JPH0898190A - Image pickup device and picture signal processing device - Google Patents

Abstract

PURPOSE: To highly sensitively obtain a picture signal suitable for a high definition television while preventing the generation of a false vertical high band signal by using the image sensor of usual resolution widely used at present. CONSTITUTION: An image pickup device consists of four-plate image sensors of B (blue), R (red), G (green) 1 and G2. The image sensor of R is arranged shifted in a vertical direction by a 1/2 picture element pitch against the image sensor of G2. The image sensor of B is arranged shifted in the vertical direction by a one-picture element pitch against the image sensor of R. Then, a high band component in the vertical direction is calculated from the obtained signals of B and G, and the resolution of the vertical direction is improved by adding this to the signal of G. Sine the high band component is obtained from the signal of the same field, the generation of the false signal can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus and image signal processing suitable for obtaining a high-resolution image signal of a high-definition system using an image sensor of a normal resolution of, for example, the NTSC system or PAL system. Regarding the device.

[0002]

BACKGROUND ART In the current NTSC television,
The screen display has an aspect ratio of 4: 3. However, recently, a landscape screen, such as a movie,
For example, a screen having an aspect ratio of 16: 9 such as high definition has been desired from the viewpoint of power and the like. The standard of this high-definition is as shown in the following Table 1, and the screen definition is 3 to 5 as compared with the conventional NTSC system.
Needed twice.

[0003]

[Table 1]

As shown in Table 1, for example, the number of horizontal scanning lines is 525 in the NTSC system and 625 in the PAL system, while in the high-definition system, it is about twice as many as 1 in the horizontal line.
The number is 125.

By the way, such a high pixel density CCD which is an image sensor for high-definition is very expensive even with today's technology. In other words, because of the high resolution, high signal processing speed is required, power consumption is high, and peripheral devices used are also technically extremely sophisticated, which greatly affects the price. There is. Therefore, it is considered that it will take a considerable amount of time before it is widely put into practical use as an imaging means for high definition.

Therefore, a method for obtaining a high-resolution image signal for high-definition using an image sensor which is widely used at present has been filed as Japanese Patent Application No. 6-141181. According to the system of this application, as shown in FIG. 10, four PAL system image sensors are used. B contained in the incident light incident from the imaging optical system (not shown)
The (blue) light is the dichroic film 10 of the B prism 10.
The light is sequentially reflected by A and the incident surface 10B, and is incident on the image sensor DB of B through the B trimming filter 10C to form an image.

Next, the R light included in the incident light passes through the dichroic film 10A of the B prism 10 and enters the R prism 12, and the dichroic film 12A and the incident surface 1 are incident.
The light is totally reflected by 2B and is incident on the R image sensor DR through the R trimming filter 12C to form an image.

Further, the G light contained in the incident light is transmitted through the dichroic film 12A of the R prism 12, enters the G first prism 16A constituting the G prism 14, and is further divided into two by the half mirror 16. . The G light reflected by the half mirror 16 is incident on the G image sensor DG1 via the G trimming filter 14A to form an image. On the other hand,
The G light transmitted through the half mirror 16 is incident on another image sensor DG2 via the G trimming filter 14B to form an image.

The color separation optical system as described above is similar to a general one for B and R, but is divided into two for G and is made incident on two image sensors respectively. , And has a total of four plates. Since the image formed by the image sensor DG1 is a reflected image from the half mirror 16, the other image sensor D
The left and right are inverted with respect to the image formation of B, DR, and DG2.
Therefore, with respect to the image sensor DG1, the right-and-left reverse reading from the CCD or the right-and-left reverse reading by the line memory or the frame memory is performed to obtain a normal image.

Each image sensor DB, DR, DG1, D
As G2, a CCD element for PAL system having an image size of 1/3 inch which is inexpensive and which is generally provided, and which has been subjected to image stabilization is used.
As shown in FIG. 1, it has 726 × 858 pixels. A prescribed area WW having a high-definition aspect ratio of 16: 9 is set therein, and signals in this area are read out.

Here, the image sensors DG1 and DG2 are displaced by one pixel in the vertical direction as shown in FIG. In the figure, the signal of the pixel of the horizontal line indicated by the solid arrow is read in the odd field, and the signal of the pixel of the horizontal line indicated by the dotted arrow is read in the field. However, with this, the image sensor DG1,
Since only the resolution equivalent to the pixels of DG2 can be obtained, the image sensors DR and DB are arranged so as to be shifted by half a pixel with respect to the image sensor DG2 as shown in FIG.

