JPS6336686A - Image information recorder - Google Patents

Abstract

PURPOSE:To attain efficient recording by applying consecutive recording at an interval corresponding to the moving speed of an object at a prescribed internal in response to the detection output obtained from a movement detection circuit. CONSTITUTION:When an image pickup element 2 is operated and a movement detection signal is outputted from a threshold value circuit of a movement detection circuit 14, a magnetic sheet is driven and a magnetic head 7 is in contact with the sheet 8 to bring it to an on-track state. When the rotation speed of the sheet 8 and the phase reach specified range an image pickup signal is recorded. The image pickup signal is compared with an image pickup signal before a prescribed time and when a noted object is within a screen and its movement is large, the increment of the count value of a timer counter is increased and when the movement is not large conversely, the count increment is limited to a degree. Thus, consecutive recording is applied at an interval corresponding to the movement of the object.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an image information recording device, and particularly to a device for recording image information captured under specific conditions, for example.

[Prior Art] Conventionally, such a device includes, for example, a monitoring system. This is, for example, a combination of a television camera using a solid-state image sensor or the like and a magnetic recording/reproducing device that constantly records the output video signal of the television camera. Such a system is effective for monitoring the inside of a bank, for example, during business hours, where people frequently come and go.

[Problems to be Solved by the Invention] However, such a system configured to constantly record the output video signal of a television camera can be used, for example, in a place where there are many people walking during the day, but at night there is no foot traffic. It is not economical and disadvantageous in terms of space to be able to use it even during the day in places where there are few people.

The purpose of the present invention is to eliminate the drawbacks of the conventional device described above,
It is an object of the present invention to provide a device that can record image information only when the movement of a subject is detected under specific conditions, and can continuously record image information at intervals corresponding to the movement speed of the subject.

[Means for Solving the Problems] The present invention includes a recording control means for recording on a recording medium a signal for comparing an imaging signal regarding a subject obtained from an image sensor with an imaging signal from a predetermined time ago. .

[Function] According to the present invention, motion detection is performed based on image information from an image sensor, and image information is continuously recorded at intervals corresponding to the amount of motion.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a monitoring recording device to which the present invention is applied.

In FIG. 1, 1 is an optical system, and 2 is an image sensor that photoelectrically converts a subject image incident through the optical system 1. In FIG. 3 is an amplifier that amplifies the image signal from the image sensor 2. 4 is a signal processing circuit that separates the imaging signal from the amplifier 3 into a luminance signal Y and a color signal C. 5 is a recording signal processing circuit for converting the luminance signal Y and color signal C into a signal format suitable for recording. 6 is a recording amplifier that amplifies the output signal of the recording signal processing circuit 5; 7 is a magnetic head; and 8 is a recording magnetic sheet. 9 is a drive motor for rotationally driving the magnetic sheet 8; 10 is a PG head that generates a PG pulse for detecting the rotational phase of the magnetic sheet 8; 11 is a PG head;
This is an amplifier that amplifies the PG pulse from the head 10.

Reference numeral 12 denotes a motor drive circuit which drives the drive motor 9 and controls the rotational phase using the PG pulse from the amplifier 11. The PG pulse is also supplied to the control circuit 15 and used as a reference pulse for the system.

Reference numeral 13 denotes an image sensor drive circuit that drives the image sensor 2 and scans the image sensor 2 horizontally and vertically.

Reference numeral 14 denotes a motion detection circuit that, based on the interframe difference signal in the luminance signal Y from the camera signal processing circuit 4,
Detect the movement of the subject. Reference numeral 15 denotes a control circuit, which includes a CPU and storage means for executing control as described later. A head drive circuit 15A controls the movement of the head 7 in the radial direction of the sheet 8, the floating of the head 7, and the contact with the sheet 8.

FIG. 2 is a block diagram showing the configuration of the motion detection circuit 14.

16 is a sample and hold circuit that samples and holds the luminance signal Y from the camera signal processing circuit 4. The sample of the image in the sample hold circuit 16 is
Do as shown.

That is, as shown in FIG. 3, N samples are extracted in the horizontal force and M samples in the vertical direction on the screen, and data at a total of NM sample points are sampled as data for one screen.

For example, even if 8 bytes of memory is used, 8000 points of data can be extracted on one screen.

An A/D conversion circuit 17 quantizes the analog data signal from the sample hold circuit 1G according to its level and converts it into, for example, an 8-bit digital signal.

A memory 18 stores the digital signal from the sample and hold circuit 16 for one frame period.

Reference numeral 19 denotes a difference circuit which calculates the final level of the difference between sample points at the same position on the screen regarding the digital signal from the A/D conversion circuit 17 and the digital signal of one frame previous read from the memory 18 in the order in which it was written. Detect. 20 is an integration circuit that integrates the difference value obtained from the difference circuit 19 over one frame period. As shown in Figure 3, the level value of the sampling point in the current frame is V (i, j), and the level value of the sampling point in the previous frame is V' (i, j ), then in the integration circuit 20, s = "; l v (i, j) - v' (i, j
) 11, j2+ The calculation value S is calculated.

21 is a threshold circuit that determines whether the integrated value S is greater than or equal to a predetermined value, and if it is greater than or equal to the predetermined value, it is determined that there is movement on the screen, and a value corresponding to the amount of movement is determined. The detection signal with the detection signal is input to the control circuit 15 manually.

The control circuit 15 performs control as shown in FIG. 4, for example.

