JP3078045B2 - Image freeze processing 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 improvement in an image freeze processing device for storing a still image.

[0002]

2. Description of the Related Art
Record image signals on a magnetic tape or magnetic disk,
2. Description of the Related Art There are known devices that store an image in a storage element such as a CD memory, a MOS memory, a magnetic bubble memory, or an IC memory and display 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. Japanese Patent Application Laid-Open No. Sho 57-44374 discloses an electrophotographic camera which can be reproduced immediately after photographing by using a similar device and can be retaken.

[0003] However, these devices are recorded or temporarily stored by pressing a release button. Therefore, when the movement of the subject is faster than the shutter speed, or when the imaging device moves during the shutter operation, so-called camera shake is performed. As a result, there are many cases where image blurring occurs in a captured image and it is necessary to retake the image. In addition, for example, when a fast-moving subject is photographed using an interlaced scanning element as an image pickup element, different images are stored between fields, so that flicker occurs and the image becomes very hard to see. Has disadvantages.

Regarding this drawback, in order to prevent inter-field flicker when a still image is stored, the motion of the subject is detected and the frame is frozen when there is no motion, and the field is frozen when there is motion. Such a device is proposed in U.S. Pat. No. 4,272,787. However, this apparatus has a drawback that the field resolution is automatically degraded with respect to a moving subject because the field freeze is automatically performed when the captured subject has a movement.

In recent years, with the progress of solid-state image pickup device manufacturing technology, the density of pixels and the size of chips have been reduced, and an endoscope having a solid-state image pickup device mounted at its tip, a so-called electronic endoscope. Equipment is being developed. These devices have the function of observing the part to be inspected by inserting it into the body cavity and recording the observation image of the same part, and the quality of the recorded image is extremely high as well as the observability. Is important,
It greatly affects the diagnosis of the inspected site. Therefore, at the time of recording, the operator of the endoscope freezes the image of the region to be inspected several times after stopping the patient and selects the most desirable image as the recorded image. Still images are recorded on a video printer, a video printer, or a still video floppy device. However, even when the patient is stationary, there is a considerable amount of movement of the part to be inspected while observing the inside of the living body, so it may be necessary to freeze again many times to eliminate image blur due to the movement. Has defects.

[0006] The 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 an image sensor, the movement of a subject during an exposure period causes image blurring, and when an interline type CCD is used for interlaced scanning, In addition to the image blur caused by the movement of the subject during the exposure time, the flicker caused by the image difference between the fields occurs. In order to reduce the diameter of the endoscope, a monochrome CCD is mounted at the tip of the endoscope, and the illumination light is, for example, RGB sequential light. Since the primary color images are displayed simultaneously, the movement of the subject is displayed as a color shift, which is a problem of so-called color shift.

On the other hand, there is a device proposed by the present applicant in Japanese Patent Application No. 63-31809 as an apparatus for reducing the above-mentioned image blur and color shift. This apparatus is activated by an instruction signal from an image freeze signal, detects the movement of an image by a video signal, and performs a recording operation in accordance with the detected amount of movement, thereby eliminating the above-described image blur and color shift. It is alleviating. However,
This device has a drawback that a time lag occurs between pressing the image freeze switch and finally obtaining a still image, and the tendency is further increased for a fast moving subject. Precious freeze timing or shutter chances may be missed.

[0008] 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. The method has the disadvantage that the color shift is large, and the method of detecting the amount of movement of the video signal after the image freeze switch is pressed and performing the freeze operation in accordance with the amount of movement is not suitable for the image. Although there is an advantage that an image with less blurring and color shift can be obtained, there is a time lag until a still image is obtained,
In some cases, there is a disadvantage that valuable timing is missed.

