JP3406680B2 - Electronic endoscope device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device in which a solid-state image pickup device is provided at the tip of an endoscope insertion portion, an observation image is converted into an electric signal and transmitted to the outside, and then reproduced on a monitor or the like. The present invention relates to an endoscope device.

[0002]

2. Description of the Related Art It is necessary to perform gamma correction in order to reproduce a video signal transmitted from a solid-state image pickup device provided at the distal end of an insertion portion of an endoscope as an image that does not give a feeling of strangeness.

Therefore, conventionally, the output value after gamma correction corresponding to the video signal (original signal) value input to the gamma correction unit is written in a look-up table constituted by a memory to look up the video signal. It is applied as an address signal of the table memory, and the gamma correction value corresponding to it is output. The corrected signal is converted into an analog signal again, processed by a video signal, and displayed on a monitor (Japanese Patent Laid-Open No. 1-178235).

[0004]

However, the gamma correction value written in the look-up table takes a large value corresponding to the magnitude of the input original signal value. Therefore, the look-up table in which all the data is written requires a very large memory capacity, and so the so-called memory efficiency is poor, the circuit becomes large, and the manufacturing cost and power consumption also increase, and the economy is poor.

Therefore, it is an object of the present invention to provide a memory-efficient electronic endoscope apparatus capable of constructing a look-up table for gamma correction with a small memory.

[0006]

In order to achieve the above object, the electronic endoscope apparatus of the present invention uses a digital image signal sent from a solid-state image sensor provided at the tip of an endoscope insertion portion. After conversion into a signal, the gamma correction unit reads out the gamma correction data written in the look-up table to perform gamma correction of the video signal. It is characterized in that data for only the gamma correction for the signal is written, and the data is added to the original signal in the gamma correction unit and output as a correction signal.

In addition, after converting the video signal sent from the solid-state image pickup device into a digital signal, gamma correction is independently performed for each of the signals corresponding to the three colors of red, green and blue. Three gamma correction units may be provided.

Further, a plurality of types of gamma correction data may be written in one memory, and gamma characteristic selecting means for selecting and using one of the gamma correction data may be provided. In that case, a plurality of types of gamma correction data may be provided. Gamma characteristic display means for indicating which gamma correction data among the gamma correction data is selectively used may be provided.

[0009]

Embodiments will be described with reference to the drawings. FIG. 2 shows the overall configuration of the electronic endoscope apparatus according to the embodiment of the present invention. For example, at an image forming position of a subject by an objective optical system 3 provided at the tip of the insertion portion 2 of the endoscope 1, for example, Charge coupled device (C
A solid-state image sensor 4 made of CD) is arranged. 5
Is a light guide fiber bundle for transmitting illumination light that illuminates the observation range.

The connector portion 6 of the endoscope 1 connected to the video processor 10 has a drive circuit 7 for amplifying signals input to and output from the solid-state image pickup device 4, and data unique to the endoscope 1. A rewritable read-only memory (EEPROM) 8 in which the above are stored is arranged.

The video processor 10 also serves as an illumination light source device, and illumination light is incident on the light guide fiber bundle 5 of the endoscope 1 from the light source lamp 11.
In the middle of the incident light path, a three-color rotary filter 12 to which three color filters of red (R), green (G) and blue (B) are attached is arranged so as to rotate at a constant speed.
The illumination light of each color of red, green and blue is sequentially incident on the light guide fiber bundle 5 with a time shift.

The output end of the CCD process unit 14 connected to the drive circuit 7 of the solid-state image pickup device 4 is connected to the timing circuit 15.
Is connected to the input end of the video process unit 16 via an output signal from the video process unit 16.
Sent to.

The operations of the CCD process unit 14, the timing circuit 15 and the video process unit 16 are performed by a system control unit 17 having a central processing unit (CPU).
Is controlled in conjunction with. Further, the data on the endoscope side is read from the EEPROM 8 connected to the peripheral driver 19 connected to the system control unit 17.

