JPH07246185A - Imaging device creating visible and infrared images - Google Patents

Abstract

PURPOSE:To obtain an optimum image considering the characteristics of visible and infrared images. CONSTITUTION:A CCD 19 which images both visible and infrared images by the rotation of a color disc 12 that incorporates a visible ray filter and infrared ray filter, a signal separation circuit 21 which separates the visible and infrared images signals, and an electronic shutter control circuit 23 which inputs the output signal from the signal separation circuit 21 and controls the electronic shutter according to each signal are provided, and the control of the electronic shutter realizes an optimum brightness fine image. This electronic shutter can be controlled by a frame sequential identification pulse for the frame sequential system, and can also be applied to the simultaneous system.

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, and more particularly to an apparatus used for an electronic endoscope apparatus or the like and capable of forming both a visible image and an infrared image.

[0002]

2. Description of the Related Art As an image pickup device, there is an electronic endoscope device for observing the inside of a body cavity such as a digestive tract or the inside of various structures using a CCD (Charge Coupled Device) which is a solid-state image pickup device. In this type of imaging device, R (red), G
There is one that forms a visible image with image signals of (green) and B (blue) light and at the same time forms an infrared image with infrared light (for example, near-infrared light) (for example, JP-A-2-49302).
Issue). According to this infrared image, a normal color image can be observed, and at the same time, the infrared light can observe the surface layer or the submucosal blood flow in the body cavity.

In the field sequential method, the visible image and the infrared image are provided at the same time by providing the light source device with a color filter having, for example, an RGB light filter and an infrared light filter, and rotating the color filter. In the formula, it can be obtained by forming an RGB light filter and an infrared light filter on the front surface of the CCD.

[0004]

However, in the image pickup apparatus for obtaining both the visible image and the infrared image described above, each of the obtained images is different due to the difference in the sensitivity characteristics of the optical member, the image pickup element and the like with respect to the visible light and the infrared light. There is a problem that the signal levels are different and it is difficult to form a good image at the same time. That is, FIG. 7 shows an example of the signal level obtained by the CCD. According to this, the level increases in the order of B signal → G signal → R signal, and the near infrared (IR) image signal is obtained. Is even higher than these signals. Therefore, when the light amount control is performed based on the visible image signal, the level of the infrared image signal becomes too large, and when the light amount control is performed based on the infrared image signal, the level of the visible image signal becomes too small.

The visible image is a color display,
Since the infrared image is a monochromatic display and the image quality is inherently different, the signal level also differs depending on the observation target, for example, when targeting a diseased part in a body cavity and a gas pipe of a structure having a high temperature part. In the case of a target, it is difficult to uniformly control the visible image and the infrared image.

The present invention has been made in view of the above problems, and an object thereof is to provide a visible image and an infrared image capable of obtaining an optimum image in consideration of the respective characteristics of the visible image and the infrared image. It is to provide an imaging device to be formed.

[0007]

In order to achieve the above object, an image pickup apparatus for forming a visible image and an infrared image according to the present invention includes an image pickup element for picking up both a visible image and an infrared image, and An electronic shutter control circuit that controls an electronic shutter based on a signal of a visible image signal or an infrared image signal obtained by an image pickup device to adjust the brightness of an image is configured. The invention according to the second aspect is applied to a frame sequential device using a color disc provided with a filter for visible light and a filter for infrared light, and the electronic shutter control circuit responds to the rotation of the color disc. It is characterized in that the electronic shutter is operated by the formed frame sequential identification pulse.

[0008]

According to the above structure, the visible image signal and the infrared image signal are fed back to the electronic shutter control circuit,
The electronic shutter is controlled so that these images have the optimum brightness, and the infrared image is controlled so that the shutter time is shorter than that in the case of the visible image, that is, the charge accumulation amount is smaller. Such control can be performed in the frame sequential device based on the frame sequential identification pulse obtained from the rotation detection signal of the color disc. Further, in the simultaneous type device, the visible image signal or the infrared image signal can be selectively fed back by switching the operation button or the like. For example, it is possible to form an optimum infrared image by normally setting a state in which the visible image has the optimum brightness and selectively performing electronic shutter control on the infrared image.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 show the construction of a field sequential image pickup apparatus for forming a visible image and an infrared image according to an embodiment. In the figure, a light source lamp 1 is provided in a light source device 100.
1, a color disc 12 and a motor 13 for driving the color disc 12 are provided.
The lamp 14 and the photo sensor 15 are arranged with the lamp sandwiched therebetween. As shown in FIG. 2, the color disc 12 has R (red), G (green), and B (blue) filters 16R, 1
An infrared filter 16IR for transmitting 6G, 16B and infrared (IR) light, and near infrared light in the embodiment is attached, and a slit for identifying the type of the filter 16 by the number of slits is provided on the center side of these filters 16. The part 17 is formed. Therefore, the type of the rotating filter 16 is detected by determining the number of slits by the photo sensor 15 described above. According to the color disk 12, the R light, the G light, the B light, and the IR light can be sequentially output from the light source device 100 (for each field).