In step Sl, the image sensor 2 is operated, and the threshold circuit 2 is operated.
1 until a motion detection signal is outputted, and then the process proceeds to step S2, where the magnetic sheet 8 is rotationally driven.

Note that when a motion is detected, a relatively large current may be applied to the drive motor 9 in order to quickly record a video signal.

Next, in step S3, the magnetic head 7 is brought into contact with the magnetic sheet 8 to be brought into an on-track state.

Next, the process proceeds to step S54, where the process waits until a signal indicating that recording is enabled by phase control is output from the motor drive circuit 12, and when it is output, the process proceeds to step S5. In step S5, the accumulated charges accumulated in the image sensor 2 for one frame period are read out.

Next, in step S6, the camera signal processing circuit 4 separates the read signal into a luminance signal Y and a color signal C, and the recording signal processing circuit 5 converts it into a signal form suitable for recording, and then the signal is transferred onto the magnetic sheet 8. to be recorded.

Next, the process proceeds to step S7, where the magnetic head 7 is floated so as not to be in contact with the magnetic sheet 8. Then, in step S8, the rotation of the magnetic sheet 8 is stopped. Next, in step S9, the process waits for a predetermined time to elapse to obtain a time interval corresponding to the motion detection output obtained in step 51 for continuous recording, and after the predetermined time has elapsed, the process returns to step S1 to perform motion detection. do. Note that this time interval becomes smaller as the above-mentioned calculated value S becomes larger;
The smaller the value, the larger the value is set. FIG. 5 is another flowchart executed by the control circuit 15.

As shown in FIG. 5, first, in step S21, an image sensor is driven to form an image signal. Next, in step S22, it is determined based on the signal output from the motion detection circuit 14 whether motion has been detected. If the motion is detected here, the rotation of the magnetic sheet 8 is started in step 323, and then the magnetic head is brought into contact with the magnetic sheet 8 in step 324.

Next, in step S25, it is determined whether the rotational speed and phase of the magnetic sheet 8 are within a specified range and a recordable state has been reached.If recording is possible, in step 326, the advertised image signal is recorded at the next timing. Then, the process proceeds to step S27.

In step S27, the head is advanced by one track by the head access mechanism, and then, in step S28, a timer is started. This timer counter sequentially counts clocks of a certain frequency and ends when a certain count value is reached. Then, in step S29, it is determined whether motion has been detected. If no movement is detected, it is determined that there is no object of interest, and in step S30 the magnetic head is removed from the magnetic sheet, the drive of the magnetic sheet is stopped, and the process returns to step S22.

If motion is detected in step S29, it is assumed that the subject of interest still exists within the screen, and the timer counter value is increased by a value corresponding to the amount of motion M in step S32, and the process proceeds to step S33. Specifically, when the amount of movement M is large, it is determined that the subject of interest is moving quickly, so the amount of increase in the count value of timer callan i is increased, and conversely, when the amount of movement M is not so sharp, the amount of increase in the count value is increased. to a certain extent. By doing this, the count value of the timer counter is increased according to the amount of movement, thereby making it possible to hasten the end timing of the timer counter.

In step S33, it is determined whether the timer counter has finished counting. If the timer counter has not counted yet, the process returns to step S29, and if it has finished, the process returns to step S25.

Further, in this embodiment, the sample points are uniformly distributed over the screen, but it is also possible to provide sample points only in the center or to make the sampling density in the center higher than in the periphery.

Furthermore, although the threshold value circuit of the motion detection circuit is fixed, it is not limited to this, and if it is made variable, it will be resistant to noise and can be used in an environment with some degree of movement.

Although the variation of the luminance signal level is used for motion detection, the present invention is not limited to this, and the color signal level or hue change may also be used.

It goes without saying that motion detection is not limited to performing motion detection over one frame, and in field readout imaging devices, motion detection may be performed for each field.

The present invention can also be used as a recording device for sports action analysis, and can take quick shots according to the movement of the subject.

Although a magnetic sheet is used as the recording medium, it is needless to say that the recording medium is not limited to this, and may be an optical disk, a magnetic tape, a semiconductor memory, or the like.

The period to obtain a video signal for one screen was defined as one frame period (1730 seconds) of an actual television signal, but A, /D
Depending on the processing conditions of the conversion, arithmetic circuit, etc., the present invention is not limited to this, and it is also possible to sample a portion of the screen over several frames to obtain one screen's worth of emotion.

In order to reduce the amount of data, the amount of movement was detected only for multiple points on the screen, but the frame memory is used to constantly compare the one-frame delayed signal and the current signal, and the level difference is detected by a predetermined amount. It may be determined that there is movement when this occurs.

Although one magnetic sheet is used, a plurality of magnetic sheets may be used.

[Effects of the Invention] As described above, according to the present invention, motion detection can be performed directly from an image signal, and a motion image can be recorded only when necessary based on the result.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram of a motion detection circuit in the same embodiment, Fig. 3 is a diagram showing sample points on one screen, and Figs. 4 and 5 are It is a flowchart which shows the example of operation of the same Example. 2... Imaging device, 14... Motion detection circuit, 15... Control circuit. N sample 0 Figure 3

Claims (1)

[Scope of Claims] Detecting means for detecting a value corresponding to the amount of movement of the subject by comparing an imaging signal related to the subject obtained from an image sensor with an imaging signal from a predetermined time ago; An image information recording apparatus comprising: recording control means for recording the imaging signal on a recording medium at predetermined intervals according to the obtained detection output.