FIG. 3 specifically shows the configurations of the CCD process unit 14 and the video process unit 16 described above. In the CCD process unit 14, the solid-state image sensor 4
After the output signal from is amplified by the amplifier 23, the video signal is extracted by the sample holding circuit 24, converted into a digital signal by the analog-digital conversion circuit 25, and then gamma correction is performed by the gamma correction circuit 26.

The gamma-corrected video signal is switched by the timing circuit 15 in synchronism with the driving of the solid-state image pickup device 4, and sequentially corresponds to each color of red (R), green (G), and blue (B). It is stored in the frame memories 28R, 28G, 28B.

The signals stored in the frame memories 28R, 28G and 28B are read out at the same time and converted into analog color signals by the digital-analog conversion circuits 29R, 29G and 29B, respectively.

The color signals of the three colors are output as the three primary color signals, and are input to the NTSC encoder 30 in parallel with them, converted into an NTSC composite video signal, and output to the monitor 18.

FIG. 1 shows the contents of the gamma correction circuit 26. The gamma correction circuit 26 is formed by a read-only memory 32 for a look-up table and an adder circuit 33.

4 and 5 show an example of data written in the lookup table memory 32 in the form of a line graph. As shown in FIG. 4, the gamma correction value to be output to the timing circuit 15 has a large value with respect to the input original signal. However, the total sum of the correction amount data indicated by the diagonal lines is much smaller than the total sum of the gamma correction values.

Therefore, in this embodiment, only the gamma correction data shown in FIG. 5 is written in the look-up table memory 32, and the original signal is applied as the address signal of the look-up table memory 32. The correction amount data corresponding to the address is read from the lookup table memory 32, and the addition circuit 33 adds the correction amount data to the original signal and outputs it as a gamma correction value.

By doing so, as shown in FIG. 1, since the gamma-corrected data is 1/4 of the full scale for a 10-bit original signal, the memory of the look-up table memory 32 is, for example, 8. The number of bits is smaller than that of the original signal, and the output signal of the adder circuit 33 has the same 10 bits as the original signal.

For example, the analog-digital conversion circuit 2
If the gamma correction value is linearly corrected as shown in FIG. 6 by applying a reference voltage to the linear correction terminal of No. 5, the amount of gamma correction data is further reduced as shown in FIG. improves.

The present invention is not limited to the above embodiment, and for example, as shown in FIG. 8, the gamma correction circuits 26R, 26G and 26B are connected to the frame memories 28R and 28G of each color in the video processing section 16. It may be connected to the output terminal of 28B to perform gamma correction independently for each color signal of red, green and blue. The configurations and operations of the gamma correction circuits 26R, 26G, and 26B in that case are the same as those in the first embodiment.

FIGS. 9 to 17 show a third embodiment of the present invention. A plurality of types of gamma correction data are written in one memory, and one gamma correction data is selected and used. In addition, which gamma correction data is selectively used can be displayed and confirmed.

The gamma correction data used here is only the correction data similar to the case of the first embodiment. In the embodiment, two types of gamma correction data are provided, but three or more types may be provided.

FIG. 9 shows the look-up table memory 3
The contents of No. 2 are schematically shown, and a memory in which the number of bits of the address is larger than the number of bits of the data is used, and the upper bits provided additionally are used for the switch.

Then, for example, addresses 0 to 1023
The first gamma correction data is written in the first look-up tables up to and the second gamma correction data is written in the second look-up tables through 1024 to 2047.

When the switch bit of the memory 32 is set to "0", the address operates in the range of 0 to 1023, and when set to "1", the address operates in the range of 1024 to 2047. As the number of bits for the switch is increased, more kinds of data can be switched.

FIG. 10 shows the connector 6 side of the endoscope, and either "0" or "1" is written in the EEPROM 8 shown in FIG. 2 according to the characteristics of the endoscope. Has been. When the connector 6 is connected to the video processor 10, the signal "0" or "1" is sent to the switch bit of the look-up table memory 32 as shown in FIG.
In 2, either one of the first and second gamma correction data is selected.

Incidentally, in order to give "0" or "1" to the look-up table memory 32 in accordance with the characteristics of the endoscope, as shown in FIG. 12, the potential set in the endoscope is changed. “0” or “1” may be fixedly made.

