JP2973410B2 - 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 endoscope apparatus for picking up a subject in a frame sequential manner, and more particularly to an electronic endoscope apparatus capable of stopping an image on a monitor screen by a freeze command.

[0002]

2. Description of the Related Art An electronic endoscope used for medical and industrial purposes includes a scope, a processor, and a monitor device, and an insertion portion of the scope is inserted into a body cavity or the like and built into the processor. Alternatively, an image signal is formed by irradiating the object with illumination light from an independent illumination device and subjecting a reflected image from the object to photoelectric conversion by a solid-state imaging device such as a CCD. The data is read out from the image sensor and transmitted to a processor. The processor performs signal processing, and then performs color display on a monitor device.

Here, a single image sensor is used to reduce the diameter of the insertion portion of the scope section, and red (R), green (G) and blue (B) are used to improve the resolution. ), Images of each color are formed for each field, and an image is displayed by superimposing the images, and the image sensor is driven by a so-called frame sequential method.

By the way, in the frame sequential system, the color image of each color channel is generated with a delay of one field or one frame, and the color image is converted to a simultaneous image and reproduced as a color image. When the camera is stopped, a color shift may occur in the still monitor image due to the movement between the subject and the endoscope tip. Generally, a color image displayed on a monitor is recorded and stored on a film with a photographic camera, but in the case of a color image having a color misregistration as described above, a photograph having significantly deteriorated image quality is obtained. Will be taken.

Therefore, conventionally, in order to prevent a color shift of a still monitor image, when a freeze command is input, it is determined whether the image currently being photographed is a still image or a moving image. An electronic endoscope apparatus has been proposed in which images stored in red, green, and blue field memories are latched to obtain a still image without color shift (Japanese Patent Laid-Open No. 2-4113).
No. 1, JP-A-2-41132, JP-A-2-5
No. 5030).

[0006]

However, in the above-mentioned conventional electronic endoscope apparatus, when the freeze command is input, if the image currently being photographed is determined to be a moving image, the image stored in the field memory for each color is determined. May not be latched, and a still image cannot be obtained immediately. In this case, a time lag occurs after a freeze command is output until a still image without color misregistration is actually obtained.

The present invention has been made in view of such circumstances, and a freeze command can always reproduce a still image with no color shift even in a frame sequential imaging method.
It is an object of the present invention to provide an electronic endoscope apparatus that allows a desired scene to be stopped immediately without feeling a time lag when the user wants to stop the scene.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a method in which R, color-separated from a distal end of an endoscope in time series.
The subject is irradiated with illumination light of G and B, a reflected image from the subject is received by a solid-state imaging device disposed at the end of the endoscope, and R, G, and B planes sequentially obtained from the solid-state imaging device are obtained. Are sequentially stored in the first image memory for each color, and the R, G, and B image signals are simultaneously read out from the first image memory. Are sequentially stored for each color, and R, G, and B image signals are simultaneously output based on the image signals output from the first image memory. A color misregistration detecting means for detecting a color misregistration due to the misregistration, a freeze operation means for outputting a freeze command, and a color misregistration detection means for detecting a color misregistration or for inputting a freeze command from the freeze operation means. Means for prohibiting updating of the storage contents of the second image memory, and switching means for switching from an output signal of the first image memory to an output signal of the second image memory when a freeze command is inputted from the freeze operation means. And, it is characterized by having.

[0009]

According to the present invention, in addition to the normal first image memory for converting a frame-sequential image signal into a simultaneous image signal, a second image memory for storing only an image signal without color shift is provided. Image memory is provided. That is, the color misregistration detecting means detects the color misregistration accompanying the misregistration of each image signal based on the image signal output from the first image memory. The contents of the second image memory are sequentially updated when the color misregistration is not detected by the color misregistration detecting means and when a freeze command is not input from the freeze operation means. Therefore, when a freeze command is not input from the freeze operation means, the storage content of the second image memory is always updated to the latest image signal without color shift. Here, when the freeze command is input,
Updating of the storage contents of the second image memory is immediately prohibited, so that the latest still image signal without color shift can be obtained from the second image memory.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electronic endoscope apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing one embodiment of an electronic endoscope apparatus according to the present invention.
In FIG. 1, reference numeral 1 denotes a light source lamp, and 2 denotes a light guide.
A lens 3, an aperture 4, and a rotary color filter 5 are interposed in the illumination optical path to. This color filter 5
Include an R filter area that transmits R (red) wavelength area light, a G filter area that transmits G (green) wavelength area light, and a B filter area that transmits B (blue) wavelength area light. Are provided, and by rotating the color filter 5, the illumination is sequentially performed by the R, G, and B wavelength lights. The sequential illumination light of R, G, and B is transmitted by the light guide 2 and is emitted from the emission end 2b to the subject through the illumination lens 6.

