JPH0530460A - Picture freeze processing device - Google Patents

Abstract

PURPOSE:To obtain a still picture faithful to the photographing intention of an operator and to obtain a still picture of less picture degradation like image blur or color deviation due to movement of an object. CONSTITUTION:A timer circuit 4 which detects the time from the start time of a still picture indicating means 3, an operation circuit 5 which operates the extent of movement from a motion detecting circuit 2 and the time output from the timer circuit 4 to subject the extent of movement to time correction, a minimum value detecting circuit 6 which detects a minimum value in a prescribed time from the extent of movement which is outputted from the operation circuit 5 and is subjected to time correction, and a write control circuit 7 which is started by the still picture indicating signal from the still picture indicating means 3 and controls the write operation of the input picture signal to a picture memory 1 in accordance with the output of the minimum value detecting circuit 6 are provided. In this case, the input picture signal is stored as a still picture when a minimum value of the corrected extent of movement is obtained in the prescribed time after the start of the still picture indicating means 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an image freeze processing device for storing still images.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Image signals can be recorded on magnetic tape or magnetic disk, or C
A device is known in which a storage element such as a CD memory, a MOS memory, a magnetic bubble memory, or an IC memory stores the image and displays the image. In particular, as a device for recording a still image, a device provided with a magnetic disk device as a recording / reproducing device inside a camera is disclosed in JP-A-49-52912 and JP-A-54-140510. Further, Japanese Patent Laid-Open Publication No. 57-44374 discloses an electrophotographic camera which can be reproduced immediately after taking an image with the same type of device.

However, since these devices are recorded or temporarily stored by pressing the release button, so-called camera shake, in which the movement of the subject is faster than the shutter speed or the image pickup device moves when the shutter is operated. As a result, image blurring occurs in the captured image, and re-shooting is often required. Further, for example, when a fast-moving subject is photographed by using an interlaced scanning type element as an image pickup element, different images are stored between fields, so flicker occurs and the image becomes very difficult to see. It has drawbacks.

With respect to this drawback, in order to prevent flicker between fields when a still image is stored, the movement of the object is detected and the frame is frozen when there is no movement, and the field is frozen when there is movement. Such a device is proposed in U.S. Pat. No. 4,272,787. However, this device has a drawback in that the field resolution automatically degrades when the imaged subject moves, so that the resolution in the vertical direction deteriorates with respect to the moving subject.

Further, in recent years, due to the progress of the manufacturing technology of the solid-state image pickup device, the density of pixels and the miniaturization of the chip have been advanced, and an endoscope in which the solid-state image pickup device is mounted at the tip, that is, an electronic endoscope. The device is being developed. These devices have a function of inserting the device into a body cavity and observing a region to be inspected, and recording an observation image of the region. In addition to its observation ability, the quality of the recorded image is very high. Is important,
It greatly affects the diagnosis of the inspected part. Therefore, at the time of recording, the operator of the endoscope freezes and displays the image of the region to be inspected several times with the patient still, and selects the most desirable image as the recorded image. Still images were recorded on a video printer, still video floppy device, or the like. However, even if the patient is stationary, there is a considerable amount of movement of the inspected part while observing the inside of the body, so it may be necessary to freeze it again and again to eliminate the blurring of the image due to that movement. Have a defect.

Such a deterioration of the recorded image due to the movement of the subject varies depending on the type of the image pickup device and the image pickup method. For example, when a frame transfer type CCD is used as the image pickup element, the movement of the subject during the exposure period causes an image blur, and when interlace type CCD is used for interlaced scanning, In addition to the blurring of the image due to the movement of the subject during the exposure time, flicker occurs due to the difference in the image between the fields. In addition, in order to reduce the diameter of the endoscope, a monochrome CCD is mounted on the tip of the endoscope, and the illumination light is, for example, RGB sequential light. In the so-called color plane sequential method, RGB images sequentially captured in time series are used. Since the primary color images are displayed simultaneously, the movement of the subject is displayed as a color shift, which is a so-called color shift.

On the other hand, as an apparatus for reducing the above-mentioned image blur and color shift, there is one proposed by the present applicant in Japanese Patent Application No. 63-31809. This device is activated by an instruction signal from the image freeze signal, detects the motion of the image by the video signal, and performs the recording operation according to the amount of the detected motion, thereby causing the above-described image blur and color shift. It alleviates. However,
This device has the drawback that there is a time lag between pressing the image freeze switch and finally obtaining a still image, and since this tendency becomes even greater for fast-moving subjects, Valuable freeze timings and photo opportunities may be missed.

