JPH07284111A - Image pickup device - Google Patents

Abstract

PURPOSE:To prevent waste of power and waste of a lighting fixture due to useless lighting and to prevent a contour of an image from being fogged due to a color aberration of a lens. CONSTITUTION:An infrared ray cut filter 51 and a visual light cut filter 52 are arranged side by side to a front side of a condenser lens 4. A light receiving element 61 having a peak sensitivity at a visual light region and a light receiving element 62 having a peak sensitivity at an infrared ray region are arranged in the vicinity of an image pickup element 13. An infrared ray cut filter 141 is arranged in front of the light receiving element 61 and a visual light cut filter 142 is arranged in front of the light receiving element 162. Output signals from the light receiving elements 61, 62 are fed to a signal processing unit 151. The filter 51 or 52 is controlled to be changed so as to over the front side of the condenser lens 4 depending on a wavelength region of a reflected light 3 based on a control signal from the signal processing unit 151. The condenser lens 4 is controlled to be moved in the optical axis direction depending on the wavelength region of the reflected light based on the control signal from the signal processing unit 151.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus suitable for use in picking up an image of a driver by, for example, a state detecting device for detecting a driver's dozing or the like.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-202045, there is a state detection device for monitoring the behavior of a vehicle driver using a TV camera and detecting the driver's drowsiness, looking aside, etc. Are known. FIG. 21 is a configuration diagram showing an outline of an optical system of a TV camera used for image pickup by a driver. In the figure, 1 is an infrared light illuminating device as an illumination body, 2 is a driver as an object, 3 is reflected light from the driver 2, 4 is a condenser lens, 5 is a visible light cut filter, 1
Reference numeral 3 is an image pickup device such as a CCD image sensor. Of the reflected light 3 from the driver 2 due to natural light and infrared illumination, the infrared light component that has passed through the filter 5 is focused on the image sensor 13 by the condenser lens 4 and is imaged.

[0003]

Since the conventional image pickup apparatus is constructed as described above, it has the following problems. That is, in the state in which the visible light cut filter 5 is fixed as in the example of FIG. 21, the infrared light illuminating device 1 is necessary even in the state where there is sufficient natural light illumination such as daytime, and power is wasted. Not only infrared light illumination device 1
However, there was a problem that the life of the product was shortened. Further, when the visible light cut filter 5 is not provided, there is a problem that the imaged image is blurred due to the influence of the chromatic aberration of the condenser lens 4.

The present invention has been made in order to solve such a problem, and prevents waste of power due to useless illumination and consumption of an illuminating body, and also prevents blurring of the contour of an image due to chromatic aberration of a lens. It is an object of the present invention to provide an image pickup apparatus that can be used.

[0005]

According to a first aspect of the present invention, there is provided an image pickup device comprising an image pickup device for picking up an image of a subject and a plurality of types of filters arranged in front of the image pickup device and having different transmission wavelengths. A variable filter that can be switched, a wavelength band selection unit that selects the wavelength band of the reflected light from the subject, and a focus adjustment unit that adjusts the focus of the image pickup element, and is variable based on the selection result of the wavelength band selection unit. The focus is adjusted by the focus adjusting means while switching the filters of the filters.

In the image pickup device according to the second aspect of the present invention, the wavelength band selection means is arranged in the vicinity of the image pickup element and substantially corresponds to the transmission wavelengths of a plurality of types of filters that can be switched by the variable filter. A plurality of light receiving elements having the above-mentioned spectral sensitivity and a comparison means for comparing the outputs of the plurality of light receiving elements are provided, and the output of the comparison means is used as the selection result.

In the image pickup apparatus according to the third aspect of the invention, the wavelength band selection means is arranged in the vicinity of the first light receiving element capable of receiving the reflected light from the subject which has passed through the variable filter and the image pickup element. The second light receiving element capable of directly receiving the reflected light from the subject and the comparison means for comparing the outputs of the first and second light receiving elements are provided, and the output of the comparison means is used as the selection result.

According to a fourth aspect of the present invention, in the image pickup device, the wavelength band selection means is arranged in the vicinity of the image pickup element, and the light receiving element capable of directly receiving the reflected light from the subject, and the image pickup element and the light receiving element. The comparison means for comparing the outputs is provided, and the output of the comparison means is used as the selection result.

In the image pickup device according to the fifth aspect of the present invention, the wavelength band selection means corresponds to the transmission wavelengths of the plurality of types of filters formed in a part of the plurality of types of filters that can be switched by the variable filter. A plurality of fixed filter parts having a transmission wavelength and a comparison means for comparing the outputs of the image pickup devices corresponding to the plurality of fixed filter parts are provided, and the output of the comparison means is used as a selection result.

According to the sixth aspect of the present invention, the wavelength band selecting means is arranged so as to cover a part of the image pickup device,
A plurality of fixed filters having different transmission wavelengths and a comparison means for comparing the outputs of the image pickup devices corresponding to the plurality of fixed filters are provided, and the output of the comparison means is used as a selection result.

According to a seventh aspect of the present invention, the image pickup device and the wavelength band selecting means are provided with a plurality of light receiving elements having different spectral sensitivity characteristics to which the reflected light from the subject that has passed through the variable filter is supplied. A comparison means for comparing the outputs of a plurality of light receiving elements is provided, and the output of the comparison means is used as the selection result.

In the image pickup apparatus according to the invention of claim 8, the variable filter can be switched between a visible light cut filter and an infrared light cut filter.

[0013]

According to the first aspect of the invention, based on the selection result of the wavelength band of the reflected light from the subject, the filter of the variable filter is switched so as to match the reflected light from the subject and, for example, Since the focus adjustment is performed by moving the optical lens, it is possible to prevent waste of power due to useless illumination and consumption of the illumination body, and it is possible to prevent the contour of the image from being blurred due to chromatic aberration of the lens.

