JPH0830785B2 - Endoscope device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an endoscope apparatus using a solid-state image sensor.

[Technical background of the invention and its problems]

Conventionally, when an endoscopic image is displayed on a television monitor for viewing, a method of attaching a television camera to the eyepiece of the fiberscope has been adopted. However, recently, because the size of the solid-state image sensor has been reduced, it is possible to store it in the tip of the endoscope probe and display the image of the subject directly on the TV monitor without going through the image fiber to perform diagnosis and treatment. It came to be taken.

As shown in FIG. 2, an example of the configuration of the solid-state image pickup device is such that each of the independent photosensitive parts (P ₁₁ ) ... (P _mn ), vertical transfer parts (CV ₁ ) ... (CV _m ), and gate (G ₁₁ ) ... (G _mn ) and a horizontal transfer section (H), and the signal charges accumulated in the photosensitive section (P ₁₁ ) ... (P _mn ) during the frame period are detected during the blanking period. Gate (G ₁₁ ) ... from the section (P ₁₁ ) ... (P _mn ) to the corresponding vertical transfer section (CV ₁ ) ... (CV _m ).
(G _mn ), new accumulation starts again when this transfer is completed, and the transferred charges are sequentially sent to the horizontal transfer unit (H) according to the television system and taken out to the outside. . Therefore, when the solid-state image pickup element is adopted, light irradiation to the subject does not cause any inconvenience even if pulse irradiation is performed. For this reason, the current light irradiation irradiates a light pulse in a period (T ₁ ) corresponding to the beginning of the field period as shown in FIGS. 3 (a) and 3 (c). . In addition, when a signal is extracted from the solid-state image pickup device by an interlace method, two adjacent signals in the vertical direction are used.
A method of simultaneously extracting signals from one photosensitive section is generally used because it is advantageous in terms of afterimage characteristics. It is the same period as the period T ₁ and is generally 1/60 second), which is known as the field accumulation mode.

By the way, diagnosis and treatment are performed because the doctor does not observe the image in real time, but it is necessary to record the image in order to make more objective diagnosis and to see the progress of the treatment. It is taken.

Therefore, when a conventional fiberscope is used, a camera is attached to the eyepiece of the probe to take a picture. At this time, since the subject is constantly moving, the shutter speed was set to 1/125 second or more, and the insufficient light amount was compensated by a flash light source or the like.

On the other hand, when a solid-state image sensor is used, a method of temporarily converting a normal image into a still image is used to take a picture of an image on a television monitor. Built-in memory,
An image of one frame is stored in this so that the stored image can be extracted many times. Then, in order to load one frame of image into the frame memory, 1/30 second for two field periods is required in the normal television system.

However, in the current endoscope apparatus as described above, as described above, since the light pulse is emitted in the period (T ₁ ) corresponding to the start end of the field period, this period (T ₁ ) There is a drawback that a still image is blurred by the amount of movement of the subject during the period.

In addition, light of three primary colors, for example, red (R), green (G), and blue (B) is sequentially irradiated to the subject for each field, and the image signal for each light is captured from the solid-state image sensor into each memory, An endoscope system that combines output signals from a memory to obtain a color image signal has been put into practical use, but in the case of continuous light irradiation, it takes three field periods (1 Since it takes about 20 seconds), it cannot cope with a moving subject, and in fact, a color breakup phenomenon occurs, which is a major obstacle for still image recording. Even when the pulsed light as shown in FIG. 5 (a) is used, if the phase of each pulse of R light, G light, and B light is not strictly controlled, it is substantially two field periods (T ₁ ′). 1/30 of
Since one set of light irradiation was completed in seconds, it was still impossible to obtain a sufficient still image.

[Object of the Invention]

The present invention has been made based on the above circumstances, and an object of the present invention is to provide an endoscope apparatus capable of reducing blurring and color misregistration that occur while accumulating image signals of a moving subject. To provide.