Then, the image sensors DG1, DG2
The array of each pixel of DB and DR viewed from the high-definition screen is as shown in FIG. In the figure, square marks are G pixels read from the image sensor DG2, circle marks are G pixels read from the image sensor DG1, and triangle marks are read from the image sensors DB and DR. B and R pixels. White marks represent even field signals in each image sensor, and black marks represent odd field signals in each image sensor. Also, the numeral is the scanning line number viewed as a high-definition image.

Image sensors DG1, DG2, DB,
The charge signal reading process from DR is performed by the device shown in FIG. Image sensors DG1, DG2, DB,
The DRs are simultaneously driven by the read control unit 50, and the even field and odd field signals are alternately output. These signals are amplified by the preamplifiers 52 to 57, and then A
It is supplied to the / D converters 58 to 63, converted into digital signals, and supplied to the signal processing circuit 65. Signal processing circuit 6
16 has the structure shown in FIG. 16, and is composed of frame memories using the field memories 84 and 85 and frame composition circuits 86 and 87, vertical high-pass filters 88 and 89, and adder 90.
The processing for obtaining the high-frequency added signals G1 ^* , G2 ^* by .about.

That is, in the vertical high-pass filters 88 and 89 and the adders 90 and 91, calculations such as equations (1) and (2) are performed based on the signals B and b and the signals R and r,
High frequency components VH1 and VH2 are generated. It should be noted that there are m horizontal pixels and n vertical lines, pixels in the odd field are represented by capital letters G, B, R, and pixels in the even field are represented by lower case letters g, b, r.

[0015]

[Equation 1]

[Equation 2]

Next, these vertical high frequency components VH
1, VH2 is added by the adder 92, 1/2 by the multiplier 93, and added by the adder 94 with the signal G1. That is, the calculation of the equation (3) is performed, and the signal G1 ^* to which the vertical high frequency component is added is obtained. On the other hand, the signal G2 ^* to which the vertical high frequency component is added is calculated by the addition of the adder 96 by the calculation of the mathematical expression (4) ^.
Is obtained.

[0017]

[Equation 3]

[Equation 4]

The high frequency additional signal and the image sensor output are alternately selected for each field by the changeover switches 95 and 97, and the signals G3 and G4 are output to the image sensor DB and the image sensor DB, respectively.
It is output together with the DR charge signal. Each signal is stored in the line memories 64 to 69 for one line and then output to the line memories 70 to 77 at high speed. Then, each stored signal is output at a high-definition frequency, that is, at a speed twice as fast as when read from the image sensor.

Next, in the changeover switch 78, the G3 and G4 signals stored in the line memories 70 and 72 are alternately and selectively output to perform scan conversion. Further, the changeover switches 80 and 81 alternately and selectively output the signals stored in the line memories 74 and 76 to perform the signal interpolation processing. The high-definition signals GH, BH, and RH thus obtained are subjected to matrix processing, and final high-definition signals Y, PB, and PR are obtained.

As described above, according to the background art, two image sensors for G are prepared, and the image sensors for B and R are arranged by shifting them by one pixel in the vertical direction. Then, a vertical high-frequency component of the G image is extracted from these B and R image sensor outputs, and this is added to the G image to obtain a high-resolution image signal for high-definition.

[0021]

However, this background art has the following disadvantages. (1) As shown in FIG. 16, the field memory is used when the high frequency component of G is extracted from the B and R signals. Therefore, there is a problem in that it is not preferable in terms of cost.

(2) Since the signal of one field before is used for extracting the high frequency component, a false vertical high frequency signal is generated in the case of an image having a fast motion. For example, FIG.
As shown in FIG. 7, it is assumed that the black vertical line at the position shown in FIG. 7A in the previous field has moved in the current field as shown in FIG. In such a case, the high frequency components VH1 and VH2 are calculated based on the equations (1) and (2).
Then, VH1 = 0.5 and VH2 = −0.5.

Focusing only on the current field in FIG. 7B, the vertical high-frequency component is "0" because it is a vertical line. However, since a high frequency component is obtained from the previous field shown in FIG. 9A, a false vertical high frequency signal is generated. The present invention focuses on these points, and when using an image sensor of normal resolution, it is possible to reduce the generation of unnecessary vertical high frequency components and obtain a high resolution image signal with high sensitivity. It is an object of the present invention to provide a method which is advantageous in terms of cost as well.

[0024]

In order to achieve the above-mentioned object, the present invention provides an R,
Of the image sensors for picking up the G and B images, at least one of the pixel positions of the B image sensor and the R image sensor is perpendicular to the pixel position of the G image sensor by 1/2 pixel. The image sensor for B and the image sensor for R are relatively displaced in the vertical direction by one pixel.