An objective lens 10 provided at the end of the endoscope
Captures an image of a subject illuminated by each of the R, G, and B illumination lights, and forms an image on a light receiving unit of the CCD 12. CCD
Reference numeral 12 denotes a CC which outputs a CCD drive signal in synchronization with a timing pulse applied from a timing pulse generator 14.
It is driven by the D drive circuit 16 and outputs an R, G, B plane-sequential image signal corresponding to each of the R, G, B illumination light to the process circuit 18.

The process circuit 18 amplifies an input image signal, samples and holds, adjusts white balance, and adjusts γ.
Processing such as adjustment is performed. Then, the frame-sequential image signal output from the process circuit 18 is converted into a digital signal by the A / D converter 20 and the field memories 22 and 24
Is added to Here, the field memory 22 includes an R memory area 22R for storing an R image signal, a G memory area 22G for storing a G image signal, and a B memory area 22B for storing a B image signal. R memory area 24R, G memory area 24G, B memory area 24
B.

The storage and readout of the field memory 22 are controlled by a memory control circuit 26. That is, the memory control circuit 26 stores the sequentially applied R, G, and B signals in a memory area corresponding to the color,
The R, G, and B image signals are simultaneously read from the memory area for each color. As a result, the R, G, and B plane-sequential image signals are converted into simultaneous image signals. The storage and readout of the field memory 24 is also controlled by the memory control circuit 26, but the update of the stored content is controlled differently from the field memory 22 as described later.

The simultaneous R, G, and B image signals read from the field memories 22 and 24 as described above are converted into D / A converters 23R, 23G, and 23B and D / A converters 25R and 25G. , 25B, and is applied to the process circuit 30 via the changeover switch 28. The process circuit 30 performs processing such as edge enhancement of an input signal, and the color encoder 32 generates an NTSC color video signal based on the input simultaneous R, G, and B image signals. The synchronizing signal generator 34 outputs a synchronizing signal to each of the circuits so that the circuits can be synchronized.

Next, freeze control of an image including update control of the contents stored in the field memory 24 will be described. The simultaneous R, G, and B image signals output from the D / A converters 23R, 23G, and 23B are output to the color misregistration detection circuit 4
It can be added to zero. The color misregistration detection circuit 40 includes an arithmetic circuit 42 and a comparison circuit 4 as shown in FIG.
4. It is composed of an integrating circuit 46 and an amplifier 48.

The arithmetic circuit 42 receives simultaneous R, G,
A color difference signal (G−Y) is generated from the B image signal, and is output to the comparison circuit 44. The color difference signal (G-Y)
Is a signal obtained by subtracting the luminance signal Y from the image signal G. From Y = 0.3R + 0.6G + 0.1B, G−Y = 0.4G−0.3R−0.1B. Therefore, for example, the color difference signal (GY) obtained when a black and white stationary chart is captured is 0,
When there is a movement, a shift occurs between the image signal G and the luminance signal Y, that is, a color shift occurs. A place where G is large and a place where Y is large occur, and the color difference signal (G−Y) is not 0, The plus part and the minus part will be included.

The comparing circuit 44 extracts a plus component of the color difference signal (GY) based on a comparison between the color difference signal (GY) and a predetermined reference value for detecting color misregistration.
6 is output. The integrating circuit 46 integrates the input signal, outputs the integrated value (DC voltage) to the amplifier 48,
Outputs a signal indicating the presence or absence of a color shift to the write inhibit command circuit 50 by shaping the waveform of the input signal.