[Outline of the Invention] An outline of the present invention for achieving the above object is to provide an endoscope probe in which a solid-state imaging device is incorporated in a distal end portion, an irradiation unit for irradiating a subject with a light pulse for each field period, In every two or more continuous field periods, the same amount of irradiation is applied to each field period so that the irradiation interval between the light pulse irradiation in the start field period and the light pulse irradiation in the end field period becomes the shortest over the blanking period. A control means for performing light pulse irradiation control and two or more continuous field image signals from the solid-state imaging device which is imaged based on the light pulse irradiation control by the control means are input, and one frame image is generated from the field image signal. An endoscope including a generating unit and a display unit that displays the frame image as a moving image or a still image. It is a device.

Embodiments of the Invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a television type endoscope apparatus which is an example of the endoscope apparatus according to the present invention. Therefore, this device will be described first.

An endoscope probe 1 has an optical system such as an objective lens 2 and a solid-state image sensor 3 incorporated in its tip. A concrete example of the solid-state image sensor 3 is shown in FIG. 2, and the details thereof are as described above. An output end 12 of the light guide is arranged at the tip of the probe, and the light incident from the light source lamp 9 to the light guide light source side end 11 is emitted to the subject 13 as illumination light a. ing. In addition, 10 is a cold mirror.

A video processor 5 receives the field image signal from the solid-state image sensor 3 through the transmission path 4, generates a frame image from the field image, and includes a frame memory for storing the generated frame image.

Reference numeral 6 denotes a TV monitor, which can input a video signal from the video processor 5 and display a frame image as a moving image or a still image.

Reference numeral 7 is a pulse power source, which is adapted to turn on the light source lamp 9 in pulses. The trigger of the pulse power supply 7 is performed by the pulse phase controller 8, and the original pulse given to the pulse phase controller is derived from the vertical synchronizing signal of the television camera circuit built in the video processor 5.

As described above, the current light pulse irradiation method is as shown in FIG. 3 (a), but the light pulse irradiation method of the present invention is the shortest period in which the light pulse irradiation extends over two or more field periods. Try to do it inside.

First, a case where one frame image is generated from first and second field image signals of continuous field image signals from the solid-state image sensor 3 will be described. In this case, as shown in FIGS. 3 (b) and 3 (c), the phase of the optical pulse controlled by the pulse phase controller 8 is changed over one blanking period (T _B ) into one field period (first period). One at the end of one field period or multiple times within a short period, and once at the beginning of the next field period (second field period) or multiple within a short period, and the blanking period (T The amount of light pulses emitted over _B ) is the same.

That is, the irradiation of the optical pulse is performed in the shortest period (T ₂ ) that extends over the two field periods excluding the blanking period (T _B ).

Normally, T ₂ / T ₁ is 1/13 to 1/15, so by controlling the phase of the optical pulse as described above, it is possible to achieve 1/10 of one field period of 1/60 seconds. It is easy to capture the image, in this case the camera shutter speed is 1/60
It is equivalent to cutting in 0 seconds. Therefore, blurring of a still image can be significantly reduced.

A rotary disc having a plurality of openings is provided immediately before the light source side end 11 of the light guide (see 14 in FIG. 1),
The same effect can be obtained by rotating in synchronization with the vertical synchronizing signal and adjusting the timing of light passage to the timing of FIG. 3 (b).

Next, in the field sequential color imaging method, that is, as shown in FIG. 5D, from the first, second, third and third field image signals of the continuous field image signal from the solid-state image sensor 3, A case of generating a color one-frame image will be described.

In this case, the disk 14 is arranged in the optical path of the light source device including the light source lamp 9 and the cold mirror 10 shown in FIG. The disk 14 is a rotary disk with a three-color filter including first, second and third color transmission filters 15, 16 and 17, and the first, second and third colors are, for example, red (R). , Green (G) and blue (B).