According to the second aspect of the present invention, since the output levels of the plurality of light receiving elements change according to the wavelength band of the reflected light from the subject, it is possible to obtain a good wavelength band selection result from the comparison means. Is possible.

According to the third aspect of the invention, when the filter switched by the variable filter is adapted to the reflected light from the object, when the output level of the second light receiving element becomes large, the first light receiving Since the output level of the element also becomes large, it becomes possible to obtain a better selection result of the wavelength band than the comparison means.

According to the fourth aspect of the present invention, when the filter switched by the variable filter is adapted to the reflected light from the object, the output level of the image pickup element increases when the output level of the light receiving element increases. Therefore, it is possible to obtain a good wavelength band selection result by the comparison means.

According to the fifth aspect of the invention, the output levels of the image pickup devices corresponding to the plurality of fixed filter portions change according to the wavelength band of the reflected light from the subject, so that the wavelength bands are selected by the comparing means. It is possible to obtain good results.

According to the sixth aspect of the invention, since the output levels of the image pickup devices corresponding to the plurality of fixed filters change according to the wavelength band of the reflected light from the subject, the comparison means selects the wavelength band. Can be satisfactorily obtained.

According to the seventh aspect of the present invention, since the output levels of the plurality of light receiving elements change according to the wavelength band of the reflected light from the subject, it is possible to obtain a good wavelength band selection result from the comparing means. Is possible.

According to the eighth aspect of the present invention, since the visible light cut filter and the infrared light cut filter can be switched, the infrared light cut filter is used when the wavelength band of the reflected light from the subject is in the visible light region. By switching to the filter, natural light can be effectively used, and it is possible to prevent waste of power and consumption of the illumination body due to useless illumination such as infrared light illumination.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Example 1. FIG. 1 is a configuration diagram showing a first embodiment of an image pickup apparatus according to the present invention. In FIG. 1, parts corresponding to those in FIG. 21 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, on the front side of the condenser lens 4, an infrared light cut filter 51 and a visible light cut filter 52 that constitute a variable filter are arranged side by side in a direction orthogonal to the optical axis. Reference numerals 5a and 5b in FIG.
The transmission wavelength range of 52 is shown. Filters 51, 52
Is controlled to move in the direction orthogonal to the optical axis by the filter changing device 201 based on the control signal from the signal processing device 151, and the filter 51 or 52 covers the front surface of the condenser lens 4.

A light receiving element 61 such as a photodiode having a peak sensitivity in the visible light region and a light receiving element 62 such as a photodiode having a peak sensitivity in the infrared light region are orthogonal to the optical axis near the image pickup device 13. They are arranged side by side in the direction. 2B, 6a and 6b are light receiving elements 61 and 6, respectively.
2 shows the spectral sensitivity characteristic of No. 2. An infrared light cut filter 141 as a fixed filter equivalent to the above-described filter 51 is arranged so as to cover the front surface of the light receiving element 61, and is equivalent to the above-described filter 52 so as to cover the front surface of the light receiving element 62. A visible light cut filter 142 as a fixed filter is disposed. Output signals of the light receiving elements 61 and 62 are supplied to the signal processing device 151. Further, the movement of the condenser lens 4 is controlled in the optical axis direction by the lens driving device 203 as the focus adjusting means based on the control signal from the signal processing device 151.

FIG. 3 is a block diagram showing an example of a concrete circuit configuration of the signal processing device 151. In the figure, an output signal (current signal) of the light receiving element 61 is converted into a voltage signal Va by an IV converter (current-voltage converter) 71, and then supplied to an adding circuit 8 and a dividing circuit 9. To be done. The output signal (current signal) of the light receiving element 62 is converted into a voltage signal Vb by the IV converter 72 and then supplied to the adding circuit 8. The adder circuit 8 adds the voltage signals Va and Vb. The addition signal output from the addition circuit 8 is supplied to the division circuit 9. In the division circuit 9, the addition signal is used as the denominator and the voltage signal Va is used as the numerator for division.

The output signal V01 as the division result output from the division circuit 9 is supplied to the positive side terminal of the comparison circuit 101 and the negative side terminal of the comparison circuit 102.
A high-level reference voltage V is applied to the negative terminal of the comparison circuit 101.
While H is supplied, the low-level reference voltage VH is supplied to the positive terminal of the comparison circuit 101. Comparison circuit 10
From 1, high level “H” when V01 ≧ VH
Then, when V01 <VH, the signal C1 that is at the low level "L" is output. Similarly, the comparison circuit 102 outputs a signal C2 that is at a high level “H” when V01 ≦ VL and at a low level “L” when V01> VL.

Output signals C1 of the comparison circuits 101 and 102
C2 is supplied to the processing circuit 121, respectively. Then, a control signal is supplied from the processing circuit 121 to the filter changing device 201 and the lens driving device 203 according to the levels of the output signals C1 and C2. The light receiving element 6
1, 62 and the signal processing device 151 as a comparison means constitute a wavelength band selection means.

FIG. 4 is a flow chart showing the operation of the processing circuit 121 of FIG. First, the comparison circuits 101 and 10
The two output signals C1 and C2 are read (step S1).
Next, it is determined whether the output signal C1 is at the high level "H" (step S2). When it is at the high level "H", a control signal for setting the position where the infrared light cut filter 51 covers the condenser lens 4 is supplied to the filter changing device 201 (step S3), and the lens driving device 203 is also provided. Then, a control signal for setting the position of the condenser lens 4 to a position corresponding to visible light, that is, a position where light can be condensed is supplied (step S4), and the process returns to step S1.

