JPH05244571A - Picture evaluation device and picture display device using said device - Google Patents

Abstract

(57) [Abstract] [Purpose] Automatically detect the motion of the stored image. [Structure] The image data stored in the first field memory 1a and the image data stored in the second field memory are simultaneously read out and compared by the data comparison means 3. Image data for the first field,
If there is a large difference from the image data of the second field, the motion detection means 4 determines that the image has a motion. By detecting the movement of the stored image and automatically switching from the frame display to the field display, a flicker-free image is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image evaluation apparatus which is used, for example, in a memory display of a video printer and detects the movement of an image to be displayed, and an image display apparatus using the image evaluation apparatus.

[0002]

2. Description of the Related Art In an apparatus for converting a video signal into a still image, such as a memory display of a video printer, as shown in FIG. 4, a sampled first field analog video signal and a second field analog video signal are digital. The processed image data is stored in the frame memory and displayed on the monitor. However, if a moving image is stored in a frame as memory, different image data will be obtained in the field 1 and the field 2, and by displaying this on the monitor as it is, a so-called flicker phenomenon occurs, which causes difficulty in viewing and deterioration of image quality. Was there. In such a case, conventionally, the image is resampled, and when it is still insufficient, it is dealt with by manually switching the mode to the field memory.

[0003]

However, if the image is re-sampled, the image may be different from the original one and the desired image may not be obtained.

The present invention has been made in view of the above circumstances and, for example, is used for a device for converting a sampled video signal into a still image, and an image at a desired time is displayed in good quality and automatically without a switching operation. An object of the present invention is to provide an image evaluation device capable of performing the above. Another object of the present invention is to provide an image display device which uses the image evaluation device and automatically displays an image at a desired time with good quality and without requiring a switching operation.

[0005]

An image evaluation apparatus according to the present invention is an image evaluation apparatus for detecting a motion of an image formed by a sampled video signal, and stores a first field video signal. A first field memory, a second field memory for storing a video signal of a second field, and a memory control means for simultaneously reading out respective image data from the first field memory and the second field in synchronization with a vertical signal. Data comparing means for comparing the respective read image data, and motion detecting means for detecting the motion of the image by monitoring the display of the data comparing means in units of vertical periods.

An image display device according to the present invention is an image display device for displaying a still image from a sampled video signal, and includes a first field memory for storing a video signal of a first field and a second field memory. Second field memory for storing the video signal of, and memory control means for simultaneously reading the respective image data from the first field memory and the second field in synchronization with the vertical signal, and the respective read image data. And a motion detection unit that detects the motion of the image by monitoring the output of the data comparison unit in units of vertical periods, and if there is a motion in the image based on the output of the detection unit, Display switching means for displaying the image data in the field and displaying the image data in a frame when the image does not move. It is a symptom.

[0007]

When there is no motion in the stored image, the image data of the first field and the image data of the second field substantially match. When the image has a motion, a corresponding difference occurs between the image data of the first field and the image data of the second field, which are sampled with a predetermined time difference. The movements of the stored images are detected by simultaneously comparing the once stored image data and monitoring the comparison results in units of vertical periods.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of an image evaluation apparatus according to the present invention.

In this embodiment, the analog video signal of the first field is stored as a digital signal in the first field memory 1a by switching a memory switch (not shown), and the analog video signal of the second field is stored in the second field memory 1b. Stored as a digital signal. The field memories 1a and 1b carry a read / write circuit 2 as a memory control means.

The read / write circuit 2 outputs a read signal to the field memories 1a and 1b in synchronization with a vertical synchronizing signal from a synchronizing signal generating circuit (not shown). As a result, the image data of the first field and the image data of the second field are simultaneously read from the field memories 1a and 1b.

The read data of the first field and the read data of the second field are input to the comparison circuit 30 as the data comparison means 3. The comparison circuit 30 successively compares the respective image data of the first field and the second field sequentially input from the field memories 1a and 1b, and when the data difference is equal to or more than a predetermined value, the clock signal is detected by the motion detecting means. Output to 4.

The motion detecting means 4 has a counter circuit 41 to which the clock signal from the comparison circuit 30 is input. The counter circuit 41 counts the input clock signal for each vertical period, and uses the output thereof as one input of the comparator 42. A predetermined number of clocks set by the setting circuit 43 is used as the other input of the comparator 42. As a result, the number of clocks in one vertical period counted by the counter circuit 41 is compared with the set value, and when the count value becomes equal to or larger than the set value, the output level of the comparator 42 rises. This rising means that there is a vertical period having a large data difference between the stored image data of the first field and image data of the second field. Therefore, the comparator 42
From the rising edge of the output of, the presence of motion in the stored image is detected.

FIG. 2 is a block diagram showing another example of the image determination apparatus according to the present invention.