A high-frequency component in the vertical direction is extracted from the image signals obtained from the B and R image sensors having such an arrangement, and is converted into an image signal of one field of the image signal obtained from the G image sensor. Is added. Therefore, high frequency components are extracted from the image of the same field, and the generation of unnecessary vertical high frequency components is reduced without using a field memory, and a high resolution image signal can be obtained. The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although there may be many embodiments of the image pickup apparatus and the image signal processing apparatus of the present invention, an appropriate number of embodiments will be shown and described in detail here.

<Arrangement of Image Sensor According to this Embodiment> First, the arrangement of the image sensor according to this embodiment will be described. The color separation optical system is the same as that of the background art. The setting of the high-definition definition area WW on each image sensor is also the same as the background art. The vertical resolution of the high-definition system is N as described above.
It is about double that of the TSC and PAL systems.
However, the high definition area W on the image sensor
For W, the number of horizontal effective scanning lines is 1/2 of the high definition standard
Is.

Therefore, the simplest method for obtaining the number of horizontal effective scanning lines corresponding to high-definition is to perform pixel scanning interpolation processing in the image area of the prescribed region WW to obtain 1035 horizontal effective scanning lines of high-definition. There is something to be gained. However, in this scanning interpolation method, the image information of the scanning lines adjacent in the vertical direction is the same, and the image resolution in the vertical direction is only 518 pixels, which is 1/2 of high definition.

Therefore, in this embodiment, the resolution is improved by shifting the R and B image sensors in the vertical direction with respect to the G image sensor. As is well known, the Y signal that determines the vertical resolution of an image is Y = 0.212R + 0.701G + 0.087B in the high-definition system, and also depends on the B component and the R component. For this reason,
If the Y signal is generated by effectively using the image sensors DB and DR, the vertical resolution can be improved.

Specifically, as shown in FIG. 1 (A), the image sensor DR is arranged with respect to the image sensor DG2 so as to be shifted by 1/2 pixel pitch in the vertical direction on the optical axis. Further, the image sensor DB is arranged with respect to the image sensor DR so as to be shifted by one pixel pitch in the vertical direction on the optical axis. When viewed from the image sensor DG2, DR, D
B is shifted by ½ pixel pitch in the opposite vertical direction.

FIG. 2 shows an enlarged part of the pixel array (part of FIG. 1A) of the image sensors DG2, DB, DR having such an arrangement. In the figure, n + m indicates the order of the horizontal lines of the image sensors DG2, DB, DR, and the portion from n + 1 to n + 518 is the above-mentioned high definition area WW. Further, the high frequency component in the vertical direction of the G image signal is generated from the B and R image signals obtained in such an arrangement as described later.

Next, the image sensors DG1 and DG2 are the same as in the background art described above. As shown in FIG. 1B, the image sensors DG1 and DG2 are arranged so as to be shifted by one pixel pitch in the vertical direction and are ½ in the horizontal direction. The pixel pitches are shifted and arranged.

Image sensor DG having the above arrangement
1, DG2, DB and DR are driven simultaneously.
That is, when the even field signal is being read from the image sensor DG1, the image sensor DG
2, the even field signal is read from DB and DR. The same applies to the odd field. 2 and 12, when the line indicated by the solid line is read from DG1, the line indicated by the solid line is also read in DG2, DR, and DB. When the line indicated by the dotted line is read from DG1, DG2, DR, DB
However, the line indicated by the dotted line is read out.

<Pixel Arrangement> Next, the arrangement of the pixels of the image sensors DG1, DG2, DB, and DR having such an arrangement as seen from the high-definition screen will be described. In FIG. 3, square marks are G pixels read from the image sensor DG2, and circle marks are G pixels read from the image sensor DG1. These pixel arrangements are similar to those of the background art. On the other hand, the upward triangle mark is the R pixel read from the image sensor DR, and the downward triangle mark is the B pixel read from the image sensor DB. The white marks represent pixels in even fields in each image sensor, and the black marks represent pixels in odd fields in each image sensor. The numbers are scan line numbers when viewed as a high-definition image.

First, let us focus on the square and circled pixels.
Since the image sensors DG1 and DG2 are arranged so as to be shifted by 1/2 pixel pitch in the horizontal direction, the squares and circles are arranged alternately in the horizontal direction. Further, since the image sensors DG1 and DG2 are arranged so as to be shifted by one pixel pitch in the vertical direction, the fields of adjacent pixels in the horizontal direction are different. That is, the image sensors DG1 and D
The pixels of G2 are arranged such that white and black alternate in the horizontal direction.