When the output signal C1 is not at the high level "H" in step S2, it is determined whether or not the output signal C2 is at the high level "H" (step S5). When it is at the high level "H", the control signal for setting the position where the visible light cut filter 52 covers the condenser lens 4 is supplied to the filter changing device 201 (step S6), and the lens driving device 203 is supplied. A control signal for setting the position of the condenser lens 4 to a position corresponding to infrared light is supplied (step S7), and the process returns to step S1. Step S5
Then, when the output signal C2 is not at the high level "H", the control signal for changing the filters 51 and 52 and moving the condenser lens 4 is not output, and the process returns to step S1.

Next, the operation will be described. As shown in FIG. 1, the reflected light 3 from the subject (driver) 2 passes through the filter 51 or 52, is condensed by the condenser lens 4 on the image sensor 13, and is imaged. Further, the reflected light 3 from the subject 2 is made incident on the filters 141, 142, is sorted into the respective wavelength ranges as shown in the transmission wavelength range in FIG. 2, and is then made incident on the light receiving elements 61, 62. Then, the visible light component 3a and the infrared light component 3b respectively incident on the light receiving elements 61 and 62 are converted into currents according to the light amounts thereof.

As shown in FIG. 3, the current corresponding to the visible light component 3a output from the light receiving element 61 is converted into a voltage Va by the IV conversion circuit 71, and the infrared light component output from the light receiving element 62. The current corresponding to 3b is converted into the voltage Vb by the IV conversion circuit 72. Then, the adder circuit 8
Then, (Va + Vb) is obtained, and V01 = V in the division circuit 9.
a / (Va + Vb) is calculated. That is, the division circuit 9
The output signal V01 of 1 indicates the ratio of the visible light component 3a to the total light amount regardless of the light amount of the reflected light 3.

When V01 ≧ VH, the output signal C1 of the comparison circuit 101 becomes the high level “H”, and the processing circuit 121
Determines that the main component of the reflected light 3 is visible light. V01 ≦ VL
In this case, the output signal C2 of the comparison circuit 102 becomes a high level “H”, and the processing circuit 121 determines that the main component of the reflected light 3 is infrared light. When VL <V01 <VH, both of the output signals C1 and C2 are low level “L”, and it is determined that the component of the reflected light 3 is in the hysteresis range of the determination level.

The filter changing device 201 includes a processing circuit 12
Based on the control signal from 1, when the output signal C1 is at the high level "H", the infrared light cut filter 51 is controlled so as to cover the condenser lens 4, and the output signal C2 is at the high level "H". At this time, the visible light cut filter 52 is controlled so as to cover the condenser lens 4. Further, the lens driving device 203, based on the control signal from the processing circuit 121,
When the output signal C1 is at the high level "H", the condenser lens 4
Control so that the position corresponds to visible light,
When the output signal C2 is at the high level "H", the condensing lens 4 is controlled to be in a position corresponding to infrared light.

Thus, in this embodiment, the subject 2
Based on the selection result of the wavelength band of the reflected light 3 from the filters 51, 52 so as to match the reflected light 3 from the subject 2.
The switching change is performed, so that the infrared light illumination is turned off at the time of imaging with natural light, so that it is possible to prevent power from being wasted and consumption of the illumination body. Further, since the position of the condenser lens 4 is changed (focus adjustment) so as to match the reflected light 3 from the subject 2, it is possible to prevent the outline of the image from being blurred due to chromatic aberration.

Example 2. FIG. 5 is a block diagram showing a second embodiment of the image pickup apparatus according to the present invention. 5, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, reference numerals 63 and 64 denote light receiving elements each having a wavelength width having the same sensitivity as that of the image pickup element 13. The light receiving elements 63 and 64 are arranged in the vicinity of the image pickup element 13 side by side in a direction orthogonal to the optical axis. To be done. Output signals of the light receiving elements 63, 63 are supplied to the signal processing device 151. 6c in FIG. 6 shows the spectral sensitivity characteristics of the light receiving elements 63 and 64. The infrared light cut filter 141, the visible light cut filter 142, the light receiving elements 63 and 64, and the signal processing device 151 constitute a wavelength band selection unit.

In the present embodiment, the reflected light 3 from the subject 2 is made incident on the filters 141, 142, the visible light component 3a and the infrared light component 3b are respectively selected and made incident on the light receiving elements 63, 64. . In the light receiving elements 63 and 64, the visible light component 3a and the infrared light component 3b are converted into currents according to the light amounts. Therefore, the light receiving elements 61 and 6 of the example of FIG.
Even if the light receiving elements 63 and 64 are used instead of 2,
In the same manner as the above example, the filter changing device 201 and the lens driving device 203 are controlled by the control signal from the signal processing device 151.
The operation is controlled, and the same effect as the example of FIG. 1 can be obtained.

Example 3. FIG. 7 is a configuration diagram showing a third embodiment of the image pickup apparatus according to the present invention. 7, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, a filter 143 is arranged so as to cover the front surfaces of the light receiving elements 61 and 62. The filter 143 is a bandpass filter having a transmission wavelength characteristic equivalent to the sensitivity wavelength range of the image sensor 13. 14c in FIG.
Indicates the transmission wavelength characteristic of the filter 143. The filter 143, the light receiving elements 61 and 62, and the signal processing device 151 constitute a wavelength band selection unit.

In this embodiment, the reflected light 3 from the subject 2 is incident on the filter 143, and this filter 143 is used.
Then, the light is incident on the light receiving elements 61 and 62 by being limited to the sensitivity wavelength component 3c equivalent to that of the image sensor 13. As a result, the light receiving element 61 converts the current into a current corresponding to the light quantity of the visible light component of the reflected light 3, and the light receiving element 62 converts into a current corresponding to the light quantity of the infrared light component of the reflected light 3. Therefore, even if the filter 143 is used instead of the filters 141 and 142 of the example of FIG. 1, the operations of the filter changing device 201 and the lens driving device 203 are controlled by the control signal from the signal processing device 151 as in the example of FIG. It is controlled, and the same effect as the example of FIG. 1 can be obtained.