In summary, the method of immediately freezing by pressing the image freeze switch has the advantage that a still image can be obtained at a desired timing, but on the other hand, for a fast-moving subject, image blurring and It has the drawback of large color misregistration, and in the method that detects the amount of movement of the video signal after the image freeze switch is pressed and performs the freeze operation according to the amount of movement, While there is an advantage that you can obtain an image with less blurring and color shift, there is a time lag until you get a still image,
In some cases, it has the drawback of missing valuable timing.

Therefore, in Japanese Patent Application Laid-Open No. 2-119388, in the present application, when the movement of the subject is detected by the movement detecting means, and when the movement of the subject is small, the writing to the image memory is prohibited and the image is displayed. A first freeze mode for freezing and a second freeze mode for freezing the image by prohibiting the writing to the image memory 1 according to the forced freeze signal from the freeze instructing means are selectively used. A device configured to be switched is proposed. With the above configuration, a case of storing a still image with little image deterioration caused by the movement of the subject,
When the still image is stored with an emphasis on the image capturing timing, the mode setting is switched according to each, so that the still image faithful to the operator's image capturing intention is obtained. In the case of the present invention, since the setting is made by the operator's discretion to selectively use the above two modes, the balance between the freeze timing and the image deterioration is always taken into consideration, and it is optimal for both conditions. It is difficult to obtain a good still image and requires skill, so there was room for improvement.

The present invention has been made in view of the above circumstances, and it is possible to obtain a still image that is faithful to the operator's intended freeze timing with respect to the operator's intended freeze timing, and An object of the present invention is to provide an image freeze processing device capable of obtaining a still image with little image deterioration such as image blurring or color shift of an image due to movement.

[0011]

As shown in the conceptual diagram of FIG. 1, an image pickup device of the present invention is a photoelectric conversion device (not shown) that photoelectrically converts a subject image formed by an imaging optical system to obtain an image signal. An image storage means 101 for storing the image signal obtained by the conversion means, a motion detection means 102 for detecting the amount of movement of a subject from the image signal, and the image storage means 1
01, a still image instruction means 103 for issuing a still image instruction signal, a time detection means 104 activated by the still image instruction means 103 for detecting a time from the activation time, and the motion detection means 102. Calculated by the calculation means and the time output by the time detection means 104, the calculation means 105 for performing a temporal correction on the movement quantity, and outputting the calculated movement quantity; From the corrected motion amount, for example, the set time detecting means 1
Minimum value detecting means 106 for detecting the minimum value of the corrected motion amount within a predetermined time set by 08,
A writing control unit 107 which is activated by a still image instruction signal from the still image instruction unit 103 and controls the writing operation of the input image signal to the image storage unit 101 according to the output of the minimum value detection unit 106. Is equipped with.

[0012]

In the present invention, when the still image instructing means 103 issues an instruction to store a still image, the still image instructing means 10
In accordance with the still image instruction signal from 3, the writing control means 10
6, and the time detection means 104 is started. The movement amount detecting means 102 sets the input time of the still image instruction signal as t0, and the movement amount M = g (t) as shown in the graph of FIG. 2, for example.
Is output.

In the conventional image freeze processing apparatus by motion detection described in Japanese Patent Laid-Open No. 2-57078, the image at the time t2 within the time set by the set time detection means 108 (t3−t0). Is output as a still image.

On the other hand, in the present invention, the output H = f (t) of the time detecting means 104 and the motion amount M = g (t) are calculated by the calculating means 105 to perform the time correction. The movement amount Y = HM is output. The minimum value detection 106 sequentially detects the minimum value of the corrected motion amount Y output by the calculation means 105. The write control means 107 is the minimum value detection means 1
The operation of writing the input image signal to the image storage unit 101 is controlled according to the output of 06. Then, the image at time t1 is stored in the image storage means 101 as a still image.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 3 to 4 relate to the first embodiment of the present invention, FIG. 3 is a block diagram showing the configuration of the image freeze processing apparatus of the present embodiment, FIG. 4 is a circuit diagram showing an example of a timer circuit, and FIG.
FIG. 3 is a circuit diagram showing an example of an arithmetic circuit.

As shown in FIG. 3, the image freeze processing apparatus of the present embodiment has an image memory 1 as an image storage means for storing a digital input image signal, and a motion detection for detecting a motion of a subject from the image signal. A motion detection circuit 2 as means, a freeze instructing means 3 as still image instructing means for instructing to store a desired still image in the image memory 1, and a freeze instructing signal output from the freeze instructing means 3. And a timer circuit 4 as a time detection means for detecting the time from the time of activation.