Further, in the vertical direction, of course, even fields and odd fields are alternately arranged, so that white and black are also alternately arranged. These pixels are located on line 1120 from the even field 603 of the high-definition image. However, when reading from the image sensor, the white marked pixels are odd fields in the sensor, and the black marked pixels are even fields in the sensor. Done in the field.

Next, pay attention to the pixels marked with triangles. Since the image sensor DR is vertically displaced from the image sensor DG2 by 1/2 pixel pitch, DG2
The line formed by the pixels of DR is located between the lines formed by the pixels of. In other words, the line of the upper triangular pixel is
It is located between the lines of the square and circle pixels.
On the other hand, since the image sensor DB is arranged so as to be shifted by one pixel pitch with respect to the image sensor DR, both fields are different. That is, although the pixels of the upper triangle and the pixels of the lower triangle are positioned so as to overlap with each other on the same line, white and black have an inverse relationship.

The pixels of these image sensors DR and DB are located on the lines 41 to 557 which are the odd fields of the high-definition image. However, when reading from the image sensor, the white pixels are the odd fields of the sensor. Black pixels are done in the even field in that sensor. The pixel array of B shown by the lower triangle is
This is a point different from the background art.

<Reading out and converting charge signal> (1) Circuit configuration Next, the image sensors DB, DR, DG as described above
1, the reading of charge signals from the DG 2 and the conversion processing of the charge signals into high-definition image signals will be described. The overall structure of the signal read processing circuit is the same as that of the background art described above.
It has the configuration shown in FIG. More specifically, the image sensors DG1, DG2, DB, and DR described above are provided with a read control unit 50 that simultaneously drives them to control signal reading. In addition, the image sensors DG1 and DG
The charge signal output sides of 2, DB and DR are preamplifiers (PA
52, 54, 56, 57 are connected respectively, and A / D converters 58, 60, 6 are provided on the output side thereof.
A signal processing circuit 65 is connected via 2, 63 respectively.

The signal output side of the signal processing circuit 65 is connected to the line memories 64, 66, 68 and 69, respectively. The output sides of the line memories 64 and 66 among these are connected to the line memories 70 and 72, respectively. The output side of the line memory 68 is connected to the line memories 74 and 76, respectively. The output side of the line memory 69 is connected to the line memories 75 and 77, respectively.

The output sides of the line memories 70 and 72 are respectively connected to the switching input sides of the scanning line selecting changeover switch 78. The output sides of the line memories 74 and 76 are respectively connected to the switching input sides of a changeover switch 80 for data interpolation processing. The output sides of the line memories 75 and 77 are respectively connected to the switching input sides of a changeover switch 81 for data interpolation processing. The operation control of the line memories 64 to 77 and the changeover switches 78 to 81 is performed by the output control unit 82.

Next, the signal processing circuit 65 has a structure as shown in FIG. In the figure, one of the image sensor DB and DR side is the signal processing circuit 6 as it is.
5 outputs R and B, and is connected to the frame synthesis circuit 65B on the other side. Frame synthesis circuit 65
The output side of B is connected to the vertical high-pass filters 65C and 65D, respectively.
The output side of 65D is connected to one addition input side of each of the adders 65E and 65F.

The image sensors DG1 and DG2 are connected to the other addition inputs of the adders 65E and 65F, respectively. Image sensor DG1 side and adder 6
The output side of 5E is connected to the switching input side of the switch 65G. Image sensor DG2 side and adder 6
The output side of 5F is connected to the switching input side of the switch 65H. The output sides of these switching devices 65G and 65H are the GA and GB outputs of the signal processing circuit 65.

(2) Operation of each part Next, the operation of each part will be described in detail. FIG. 5 shows the sequence of signal reading (one horizontal pixel column reading method) from the image sensors DG1, DG2, DB, and DR. The numbers in the figure show the order of the scanning lines on the image sensor, but the numbers DG1 and DG2 show the order of the scanning lines in the HDTV. B and R in the figure
Focusing on (1), the lines read by DR and the lines read by DB are arranged alternately because of the arrangement shifted by one pixel pitch in the vertical direction.

On the other hand, the reading of signals from the image sensors DG1 and DG2 by the read controller 50 is as shown in FIG. Then, the high-definition first field is constituted by the signal read out as indicated by the solid line arrow in the figure, and the high-definition second field is constituted by the signal read out as indicated by the dotted line arrow.