Example 4. FIG. 9 is a block diagram showing a fourth embodiment of the image pickup apparatus according to the present invention. 9, parts corresponding to those in FIGS. 1 and 5 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, reference numeral 63 is a light receiving element having a sensitivity wavelength range equivalent to that of the image pickup element 13, and is arranged at a position where the reflected light 3 from the subject 2 can be directly received. The output signal of the light receiving element 63 is a signal processing device 152.
Is supplied to. Further, 64 is a light receiving element having a sensitivity wavelength region equivalent to that of the image pickup device 13, and is arranged in the vicinity of the image pickup device 13 so as to receive the transmitted light 3d of the filter 51 or 52 covering the condenser lens 4. It This light receiving element 64
Is output to the signal processor 152.

FIG. 10 is a block diagram showing an example of a concrete circuit configuration of the signal processing device 152. 10, parts corresponding to those in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, the output signal (current signal) of the diode 63 is supplied to the division circuit 9 after being converted into a voltage signal _VA by the IV converter 71. The output signal (current signal) of the diode 64 is supplied to the division circuit 9 after being converted into a voltage signal V _B by the IV converter 72.

The division circuit 9 calculates V02 = VB / VA. That is, the output signal V of the division circuit 9
_When the condenser lens 4 is covered with the filter 51, _O2 shows the ratio of the visible light component to the total quantity of light, regardless of the quantity of light of the reflected light 3, while the condenser lens 4 makes the filter 5
When it is covered with 2, the ratio of the infrared light component to the total light amount is shown regardless of the light amount of the reflected light 3.

The output signal V _O2 as the division result output from the division circuit 9 is supplied to the positive side terminal of the comparison circuit 101 and the negative side terminal of the comparison circuit 102. Then, the output signals C1 and C2 of the comparison circuits 101 and 102
Are respectively supplied to the processing circuit 122. Processing circuit 1
A control signal is supplied from 22 to the filter changing device 201 and the lens driving device 203 according to the levels of the output signals C1 and C2. The light receiving elements 63 and 64 and the signal processing device 152 as the comparison means constitute a wavelength band selection means.

FIG. 11 is a flow chart showing the operation of the processing circuit 122 of FIG. First, the comparison circuit 101,
The output signals C1 and C2 of 102 are read (step S1
0). Next, the condenser lens 4 is set to the infrared light cut filter 51.
Or the visible light cut filter 52 is determined (step S11). When it is the filter 51, it is determined whether or not the output signal C1 is at the high level "H" (step S12). When it is high level "H",
While supplying the control signal for making the position where the infrared light cut filter 51 covers the condenser lens 4 to the filter changing device 201 (step S13), the lens driving device 2
A control signal for setting the position of the condenser lens 4 to the position corresponding to visible light is supplied to 03 (step S14), and the process returns to step S10.

When the output signal C1 is not at the high level "H" in step S12, it is determined whether the output signal C2 is at the high level "H" (step S15). When the level is “H”, the filter changing device 201
To the position where the visible light cut filter 52 covers the condensing lens 4 (step S16), and the position of the condensing lens 4 to the lens driving device 203 corresponds to the infrared light. Then, a control signal for setting the above is supplied (step S17), and the process returns to step S10. When the output signal C2 is not at the high level "H" in step S15, the process returns to step S10 without changing the control signals for changing the filters 51 and 52 and moving the condenser lens 4.

In step S11, when the filter 52 is the filter 52, it is determined whether the output signal C1 is at the high level "H" (step S18). When it is at the high level "H", a control signal for setting the position where the visible light cut filter 52 covers the condenser lens 4 is supplied to the filter changing device 201 (step S19), and the lens driving device 203 is supplied. A control signal for setting the position of the condenser lens 4 to a position corresponding to infrared light is supplied (step S2).
0), and returns to step S10.

When the output signal C1 is not at the high level "H" in step S18, it is determined whether the output signal C2 is at the high level "H" (step S21). When the level is “H”, the filter changing device 201
Is supplied with a control signal for setting the position where the infrared light cut filter 51 covers the condenser lens 4 (step S22), and the position of the condenser lens 4 is set to the lens driving device 203 at a position corresponding to visible light. Then, a control signal for setting the above is supplied (step S23), and the process returns to step S10. When the output signal C2 is not at the high level "H" in step S21, the process returns to step S10 without changing the control signals for changing the filters 51 and 52 and moving the condenser lens 4.

Next, the operation will be described. As shown in FIG. 9, the reflected light 3 from the subject 2 passes through the filter 51 or 52, is condensed by the condenser lens 4 on the image sensor 13, and is imaged. In addition, the reflected light 3 from the subject 2
Is incident on the light receiving element 63 and is converted into a current according to the amount of the reflected light 3. Further, the transmitted light 3d of the filter covering the condenser lens 4 is incident on the light receiving element 64 and converted into a current according to the light amount of the transmitted light 3d.

The output signal V02 of the division circuit 9 in FIG.
As described above, when the condenser lens 4 is covered with the filter 51, the ratio of the visible light component to the total light amount is shown regardless of the light amount of the reflected light 3. Therefore, V02 ≧
When it is VH, the output signal C1 of the comparison circuit 101 becomes a high level “H”, and the processing circuit 122 determines that the main component of the reflected light 3 is visible light. When V02 ≦ VL, the comparison circuit 10
The output signal C2 of 2 becomes high level “H”, and the processing circuit 122 determines that the main component of the reflected light 3 is infrared light. VL <
When V02 <VH, both output signals C1 and C2 are low level "L", and it is determined that the component of the reflected light 3 is in the hysteresis range of the determination level.