As shown in FIG. 1, a freeze hold circuit 54 is connected to another input of the write inhibit command circuit 50. When the freeze switch 52 is one-pushed, the freeze holding circuit 54 outputs a freeze command signal for a predetermined time (for example, a shutter time of a camera for capturing a freeze image). The write inhibit command circuit 50 becomes operable when a signal indicating a color shift from the color shift detecting circuit 40 or a freeze command signal from the freeze hold circuit 54 is input, and outputs a write inhibit command signal to the memory control circuit 26.

When the memory control circuit 26 receives the write inhibit command signal, the memory control circuit 26 inhibits the writing of R, G, and B signals in the field sequence applied to the field memory 24. As a result, the content stored in the field memory 24 is not updated, and the same image signal is repeatedly read from the field memory 24. In other words, before the operation of the freeze switch 52, the write prohibition command circuit 50 detects the color shift by the color shift detection
4 is prohibited, and when no color shift is detected, the prohibition of writing to the field memory 24 is released. As a result, the latest image signal without color shift before the freeze command is stored in the field memory 24.

On the other hand, a freeze holding circuit 54 outputs a freeze command signal to the changeover switch 28 and a camera (not shown). When the freeze command signal is input, the changeover switch 28 reads the D / A converters 25R, 25R from the field memory 24.
Switching to the simultaneous R, G, B signal side applied via 5G, 25B is conducted to the process circuit 30. As a result, a still image without color misregistration is reproduced on a monitor TV (not shown) for inputting a color video signal from the color encoder 32, and a camera that shoots this still image releases a shutter in conjunction with a freeze command signal. Can be

Incidentally, the color misregistration detection circuit is not limited to the present embodiment.
Any device may be used as long as it detects color misregistration using the R, G, and B signals converted simultaneously.

[0022]

As described above, according to the electronic endoscope apparatus of the present invention, when color misregistration is detected using the R, G, and B signals converted simultaneously, an image memory dedicated to freeze is used. Update of the stored contents of the image is prohibited, and the latest image signal without color shift is always stored in the image memory dedicated to freeze. It is possible to reproduce a still image without deviation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an electronic endoscope apparatus according to the present invention.

FIG. 2 is a block diagram illustrating an example of a color misregistration detection circuit illustrated in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source lamp 2 ... Light guide 5 ... Color filter 12 ... CCD 22, 24 ... Field memory 26 ... Memory control circuit 28 ... Changeover switch 40 ... Color misregistration detection circuit 42 ... Operation circuit 44 ... Comparison circuit 46 ... Integration circuit 50 ... Write inhibit command circuit 52 ... Freeze switch 54 ... Freeze holding circuit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A61B 1/00-1/32

Claims (2)

(57) [Claims] 1. A solid-state imaging device in which R, G, and B illumination lights, which are color-separated in a time series, are irradiated from a distal end portion of an endoscope to a subject, and a reflection image from the subject is disposed at the distal end portion of the endoscope. , And sequentially stores the R, G, and B plane-sequential image signals obtained from the solid-state imaging device in a first image memory for each color, and outputs R, G, and B images from the first image memory. In an electronic endoscope apparatus that simultaneously reads out signals, a field-sequential image signal of one field or one frame is sequentially stored for each color, and these are output simultaneously from a second image memory and the first image memory. Color misregistration detecting means for detecting a color misregistration accompanying a misregistration of each of the R, G, and B image signals output simultaneously based on the image signal, freeze operation means for outputting a freeze command, and the color misregistration detecting means. When color misregistration is detected or Means for prohibiting updating of the storage contents of the second image memory when a freeze command is input from the freeze operation means, and when a freeze command is input from the freeze operation means, the output signal of the first image memory An electronic endoscope apparatus comprising: a switching unit that switches to an output signal of a second image memory. 2. The color misregistration detecting means according to claim 1, wherein said color misregistration detecting means includes a color difference signal (G) based on an image signal output from said first image memory.
-Y), and the color difference signal (GY)
2. An electronic endoscope apparatus according to claim 1, further comprising: means for detecting a color shift based on a comparison between the reference value and a predetermined reference value for color shift detection.