Therefore, in Japanese Patent Application Laid-Open No. 2-119388, the present application discloses a technique in which the motion of a subject is detected by a motion detecting means, and when the motion of the subject is small, writing to an image memory is prohibited, and A first freeze mode in which freeze is performed and a second freeze mode in which writing to the image memory 1 is inhibited and image freeze is performed in response to a forced freeze signal from freeze instructing means are selectively performed. A device configured to be switchable is proposed. And storing a still image with less image degradation due to the movement of the subject,
When a still image is stored with emphasis on the timing of imaging, the mode setting is switched accordingly, so that a still image faithful to the operator's imaging intention is obtained. In the case of the present invention, the two modes are selectively used depending on the judgment of the operator. Therefore, the balance between the freeze timing and the image deterioration is always taken into consideration, and the optimum condition is set for both conditions. Obtaining a still image is difficult and requires skill, so there is room for improvement.

SUMMARY OF THE INVENTION 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 imaging intention with respect to a freeze timing intended by the operator, and to obtain a still image of the subject. It is an object of the present invention to provide an image freeze processing apparatus capable of obtaining a still image with less image degradation such as image blurring or color shift of an image due to motion.

[0011]

As shown in the conceptual diagram of FIG. 1, an image pickup apparatus according to the present invention includes a photoelectric conversion device (not shown) for photoelectrically converting a subject image formed by an imaging optical system to obtain an image signal. An image storage unit 101 for storing an image signal obtained by the conversion unit, a motion detection unit 102 for detecting a motion amount of a subject from the image signal, and the image storage unit 1
01, a still image instructing unit 103 for issuing a still image instructing signal for storing a still image, a time detecting unit 104 activated by the still image instructing unit 103 and detecting a time from the activation time, and the motion detecting unit 102 Calculates the amount of motion detected by, and the time output by the time detecting means 104, performs a temporal correction on the amount of motion and outputs the result, and the time output by the calculating means 105 From the corrected motion amount, for example, the set time detecting means 1
08, a minimum value detecting means 106 for detecting a minimum value of the corrected amount of motion within a predetermined time set by
A write control unit 107 which is started by a still image instruction signal from the still image instruction unit 103 and controls a write operation of an input image signal to the image storage unit 101 in accordance with an output of the minimum value detection unit 106; It has.

[0012]

According to the present invention, when an instruction to store a still image is issued by the still image instruction means 103, the still image instruction means 10
3 in response to the still image instruction signal from
6, and the time detecting means 104 is activated. The movement amount detection means 102 sets the input time of the still image instruction signal to t0, and for example, the movement amount M = g (t) as shown in the graph of FIG.
Is output.

In a conventional image freeze processing apparatus based on motion detection described in Japanese Patent Application Laid-Open No. 2-57078, the image at time t2 is set within the time (t3-t0) set by the set time detecting means 108. 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 amount of motion M = g (t) are calculated by the calculating means 105 to perform temporal correction. The motion 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 a minimum value detection means 1
In response to the output 06, the writing operation of the input image signal to the image storage means 101 is controlled. 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 and 4 relate to the first embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of an image freeze processing apparatus according to this embodiment. FIG. 4 is a circuit diagram showing an example of a timer circuit.
FIG. 3 is a circuit diagram illustrating an example of an arithmetic circuit.

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

The image freeze processing device calculates the amount of motion detected by the motion detection circuit 2 and the time output by the timer circuit 4 and performs temporal correction on the amount of motion to output the result. The arithmetic circuit 105 and the arithmetic circuit 5
A minimum value detection circuit 6 for detecting a minimum value of the corrected motion amount within a predetermined time set by the set time detection circuit 12 from among the temporally corrected motion amounts output by A write control unit 107 which is started by a freeze instruction signal from the freeze instruction unit 3 and controls a writing operation of an input image signal to the image memory 1 in accordance with an output of the minimum value detection circuit 6 is provided.

The write control circuit 7 is activated by a freeze instruction signal output from the freeze instruction means 3, and operates in response to an output signal from the minimum value detection circuit 6.
A write-inhibiting gate 8 for controlling whether or not writing to the image memory 1 is inhibited;
(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 applied directly 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 stored in the image memory 1
And the motion detection circuit 2. In the motion detecting means 2,
A motion detection amount corresponding to the motion of the subject is obtained from the input image signal, and the value is output to the arithmetic circuit 5.

