JP2552558B2 - Imaging device capable of electronically magnifying images - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus capable of electronically magnifying an image, and in particular, a video signal corresponding to a screen is divided into an odd field and an even field, BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically magnified image pickup apparatus which magnifies images by independently writing and reading a video signal corresponding to an even field.

[Prior Art] FIG. 6 is a block diagram for explaining a magnifying photographing function of a conventional image pickup apparatus capable of magnifying electronically. Sixth
Referring to the figure, the conventional magnifying image capturing unit uses a luminance signal (hereinafter referred to as Y
A / D converter 6 for A / D conversion)
A field memory 9 for storing the Y signal A / D converted by the converter 6, a D / A converter 11 for D / A converting the Y signal read from the field memory 9, and a color difference signal RY / B-Y multiplexer 7 for switching a certain RY signal and BY signal based on the MPX signal
And the output signal from the RY / BY multiplexer 7 is A
A / D converter 8 for A / D conversion, field memory 10 for storing the signal from A / D converter 8, and RY signal of the read signals from field memory 10 is A / D A / D converter 12 for converting, and D / A for converting the BY signal among the signals output from the field memory 10 into D / A.
It includes a converter 13 and a memory controller 14 for controlling write and read operations of field memories 9 and 10. The field memories 9 and 10 can independently write and read the video signal, for example, 2
In the case of doubling, reading is performed with a clock having a frequency half that of writing.

FIG. 7 is a schematic diagram for explaining the operation of writing the video signal into the field memory shown in FIG. Referring to FIG. 7, an enlarged area 41a of the odd field 41
Only write to field memories 9 and 10. Similarly, the enlarged portion 42a of the even field 42 is also included in the field memories 9 and 10.
Write in. The field memories 9 and 10 to be written are divided into four areas, and an enlarged portion 41a of the odd field 41 and an enlarged portion 42a of the even field 42 are written in half of the divided areas. As described above, conventionally, when enlarging an image, only half of the storage areas of the field memories 9 and 10 are used for storage.

8A and 8B are schematic diagrams for explaining a conventional method of reading a video signal from a field memory. Referring to FIGS. 8A and 8B, first, the read method shown in FIG. 8A is a read method in which the same line is output twice, and data written in an odd (even) field is converted into an even (odd) field. ) Is read in the field. The reading method shown in FIG. 8B is to alternately read the data in the odd field and the data in the even field line by line.

[Problems to be Solved by the Invention] As described above, in the reading method shown in FIG. 8A, the same line is repeatedly output twice. This method has no problem when the movement of the subject is large, but has a problem that the deterioration of the resolution in the vertical direction is large when the movement of the subject is small. On the other hand, in the reading method shown in FIG. 8B, since the data in the odd field and the data in the even field are alternately read line by line, the vertical resolution can be obtained even when the motion of the subject is small. There is an advantage that the deterioration of is not so large. However, the method shown in FIG. 8B has a problem that the dynamic resolution is largely deteriorated when the movement of the subject is large.

As described above, conventionally, when the read method as shown in FIG. 8A is adopted, the dynamic resolution when the motion is large is maintained, but the vertical resolution is deteriorated when the motion is small. However, when the reading method shown in FIG. 8B is adopted, the vertical resolution when the motion of the subject is small is improved to some extent, but the dynamic resolution is largely deteriorated when the motion is large. there were.

That is, conventionally, there is an image pickup apparatus capable of electronically magnifying an image, which can improve the dynamic resolution when the movement of the object is large and the vertical resolution when the movement of the object is small during the magnifying image. I didn't.

The present invention has been made to solve the above problems, and it is possible to improve the dynamic resolution when the movement of the subject is large and the vertical resolution when the movement of the subject is small during the magnified photographing. An object of the present invention is to provide an image pickup apparatus capable of electronically magnifying images.

[Means for Solving the Problems] An image pickup apparatus capable of electronically magnifying images according to the present invention is
At the time of magnifying the image, field storage means for storing the video signals corresponding to the odd field and the even field in the frame at that time and the immediately preceding frame in the respective divided storage areas, and one of the divided ones of the field storage means. Writing and reading control means for writing the video signals of the odd field and the even field of one frame into the storage area and reading the video signals of the odd field and the even field of the other frame from the other divided storage area; The delay means delays the video signals of the odd field and the even field of the frame read from the storage means by a predetermined period, and the video signal read from the field storage means and the video signal delayed by the delay means. Predetermined reference value for subtraction result by subtraction comparison pixel by pixel A first comparison unit that determines whether or not it is larger, and a video signal corresponding to a screen is interpolated based on both the video signal read from the field storage unit and the signal delayed by the delay unit. An interpolating means, and a second interpolating means for interpolating a video signal corresponding to a screen by the video signal delayed by the delay means,
The output of the first interpolating means is selected in response to the comparison determining means being determined to be smaller than the predetermined reference value, and the second interpolation is selected to be greater than the predetermined reference value. Interpolation method selecting means for selecting the output of the means.

