JPH02213287A - Signal processor for picture freeze - Google Patents

Abstract

PURPOSE:To form a still picture suitably corresponding to the request of a user, etc., by detecting the picture signal of smallest moving amount by a minimum value detecting means, impressing the picture signal to a write/read control means and controlling the writing and recording of the input picture signal to a storing/recording means. CONSTITUTION:When a picture freeze instruction signal is outputted from either a first or second picture freeze instruction circuit 42a or 42b, a detection time set circuit 43 and a minimum value detection circuit 41 are activated. The minimum value detection circuit 41 detects the minimum value of the moving amount in a time set by the detection time set circuit 43 and the freeze of the picture is held to a freeze memory part 35. Then, a detection signal is sent to an R/W controller 44 so that the held picture data can be outputted. For example, when the user desires to stop the picture and to observe it and the first picture freeze instruction circuit 42a is operated, after the lapse of a short time T1, the picture of a moving amount m2 is displayed as the still picture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal processing device for image freezing that is capable of storing or recording still images with less image blur.

[Prior Art] Conventionally, image signals have been recorded on magnetic tapes or magnetic disks, COD memory, MOS memory, magnetic bubble memory, etc.
Alternatively, devices for displaying images stored in a storage element such as an IC memory are known, but devices for obtaining still images are particularly known as those disclosed in Japanese Patent Laid-Open Nos. 49-52912 and 1973.
A prior art example disclosed in Japanese Patent No. 4-140510 is known. Further, an electrophotographic camera of the same type that can be immediately reproduced and retaken after image removal is disclosed in Japanese Patent Application Laid-Open No. 57-44374.

However, since these devices record or store information by pressing the release button, there may be problems when the subject moves faster than the shutter speed, or when the imaging device moves after the shutter is operated, resulting in so-called camera shake. In many cases, image blur occurs in the captured image and the image must be retaken. For example, if an interlaced scanning type image sensor is used to capture a fast-moving subject, different images will be recorded between fields, resulting in flickering and making the image extremely difficult to see. It has drawbacks.

In relation to this drawback, in order to prevent inter-field flicker when storing still images, the movement of the subject is detected and the frame is frozen when there is no movement, and the field is frozen when there is movement. A constructed device is disclosed in U.S. Pat. No. 4,272,787.

However, this device has the disadvantage that the vertical resolution is degraded for moving objects because the field is automatically frozen when the imaged object moves.

Furthermore, in recent years, advances in solid-state imaging technology have led to higher pixel density and ultra-miniaturization of chips, and endoscopes with solid-state imaging elements mounted at their tips, so-called electronic endoscope devices, have been developed. . These devices have the function of inserting into a body cavity to observe the area to be examined and also record the observed images of the same area, and not only the observation function but also the quality of the recorded images is extremely important. This has a significant impact on the diagnosis of the area being examined. Therefore, when recording, the endoscope operator holds the patient still, freezes and displays the image of the area to be examined several times, selects the most desirable image as the recorded image, and selects, for example, the monitor image. Still images were recorded on photographic devices, video printers, still video floppy devices, etc. However, even if the patient is held still, there will be considerable movement of the area to be examined as long as the inside of the body is being observed, and it may be necessary to refreeze the image many times to eliminate blurring of the image due to this movement. There was a problem.

Deterioration of recorded images due to the movement of the subject, as described above,
The form of occurrence differs depending on the type of imaging device and imaging method. For example, as an image sensor, a frame transfer type CO
When using D (hereinafter referred to as FT type COD),
Movement of the subject during the exposure period causes image blur, and interline type COD (hereinafter referred to as IT type COD)
When interlaced scanning is performed using a camera (referred to as ``1''), in addition to image blur caused by the movement of the subject during the exposure period, flicker occurs due to image differences between fields.

In addition, for the purpose of reducing the diameter of the endoscope, a monochrome COD is mounted at the tip of the endoscope, and the illumination light is, for example, RGB sequential light. Since each primary color image is displayed simultaneously, so-called color shift, in which the movement of the subject is displayed as a shift in color, becomes a problem.

In order to solve the above-mentioned problem, instead of displaying a still image on a monitor etc. at the same time that the freeze function is activated, the image blur (
An apparatus has been proposed that detects color shift (color shift, etc.) and displays the image signal with the smallest detected amount on a monitor or the like as a still image.

[Problems to be Solved by the Invention] However, the setting of the detection time length is a major factor when it is desired to keep the image still for the time being and when the image is to be recorded on a medium such as film.