Writing / reading of the image signal input to the image memory 1 is controlled by a memory R / W controller 9 provided in a write control circuit 7, and in normal times, the sequentially input images are sequentially output as they are. Output
The moving image is displayed by 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 the write.

On the other hand, when a still image is stored, a freeze operation is started based on a freeze instruction signal output from the freeze instruction means 3. When a 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 outputs the elapsed time since the issuance of the freeze instruction signal to the arithmetic circuit 5.
The arithmetic circuit 5 calculates the elapsed time and the motion detection amount output by the motion detection circuit 2, performs temporal correction on the motion detection amount, and outputs the result to the minimum value detection circuit 6. Each time the minimum value detection circuit 6 detects the minimum value after the issuance of the freeze instruction signal, it is transmitted to the write inhibit gate 8. The write inhibit gate 8 does not inhibit writing to the image memory 1 when the minimum value is detected, that is, permits writing, and inhibits 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, based on the memory read signal of the memory R / W controller 9, the image signal written in the image memory 1 when the amount of motion detection is minimum is displayed as an optimal still image by an external display device (not shown).

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

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

As described above, according to the present embodiment, the minimum detection circuit 6 calculates the motion amount from the motion detection amount corrected based on the elapsed time since the start in response to the freeze instruction signal from the freeze instruction means 3. Since the minimum value is detected, and when the minimum value is detected, the image is written to the image memory 1 and the image is frozen, a still image faithful to the operator's imaging intention can be obtained. At the same time, it is possible to obtain a still image with less image degradation such as image blurring or color shift of the image due to the movement of the subject.

FIGS. 6 and 7 relate to a 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 in which the input image signal is an analog type signal. The analog type input image signal is converted into a digital signal by an A / D converter 10 as shown in FIG. After being converted into a signal, it is written into the image memory 1. The image signal read from the image memory 1 is supplied to a D / A converter 1.
The signal is converted into an analog type signal by 1 and output to a subsequent stage.

The motion detection circuit 2, the timer circuit 4,
Arithmetic circuit 5, minimum detection circuit 6, and set time detection circuit 1
Reference numeral 2 is an analog circuit. In addition, the same configurations and operations as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

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

Each of the analog switches 53 and 56 is formed of an element which becomes non-conductive when a freeze instruction signal is input to a control terminal. Further, 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 non-conductive, while the analog switch 56 is conductive. Therefore, the output of the timer circuit 4 is at the ground level (0 V).
It 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 supply 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 other constructions and functions and effects are the same as those of the first embodiment, and the description 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 faithful to the operator's intention to capture an image, and to reduce the image blur caused by the movement of the subject. There is an effect that a still image with less image degradation such as color shift or color shift can be obtained.

[Brief description of the drawings]

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

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

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

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

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

FIG. 6 is a block diagram illustrating a configuration of an image freeze processing apparatus according to a second embodiment.

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

[Explanation of symbols]

 DESCRIPTION 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 ... Writing control means 108 ... Set time detection means

Continuation of front page (56) References JP-A-4-212591 (JP, A) JP-A-2-119389 (JP, A) JP-A-2-57078 (JP, A) JP-A-2-55485 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 1/04 H04N 5 / 232,5 / 91

Claims (1)

(57) [Claims] An image storage means for storing an obtained image signal by photoelectric conversion means for obtaining an image signal by photoelectrically converting a subject image formed by an image forming optical system; An image freeze processing device comprising: a motion detection unit that detects an amount; and a still image instruction unit that issues a still image instruction signal for storing a still image in the image storage unit. Time detecting means for detecting a time from the start time, a motion amount output from the motion detecting means, and a time from the start time output by the time detecting means are calculated, and the motion amount is temporally calculated. Calculating means for correcting; a minimum value detecting means for detecting and outputting a minimum value of the movement amount within a predetermined time from the movement amounts corrected by the calculating means; and a still image finger from the still image instruction means. An image freeze processing apparatus, which is activated by an indication signal and controls a writing operation of an input image signal to the image storage means according to an output of the minimum value detection means. .