JP2002199265A - Electronic zoom device and video camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic zoom device that can provide a magnified image with high image quality and whose circuit scale is reduced. SOLUTION: The electronic zoom device is configured with a plurality of field memories 1, 2, a plurality of line memories 3, 4, 5, 6, a selection means 7, an in-field vertical magnification means 8, an inter-field vertical magnification means 9, a motion detection section 10, an image composition means 11, a horizontal magnification means 12, a memory control means 13, a selection control means 14, an in-field vertical interpolation coefficient generating means 15, an inter-field vertical interpolation coefficient generating means 16 and a horizontal interpolation coefficient generating means 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electronic zoom device for applying an enlarged / reduced image process to an input moving image signal and outputting the processed image signal, and a video camera having the same.

[0002]

2. Description of the Related Art FIG. 6 is a schematic block diagram of an image signal processing device of the image signal processing device disclosed in Japanese Patent Application Laid-Open No. 08-205193. The image signal processing device shown in FIG. 6 includes two field memories 61 and 62, a motion detecting unit 68 for detecting the presence or absence of a motion of an image of a pixel read from these field memories 61 and 62, and a field memory 61. , 62, enlargement processing means having four line memories 63, 64, 65, 66, and field interpolation means for in-field interpolation of an image signal of a detected pixel when a motion is detected. 69.

FIG. 7 is a schematic configuration diagram of a conventional video signal processing apparatus, and includes two field memories 71 and 72,
Comparison means 75 for comparing signal levels of two fields
Interpolating means 74 for obtaining an interpolated value from the signals of the first field and the second field; and synthesizing the signal from the interpolating means 74 and the read signal of the first field according to the result of the comparing means 75. Means 76 and selecting means 77 for selecting the signal of the second field and the output of the synthesizing means 76
have.

[0004]

However, the image signal processing apparatus shown in FIG. 6 switches between inter-field interpolation when there is no motion and intra-field interpolation when there is motion due to motion detection. The image quality is greatly degraded by the accuracy of detection. For example, if it is determined that there is a motion without a motion, the resolution is degraded due to intra-field interpolation. Conversely, when it is determined that there is no motion, there is image blur due to the motion. Further, since the line memories are used for the motion detecting means and the enlarging means, there is a disadvantage that the circuit scale becomes large.

In the video signal processing device shown in FIG.
Since the mixture ratio of the field image and the frame image can be changed depending on the degree of the detected motion, the image quality is less likely to be reduced when the motion is erroneously detected, but cannot be realized during the electronic zoom.

Accordingly, it is an object of the present invention to provide an electronic zoom device capable of obtaining a high-quality enlarged image and reducing the circuit scale.

It is another object of the present invention to provide a video camera capable of improving the image quality of an electronic zoom function.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of field memories each storing an image signal of one field are connected to each field memory continuously. A plurality of line memories for storing image signals of one line, a selection means for selecting a signal necessary for vertical enlargement from outputs of the plurality of line memories, and an image signal based on an image signal of the same field in an output signal of the selection means. An intra-field vertical enlarging means for enlarging / reducing an image; an inter-field vertical enlarging means for enlarging / reducing an image from image signals of a plurality of fields in an output signal of the selecting means; A motion detecting means for estimating the amount of motion of each pixel by comparing the image signals of the fields; and the filter according to the amount of motion detected by the motion detecting means. Image synthesizing means for synthesizing the output image of the in-field vertical enlarging means and the output signal of the inter-field vertical enlarging means by changing the mixing ratio; horizontal enlarging means for enlarging / reducing the horizontal direction from the output of the image synthesizing means A memory control means for controlling reading and writing of data from and to a field memory and a line memory; a selection control means for controlling a selection process by the selection means; and a field for generating an interpolation coefficient in a vertical expansion means within a field according to an enlargement ratio. Internal vertical interpolation coefficient generation means, an inter-field vertical interpolation coefficient generation means for generating an interpolation coefficient in the inter-field vertical expansion means according to an enlargement ratio, and an interpolation coefficient in a horizontal enlargement means according to the enlargement rate. An electronic zoom device includes horizontal interpolation coefficient generating means.