In other words, if you want to stop the image and observe it as a still image (hereinafter referred to as release operation), you need to quickly freeze the image even if there is some blurring, etc. On the other hand, if you want to record the still image on some kind of media , it is required to leave an image with little blur.

In this way, it is not possible to respond to different user requests regarding the amount of image blur.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a signal processing device for image freezing that performs signal processing that can obtain a still image that appropriately corresponds to the user's requirements.

[Means and effects for solving the problems] As shown in the conceptual diagram of FIG. a motion detecting means 2 for detecting the movement of the subject from a signal; and a minimum value detecting means 3 for detecting the minimum value of the subject's movement range from the motion detecting means 2.
a detection time setting means 4 for arbitrarily setting the operating time of the minimum value detection means 3; and a first step for instructing to start the minimum value detection means 3 and the detection time setting means 4 to freeze the image. and second image freeze instruction means 5a,
5b, and a writing/recording control means 6 for controlling the writing operation and recording operation of the input image signal to the image recording/storage means 1 based on the minimum value from the minimum value detection means 3. be.

The input image signal is input to the motion detection means 2, the amount of movement of the subject is detected from this input image signal, and the amount of motion is sent to the minimum value detection means 3. Then, the minimum value detection means 3 is activated by an instruction signal from the image freeze instruction means 5a or 5b selected by the user, and the detection time of the detection time setting means 4 is set. The minimum value detection means 3 detects the image signal with the least amount of motion within the detection time range. Minimum value detection means 3
The minimum value detected by
Writing and recording of input image signals to the recording means 1 is controlled. Through the above operations, the detection time of the minimum value detection means 3 is set according to the input image signal, and the image signal with the least movement within the set time is stored or recorded.

[Example] Hereinafter, each example of the present invention will be described with reference to the accompanying drawings.

2 to 4 relate to the first embodiment of the present invention, in which FIG. 2 is a block diagram showing the configuration of a signal processing device for image freezing, FIG. 3 is a diagram showing an example of a motion detection circuit, and FIG. The figure is a diagram showing changes in the amount of motion over time.

FIG. 2 shows an example in which the present invention is applied to an endoscope apparatus 11 using the RG 8-plane sequential method.

This endoscope device 11 includes an electronic scope 12 incorporating a field-sequential image conveying means, a field-sequential light source unit 13, an image freezing signal processing device 14 of the first embodiment for the electronic scope 12, and It consists of a display device that does not

In the electronic scope 12, a light guide 15 is inserted into the elongated insertion portion, and by connecting the light guide 15 to the light source unit 13, light is supplied from the light source unit 13 in a field-sequential manner.

In this light source unit 13, white light from a lamp 16 is rotated by a motor 17 and passed through a rotating color filter 18 in which red, green, and blue color transmission filters are attached in a fan shape. The light is converted into light, which passes through the condenser lens 19 and is irradiated onto the incident end surface of the light guide 15.

The light is transmitted by the light guide 15 and irradiated from the output end face of the distal end of the insertion portion toward the subject in front. The illuminated subject is captured by the objective lens 19 attached to the distal end of the insertion tube.
As a result, an image is formed on C0D21. This C0D21 is
Converts optical images to photoelectricity. The A drive signal output from the COD drive circuit 22 reads out the A
/D converter 23 converts the digital color plane sequential signal into an R memory 32 . G memory 33. The colors are stored in the B memory 34 in correspondence with each color. Said R
Memory 32. The image signals stored in the G memory 33 and the B memory 34 are read out after synchronizing each color signal, and are read out as a color plane synchronization signal from the R memory 3 in the freeze memory section 35.
6. G memory 37. Each of the data is sequentially written to the B memory 38. The RGB image signals written in each memory in the freeze memory section 35 are read out sequentially in synchronization with a synchronization signal of a display device 2 or a processing device (not shown) connected at a subsequent stage.

The color plane synchronization signal read out from the synchronization memory section 31 is simultaneously transmitted to a motion detection circuit 39, and the motion detection circuit 39 detects the motion of the subject.
The signal is sent to the minimum value detection circuit 41.

Here, when an image freeze instruction signal is issued by the first or second image freeze instruction circuit 42a or 42b,
The detection time setting circuit 43 and the minimum value detection circuit 41 are activated. This detection time setting circuit 43 sets the minimum value detection time according to the first or second image freeze instruction circuit 42a or 42b.