On the other hand, when the condenser lens 4 is covered with the filter 52 as described above, the output signal V _O2 of the division circuit 9 is the infrared light with respect to the total light quantity regardless of the light quantity of the reflected light 3. It shows the ratio of the components. Therefore, V02 ≧ VH
In this case, the output signal C1 of the comparison circuit 101 becomes a high level “H”, and the processing circuit 122 determines that the main component of the reflected light 3 is infrared light. When V02 ≦ VL, the comparison circuit 102
Output signal C2 of high level "H", processing circuit 1
22 determines that the main component of the reflected light 3 is visible light. VL <V
When 02 <VH, both output signals C1 and C2 are low level “L”, and it is determined that the component of the reflected light 3 is in the hysteresis range of the determination level.

The filter changing device 201 includes the processing circuit 12
When the main component of the reflected light in 2 is visible light, the infrared light cut filter 51 controls so as to cover the condenser lens 4, and when it is determined to be infrared light, the visible light cut filter 52 is Control is performed so as to cover the condenser lens 4. Also,
When the processing circuit 122 determines that the main component of the reflected light is visible light, the lens driving device 203 controls the condensing lens 4 to be in a position corresponding to visible light and determines that the light is infrared light. At this time, the condensing lens 4 is controlled to be in a position corresponding to infrared light.

Thus, in this embodiment, the subject 2
Based on the selection result of the wavelength band of the reflected light 3 from the filters 51, 52 so as to match the reflected light 3 from the subject 2.
The switching change is performed, so that the infrared light illumination is turned off at the time of imaging with natural light, so that it is possible to prevent power from being wasted and consumption of the illumination body. Further, since the position of the condenser lens 4 is changed so as to match the reflected light 3 from the subject 2, it is possible to prevent the outline of the image from being blurred due to chromatic aberration. In addition, there is an advantage that the number of filters can be reduced.

Example 5. FIG. 12 is a block diagram showing the fifth embodiment of the image pickup apparatus according to the present invention. 12, parts corresponding to those in FIGS. 1 and 5 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, 67 is a light receiving element having a wavelength sensitivity characteristic equivalent to that of the image sensor 13,
It is arranged at a position where the reflected light 3 from the subject 2 can be directly received. The output signal of the light receiving element 67 is the signal processing device 15
3 is supplied. Further, the image pickup signal output from the image pickup device 13 is supplied to the signal processing device 153.

In the signal processing device 153, the voltage conversion value of the current output from the light receiving element 67 according to the light amount of the reflected light 3 from the subject 2 is compared with at least a part of the image pickup signal. According to the comparison result, the signal processing device 153 supplies a control signal to the filter changing device 201 and the lens driving device 203. The light receiving element 67 and the signal processing device 153 constitute a wavelength band selection unit.

FIG. 13 is a flowchart showing the operation of the signal processing device 153 shown in FIG. First, the image sensor 13
The signal L1 of a part of the output signal of 1 is read (step S31). Next, the signal L1 is compared with the reference voltage D1 which is determined to be the minimum imageable brightness (step S3).
2). If L1> D1, it is determined that imaging can be performed with the current filter, and the filter is not changed, and step S
Return to 31. If L1> D1 is not satisfied, the current filter is not suitable, or the reflected light 3 is reflected by the image sensor 1.
It is determined that the quantity of light that can be imaged is not 3 and the voltage conversion value VT of the output current of the light receiving element 67 is read (step S3).
3).

Next, the voltage conversion value VT is compared with the reference voltage D2 for determining the minimum imageable brightness (step S).
34). If VT> D2, it is determined that the brightness is not imageable, the filter is not changed, and step S3 is performed.
Return to 1. If VT> D2, it is determined that the current filter is not suitable, the filter is changed and the lens position is changed (steps S35 and S36), and the process returns to step S31.

Thus, also in this embodiment, the subject 2
Since the filters 51 and 52 are switched and changed so as to match the reflected light 3 from the light source, the infrared light illumination is turned off when capturing the image with natural light, so that it is possible to prevent power from being wasted and power consumption of the illumination body. . Further, since the position of the condenser lens 4 is changed so as to match the reflected light 3 from the subject 2, it is possible to prevent the outline of the image from being blurred due to chromatic aberration. In addition, there is an advantage that the number of filters can be reduced.

Example 6. FIG. 14 is a block diagram showing a sixth embodiment of the image pickup apparatus according to the present invention. 14, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, filters 53 and 54 are arranged side by side in the direction orthogonal to the optical axis on the front side of the condenser lens 4. The filter 53 is composed of an infrared light cut filter 51 as a main filter section and fixed filter sections 55 and 56 arranged in parallel at the lower part. Further, the filter 54 is a visible light cut filter 5 as a main filter unit.
2 and fixed filter parts 55 and 56 arranged in parallel at the bottom.
Composed of and. The fixed filter unit 55 is an infrared light cut filter, and the fixed filter unit 56 is a visible light cut filter.

The reflected light 3 from the subject 2 is reflected by the main filter 5
The light passes through 1 or 52 and is condensed by the condenser lens 4 on the image sensor 13 to be imaged. Further, the reflected light 3 from the subject 2 passes through the fixed filter sections 55 and 56, and the condenser lens 4 respectively causes the image pickup surface periphery 13 of the image pickup device 13.
It is condensed to 1,132. The output signal of the image sensor 13 is supplied to the signal processing device 154. Signal processing device 154
Then, among the output signals of the image pickup signal 13, the image pickup surface periphery 13
The signals SV and SI corresponding to 1,132 are compared. According to the comparison result, the signal processing device 154 supplies the control signal to the filter changing device 201 and the lens driving device 203. The fixed filter units 55 and 56 and the signal processing device 154 as a comparison unit constitute a wavelength band selection unit.