As shown in FIG. 15, the image sensor D
The frequency from scanning and reading from G1, DG2, DB, DR to signal storage in the line memories 64, 66, 68, 69 is 1/2 of the frequency fH in the case of the high-definition system.
(16.875KHz). As described above, the charge signal read scanning frequency of the PAL CCD is 15.625 KHz, but since this value is approximately the same as fH / 2, it can be used without taking any special measures. However, after the signals are read from the line memories 70 to 77, the frequency fH in the case of the high definition system is used. The charge reading scanning method in this example is the same as the normal method except for the reading frequency.

Next, the line memories 64 to 69 are for storing the signals output from the signal processing circuit 65, and when the signal data for one line are stored, the line memories 70 to 77 in the subsequent stages are stored. Each is output in parallel at high speed. And the line memories 70 to 7
The signal stored in 7 is output at a high-definition frequency, that is, at a speed twice as fast as when read from the image sensor.

Next, the change-over switch 78 selectively outputs the signals stored in the line memories 70 and 72 alternately line by line so that the signals are scanned in the high-definition order to perform scan conversion. It is a thing. The changeover switch 80 is for alternately outputting the signals stored in the line memories 74 and 76 line by line to interpolate the signal data. The same applies to the changeover switch 81. The operation of the line memory and the changeover switch is performed by the output control unit 8
2 controls the operation.

The R, G, B outputs thus obtained are converted into high-definition signals Y, PB, PR by a matrix (not shown). The conversion is performed by Y = 0.715G + 0.0721B + 0.2125R PB = 0.5389 (-0.7154G + 0.9279B-0.2125R) PR = 0.6349 (-0.7154G-0.0721B + 0.7875R).

(3) Signal Processing Circuit Next, the signal processing circuit 65 shown in FIG. 4 will be described. Arbitrary position (horizontal m pixel, vertical n
The pixels of (line) are taken and numbered, as shown in FIG. In the figure, capital letters G, B, and R represent pixels read out in odd fields, and small letters g, b, and r represent pixels read out in even fields, respectively. Note that "G" and "g"
Indicates a green signal, "R" and "r" indicate a red signal, and "B" and "b" indicate a blue signal. Also, capital letters “1” and “2” indicate pixels read from the image sensors DG1 and DG2, respectively.

Since the four image sensors are driven simultaneously, the same pixels of (m, n) are read out at the same time. For example, four of G1m, n, G2m, n, Rm, n and Bm, n are read simultaneously in an odd field, and g1m, n, g2m, n
Four of n, rm, n and bm, n are read simultaneously in even fields.

Focusing on the positions of the R, r, B, and b pixels, the combination of "R and b" or "r and B" is present at any pixel position, and in any even or odd field. Also, either of the pixels exists. This is because the image sensor DB is arranged so as to be shifted by one pixel pitch in the vertical direction with respect to the image sensor DR, and in FIG. 3, the black triangle and the white triangle correspond to the same position.

Due to such a relationship, if the signals from the image sensors DB and DR are simply added, the frame composition can be performed without using the field memory.
The frame synthesizing circuit 65B is for performing such processing. When pixels are represented as shown in FIG. 6, in the vertical high-pass filters 65C and 65D, operations such as equations (5) and (6) are performed in odd fields to generate high-frequency components VHA and VHB. It

[0054]

[Equation 5]

[Equation 6]

This calculation is a calculation for subtracting the signal of the pixel adjacent in the vertical direction from the signal of a certain pixel, and this corresponds to the calculation for obtaining the variation in the vertical direction. As a result, a high frequency component in the vertical direction is obtained. in this way,
Since high frequency components are obtained from signals in the same field, the generation of unnecessary vertical high frequency components is reduced. Next, in the adders 65E and 65F, the operations of the formulas (7) and (8) are performed, the high frequency components obtained from B and R are added to the G signal, and the wide band G signal GA, GB is obtained.

[0056]

[Equation 7]

[Equation 8]

This calculation is similar to that of the background art (see formulas (3) and (4)). As described above, according to the signal processing circuit 65 of this embodiment, a signal in a frame state can be obtained without using the field memory as in the background art shown in FIG.

Next, the switches 65G and 65H are switched by a field pulse, and are switched to the adder side in the odd field and to the image sensor side in the even field. As a result, the vertical high frequency additional signals GA and GB are used for the image of the odd field (corresponding to the high definition first field), and the image sensor output signal g1, for the image of the even field (corresponding to the high definition second field). g2 will be used.