Alternatively, as shown in FIG. 13, "0" or "1" may be created by opening and closing the switch 41 in the video processor 10 by the concave and convex portions formed on the connector 6.

Further, a manual switch 42 as shown in FIG. 14 is provided on the endoscope 1 side or the video processor 10 side, and the operator arbitrarily sets "0" or "1" according to the state of the subject. You may make it selectable.

FIG. 15 shows the screen of the monitor 18.
The selected gamma correction data is displayed in the lower right part of the screen. In such a display, as shown in FIG. 11, a signal of “0” or “1” for selecting the branched gamma correction data is input to the CPU 17a of the system control unit 17 as shown in FIG. Then, character processing is performed by the OSD 17b (on-screen display), and the signal is added to the three-color video signal and sent to the monitor 18. Note that the gamma correction data may be displayed on the operation panel 43 portion of the video processor 10 or the like as shown in FIG.

[0034]

According to the present invention, since only the gamma-corrected data for the original signal needs to be written in the look-up table for gamma correction, the look-up table can be constructed with a small memory. Therefore, the memory efficiency is good, and it is possible to achieve miniaturization of the circuit and reduction of manufacturing cost and power consumption.

As a result, when a plurality of types of gamma correction data are selected and used, it is possible to store them in one memory, which physically reduces the number of parts and miniaturizes the circuit. can do. Further, by displaying the gamma characteristic that is selectively used, image adjustment becomes easy, and reliable diagnosis can be performed.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a gamma correction circuit according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of an electronic endoscope apparatus according to a first embodiment of the present invention.

FIG. 3 is a circuit block diagram of a first embodiment of the present invention.

FIG. 4 is an explanatory diagram of gamma correction data according to the first embodiment of this invention.

FIG. 5 is a gamma correction data explanatory diagram of the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of gamma correction data which is linearly corrected according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of gamma correction data which is linearly corrected according to the first embodiment of the present invention.

FIG. 8 is a circuit block diagram of a second embodiment of the present invention.

FIG. 9 is a schematic diagram showing the contents of a lookup table memory according to a third embodiment of the present invention.

FIG. 10 is a schematic view of the connector of the third embodiment of the present invention.

FIG. 11 is a circuit diagram of a gamma correction circuit according to a third embodiment of the present invention.

FIG. 12 is a schematic view of a modified example of the connector of the third embodiment of the present invention.

FIG. 13 is a schematic view of a modified example of the connector of the third embodiment of the present invention.

FIG. 14 is a schematic view of a selection switch according to a third embodiment of the present invention.

FIG. 15 is a schematic view of a monitor screen according to the third embodiment of the present invention.

FIG. 16 is a circuit block diagram of a third embodiment of the present invention.

FIG. 17 is a schematic view of an operation panel according to a third embodiment of the present invention.

[Explanation of symbols]

26 Gamma correction circuit 32 Look-up table memory 33 adder circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-178235 (JP, A) JP-A-6-30301 (JP, A) JP-A-2-81594 (JP, A) JP-A-3- 213064 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61B 1/00-1/32 H04N 5/14-5/217

Claims (2)

(57) [Claims] 1. A video signal sent from a solid-state image pickup device provided at a tip of an insertion portion of an endoscope is connected to the endoscope.
In a video processor to which a video signal is connected, the gamma correction data is converted into a digital signal, and then the gamma correction data written in the look-up table is read by the gamma correction unit to gamma-correct the video signal. As the gamma correction unit, three gamma correction units for independently performing gamma correction on each of the signals corresponding to the three colors of red, green, and blue are provided, and the look-up table includes the original signal The data for only the gamma correction for the above is written, the data is added to the original signal in each of the gamma correction units and output as a correction signal, and a plurality of types of correction data are stored in one memory as the gamma correction data. And write one of the correction data from the endoscope according to the characteristics of the endoscope.
An electronic endoscope apparatus characterized in that it is selected and used based on an obtained selection signal . 2. The electronic endoscope apparatus according to claim 1, further comprising gamma characteristic display means for indicating which correction data among the plurality of types of correction data is selected and used as the gamma correction data. .