According to a second aspect of the present invention, there is provided a video camera including the electronic zoom device according to the first aspect and a microcomputer for controlling the electronic zoom.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a block diagram showing a schematic configuration of an electronic zoom apparatus according to the present invention.

In the electronic zoom device according to the present invention,
The field memories 1 and 2 store the input image of one field alternately. That is, as shown in FIG. 2, the TV signal is interlaced read every other scanning line. Therefore, the field memory 1 stores the signal of the odd field composed of the horizontal lines 1, 3, 5, and 7 of the odd line number. The field memory 2 stores an even field signal composed of horizontal lines 2, 4, 6, and 8 having even line numbers.

In the process of reading and writing signals to and from the field memories 1 and 2, an appropriate address is selected according to the enlargement ratio of the electronic zoom in accordance with the address generated by the memory control means 13. The signal of one horizontal line read from the field memory 1 is stored in the line memory 5, and the output signal of the line memory 5 is stored in the line memory 3.

The signal of one horizontal line read from the field memory 2 is stored in the line memory 6, and the output signal of the line memory 6 is stored in the line memory 6. With this processing, the outputs of the line memories 3, 4, 5, and 6 become continuous 4
It becomes the signal of the horizontal line of the line. That is, as shown in FIG. 2, the signals of the horizontal lines 1, 2, 3, and 4 are output from the line memories 3, 4, 5, and 6, respectively. During the next horizontal line period, the horizontal lines 3, 4, 5, and 5 are output. , 6 are output. The read / write processing of the line memories 3, 4, 5, and 6 also follows the address generated by the memory control means 13.

The selecting means 7 comprises line memories 3, 4, 5,
Select any three lines from the six output signals. Which line is to be selected is in accordance with the instruction of the selection control means 14 according to the enlargement ratio of the electronic zoom. By the address processing in the memory control means 13 and the processing in the selection control means 14, three consecutive arbitrary signals are selected. These three lines are a combination of two lines of an odd field and one line of an even field sandwiched between the two lines (for example, horizontal lines 1 and 3 and horizontal line 2), or two lines of an even field and two lines thereof. One combination of the odd fields (for example, horizontal lines 2 and 4 and horizontal line 3) is obtained.

The in-field vertical enlargement means 8 includes the selection means 7
Out of the three lines selected in the above, the two lines of the same field are used as input signals, and the vertical interpolation coefficient
The interpolation processing is performed according to the complement relation number generated in step 5 to perform the enlargement processing. In addition, the inter-field vertical enlargement means 9 performs an enlargement process by performing an interpolation operation in accordance with the interpolation coefficient generated by the inter-field vertical complement relation number generation means 16 with the three lines selected by the selection means 7 as input signals.

Next, the interpolation coefficients and interpolation processing of each of the vertical enlargement means 8 and 9 will be described with reference to FIGS.

FIG. 3 shows the processing performed by the intra-field vertical enlargement means 8. Odd field signal lines (L ₁ , L ₃ , L
₅ ) is enlarged by a factor of 4/3 to generate new odd field signals (L' ₁ , L' ₃ , L' _5, ...). L _'1 is to become the same signal as L _1, directly outputs the L ₁ signal. L _'3 is located between positions L ₁ and L _3, the L ₁ and L ₃ 1: mixing to interpolate 2 ratio.
Similarly for L' _{5 and} above, interpolation is performed based on signals of two nearby lines. The interpolation coefficients represent the mixture ratio and are generated in arithmetic progression.

FIG. 4 shows the processing of the inter-field vertical enlargement means 9. The signal lines of the odd and even fields are subjected to 4/3 times enlargement processing to generate new odd field signals. The processing content is the same as that of the intra-field vertical enlargement processing. However, since the signals of two fields are used, the distance between adjacent lines is reduced, and L ′ ₃ is obtained by mixing L ₂ and L ₃ at a ratio of 2: 1. Will be interpolated.

As described above, the intra-field vertical enlargement has a drawback that the vertical resolution is reduced because the line interval of the signal to be interpolated is wider than the inter-field vertical enlargement.
On the other hand, in the inter-field vertical enlargement, although the vertical resolution is high, interpolation is performed from two fields with a time lag, so that if there is a motion in the image, the blurred image is enlarged. .