FIG. 15 is a flow chart showing the operation of the signal processing device 154 of FIG. First, the signals SV and S
I is read (step S41). Next, the signals SV and S
It is determined whether I is at the same level (step S4).
2). If SV = SI, the process returns to step S41 without changing the filter. When SV = SI is not satisfied,
It is determined whether the signal SV is smaller than the signal SI (step S43). When SI> SV, that is, when the main component of the reflected light 3 from the subject 2 is infrared light, the process returns to step S41 via the subroutine of step S44. On the other hand, when SI <SV, that is, when the main component of the reflected light 3 from the subject 2 is visible light, the process returns to step S41 via the subroutine of step 45.

FIG. 16 is a flowchart showing the subroutine of step S44. First, a control signal for setting the position where the filter 54 covers the condensing lens 4 is supplied to the changing device 201 (step S51), and the position of the condensing lens 4 is adapted to the lens driving device 203 for infrared light. A control signal for setting the selected position is supplied (step S52). Next, the signal SI is compared with the reference voltage EI for determining the minimum imageable brightness (step S53).
If SI ≧ EI, the filter 54 maintains the position where it covers the condenser lens 4, and if SI ≧ EI is not satisfied, the process returns.

FIG. 17 is a flowchart showing the subroutine of step S45. First, the change device 201 is supplied with a control signal for setting the position where the filter 53 covers the condenser lens 4 (step S61), and the position of the condenser lens 4 is adapted to the lens drive device 203 for visible light. A control signal for setting the position is supplied (step S62). Next, the signal SV is compared with the reference voltage EV for determining the minimum imageable brightness (step S63).
If SV ≧ EV, the filter 53 maintains the position where the condenser lens 4 is covered, and if SV ≧ EV, the process returns.

As described above, also in this example, since the filters 53 and 54 are switched and changed so as to match the reflected light 3 from the subject 2, it is useless by turning off the infrared light illumination during the imaging with natural light. It is possible to prevent waste of power due to lighting and consumption of the lighting body. Further, since the position of the condenser lens 4 is changed so as to match the reflected light 3 from the subject 2, it is possible to prevent the outline of the image from being blurred due to chromatic aberration. Further, there is an advantage that a light receiving element need not be separately provided.

Example 7. FIG. 18 is a configuration diagram showing a seventh embodiment of the image pickup apparatus according to the present invention. 18, parts corresponding to those in FIGS. 1 and 14 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, filters 141 and 142 are arranged corresponding to the front surfaces of the imaging surface periphery 131 and 132 of the image sensor 13, respectively. As described in the example of FIG. 1, the filter 141 is an infrared light cut filter, and the filter 142 is a visible light cut filter.

The reflected light 3 from the subject 2 passes through the filter 51 or 52, and is condensed by the condenser lens 4 into the image sensor 1.
It is focused on 3 and imaged. Further, the reflected light 3 from the subject 2 is transmitted through the filter 51 or 52 and then through the filters 141 and 142, and is condensed by the condenser lens 4 on the image pickup surface periphery 131 and 132 of the image pickup device 13. The output signal of the image sensor 13 is supplied to the signal processing device 154. In the signal processing device 154, the signals SV and SI corresponding to the imaging surface surroundings 131 and 132 among the output signals of the imaging signal 13 are compared. According to the comparison result, the signal processing device 154 supplies the control signal to the filter changing device 201 and the lens driving device 203. In addition,
The filters 141 and 142 and the signal processing device 154 form a wavelength band selection unit. In this embodiment, the same operation and effect as in the example of FIG. 14 can be obtained.

Example 8. FIG. 19 is a block diagram showing the eighth embodiment of the image pickup apparatus according to the present invention. In FIG. 19, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, reference numerals 61 and 62 denote a light-receiving element 61 having a peak sensitivity in the visible light region and a light-receiving element 62 having a peak sensitivity in the infrared light region, which are arranged in the vicinity of the image sensor 13 side by side in a direction orthogonal to the optical axis. It Light receiving element 6
The transmitted light 3e of the filter 51 or 52 is incident on 1,2. The output signals of the light receiving elements 61 and 62 are supplied to the signal processing device 155, respectively. A control signal is supplied from the signal processing device 155 to the filter changing device 201 and the lens driving device 203.

FIG. 20 is a block diagram showing an example of a concrete circuit configuration of the signal processing device 155. 20, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, the output signal (current signal) of the diode 61 is converted into the voltage signal Va by the IV converter 71 and then supplied to the negative side terminal of the comparison circuit 103.
The output signal (current signal) of the diode 62 is IV
After being converted into the voltage signal Vb by the converter 72, the comparison circuit 1
04 negative terminal.

The reference voltage V is applied to the positive terminal of the comparison circuit 103.
In addition to being supplied with 1, the reference voltage V2 is supplied to the positive terminal of the comparison circuit 104. From the comparison circuit 103, V
When 1 ≧ Va, the high level becomes “H”, and V1 <
When it is Va, a low level signal "L" is output. Similarly, the comparison circuit 104 outputs a signal that is high level “H” when V2 ≧ Vb and low level “L” when V2 <Vb. The output signals of the comparison circuits 103 and 104 are supplied to the OR circuit 111, and the output signals of the OR circuit 111 are supplied to the filter changing device 201 and the lens driving device 203 as control signals. The light receiving elements 61 and 62 and the signal processing device 155 as the comparing means constitute a wavelength band selecting means.

Next, the operation will be described. Consider a case where the condenser lens 4 is covered with the visible light cut filter 52. In this case, the light receiving elements 61 and 62 are also covered with the filter 52. If the reflected light 3 from the subject 2 is visible light, the reflected light 3 is blocked by the filter 52 and is not incident on the light receiving elements 61 and 62. Therefore, the output signals of the comparison circuits 103 and 104 are both at the low level “L”. If the reflected light 3 from the subject 2 is infrared light, the reflected light 3 passes through the filter 52 and is incident on the light receiving elements 61 and 62. Therefore, the output signal of the comparison circuit 103 becomes low level “L” and the output signal of the comparison circuit 104 becomes high level “H”.