As shown in FIG. 1, the light source device 10 is provided.
A light guide 18 is optically connected to 0, and the light guide 18 is arranged in the electronic scope 200 up to the tip. In addition, in this electronic scope 200,
A CCD 19, which is a solid-state image sensor, is provided.
The observed portion is captured by 19. The electronic scope 200 and the light source device 100 are connected to an external processor device, and the other circuit of FIG. 1 is arranged in this external processor device.

That is, the CCD 19 has a preamplifier 2
The signal separation circuit 21 is connected via 0, and the light source device 10
A gate pulse generation circuit 22 for inputting the detection signal of the photosensor 15 of 0 is provided. The gate pulse generation circuit 22 forms R, G, B and IR gate pulses for extracting (sampling) the RGB signal and the IR signal, and the signal separation circuit 21 outputs the video signal input from the preamplifier 20. A predetermined signal is separated and extracted from the above by the gate pulse.

Then, the CCD 19 and the signal separation circuit 2
The electronic shutter control circuit 23 is connected to the output side of the digital camera 1. As shown in FIG. 3, the electronic shutter control circuit 23 includes a level determining section 23A and a control signal generating section 23B. The level determining section 23A receives the levels of the input visible image signal V1 and infrared image signal V2. Is compared with a reference value and the difference voltage is output to the control signal generator 23B.

In the control signal generator 23B,
A control signal corresponding to the difference voltage is generated. As the control signal, the substrate voltage of the CCD 19 can be used, or the sweep pulse and the read pulse can be used. The electronic shutter is controlled by variably controlling it. In the embodiment, shutter control is performed so that the infrared image signal V2 has a smaller accumulated charge amount than the visible image signal V1. Further, the control signal generating section 23B is supplied with an identification (gate) pulse for identifying the RGB light output time or the IR light output time from the gate pulse generation circuit 22, and the control signal is generated based on the identification pulse. It is given to the CCD 19.

In the figure, on the output line of the visible image signal V1 of the signal separation circuit 21, through the A / D converter 25, memories 26R and 26G for storing RGB signals constituting a visible image for each signal. , 26B are provided, and the memories 26R, 26G, 26B are provided with D / A converters 27R,
The display circuit 28 is connected via 27G and 27B. Then, a freeze command signal based on an operation of a freeze button (not shown) is supplied to the memories 26R, 26G, and 26B, and the freeze command controls writing / reading of an image signal to perform a freeze operation. Further, a motion detection circuit 30 for inputting the visible image signal V1 is provided, and in the embodiment, the freeze operation is controlled according to the motion state. That is, in the memories 26R, 26G, and 26B, when the motion detecting circuit 30 detects that there is a motion in the observed portion and a freeze command signal is output, the freeze operation is prohibited, and there is no motion. The freeze operation is executed only when.

On the other hand, in the output line of the infrared image signal V2 of the signal separating circuit 21, a memory 32 for storing an infrared (IR) image signal via an A / D converter 31 and an adding circuit as a noise reducing circuit. 33 and a motion detection circuit 34 are provided, and the memory 32 is connected to the display circuit 28 via a D / A converter 35. In the embodiment, the noise reduction operation is executed according to the movement state of the observed portion detected by the movement detection circuit 34, and the addition circuit 33 adds the noise when the degree of movement exceeds a predetermined value. Cancel the operation,
The addition operation is executed when the degree of movement becomes less than a predetermined value. That is, when it is determined that there is no motion, noise is reduced by weighting and performing the addition operation according to the comparison result (degree of deviation) of the image information signals.

The display circuit 28 performs output processing for outputting to a connected monitor, and an encoder or the like is used for a visible image. Although not shown, a signal processing circuit for performing processing such as gamma correction and white balance is provided at an appropriate place in the circuit of FIG.

The embodiment has the above construction, and its operation will be described below with reference to FIGS. 4 and 5. First, Fig. 1
The color disc 12 of the light source device 100 of FIG. 2 is rotationally driven, and R light, G light, B light, I
When the R light is sequentially applied to the observed portion via the light guide 18, the CCD 19 captures an image of the observed portion. When the color disk 12 is rotated, it is shown in FIG.
For each vertical synchronization (VD) signal of 1 field shown in
The slit signal of FIG. 4B is detected by the photo sensor 15. Then, in the gate pulse generating circuit 22,
The R gate signal, G gate signal, B gate signal, and IR gate signal shown in (C) to (F) are formed. In the signal separation circuit 21 in the subsequent stage, based on the above gate signal, C
From the image signals output from the CD 19, FIG.
R (image) signal, G signal, and B signal shown in FIG.
The infrared (IR) signal shown in (H) is extracted and separated. Therefore, the infrared image signal is obtained once every four fields.