Further, the minimum value detection circuit 41 detects the minimum value of the movement claw within the time set by the detection time setting circuit 43, and stores the image signal in the freeze memory section 35 for the image signal determined to have the least amount of movement. It holds the image data and sends a detection signal to the memory R/W controller 44 so as to output the held image data.

An example of the motion detection circuit 39 in this embodiment is shown in FIG. By the way, the RGB primary color images that have been converted to 1 by the field sequential method are generated chronologically in the order of RlG, B, for example, so the movement of the subject is R, G, G, !
: B, which appears as a difference between the B and R images. Therefore, the difference between each image is R and G, G and 8. At least one of B and R can be determined and used to calculate the motion detection amount. In the example shown in Figure 3, R and G,
and B, the subtraction circuits 50 and 51 calculate the difference, and the absolute value circuits 52 and 53 convert the differences into absolute values, and then the addition circuit 54 adds them.
The configuration is such that the detected amount of movement of the subject is output through the LPF 55.

The freezing operation of the minimum value detection circuit 41 is shown in FIG. In FIG. 4, 0 indicates an image that has not been frozen, ◎ indicates an image that is frozen, and ◎ indicates an image that is frozen at the end.

As shown in this figure, in the minimum value detection circuit 41, first,
The movement flms of the image signal at time ts is held, and a detection signal is sent to the memory W/R controller 44 so as to read the image signal from the freeze memory section 35. Next, the movement mm1 at time t1 is compared with the ms, and the image signal with the smaller value is held (frozen) in the freeze memory section 35, and the frozen image signal is read out. In this case, if ms < ml, the image signal at time ts is read from the freeze memory section 35, and the value of the amount of motion ms is held. Similarly, time t
If the second <ms, the image signal of the motion m2 is read out from the freeze memory section 35, and the value of the motion ff1m2 is held.

The above operations are repeated until time te determined by the detection time setting circuit 43, and the image signal with the least movement within the time te-ts is frozen in the freeze memory 35, and The resulting image signal is read out from this freeze memory 35.

Note that the detection time setting circuit 43 uses a one-shot multivibrator, for example, to set the first and second detection times.
This can be realized by outputting a pulse having a pulse width corresponding to the detection time according to the image freeze instruction circuits 42a and 42b.

For example, when the first image freeze instruction circuit 42a is operated, a short detection time T1 is set, and when the second image freeze instruction circuit 42b is operated, a long detection time T2 is set. In this case, if the user wishes to observe the image still, the first
When the image freeze instruction circuit 42a is operated, for example, in the example shown in FIG. 4, after a short time T1, an image with a second movement amount is displayed as a still image.

On the other hand, if it is desired to record an image with less image blur, it is sufficient to operate the second image freeze instruction circuit 42b. images can be obtained.

As described above, according to the first embodiment, 1q still images suitable for the user's request can be produced.

FIG. 5 shows a second embodiment of the invention.

In this embodiment, the first and second image freeze instruction circuits 42a and 42b are respectively connected to a freeze switch 61a,
It is formed by a release switch 61b. Further, the output signal of the freeze memory section 35 is converted into, for example, a composite video signal by the signal processing circuit 62, and outputted to an external recording device @63.

The above freeze switch 61a and release switch 61b
The operation signal is input to the system controller 64, and the system controller 64 determines which switch 618.
A signal is sent to set the detection time according to the minimum value detection circuit 41, and the minimum value detection circuit 41 is activated.

For example, when the freeze switch 61a is operated, l
When the release switch 61b is operated, a signal 11LIT is sent to switch the detection time, and after the detection time, a signal to activate the external storage device 63 is sent. The detection time setting circuit 43
The detection time is switched depending on HIT or 'L'.

The detection time by the freeze switch 61a is set to such a time that, for example, there is some image blurring and the waiting time until the image becomes a still image is not a concern.

For example, when used for an electronic scope, half the period of vibration inside the body is about 0.5 seconds, so 0.
．． The time is set to about 2 seconds to 0.5 seconds. This time is set to a time that does not feel unpleasant to the general human sense, and the color framing of this device is 30H.
z (repeating m R-G-B image cycles 30 times per second), it is possible to obtain an image with the smallest amount of pre-reflection between 6 to 15 frames.

On the other hand, when the release switch 61b is operated,
The system controller 62 causes the detection time setting circuit 43 to set the detection time to a long time.

In other words, this release switch 61b is for recording an image with as little image blur as possible, so
Even if it takes a little longer to obtain a still image, the detection time is set to be longer than the detection time of the freeze switch 61a in order to increase the probability of obtaining a still image with less image blur.