(4) Overall Operation Next, the overall operation of the embodiment configured as described above will be described. The image sensors DG1, DG2, DB, DR are
The signals are driven simultaneously by the read control unit 50 to alternately output even field and odd field signals. These signals are A / D after being amplified by the preamplifiers 52 to 57.
The signals are supplied to the converters 58 to 63, converted into digital signals, and supplied to the signal processing circuit 65. In the signal processing circuit 65, the above-described mathematical expressions (5) to (8) are calculated to obtain the high-frequency added signals GA and GB, and this and the image sensor output are alternately selected for each field. , G4
Are output together with the signals B, b, R and r.

These signals are double-speed converted and output. That is, after one line is stored in each of the line memories 64-69, it is output at high speed to each of the line memories 70-77. Then, each stored signal is output at a high-definition frequency, that is, at a speed twice as fast as when read from the image sensor.

Next, in the changeover switch 78, the G3 and G4 signals stored in the line memories 70 and 72 are alternately and selectively output to perform scan conversion. Further, in the changeover switch 80, the signals stored in the line memories 74 and 76 are alternately and selectively output to interpolate the signals. 7A and 7B show these states. The signals A and B of the two line memories shown in FIGS. 7A and 7B are alternately selected one line at a time, and shown in FIG. 7C. Is output at high speed. The same applies to the changeover switch 81.

The matrix processing is performed on the high-definition signals GH, BH, and RH thus obtained, and final high-definition signals Y, PB, and PR are obtained. As described above, since the image formed by the image sensor DG1 is a reflected image by the half mirror 16, the image is horizontally reversed with respect to the image formed by the other image sensors DB, DR, DG2. For this reason, when the image sensor DG1 that can be read in the left-right reverse direction is used, the read control unit 50 performs the left-right reverse reading.
Alternatively, a memory means such as a line memory or a field memory may be provided in the preceding stage of the signal processing circuit 65 to store the signal, and the left-right inverted reading may be performed at the time of reading.

<Spatial Frequency of Image Signal> Here, the spatial frequency of the image signal in this embodiment will be described with reference to FIG. The horizontal axis of the graph in the figure is the horizontal frequency, and the vertical axis is the vertical frequency. First, FIG. 3A shows the spatial frequency of the G signal, where the region EG1 is B,
It is a high-frequency band addition part by signals of b, R, and r. Further, as shown in the area EG2, the horizontal frequency extends to the high frequency because the image sensors DG1 and DG2 are arranged in the horizontal direction with a shift of half a pixel pitch. Same figure (B)
Indicates the spatial frequency of the B and b signals or the R and r signals. FIG. 7C shows the spatial frequency of the luminance signal Y that contributes to the resolution of the high-definition image, and is the sum of FIG. 8A and FIG.

<Effects of Embodiment> As described above, according to this embodiment, two image sensors for G are prepared, and the image for R is shifted by 1/2 pixel in the vertical direction. The sensor is arranged. Further, the image sensor for B is arranged by shifting one pixel in the vertical direction with respect to the image sensor for R. Then, the high frequency component in the vertical direction of the G image is extracted from the outputs of the B and R image sensors to obtain an image signal for high definition. This has the following effects.

(1) Since the image sensor for PAL of 1/3 inch is used as the image sensor, it is possible to provide a very low-priced and realistic high-definition video camera. (2) Since B and R both have a single plate structure, they are very effective in reducing size, weight and cost, although they are inferior in terms of resolution. It should be noted that improvement can be achieved by correcting and interpolating the signal using a high resolution G image signal containing more information than B and R.

(3) Since the high frequency components of the B and R images in the vertical direction are extracted and added to the G image, a high resolution image signal for high definition can be obtained. (4) Moreover, since the masking process for the image sensor is not required, the aperture ratio can be increased, and as a result, a clear image signal with good S / N can be obtained even in low illuminance.

(5) High-definition signals generally require high-speed processing, but since an image sensor for PAL is used in this embodiment, no special high-speed processing technique is required, General devices currently used as devices can be used. In particular, a DSP currently popular for signal processing such as multiplex and scan conversion can be used, and it is very advantageous in that cost can be reduced by using general-purpose components.

(6) Since the B and R image sensors are arranged so as to be offset by one pixel, vertical high frequency components can be obtained without using a field memory, which is advantageous in terms of cost. In addition, since it is possible to perform frame synthesis from signals in the same field, it is possible to reduce the generation of unnecessary vertical high frequency components and obtain a high-resolution image signal with high sensitivity.

<Other Embodiments> The present invention can be variously modified based on the above disclosure, and includes, for example, the following. (1) In the image pickup optical system shown in FIG. 10, for example, a half mirror 16 may be provided as shown by a dotted line, and the image sensor DG1 may be arranged on the image sensor DR side.