Further, the image freeze processing apparatus calculates the amount of motion detected by the motion detection circuit 2 and the time output by the timer circuit 4, and then corrects and outputs the amount of motion. Arithmetic circuit 105 and the arithmetic circuit 5
A minimum value detection circuit 6 for detecting the minimum value of the corrected movement amount within a predetermined time set by the set time detection circuit 12, from among the temporally corrected movement amounts output by A write control means 107 is provided which is activated by a freeze instruction signal from the freeze instruction means 3 and controls the write operation of the input image signal to the image memory 1 according to the output of the minimum value detection circuit 6.

The write control circuit 7 is activated by the freeze instruction signal output from the freeze instruction means 3, and in response to the output signal from the minimum value detection circuit 6,
A write inhibit gate 8 for controlling whether or not writing to the image memory 1 is inhibited, and the image memory 1
(Write; W) and read (read;
R) and a memory R / W controller 9 for controlling The memory write control signal from the memory R / W controller 9 is applied to the image memory 1 via the write inhibit gate 8 and the memory read control signal is directly applied to the image memory 1.

Next, the operation of the image freeze processing apparatus of this embodiment will be described. The input image signal is the image memory 1
And the motion detection circuit 2. In the motion detecting means 2,
From the input image signal, a motion detection amount corresponding to the motion of the subject is obtained, and the calculated value is output to the arithmetic circuit 5.

Writing / reading of the image signal input to the image memory 1 is controlled by the memory R / W controller 9 provided in the writing control circuit 7, and normally, the images sequentially input are successively read as they are. Is output,
A moving image is displayed on an external display device (not shown). In this case, the timer circuit 4 is not activated and the write inhibit gate 8 does not inhibit writing.

On the other hand, when a still image is stored, the freeze operation is started based on the freeze instruction signal output from the freeze instruction means 3. When the freeze instruction signal is issued from the freeze instruction means 3 and transmitted to the timer circuit 4, the timer circuit 4 is activated, and the elapsed time after the freeze instruction signal is issued is output to the arithmetic circuit 5.
The arithmetic circuit 5 calculates the elapsed time and the motion detection amount output from the motion detection circuit 2, corrects the motion detection amount temporally, and outputs it to the minimum value detection circuit 6. The minimum value detection circuit 6 notifies the write inhibit gate 8 each time the minimum value is detected after the freeze instruction signal is issued. The write prohibition gate 8 does not prohibit writing to the image memory 1 when the minimum value is detected, that is, permits writing, and prohibits writing to the image memory 1 when the minimum value is not detected. When the motion detection amount is the minimum value, the image written in the image memory 1 is stored as a still image. Then, by the memory read signal of the memory R / W controller 9, the image signal written in the image memory 1 when the motion detection amount is minimum is displayed as an optimum still image by an external display device (not shown).

An example of the timer circuit 4 is shown in FIG.
The timer circuit 4 can be configured using a counter 41 with a clear terminal CLR. In the illustrated example, the vertical synchronizing signal from the video synchronizing signal generating circuit (not shown) is applied to the clock terminal CK, and the freeze instructing signal by the freeze instructing means 3 is applied to the clear terminal CLK.
When the freeze instruction signal is input to the timer circuit 4, the clearing of the counter 41 is released and the counting of the vertical synchronizing signal which is the clock is started. This is output to the arithmetic circuit 5 as a time output.

An example of the arithmetic circuit 5 is shown in FIG. The arithmetic circuit 5 can be configured by using a look-up table (LUT) 51 by ROM as shown in the figure. The motion detection amount from the motion detection circuit 2 is assigned to the lower address of the ROM, the elapsed time from the timer circuit 4 is assigned to the upper address, and the calculation result by the curve of H = f (t) shown in FIG. 2 is stored in the LUT 51 in advance. By doing so, the amount of movement can be corrected temporally. That is, the LUT 51 performs temporal weighting (HM * Y) on the motion detection amount M shown in FIG. 2, and the weighting becomes lighter as the elapsed time becomes shorter after the freeze instruction signal is issued. The motion detection amount is corrected and output so that the minimum value detection circuit 6 is more likely to detect the minimum value as the motion detection amount when the elapsed time is shorter. This is intended when the minimum value of the motion amount is obtained, that is, the good timing for obtaining the still image is the timing as close as possible in time after the freeze instruction signal is issued. Therefore, the timing of obtaining a still image can be arbitrarily changed by temporal weighting.