When applied to an electronic endoscope device, the movement inside the human body is 0.8
Considering that the frequency is approximately 1.2 Hz, there is a high probability that the movement will be at its minimum within approximately 1 second, so the detection time is set to approximately 1 second.

When the release switch 61b is operated, the system controller 64 activates the external recording device 63 to record the still image displayed on the monitor image after the detection time has ended. In this case, as the external recording device 63,
Not limited to still cameras that take pictures of TV monitor screens.
Optical disc that directly records image signals! iiw, or an image recording device that performs image recording using an external trigger signal (in this case, an output signal from the system controller 64).

The rest is the same as the first embodiment.

FIG. 6 shows a third embodiment of the invention. In the first embodiment and the second embodiment, the present invention is applied to an RGB plane sequential type image carrier, but in the third embodiment, the Mojik filter 71 is attached to the image plane. This is applied to a color simultaneous imaging system using the element 72.

In this third embodiment, the optical image of the subject that is imaged by the imaging optical system 73 and formed on the imaging surface of the [@ element 72] is transmitted to the signal processing circuit 75 under the control of the scanning circuit 74.
The signal is processed by , and an analog luminance signal AY and an analog color line sequential signal AC are generated. The luminance signal AY and color line sequential signal AC are input to an A/D converter 76, which converts the luminance signal AY into a digital luminance signal D.
Y and a digital color line sequential signal DC are converted and written into the image memory 77. The signal read from the image memory 77 is converted into an analog signal by a D/A converter 78, and then converted into an NTSC signal by an NTSC encoder 79.
It is converted into a signal and displayed on the external monitor 81.

In this embodiment, the digital luminance signal DY is input to a motion detection circuit 39, and freeze control is performed based on the detected motion a.

This takes into consideration the visibility of the human eye, and if it is desired to detect movement with particular focus on the color of the subject, the digital color signal DC may be used to detect movement.

The motion detected by the motion detection circuit 39 is determined by the minimum value detection circuit 41 detecting the minimum amount of motion within the set time corresponding to the operation of the first or second image freeze instruction circuit 42a or 42b. The image signal determined to be the value is displayed on the monitor 96.

Note that the detection time can be set using the method shown in the first embodiment or the second embodiment.

In each of the above embodiments, for example, when the first image freeze instruction circuit 42a issues a freeze instruction, it is not limited to outputting a signal set to a single detection time, but any one of a plurality of detection times It may also indicate the detection time.

Alternatively, a single image freeze instructing means may be used, and a plurality of freeze instructing signals may be selectively output from this image freeze instructing means.

[Effects of the Invention] As described above, according to the present invention, a plurality of still image instruction signal output means and an actual still image storage/recording operating condition can be selected according to the still image instruction signals. Therefore, still image storage/recording suitable for the user's needs can be performed.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram showing the configuration of the present invention, Figures 2 to 4
The figures relate to the first embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a signal processing device for image freezing, FIG. 3 is a diagram showing an example of a motion detection circuit, and FIG. FIG. 5 is a block diagram showing the configuration of a signal processing device for image freezing according to a second embodiment of the present invention,
FIG. 6 is a block diagram showing the configuration of an image freezing signal processing device according to a third embodiment of the present invention. 1... Image storage/recording means 2... Motion detection means 3... Minimum value detection means 4
...Detection time setting means 5a...First image freeze instruction means 5b...Second
Image freeze instruction means 6...Writing/recording control means 1. Color plane equalization 1. Bow 3. 4. Procedure m Orthography (spontaneous) November 28, 1999 Commissioner of the Japan Patent Office Yoshi 1 ) Moon Yi 1, Indication of the case: 1999 Patent Application No. 34429 2, Title of the invention: Signal processing device for image freezing 3,
Relationship with the case of the person making the amendment

Claims (1)

[Claims] a motion detection means for detecting movement of a subject from an input image signal; an image freeze instruction means for outputting a plurality of image freeze instruction signals; activated by the image freeze instruction means;
minimum value detection means for detecting a minimum value of the amount of movement of the subject within a set time from an output signal of the movement detection means; and a detection time of the minimum value detection means responsive to the plurality of image freeze instruction signals. A detection time setting means for setting a time, and a control means for controlling a writing operation of the image signal to the means for storing or recording the image signal according to the output of the minimum value detection means. Signal processing device for image freezing.