Therefore, the disk 14 is rotated so that the three kinds of light are sequentially guided to the end portion 11 on the light guide light source side, and the filters 15, 16, 17 are respectively controlled by the pulse power supply 7 and the pulse phase controller 8.
The light that passes through is converted into pulsed light, and the light pulse generation timing is as shown in FIGS. 5 (b) and 5 (c). The R light is terminated at the end of the first field over the blanking period (T _B ). Part, G light at any time of the second field, B
Light is emitted at the beginning of the third field, and the subject is sequentially illuminated via the light guide.

That is, the irradiation of the light pulse is performed in the shortest period (T ₂ ′) that extends over the three field periods excluding the blanking period (T _B ).

Thus, three kinds of light irradiation, one field period slightly exceeding period (T ₂ ') can be in two field period as the current method is shown in FIG. 5 (a) (T _1' )
Blurring and color breakup can be greatly reduced compared to the case where it is applied.

Also in this case, image blurring and color shift due to the movement of the subject occurring within the (T ₂ ′) period are unavoidable,
Depending on the color tone in the body cavity, the color shift can be made practically inconspicuous by moving the phase of the G light pulse.
For example, when R and G have a dominant color tone, the timing of the G pulse should be close to the timing of the R light pulse. If image blurring and color misregistration become a problem, B light may be cut even if the color reproducibility is sacrificed. That is, in an extreme case, a still image may be obtained by changing the irradiation light into two colors according to the color tone of the subject. However, rather than sacrificing color reproducibility, the field rate is doubled, and three types of light irradiation are completed in half the normal field period (1/60 seconds), so conventional photography is possible. We were able to get close to 1 / 125s of the camera shutter speed at, which was a significant improvement.

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above embodiments and can be appropriately modified within the scope of the gist of the present invention.

Also, the term "shortest period" is used to facilitate understanding of the invention, but this does not mean a period between one field trailing edge and another field leading edge (T ₂ As is understood from the meaning of (T ₂ ′), it means a period having a certain width within the range in which the object of the present invention can be achieved.

〔The invention's effect〕

As described in detail above, according to the endoscope apparatus of the present invention,
In each of the above continuous field periods, the same amount of light is emitted in each field period so that the irradiation interval between the light pulse irradiation in the start field period and the light pulse irradiation in the end field period becomes the shortest over the blanking period. Since pulse irradiation control is performed and one frame image is generated from two or more continuous field image signals from the solid-state imaging device that is imaged based on such light pulse irradiation control, an image signal of a moving subject is generated. Blurring and color shift that occur during storage can be significantly reduced, a frame still image with high resolution can be obtained, and it can greatly contribute to the improvement of the efficiency and the diagnosis performance at the diagnosis site.

[Brief description of drawings]

FIG. 1 is a block diagram showing a television-type endoscope apparatus according to an embodiment of the present invention, FIG. 2 is a schematic explanatory view showing an example of a solid-state image sensor, and FIGS. 3 (a) (b) (c) are Drawing which shows the phase relationship of a light pulse and an image signal, Drawing 4 is a front view showing an example of a three-color filter rotation board, and Drawing 5 shows a light pulse and an image signal when it differs from Drawing 3. 5 is a diagram showing a phase relationship of FIG. 3 ...... solid-5 ...... video processor, 6 ...... TV monitor, 7 ...... pulse power source, 8 ...... pulse phase control _{device, (T 2) (T 2} ') ...... minimum duration.

Claims (2)

[Claims] 1. An endoscope probe in which a solid-state image sensor is incorporated in a tip portion, an irradiation unit for irradiating a subject with a light pulse in each field period, and a start field for each of two or more continuous field periods. Control means for performing the same amount of light pulse irradiation control in each field period so that the irradiation interval between the light pulse irradiation in the period and the light pulse irradiation in the terminal field period becomes the shortest over the blanking period, and the control means. Means for inputting two or more continuous field image signals from the solid-state image pickup device, which are imaged based on the light pulse irradiation control by the, and generating one frame image from the field image signals; An endoscope apparatus comprising: a display unit for displaying as. 2. The control means controls the light pulse irradiation once or a plurality of times within a short period at the end of the start field period and the start of the end field period over the blanking period. The endoscopic device according to claim 1, wherein: