after the heat ray cut filter 114
Are driven by the liquid crystal drive unit 12. LCD drive unit 12
Is driven and controlled by the color shift detection signal from the white balance circuit 6, and simultaneously controls the aperture of the RGB liquid crystal 120 based on the gain information from the first image pickup circuit 5.

FIG. 12 shows an example of a color liquid crystal in which a red (R) filter, a green (G) filter and a blue (B) filter in this embodiment are arranged, and the characteristics of the transmittance of each filter with respect to the wavelength are shown in FIG. It is shown in (A), (B) and (C). These filters can also be arranged on the side of the imaging lens. Therefore, according to the above-described embodiment, the white balance adjustment and the light amount control can be performed at the same time, and the overall configuration can be simplified. By passing the light whose white balance is adjusted as described above through the diffusion box, it is possible to emit the light whose color temperature is continuously changed without color unevenness.

The embodiment of the present invention has been described above.
The present invention is useful in a variety of situations. For example, since the color temperature varies depending on the light source such as a halogen lamp or a metal halide lamp, the present invention can be applied to initially adjust and set the white balance according to the light source used, or the color due to the change over time of the light source characteristics. The change in temperature can also be adjusted by the user. It is also effective when it is desired to perform color correction individually using a film scanner. Another embodiment of the present invention can be summarized as follows. That is, a plurality of unit filter units which are provided so as to be inserted in the optical path of the irradiation light from the applicable light source, have different light transmission characteristics with respect to color temperature, and have a light transmittance that changes according to the drive signal. An image pickup apparatus comprising: a liquid crystal light transmission adjusting unit having: and a driving unit for driving the liquid crystal light transmission adjusting unit.

[0021]

As described above, according to the image pickup apparatus of the present invention, it is possible to adjust the white balance without deterioration of the S / N of the color signal and with excellent operability.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a color temperature conversion filter used in an embodiment of the present invention.

FIG. 3 is a diagram showing a color temperature conversion filter used in an embodiment of the present invention.

FIG. 4 is a diagram showing a color temperature conversion filter used in an embodiment of the present invention.

FIG. 5 is a diagram showing a spectral distribution of a color temperature conversion filter in an example of the present invention.

6 is a diagram for explaining white balance adjustment using the color temperature conversion filter shown in FIG.

FIG. 7 is a diagram showing another configuration example of a color temperature conversion filter.

FIG. 8 is a diagram showing spectral characteristics of a blue side emphasis filter, a red side emphasis filter, and a green filter in the example of the present invention.

9 is a diagram showing a filter output light intensity distribution corresponding to a light position from a light source when the color temperature conversion filter shown in FIG. 7 is used.

10 is a diagram showing each color signal level after white balance adjustment in the state shown in FIG.

FIG. 11 shows still another embodiment of the image pickup apparatus according to the present invention.

12 is a diagram showing an example of a color liquid crystal in which a red (R) filter, a green (G) filter and a blue (B) filter in the embodiment shown in FIG. 11 are arranged.

13 is a diagram showing the characteristics of the transmittance of the red (R) filter, the green (G) filter, and the blue (B) filter with respect to wavelength in the embodiment shown in FIG.

FIG. 14 is a diagram illustrating a configuration example of a conventional imaging device.

FIG. 15 is a diagram for explaining conventional white balance adjustment.

[Explanation of symbols]

1 Light Source Section 2 Film 3 Imaging Lens 4 Imaging Device 5, 7 Imaging Circuit 6 White Balance Circuit 8 Timing Generator 9 CP
U 10 Lamp power supply 11 Filter driving unit 12 Liquid crystal driving unit 111 Condensing mirror 112 Lamp 113 Condensing lens 114 Heat ray cut filter 115 Diffusing lens 116, 117 Diffusing plate 118 Reflecting box 119 Color temperature converting filter 120 RG
B color liquid crystal

[Procedure amendment]

[Submission date] February 7, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1] ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 7, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

The embodiment of the present invention has been described above.
The present invention is useful in a variety of situations. For example, since the color temperature varies depending on the light source such as a halogen lamp or a metal halide lamp, the present invention can be applied to initially adjust and set the white balance according to the light source used, or the color due to the change over time of the light source characteristics. The change in temperature can also be adjusted by the user. It is also effective when it is desired to perform color correction individually using a film scanner. Another embodiment of the present invention can be summarized as follows. That is, a plurality of unit filters that are provided so as to be inserted in the optical path of the irradiation light from the applicable light source, have different light transmission characteristics with respect to color temperature, and have a light transmittance that changes according to the drive signal ( (For example, red side emphasis filter, blue side emphasis filter, etc.)
An image pickup apparatus comprising: a liquid crystal light transmission adjusting unit having a section; and a driving unit for driving the liquid crystal light transmission adjusting unit.

Claims (1)

[Claims] 1. A plurality of devices, which are arranged so as to be inserted in an optical path of irradiation light from the applicable light source and are displaceable in a predetermined direction intersecting an optical axis of the optical path and have different light transmission characteristics with respect to color temperature. An image pickup apparatus comprising: a filter member having the filter part of 1. and a filter driving means for driving the filter member in the predetermined direction.