The motion detecting means 10 receives the three-line signals used in the inter-field vertical enlargement means 9 and detects the degree of motion between fields for each pixel. Specifically, 3
A control signal that compares the signal levels of the pixels in the line and indicates the degree of motion assuming that the motion is small when the difference between the signal level of the pixel in the same field and the signal level of the pixel in another field is small, and that the motion is large when the difference is large. Occurs.

The image synthesizing means 11 synthesizes the output signals of the intra-field vertical enlarging means 8 and the inter-field vertical enlarging means 9 according to a control signal indicating the degree of motion detected by the motion detecting means 10 by changing the mixing ratio for each pixel. I do. At the time of synthesis, the synthesis is performed so that the output of the inter-field vertical expansion means 9 increases when the motion is small, and the output of the intra-field vertical expansion means 8 increases when the motion is large.

The horizontal enlarging means 12 receives the output signal of the image synthesizing means 11 as an input signal, and performs an interpolation operation on each pixel arranged in the horizontal direction in accordance with the interpolation coefficient generated by the horizontal interpolation coefficient generating means 17, thereby obtaining a signal in the horizontal direction. Perform enlargement processing.

Memory control means 13, selection control means 14,
Each control in the intra-field vertical interpolation coefficient generation means 15, the inter-field interpolation coefficient generation means 16 and the horizontal interpolation coefficient generation means 17 is determined by the enlargement ratio of the present electronic zoom apparatus and the positions of lines and pixels to be enlarged. Is performed from an external microcomputer 18.

According to the above-described processing, a high-quality enlarged image can be obtained by changing the mixing ratio between the image subjected to the intra-field enlargement processing and the image enlarged between the fields according to the degree of motion.

The circuit scale can be reduced by sharing a line memory for motion detection and electronic zoom. In the above description, the interpolation processing in each enlargement means has been described as linear interpolation of two lines. However, by increasing the number of line memories, even when interpolation processing is performed on multiple lines, the mixing processing may be performed depending on the degree of motion. A similar effect can be obtained by changing the rate.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 5 is a block diagram showing a schematic configuration of a video camera provided with the electronic zoom device shown in the first embodiment.

The input image passes through an imaging lens group 19 including a movable lens for optical zoom, and is converted into an electric signal by a CCD 20.

The output of the CCD 20 is a sample hold (S
/ H) Automatic gain control (AGC) circuit 2 via circuit 21
2 is input. The output of the AGC circuit 22 is converted into a digital signal by the A / D conversion circuit 23.

The Y / C separation circuit 24 comprises two 1H delay lines and an adder for adding the input and the 2H delay signal. The output of the adder is used as a color signal, and the 1H delay signal is used as a luminance signal as a camera process. Input to the circuit 25. The camera process circuit 25 performs edge enhancement, gamma correction, and the like from the output of the Y / C separation circuit 24. Camera process circuit 25
Are alternately stored in the field memory 1 and the field memory 2 for each field.

In the process of reading / writing signals from / to the field memories 1 and 2, an appropriate address is selected according to the address generated by the memory control means 13 and in accordance with the enlargement ratio of the electronic zoom. The signal of one horizontal line read from the field memory 1 is stored in the line memory 5, and the output signal of the line memory 5 is stored in the line memory 3. The signal of one horizontal line read from the field memory 2 is stored in the line memory 6, and the output signal of the line memory 6 is stored in the line memory 6.

The read / write processing of the line memories 3, 4, 5, and 6 also follows the address generated by the memory control means 13.

The selection means 7 comprises line memories 3, 4, 5,
Select any three lines from the six output signals. Which line is to be selected is in accordance with the instruction of the selection control means 14 according to the enlargement ratio of the electronic zoom.

The intra-field vertical enlargement means 8 takes two lines of the same field among the three lines selected by the selection means 7 as input signals, and performs an interpolation operation according to the interpolation coefficient generated by the intra-field vertical interpolation coefficient generation means 15. To perform enlargement processing. In addition, the inter-field vertical enlargement unit 9 performs the enlargement process by performing an interpolation operation in accordance with the interpolation coefficient generated by the inter-field vertical interpolation coefficient generation unit 16 using the three lines selected by the selection unit 7 as input signals.

The motion detecting means 10 receives the three-line signals used in the inter-field vertical enlargement means 9 and detects the degree of motion between fields for each pixel.