In this embodiment, the video signal of the first field is stored in the first field memory 1a and the video signal of the second field is stored in the second field memory 1b, as in the above embodiment. The respective video signals in the field memories 1a and 1b are simultaneously read by the read / write circuit 2 and input to the data comparison means 3. The data comparison means 3 is an analog type, and the video signals for the first field and the second field, which are simultaneously input, are converted into a first D / A signal.
The converter 31a and the second D / A converter 31b convert again into analog signals A and B, respectively. Then, the analog signals A and B are input to the difference circuit 32, and the difference output (AB) is output from the difference circuit 32 in real time as the motion detection unit 4.
Entered in.

The motion detecting means 4 has an integrating circuit 44 which integrates the difference output (AB) from the difference circuit 32. The integrating circuit 44 is discharged for each vertical synchronizing signal. The integrated output for each vertical period is used as one input of the comparator 45.
The other input of the comparator 45 is a predetermined analog output set by the setting circuit 46. The output level of the comparator 45 rises when the integrated value of the differential output (AB) becomes equal to or larger than the set value in one vertical period. This rising also detects that there is motion in the stored image.

FIG. 3 is a block diagram showing an example of an image display device according to the present invention, showing a color image display device.

The sampled video signal is input to the analog circuit 5. The analog circuit 5 decomposes the input video signal into color signals (R, G, B). Further, the vertical sync signal by the sync separation is shaped by the sync signal generation circuit 13 and input to the motion detection circuit 9 described later. The video signal decomposed into color signals (R, G, B) is converted into a digital signal by the A / D converter 6. On the other hand, the control circuit 8 outputs a write signal to the read / write circuit 2 according to the information from the operation circuit 7. As a result, each color data of the first field is written in the first field memory 1a and each color data of the second field is continuously written in the second field memory 1b in synchronization with the vertical synchronizing signal.

Each data in the field memories 1a and 1b is input to the motion detection circuit 9. The motion detection circuit 9
The field memory 1 is composed of the data comparison means 3 and the motion detection means 4 of the image evaluation apparatus described above.
Based on the data from a and 1b, it is determined whether there is a motion in the stored image. The determination result of the motion detection circuit 9 is input to the control circuit 8. When the motion detection circuit 9 determines that there is no motion in the image, that is, when the comparator output of the motion detection means 4 does not rise, the signal switching circuit 10 as the display switching means switches the switch every vertical period. A switching control signal is input from the control circuit 8 to the signal switching circuit 10 so as to be switched alternately ,. The output of the signal switching circuit 10 is converted into an analog signal by the D / A converter 11 and output as a frame signal for monitoring.

When the motion detecting circuit 9 determines that there is a motion in the image, that is, when the comparator output of the motion detecting means 4 rises, the signal switching circuit 10 turns off the switch in response to an instruction from the control circuit 8. Fix it. This makes the first
Only the image data of the field is D / A converted and output to the monitor.

As described above, it is automatically determined whether or not there is a motion in the stored image, and the frame display and the field display are automatically switched based on the determination, so that a high-quality image without a flicker phenomenon is obtained. , It is displayed at the desired time and without the need for switching operation.

[0021]

As described above, according to the image evaluation apparatus of the present invention, the first field memory stored in the first field memory is used.
The image data of the field and the image data of the second field stored in the second field memory are simultaneously read in synchronization with the vertical signal, and the respective image data are compared with each other, whereby the movement of the stored image Is accurately detected automatically. In the case of the image display device according to the present invention, the frame display and the field display are automatically switched based on the detection, and when the image has a motion, the field display is displayed, and when the image has no motion, Since each frame display is selected, a high-quality image without flicker phenomenon is displayed at a desired time and without requiring a switching operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an image evaluation apparatus according to the present invention.

FIG. 2 is a block diagram showing another example of the image evaluation apparatus according to the present invention.

FIG. 3 is a block diagram showing an example of an image display device according to the present invention.

FIG. 4 is a waveform diagram showing an example of a video signal.

[Explanation of symbols]

1a 1st field memory memory 1b 2nd field memory 2 Memory control means (read / write circuit) 3 Data comparison means 4 Motion detection means 9 Motion detection circuit (data comparison means 3 + motion detection means 4) 10 Display switching means (signal switching) circuit)

Claims (2)

[Claims] 1. An image evaluation device for detecting movement of an image formed by a sampled video signal, comprising: a first field memory storing a video signal of a first field; and a video signal of a second field. A second field memory for storing, a first field memory and a second field memory
Memory control means for simultaneously reading out the respective image data from the field in synchronization with the vertical signal, data comparing means for comparing the respective read out image data, and monitoring the output of the data comparing means in units of vertical periods. An image evaluation apparatus comprising: a motion detection unit that detects a motion of an image. 2. An image display device for displaying a still image of a sampled video signal, the first field memory storing a video signal of a first field, and the first field memory storing a video signal of a second field. A second field memory, a memory control means for simultaneously reading out respective image data from the first field memory and the second field in synchronization with a vertical signal, and a data comparing means for comparing the respective read out image data. A motion detection unit that monitors the output of the data comparison unit in units of vertical periods to detect the motion of an image; and based on the output of the detection unit, when the image has a motion, the image data is displayed in a field, An image display device comprising: a display switching unit for displaying image data in a frame when the image does not move.