(2) In the above embodiment, only G has two plates,
Although B and R have a four-plate configuration with one plate, even if all R, G, and B are one plate, by arranging at least one of B and R in the vertical direction, high frequency components in the vertical direction can be obtained. If it is obtained, the same effect can be obtained. Further, all R, G, and B may be two plates, and a total of six plates may be configured. Further, although the image sensors DG1 and DG2 are arranged so as to be shifted by a 1/2 pixel pitch in the horizontal direction, this is done in order to enhance the resolution in the horizontal direction, and it is not always necessary to make such a horizontal arrangement. That is, the image sensors DG1 and DG2 may be at the same position.

(3) In the above embodiment, the image sensor is arranged so as to be shifted by one pixel in the vertical direction, but this arrangement itself is arranged at the same position in the vertical direction with respect to the incident optical axis, and the signal reading is performed by one. The same effect can be obtained by shifting the lines. The present invention also includes the case where the signal read area is shifted between the two image sensors in this way. In this case, one of the two image sensors is driven by being shifted by one line in the vertical direction with respect to the other. However, in general, it is more convenient for the R, G, and B image sensors to be driven simultaneously. Therefore, the image sensors are arranged so as to be displaced with respect to the incident optical axis as in the above embodiment. The same applies to the horizontal direction.

(4) In the above embodiment, the case where an image with a high-definition aspect ratio of 16: 9 is obtained has been described.
The ratio is not necessarily limited thereto, and the ratio may be set appropriately.

(5) Further, in the above-mentioned embodiment, the required high-definition image area WW is set at the substantially center of the image sensor, but it may be set at a position shifted vertically and horizontally.

(6) As described above, the image sensor D
Since the image formation of G1 is reversed left and right with respect to the other image sensors DB, DR, DG2, a normal image formation is obtained by the following method. A CCD is used that has the capability of reading out the signal with left-right inversion. A signal is read from the image sensor DG1 while being left-right inverted, and the signal is stored in a memory means such as a line memory or a frame memory. When read out, the signal is left-right inverted to obtain a normal vertical image signal.

However, as shown in FIG. 9, the right and left may be optically reversed to obtain a normal image. First, in the example of FIG. 3A, the G first prism 100 is provided via the R prism 12 and a minute air layer (not shown). A half mirror 104 is provided between the G first prism 100 and the G second prism 102.

The G light included in the incident light is the R prism 1
The light passes through 2 and enters the G first prism 100. G first
The G light incident on the prism 100 is further reflected by the half mirror 1.
The G light that is incident on 04 and is reflected and split by the half mirror 104 is in contact with the R prism 12 via the air layer.
The light is totally reflected by the incident surface 106 of the first prism 100, and the image sensor DG1 passes through the G trimming filter 14A.
The incident image is formed on the image plane of. And the half mirror 104
The G light that has passed through is incident on the image forming surface of the other image sensor DG2 via the G trimming filter 14B and forms an image.

Next, in the example shown in FIG.
2 and the dummy prism 110 are in contact with each other, and the G first prism 112 is provided via the dummy prism 110 and a minute air layer (not shown). Also, this G first
A half mirror 116 is provided between the prism 112 and the G second prism 114.

The G light included in the incident light is the R prism 1
2, G first prism 1 through the dummy prism 110
It is incident on 12. The G light incident on the G first prism 112 is further incident on the half mirror 116, and the G light reflected and split by the half mirror 116 is the dummy prism 1.
10 is totally reflected by the incident surface 118 of the G first prism 112 which is in contact with the G first trimming filter 14A through the air layer.
The incident image is formed on the image forming surface of the image sensor DG1 via. Then, the G light transmitted through the half mirror 116 is
The incident image is formed on the image forming surface of the other image sensor DG2 through the G trimming filter 14B.

In any of the above, since the light incident on the image sensor DG1 is reflected twice like B and R, the same erect image can be obtained. Therefore, there is no need for left-right inversion, and four image sensors D
B, DR, DG1, and DG2 having the same performance can be used.

(7) In the above embodiment, the image sensor compatible with the PAL system was used, but any other system may be used as long as it is equivalent to it. (8) Similar effects can be obtained by reversing the vertical arrangement of the image sensors DB and DR in the above embodiment. Further, although the high band component is obtained from the odd field signal of the outputs of the image sensors DB and DR, the high band component may be obtained from the even field signal.

[0081]

As described above, according to the present invention,
It has the following effects. (1) Since it is possible to obtain a high-resolution image signal such as a high-definition image by using an image sensor having a relatively low vertical resolution such as a PAL system, it is possible to obtain a very inexpensive and realistic high-resolution video camera. it can. (2) Also, general general-purpose parts can be used including peripheral devices, and technical difficulty is low.