[Operation] In the electronically magnified image pickup apparatus according to the present invention, the video signals corresponding to the odd field and the even field in the frame at that time and the immediately preceding frame are divided by the field storage means at the time of the magnified image pickup. And the video signals of the odd field and the even field of one frame are written in one of the divided storage areas of the field storage means by the write / read control means and the other storage area is divided. From the other frame, the video signals of the odd field and the even field of the other frame are read out, and the video signals of the odd field and the even field of the frame read out from the field storage means are delayed by the delay means for a predetermined period and stored in the field storage means. The video signal read from the means and the delay means The delayed video signal is subtracted and compared pixel by pixel by the comparison and determination means to determine whether or not the subtraction result is larger than a predetermined reference value, and the interpolation method selection means and the predetermined reference by the comparison and determination means. Corresponding to the screen based on both the video signal read from the selected field storage means and the video signal delayed by the delay means when the output of the first interpolation means is determined to be smaller than the value. The video signal corresponding to the screen is selected by the video signal delayed by the delay means when the output of the second interpolation means is selected in response to the determination that the video signal is interpolated and is determined to be larger than a predetermined reference value. Is interpolated.

That is, in response to the comparison judgment means comparing and judging the video signals read from the field storage means and the delay means, and the interpolation method selecting means judging that the picture signals are smaller than the predetermined reference value by the comparison judging means. First
The interpolating means is selected, the video signal corresponding to the screen is interpolated based on the read signals from the field storing means and the delaying means, and it is determined that the interpolating means is larger than a predetermined reference value. Since the interpolation means is selected and the interpolation is performed by the signal from the delay means, the optimum video signal interpolation is performed according to the magnitude of the movement of the subject.

[Embodiment of the Invention] FIG. 1 is a block diagram for explaining a magnifying photographing function of an electronically magnifying image pickup apparatus showing one embodiment of the present invention. Referring to FIG. 1, the magnifying image capturing unit of this embodiment includes an A / D converter 6 for A / D converting a Y signal, and a Y signal A / D converted by the A / D converter 6. , A line memory 2 for delaying the Y signal read from the field memory 9 by one horizontal period (hereinafter referred to as 1H), an output signal from the field memory 9 and an output signal from the line memory 2. Is input, the D / A converter 11 for D / A converting the output signal from the comparison / calculation / interpolation circuit 3, the RY signal and the B signal.
R-Y / B for selecting between -Y signal and MPX signal
-Y multiplexer 7 and A / D converter 8 for A / D converting the output signals from the RY / BY multiplexer 7.
And a field memory 10 for storing the output signal from the A / D converter 8, a line memory 4 for delaying the output signal from the field memory 10 by 1H, and an output from the field memory 10 and the line memory 4. A comparison / calculation / interpolation circuit 5 to which a signal is input, and a comparison / calculation / interpolation circuit 5
The output signal corresponding to RY among the output signals from the D / A
A D / A converter 12 for converting, a D / A converter 13 for D / A converting an output signal corresponding to the BY signal among the output signals from the comparison / calculation / interpolation circuit 5, A memory controller 1 for controlling writing and reading of the field memory 9 and the field memory 10.

FIG. 2 is a block diagram for explaining the configuration of the comparison / calculation / interpolation circuit shown in FIG. Referring to FIG. 2, the comparison / calculation / interpolation circuit includes an averaging circuit 21 for averaging the output signal from the field memory and an output signal from the line memory, and an output signal from the averaging circuit 21. And a data selector 22 to which an output signal from the field memory is input, a data selector 23 to which an output signal from the field memory and the line memory is input, and an output signal from the field memory and an output signal from the line memory are subtracted. The subtraction / comparison circuit 24 for determining whether or not it is larger than the reference data and the subtraction / comparison circuit 24
Of the output signal of the data selector 22 and the output signal of the data selector 23 in response to the output signal of.

FIG. 3 is a schematic diagram for explaining the write operation to the field memory shown in FIG. Referring to FIG. 3, writing to field memories 9 and 10 is performed only for a portion enlarged for each of fields A to D. Four
Fields are written in one field memory plane. Arranging A to the right of B and C to the right of D is to simplify reading. This arrangement applies to NTSC, and to the right of A for PAL, B to the right
Is placed, and D is placed to the right of C.

FIG. 4 is a schematic diagram showing the read results of the field memory and the line memory read at the time of writing the frame 1 shown in FIG. Referring to FIG. 4, for example, in frame I, after reading the data of the first line of field D, the next 1H reads the data of the first line of field C. In this read, both are read at a frequency half that of the write clock. Since C (A) is arranged to the right of D (B) as described above, the row address of the memory may have the same value during this period. In frame I, writing is performed on A or B, and reading is C or D.
The write and read addresses do not collide. Therefore, as in the conventional art, the break of the image due to the presence of the old data and the new data at the same time in the output video is not generated. Writing and reading of the field memory as described above are controlled by the memory controller 1 shown in FIG. Here, the data read from the field memory is directly input to the line memory and delayed by 1H. At this time, the input and output of the line memory are not only delayed by 1H but also shifted by one field.