Consider a case where the condenser lens 4 is covered with the infrared light cut filter 51. In this case, the light receiving elements 61 and 62 are also covered with the filter 51. If the reflected light 3 from the subject 2 is infrared light, the reflected light 3 is blocked by the filter 51, so that the light receiving elements 61 and 62 are received.
Is not incident on. Therefore, the comparison circuits 103 and 104
The output signals of both become low level "L". If the reflected light 3 from the subject 2 is visible light, the reflected light 3 passes through the filter 51 and is incident on the light receiving elements 61 and 62.
Therefore, the output signal of the comparison circuit 103 is high level “H”, and the output signal of the comparison circuit 104 is low level “L”.
Becomes

Therefore, the output signal of the OR circuit 111 is at the high level "H" when the filter is compatible with the wavelength band of the reflected light 3, and is at the low level "L" when it is not compatible. . When the output signal of the OR circuit 111 is at the high level “H”, the filter changing device 201 determines that the filter is suitable, and the filters 51 and 52.
On the other hand, when the output signal of the OR circuit 111 is at the low level "L", the filter is judged to be incompatible and the filter is changed. In addition, the lens driving device 2
03 is also driven by the same logic.

Thus, in this embodiment, the subject 2
Based on the selection result of the wavelength band of the reflected light 3 from the filters 51, 52 so as to match the reflected light 3 from the subject 2.
The switching change is performed, so that the infrared light illumination is turned off at the time of imaging with natural light, so that it is possible to prevent power from being wasted and consumption of the illumination body. Further, since the position of the condenser lens 4 is changed so as to match the reflected light 3 from the subject 2, it is possible to prevent the outline of the image from being blurred due to chromatic aberration.

[0070]

According to the first aspect of the present invention, there is provided an image pickup device for picking up an image of a subject, and a variable filter arranged in front of the image pickup device and capable of switching to a plurality of types of filters having different transmission wavelengths. A wavelength band selection unit for selecting a wavelength band of reflected light from a subject and a focus adjustment unit for adjusting the focus of the image sensor, and based on the selection result of the wavelength band selection unit, switches the variable filter. Focus adjustment is performed by the focus adjustment means, and it is possible to prevent waste of power due to useless illumination and consumption of the illuminating body, and it is possible to prevent the contour of the image from being blurred due to chromatic aberration of the lens. is there.

According to the second aspect of the present invention, the wavelength band selection means is arranged in the vicinity of the image pickup device, and the spectral sensitivities corresponding to the respective transmission wavelengths of a plurality of types of filters that can be switched by the substantially variable filter. A plurality of light receiving elements having
A comparison means for comparing the outputs of the plurality of light receiving elements is provided, and the output of the comparison means is used as a selection result. The output levels of the plurality of light receiving elements are determined according to the wavelength band of the reflected light from the subject. Since there is a change, there is an effect that the selection result of the wavelength band can be favorably obtained by the comparison means.

According to the third aspect of the invention, the wavelength band selecting means is arranged in the vicinity of the first light receiving element capable of receiving the reflected light from the subject that has passed through the variable filter and the image pickup element, The variable filter is provided with a second light receiving element capable of directly receiving reflected light from and a comparing means for comparing the outputs of the first and second light receiving elements, and the output of the comparing means is used as a selection result. When the filter switched in step 1 is adapted to the reflected light from the subject, the output level of the first light receiving element also increases when the output level of the second light receiving element increases, so There is an effect that a selection result can be obtained favorably.

According to the fourth aspect of the invention, the wavelength band selecting means is disposed in the vicinity of the image pickup element and outputs the light receiving element capable of directly receiving the reflected light from the subject and the output of the image pickup element and the light receiving element. The output level of the light receiving element becomes large when the filter switched by the variable filter is adapted to the reflected light from the subject. Since the output level of the image pickup device also becomes large, there is an effect that the selection result of the wavelength band can be obtained better than the comparison means.

According to the fifth aspect of the invention, the wavelength band selection means has transmission wavelengths corresponding to the transmission wavelengths of the plurality of types of filters formed in a part of the plurality of types of filters that can be switched by the variable filter. A plurality of fixed filter sections having a plurality of fixed filter sections and a comparing section for comparing the outputs of the image pickup devices corresponding to the plurality of fixed filter sections, and the output of the comparing section is used as a selection result. Since the output levels of the image pickup devices corresponding to the plurality of fixed filter sections change according to the wavelength band of, there is an effect that the comparison result of the wavelength band can be obtained favorably.

According to the sixth aspect of the invention, the wavelength band selecting means is arranged so as to cover a part of the image pickup device, and the plurality of fixed filters having different transmission wavelengths, and the plurality of fixed filters. And a comparison means for comparing the outputs of the image pickup elements corresponding to the above, and the output of the comparison means is used as a selection result, and the image pickup elements corresponding to a plurality of fixed filters according to the wavelength band of the reflected light from the subject. Since the output level of 1 changes, the selection result of the wavelength band can be obtained better than the comparison means.

According to the seventh aspect of the present invention, the wavelength band selection means includes a plurality of light receiving elements having different spectral sensitivity characteristics to which the reflected light from the subject that has passed through the variable filter is supplied, and the plurality of light receiving elements. Comparing the output of the individual light receiving elements, and the output of the comparing means as a selection result,
Since the output levels of the plurality of light receiving elements change according to the wavelength band of the reflected light from the subject, there is an effect that the comparison result of the wavelength band can be obtained favorably.