(3) Since the high frequency components of the B and R images in the vertical direction are extracted and added to the G image, a high resolution image signal can be obtained. (4) Moreover, since no masking or the like is required for the image sensor, the aperture ratio can be increased, and as a result, a clear S / N image signal can be obtained even at low illuminance.

(5) Since the R image sensor and the B image sensor are arranged so as to be shifted by one pixel in the vertical direction, the generation of unnecessary vertical high frequency components is reduced and a high resolution image signal is obtained. Can be obtained with high sensitivity, which is advantageous in terms of cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an arrangement of image sensors according to an embodiment.

FIG. 2 is an enlarged view showing the arrangement of the image sensor of the embodiment.

FIG. 3 is a diagram showing the pixel position of the image sensor of the embodiment on a high-definition screen.

FIG. 4 is a block diagram showing a main part of a signal processing device according to an embodiment.

FIG. 5 is a diagram showing a relationship between scanning lines of the image sensor of the embodiment.

FIG. 6 is a diagram showing a pixel arrangement of an example with reference numerals.

FIG. 7 is a time chart showing a state of double speed conversion.

FIG. 8 is a diagram showing a frequency band of an image signal in the example.

FIG. 9 is a diagram showing another embodiment of the color separation optical system.

FIG. 10 is a diagram showing a color separation optical system of Examples and the background art.

FIG. 11 is a diagram showing a high-definition area set on an image sensor.

FIG. 12 is a diagram showing an arrangement of image sensors in the background art.

FIG. 13 is a diagram showing an arrangement of image sensors in the background art.

FIG. 14 is a diagram showing a pixel array in the background art.

FIG. 15 is a block diagram showing a signal processing device according to an example and background art.

FIG. 16 is a block diagram showing a part of a signal processing device in the background art.

FIG. 17 is a diagram showing an example in which an image moves between fields.

[Explanation of symbols]

10 ... B prism 12 ... R prism 14,100,102,112,114 ... G prism 16,104,116 ... Half mirror 50 ... Read control part 52,54,56,57 ... Preamplifier 58,60,62,63 ... A / D converter 64, 66, 68, 69, 70, 72, 74, 75, 7
6, 77 ... Line memory 65 ... Signal processing circuit 65B ... Frame synthesizing circuit 65C, 65D ... Vertical high-pass filter 65E, 65F ... Adder 65G, 65H ... Changer 78, 80, 81 ... Changeover switch 82 ... Output control unit DB , DR, DG1, DG2 ... Image sensor WW ... High definition image area

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroyuki Kitamura 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Nihon Victor Company of Japan (72) Inventor Tetsuya Suwa 3-12 Moriya-cho, Kanagawa-ku, Yokohama Address inside Victor Company of Japan, Ltd.

Claims (3)

[Claims] 1. A color separation optical system for color-separating imaging light to obtain blue, green, and red images; a blue image sensor for capturing a blue image corresponding to a normal resolution television system. An image sensor for green, which corresponds to a television system of normal resolution and captures a green image; and an image sensor for red, which corresponds to a television system of ordinary resolution and captures a red image; The pixel position of at least one of the image sensor for blue and the image sensor for red is displaced by a distance of 1/2 pixel in the vertical direction relative to the pixel position of the image sensor for green, and the image sensor for blue and An image pickup device in which the red image sensor is displaced by one pixel. 2. A color separation optical system for color-separating imaging light to obtain each of blue, green, and red images; a splitting optical system for splitting a green image into first and second green images; normal resolution Image sensor for blue to pick up a blue image, corresponding to the television system of No. 1; an image sensor for red to pick up a red image, corresponding to a television system of normal resolution; a television system at normal resolution Corresponding to the first green image sensor for picking up a first green image; a second green image for picking up a second green image corresponding to a normal resolution television system A sensor; and at least one pixel position of the image sensor for blue and the image sensor for red is shifted by a half pixel in the vertical direction relative to the pixel position of the second image sensor for green. And for blue The image sensor and the image sensor for red are relatively displaced by one pixel, and the pixel position of the first image sensor for green is at least one direction in the horizontal and vertical directions with respect to the pixel position of the second image sensor for green. An image pickup device that is arranged relatively offset to. 3. A high-frequency component extracting means for extracting a high-frequency component in the vertical direction from an image signal obtained from the blue and red image sensors of the image pickup device according to claim 1; An image signal processing device comprising: a high frequency component adding means for adding a high frequency component to an image signal of one field of an image signal obtained from a green image sensor.