5A and 5B are schematic diagrams for explaining the interpolation operation by the comparison / calculation / interpolation circuit shown in FIG. The interpolation operation will be described with reference to FIG. 2, FIG. 5A, and FIG. 5B. Here, the comparison / calculation / interpolation circuit shown in FIG. 2 has a function of detecting the movement between fields by comparing the input and output of the line memory, and switching between the field interpolation and the line interpolation. Subtraction / comparison circuit 24
Determines whether the difference between the input and output of the line memory is larger or smaller than the reference data. If it is determined to be large, it means that the movement of the subject is large, and if it is determined to be small, it means that the movement of the subject is small. The adding / averaging circuit 21 creates an even field signal when the subtraction / comparison circuit 24 determines that the motion is small. That is, according to the field discrimination signal FI, as shown in FIG. 5A, the field signal is output as it is when it is odd, and the output signal of the adder / averaging circuit 21 is output when it is even. Further, when the subtraction / comparison circuit 24 determines that the movement of the subject is large, the FH / 2 pulse is used to select odd data and even data according to the field to be read. That is, C (A) data is always output in the odd field, and D (B) data is always output in the even field. Where FH
The / 2 pulse is a pulse of 2H cycle in which L and H are repeated every 1H.

As described above, in this embodiment, the inter-field interpolation including the average interpolation circuit is selected when the motion of the subject is small, and the pre-interpolation in which the signal of the previous line is directly inserted when the motion of the subject is large. Type interline interpolation is selected. Therefore, when the motion of the subject is small, a smooth video signal that fully utilizes the signals of both fields is output, and when the motion of the subject is large, gathers and afterimages due to the time difference between the fields are eliminated, and the dynamic resolution is improved.

[Effects of the Invention] As described above, according to the present invention, the comparison / determination means compares and determines the video signals read from the field storage means and the delay means, and the interpolation method selection means determines in advance the comparison / determination means. The first interpolating means is selected in response to the determination that the value is smaller than the predetermined reference value, the video signal corresponding to the screen is interpolated based on the video signal read from the field storing means and the delaying means, and the predetermined interpolation is performed. The second interpolation means is selected in response to the determination that the value is larger than the reference value, and the interpolation is performed by the signal from the delay means, so that the optimum video signal interpolation according to the magnitude of the motion of the subject is performed. Therefore, during magnified shooting, it is possible to improve the dynamic resolution when the movement of the subject is large and improve the vertical resolution when the movement of the subject is small. Can be made.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining the enlargement photographing function of an image pickup apparatus capable of electronic enlargement photographing, and FIG. 2 is a block diagram for explaining the configuration of the comparison / calculation / interpolation circuit shown in FIG. 3, FIG. 3 is a schematic diagram for explaining the write operation to the field memory shown in FIG. 1, and FIG. 4 is a field memory and line memory read at the time of writing frame I shown in FIG. 5A and 5B are schematic diagrams for explaining the interpolation operation by the comparison / calculation / interpolation circuit shown in FIG. 4, and FIG. 6 is a conventional electronically magnified image. FIG. 7 is a block diagram for explaining an enlarged image pickup function of a possible image pickup device, FIG. 7 is a schematic diagram for explaining a video signal writing operation to the field memory shown in FIG. 6, FIGS. 8A and 8B. The figure shows the video signal from the field memory shown in FIG. How out is a schematic diagram for explaining. In the figure, 1 is a memory controller, 2 and 4 are line memories, 3 and 5 are comparison / calculation / interpolation circuits, 21 is an addition / averaging circuit, 22 is a data selector, 23 is a data selector, 24 is a subtraction / comparison circuit, 25 is a data selector. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A magnified image is electronically magnified by dividing a video signal corresponding to a screen into an odd field and an even field, and independently writing and reading the video signal corresponding to the odd field and the even field. An image pickup apparatus capable of shooting, and field storage means for storing, in magnified shooting, video signals corresponding to odd fields and even fields in a frame at that time and an immediately preceding frame in respective divided storage areas. Writing video signals of the odd field and even field of one frame into one of the divided storage areas of the field storage means, and writing the video signals of the odd field and even field of the other frame from the other divided storage area. A read / write control means for reading a video signal, and the field storage means. Delay unit for delaying the video signals of the odd field and the even field of the read frame of 1), the video signal read from the field storage unit and the video signal delayed by the delay unit. Both a comparison determination unit that determines whether or not the subtraction result is greater than a predetermined reference value by performing subtraction comparison for each pixel, and a video signal read from the field storage unit and a signal delayed by the delay unit. A first interpolating means for interpolating a video signal corresponding to the screen based on the signal of, and a second interpolating means for interpolating a video signal corresponding to the screen by a read signal from the delay means, The output of the first interpolating means is selected in response to the comparison determining means determining that the output is smaller than the predetermined reference value, Depending on what was determined to be greater than the order was a reference value and an interpolation method selection means for selecting an output of said second interpolation means, electronically enlarged photographable imaging device.