For the visible image, the sweep pulse Pa and the read pulse Pb shown in FIG. 5B are formed by the visible image signal V1. Therefore, the CCD 19 reads the electric charge accumulated at the times t1 and t2 between the sweep pulse Pa and the read pulse Pb. On the other hand, for the infrared image, the sweep pulse Pa and the read pulse Pb shown in FIG. 5C are formed by the infrared image signal V2. Therefore, in this case, the charges accumulated in the shorter times t3 and t4 than in the case of the visible image are read out. As a result, an image signal with an optimum light amount can be obtained for each selected image.

In this way, each image signal obtained by the electronic shutter control is temporarily stored in the memories 26 and 32, and then output to each monitor through the display circuit 28, whereby a visible image and a red image are displayed. Both images of the outside image are displayed on the monitor. At this time, the visible image and the infrared image are displayed with the optimum brightness, which enables more accurate observation than before. Then, in the visible image, when the freeze command is issued, the freeze operation is prohibited when there is motion as described above, and the freeze operation is executed when there is no motion. In the infrared image, when a freeze command is issued, the image information at that time is displayed in a single color on the monitor regardless of whether there is motion, and when there is no motion, the S / N ratio of the image is reduced by noise reduction operation. Can be improved.

In the above-described embodiment, the example in which the electronic shutter control is performed on both the visible image and the infrared image has been shown, but the electronic shutter control of the present invention can be limited to either image formation. For example, the CCD 19 may be driven without the electronic shutter control so that a good image of the visible image can be obtained, and when the infrared image is selected, the electronic shutter control based on the infrared image signal may be executed.

The present invention can also be applied to a simultaneous device, in which case a CCD as shown in FIG. 6 is used.
Will be used. That is, the CCD 36 of FIG. 6 has a visible light filter 37 and an infrared light filter 38 alternately formed on the front surface thereof. If the image signals of the CCD 36 obtained by the filters 37 and 38 are separated, Visible images and infrared images can be extracted. In this case, as shown in FIG. 1, the electronic shutter control circuit 23
A switching circuit 24, which is switched by the operation of the operation unit or the like, is arranged in the front stage of the switching circuit 24. The switching circuit 24 has terminals a and b.
Either the visible image signal V1 or the infrared image signal V2 separated by the signal separation circuit 21 is selected by switching the terminals. According to this, the visible image signal V
Either 1 or the infrared image signal V2 is supplied to the electronic shutter control circuit 23, so that the optimum brightness can be obtained in the selected image.

[0022]

As described above, according to the present invention,
In an image pickup apparatus that forms a visible image and an infrared image, the electronic shutter of the image pickup device is controlled based on the signal of the visible image signal or the infrared image signal, and the brightness of the image is adjusted. It is possible to obtain an image with optimum brightness in consideration of each feature of the infrared image.

When the present invention is applied to a frame sequential device, the electronic shutter can be operated by a frame sequential identification pulse formed according to the rotation of the color disc, and the above effects can be obtained. You can Moreover, there is an advantage that a good image can be displayed on various objects such as when observing an affected part in a body cavity or when observing the inside of a structure.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a frame sequential image pickup apparatus for forming a visible image and an infrared image according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of the color disc of FIG.

3 is a block diagram showing an internal configuration of an electronic shutter control circuit of FIG.

FIG. 4 is a waveform diagram showing the operation of the embodiment.

FIG. 5 is a waveform diagram showing a control signal of the electronic shutter control circuit of the embodiment.

FIG. 6 is a diagram showing a configuration of a CCD when applied to a simultaneous imaging device.

FIG. 7 is a graph showing the level of each video signal obtained by the CCD.

[Explanation of symbols]

 12 ... Color disk, 19, 36 ... CCD, 21 ... Signal separation circuit, 22 ... Gate pulse generation circuit, 23 ... Electronic shutter control circuit, 24 ... Switching circuit, 26R, 26G, 26B, 32 ... Memory.

Claims (2)

[Claims] 1. An image sensor for capturing both a visible image and an infrared image, and an electronic shutter is controlled based on a visible image signal or an infrared image signal obtained by the image sensor,
An electronic shutter control circuit that adjusts the brightness of an image, and an imaging device that forms a visible image and an infrared image. 2. A surface-sequential type device using a color disc provided with a visible light filter and an infrared light filter, wherein a surface formed according to rotation of the color disc in the electronic shutter control circuit. The image pickup apparatus for forming a visible image and an infrared image according to claim 1, wherein an electronic shutter is operated by a sequential identification pulse.