As described above, according to this embodiment, the minimum detection circuit 6 determines the motion amount from the motion detection amount corrected on the basis of the elapsed time after the activation of the freeze instructing signal from the freeze instructing means 3. Since the minimum value is detected, and when the minimum value is detected, the image memory 1 is written and the image is frozen, so that a still image faithful to the operator's intention of capturing an image can be obtained. At the same time, it is possible to obtain a still image with little image deterioration such as image blurring or color shift of the image due to the movement of the subject.

6 and 7 relate to the second embodiment of the present invention. FIG. 6 is a block diagram showing the configuration of an image freeze processing apparatus, and FIG. 7 is a circuit diagram showing an example of a timer circuit.

The second embodiment is an example showing a case where the input image signal is an analog type signal. This analog type input image signal is digitalized by the A / D converter 10 as shown in FIG. After being converted into a signal, it is written in the image memory 1. The image signal read from the image memory 1 is the D / A converter 1
The signal is converted into an analog type signal by 1 and output to the subsequent stage.

Further, the motion detection circuit 2, the timer circuit 4,
Arithmetic circuit 5, minimum detection circuit 6, and set time detection circuit 1
2 is composed of an analog circuit. Other configurations and operations similar to those of the first embodiment are designated by the same reference numerals and description thereof will be omitted.

In the present embodiment, the timer circuit 4 supplies the voltage from the power source 52 to the CR time constant circuit composed of the resistor 54 and the capacitor 55 through the analog switch 53, as shown in FIG. is doing. further,
A resistor 57 is connected in parallel with the time constant number circuit via an analog switch 56.

The analog switches 53 and 56 are composed of elements that become non-conductive when a freeze instruction signal is input to the control terminal. Then, a freeze instruction signal is applied to the analog switch 56 via an inverter 58. When the freeze instruction signal is issued, the analog switch 53 becomes conductive. On the other hand, the analog switch 56 is turned off.

The operation of the timer circuit 4 of this embodiment will be described below. When the freeze instruction signal is not applied, the analog switch 53 is in the non-conductive state, while the analog switch 56 is in the conductive state. Therefore, the output of the timer circuit 4 is at the ground level (0V).
Has become. When the freeze instruction signal is applied, the analog switch 53 changes to the conductive state and the analog switch 56 changes to the non-conductive state. Therefore, the voltage from the power source 52 is applied to the time constant circuit composed of the resistor 54 and the capacitor 55, and the voltage generated at the contact point between the resistor 54 and the capacitor 56 can be output as time. When the freeze instruction signal is released, the electric charge charged in the capacitor 55 is discharged through the analog switch 56 and the resistor 57.

The rest of the configuration, operation and effect are the same as those of the first embodiment, and the explanation is omitted.

[0032]

[0033]

As described above, according to the image freeze processing apparatus of the present invention, it is possible to obtain a still image that is faithful to the operator's intention to pick up the image, and to reduce the image blur of the image caused by the movement of the subject. There is an effect that it is possible to obtain a still image with little image deterioration such as color misregistration.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an image freeze processing apparatus according to the present invention.

FIG. 2 is a graph showing an example of the operation of the present invention.

FIG. 3 is a block diagram showing the configuration of an image freeze processing apparatus according to the first embodiment.

FIG. 4 is a circuit diagram showing an example of a timer circuit.

FIG. 5 is a circuit diagram showing an example of an arithmetic circuit.

FIG. 6 is a block diagram showing the arrangement of an image freeze processing apparatus according to the second embodiment.

FIG. 7 is a circuit diagram showing an example of a timer circuit.

[Explanation of symbols]

 101 ... Image storage means 102 ... Motion detection means 103 ... Still image instruction means 104 ... Time setting means 105 ... Calculation means 106 ... Minimum value detection means 107 ... Write control means 108 ... Set time detection means

Claims (1)

Claim: What is claimed is: 1. An image storage means for storing an image signal obtained by photoelectric conversion means for photoelectrically converting an object image formed by an image forming optical system to obtain an image signal, An image freeze processing apparatus comprising: a motion detection unit that detects a motion amount of a subject from an image signal; and a still image instruction unit that issues a still image instruction signal that causes a still image to be stored in the image storage unit. Time detection means that is activated by the means and detects a time from the activation time, a motion amount output from the motion detection means, and a time from the activation time output from the time detection means, and Calculating means for temporally correcting the motion amount; minimum value detecting means for detecting and outputting the minimum value of the motion amount within a predetermined time from the motion amounts corrected by the calculating means; and the still image finger. A control means that is activated by a still image instruction signal from the means, and controls the writing operation of the input image signal to the image storage means in accordance with the output of the minimum value detection means. Image freeze processing device.