According to the eighth aspect of the present invention, the variable filter can be switched to the visible light cut filter and the infrared light cut filter, and can be switched to the visible light cut filter and the infrared light cut filter. Therefore, when the wavelength band of the reflected light from the subject is in the visible light range, by switching to the infrared light cut filter,
There is an effect that natural light can be effectively used, and it is possible to prevent waste of electric power and consumption of the illumination body due to useless illumination such as infrared light illumination.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a transmission characteristic of a filter and a spectral sensitivity characteristic of a light receiving element used in the example of FIG.

3 is a block diagram showing a signal processing device used in the example of FIG. 1. FIG.

FIG. 4 is a flowchart showing an operation of the processing circuit of the example of FIG.

FIG. 5 is a configuration diagram showing a second embodiment of the image pickup apparatus according to the present invention.

6 is a diagram showing a spectral sensitivity characteristic of a light receiving element used in the example of FIG.

FIG. 7 is a configuration diagram showing a third embodiment of the image pickup apparatus according to the present invention.

8 is a diagram showing a spectral sensitivity characteristic of a light receiving element used in the example of FIG.

FIG. 9 is a configuration diagram showing a fourth embodiment of the image pickup apparatus according to the present invention.

10 is a block diagram showing a signal processing device used in the example of FIG. 9. FIG.

11 is a flowchart showing an operation of the processing circuit of the example of FIG.

FIG. 12 is a configuration diagram showing a fifth embodiment of the image pickup apparatus according to the present invention.

13 is a flowchart showing the operation of the signal processing device of the example of FIG.

FIG. 14 is a configuration diagram showing a sixth embodiment of the image pickup apparatus according to the present invention.

FIG. 15 is a flowchart showing an operation of the signal processing device of the example of FIG.

16 is a diagram showing a subroutine of the flowchart of FIG.

17 is a diagram showing a subroutine of the flowchart of FIG.

FIG. 18 is a configuration diagram showing a seventh embodiment of the image pickup apparatus according to the present invention.

FIG. 19 is a configuration diagram showing an eighth embodiment of the image pickup apparatus according to the present invention.

20 is a configuration diagram showing a signal processing device used in the example of FIG. 19. FIG.

FIG. 21 is a configuration diagram showing a conventional imaging device.

[Explanation of symbols]

1 infrared light illuminating device, 2 driver (subject), 3 reflected light, 4 condensing lens 13 imaging device, 51, 53, 55, 141 infrared light cut filter, 52, 54, 56, 142 visible light cut filter , 61 to 64, 67 light receiving element, 143 band pass filter, 151 to 155 signal processing device,
201 filter changing device, 203 lens driving device.

Claims (8)

[Claims] 1. An image pickup device for picking up an image of a subject, a variable filter which is arranged in front of the image pickup device and which can be switched to a plurality of types of filters having different transmission wavelengths, and a wavelength band of reflected light from the subject. A wavelength band selection unit for selecting and a focus adjustment unit for adjusting the focus of the image pickup device are provided, and the filter of the variable filter is switched based on the selection result of the wavelength band selection unit, and the focus adjustment unit performs focus. An imaging device characterized by making adjustments. 2. The wavelength band selection means is arranged in the vicinity of the image pickup device, and has a plurality of light receiving elements having spectral sensitivities respectively corresponding to transmission wavelengths of a plurality of types of filters which can be switched by the variable filter. An element and a comparing means for comparing the outputs of the plurality of light receiving elements, wherein the filter of the variable filter is switched based on the output of the comparing means, and the focus adjusting means adjusts the focus. The image pickup apparatus according to claim 1. 3. The wavelength band selection means is arranged in the vicinity of the image pickup device, and is provided in the vicinity of the image pickup device and a first light receiving device which can receive reflected light from the subject that has passed through the variable filter. A second light receiving element which is arranged and is capable of directly receiving reflected light from the subject, and a comparison means for comparing the outputs of the first and second light receiving elements, and based on the output of the comparison means, The image pickup apparatus according to claim 1, wherein the focus adjustment unit adjusts the focus while switching the filter of the variable filter. 4. The wavelength band selection means is arranged in the vicinity of the image pickup element and is capable of directly receiving the reflected light from the subject, and a comparison means for comparing the outputs of the image pickup element and the light receiving element. The image pickup apparatus according to claim 1, further comprising: a switch for changing the filter of the variable filter based on an output of the comparison unit, and the focus adjustment unit performing focus adjustment. 5. The wavelength band selection means comprises a plurality of fixed filters each having a transmission wavelength corresponding to a transmission wavelength of the plurality of types of filters formed in a part of the plurality of types of filters that can be switched by the variable filter. A filter unit and a comparing unit that compares the outputs of the image pickup devices corresponding to the plurality of fixed filter units are provided, and the filter of the variable filter is switched based on the output of the comparing unit and the focus adjusting unit. The image pickup apparatus according to claim 1, wherein the focus adjustment is performed by. 6. The wavelength band selection means is arranged so as to cover a part of the image pickup device, and a plurality of fixed filters having different transmission wavelengths, and the image pickup device corresponding to the plurality of fixed filters. 2. The comparison means for comparing the outputs of the above-mentioned means, the filter of the variable filter is switched based on the output of the comparison means, and the focus adjustment means adjusts the focus. Imaging device. 7. The wavelength band selection means outputs a plurality of light receiving elements having different spectral sensitivity characteristics to which reflected light from the subject that has passed through the variable filter is supplied, and outputs of the plurality of light receiving elements. The image pickup apparatus according to claim 1, further comprising: a comparison unit for comparing, wherein the filter of the variable filter is switched based on an output of the comparison unit, and focus adjustment is performed by the focus adjustment unit. . 8. The image pickup apparatus according to claim 1, wherein the variable filter is switchable between a visible light cut filter and an infrared light cut filter.