The image synthesizing unit 11 changes the mixing ratio of the output signals of the intra-field vertical enlarging unit 8 and the inter-field vertical enlarging unit 9 for each pixel according to a control signal indicating the degree of motion detected by the motion detecting unit 10. Combine. At the time of synthesis, the images are synthesized such that the output of the inter-field vertical enlargement means 9 increases when the motion is small, and the output of the intra-field vertical enlargement means 8 increases when the motion is large.

The horizontal enlarging means 12 takes the output signal of the image synthesizing means 11 as an input signal, and performs an interpolation operation on each plane element arranged in the horizontal direction in accordance with the complement relation number generated by the horizontal interpolation coefficient generating means 17. Perform horizontal enlargement processing.

The memory control means 13, the selection control means 14,
Each control in the intra-field vertical interpolation coefficient generation means 15, the inter-field interpolation coefficient generation means 16 and the horizontal interpolation coefficient generation means 17 is determined by the enlargement ratio of the electronic zoom device and the positions of the lines and pixels to be enlarged. This is performed from the electronic zoom microcomputer 18.

The output from the horizontal enlargement means 12 is converted into an analog signal by a D / A conversion circuit 26 and input to a recorder 28 and a display 27. The recorder 28 records the input image signal, and the display 27 displays the input image.

According to the above-described processing, a video camera having a high-quality electronic zoom function can be obtained by using the electronic zoom device described in the first embodiment for a video camera.

[0042]

As is apparent from the above description, according to the present invention, the degree of movement between fields is detected to change the mixing ratio between the image subjected to the intra-field enlargement processing and the image enlarged between the fields. Therefore, a magnified image with high image quality can be obtained.

Further, the circuit scale can be reduced by sharing a line memory for motion detection and electronic zoom.

Further, the image quality of the electronic zoom function of the video camera can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an electronic zoom device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a memory control system.

FIG. 3 is a diagram showing a process of an intra-field vertical enlargement unit.

FIG. 4 is a diagram showing a process of an inter-field vertical enlargement unit.

FIG. 5 is a block diagram showing a schematic configuration of a video camera according to the present invention.

FIG. 6 is a schematic configuration diagram of an image signal processing device of a conventional image signal processing device.

FIG. 7 is a schematic configuration diagram of a conventional video signal processing device.

[Explanation of symbols]

 1, 2 field memory 3 to 6 line memory 7 selection means 8 in-field vertical enlargement means 9 inter-field vertical enlargement means 10 motion detection means 11 image synthesis means 12 horizontal enlargement means 13 memory control means 14 selection control means 15 in-field vertical interpolation Coefficient generation means 16 Inter-field vertical interpolation coefficient generation means 17 Horizontal interpolation coefficient generation means

Claims (2)

[Claims] 1. A plurality of field memories each storing an image signal of one field, a plurality of line memories continuously connected to each field memory, each storing an image signal of one line, and a plurality of line memories. Selecting means for selecting a signal necessary for vertical enlargement from the output of the selector, an in-field vertical enlarging means for enlarging or reducing an image from an image signal of the same field in the output signal of the selecting means, Motion detection for estimating the amount of motion of each pixel by comparing the inter-field vertical enlargement means for enlarging or reducing the image from the image signals of the plurality of fields, and the image signals of the plurality of fields in the output signal of the selection means Means, and an output image of the intra-field vertical enlarging means and an output of the inter-field vertical enlarging means according to the amount of motion detected by the motion detecting means. Image synthesizing means for synthesizing by changing the mixing ratio of signals, horizontal enlarging means for enlarging and reducing in the horizontal direction from the output of the image synthesizing means, and memory control means for controlling reading and writing of data to and from a field memory and a line memory Selection control means for controlling a selection process in the selection means, an intra-field vertical interpolation coefficient generation means for generating an interpolation coefficient in the in-field vertical expansion means according to an enlargement ratio, An electronic zoom apparatus comprising: an inter-field vertical interpolation coefficient generating means for generating an interpolation coefficient by a vertical enlargement means; and a horizontal interpolation coefficient generation means for generating an interpolation coefficient by a horizontal enlargement means according to an enlargement ratio. 2. A video camera comprising: the electronic zoom device according to claim 1; and a microcomputer for controlling the electronic zoom.