JPH0452671B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an imaging method in which a single image sensor is used to simultaneously scan each horizontal line for a plurality of adjacent lines, read out signals, and generate luminance signals and color signals based on the signals. In particular, the present invention relates to a device capable of obtaining a color television signal for reproduction of pseudo-interlaced still images.

In recent years, solid-state image sensors that apply LSI technology have come to be used as image sensors in imaging devices.
2. Description of the Related Art As imaging devices become more compact, lighter, and consume less power, they are attracting a lot of attention. Various methods are known for this type of imaging device, but
When capturing video, two-line technology has the advantages of less screen flow, high resolution of color information, and no need for expensive electronic components such as a delay line for delaying one horizontal scanning period as a means of color reproduction. Imaging devices using a simultaneous readout method are particularly useful.

FIG. 1 is a block diagram showing an example of such a conventional imaging device, in which 1 is a solid-state imaging device (hereinafter referred to as a sensor), 2W, 2G, _2CY , _2Ye are output terminals of the solid-state imaging device, and 3 is a solid-state imaging device (hereinafter referred to as a sensor). 4 is a luminance signal reproduction matrix circuit, 4 is a chrominance signal reproduction matrix circuit, 5 is a luminance signal output terminal, 6 ₁ and 6 ₂ are chrominance signal output terminals,
7 is a drive scanning circuit.

Next, the operation of this prior art will be explained.

In the figure, a color filter is provided in the light receiving section of the sensor 1 for each picture element (not shown).
The color filters used include a white filter (hereinafter referred to as W filter), a green filter (hereinafter referred to as G filter), a cyan filter (hereinafter referred to as G _Y filter), and a yellow filter (hereinafter referred to as Y _e filter). There is. In odd-numbered horizontal lines l ₁ , l ₂ , l _{5 .} . . , W filters and G filters are arranged alternately, and in even-numbered horizontal lines l ₂ , l ₄ , _. filter and
Y _e filters are arranged alternately.

In the case of an NTSC type imaging device, the number of picture elements per horizontal line is approximately 400, and this number determines the horizontal resolution of the image. The number of vertical lines is 525, and this number determines the resolution in the vertical direction. In an actual sensor, the upper and lower edges of the light receiving area are not displayed on the television receiver, so the number of horizontal lines displayed is approximately 490, but in the following explanation, the number of horizontal lines is important. Number of horizontal lines for NTSC format
This will be explained as 525 pieces.

The sensor 1 sequentially scans each horizontal line in response to a signal from a drive scanning circuit 7. This scanning is performed simultaneously on two adjacent horizontal lines. That is, in the first horizontal scan, horizontal lines l ₁ and l ₂ are scanned simultaneously, and the second
In the second horizontal scan, horizontal lines l ₃ and l ₄ are scanned simultaneously. Thereafter, two horizontal lines are scanned in the same manner. The time required to scan the entire light receiving section once is 1/60 second (hereinafter, this time is referred to as one field time).

Therefore, first, when the horizontal lines l ₁ and l ₂ are simultaneously scanned in the first scan, the horizontal line l ₁
From then on, a signal from the picture element corresponding to the W filter (hereinafter referred to as the "w signal") and a signal from the picture element corresponding to the G filter (hereinafter referred to as the "g signal") are alternately transmitted.
That is, signals are obtained in the order of w, g, w, g, . . . , of which the w signal is output to the output terminal 2W, and the g signal is output to the output terminal 2G. On the other hand, from the horizontal line _l2 , a signal from a pixel corresponding to the C _Y filter (hereinafter referred to as the C _y signal) and a signal from the pixel corresponding to the Y _e filter (hereinafter referred to as the Y _e signal) are alternately transmitted. , that is, signals are obtained in the order of c _y , _{y e} , c _{y , y e , .}

Next, by the second scan, horizontal lines l ₃ ,
When l ₄ is scanned simultaneously, the w signal obtained by scanning horizontal line l ₃ is output to output terminal 2 in the same way.
W, the g signal is output to the output terminal 2G, and
The _cy signal obtained by scanning the horizontal line _l4 is output to the output terminal _CY , and the _ye signal is output to the output terminal _2Ye .
Thereafter, in the same manner, two adjacent horizontal lines are simultaneously scanned, and for each scan, the output terminals 2W, 2
G, 2Cr, 2Y _e respectively have w signal, g signal, c _y signal,
y _e signal is output.

In this way, the horizontal line of the entire light receiving section of the sensor 1 is scanned within one feed time, and the respective signals obtained at the output terminals 2W, 2G, 2C _Y , and 2Y _e by this scanning are reproduced as luminance signals. The luminance signal Y is supplied to the matrix circuit 3 and the color signal reproduction matrix circuit 4, and the luminance signal Y is supplied to the output terminal 5, and the luminance signal Y is supplied to the output terminal 6 ₁ ,
A color signal is generated at 6 ₂ .

By the way, when the color filters are arranged as described above, the luminance signal reproduction matrix circuit 3 is an adder circuit. In other words, the red signal, which is the new primary color, is the r signal, and the green signal is the g signal (output terminal 2G
₍ same as the g signal _obtained in The transmittance of each color filter is usually approximately equal for R and G.
Since the transmittance of B is about 1/3 of that of R and G, it is desirable that Y=r+2g+b. However, as mentioned above, since the b signal is about a fraction of the amount of the r and g signals, w+c _y =r+2g+2b g+y _e =r+2g are both practically acceptable as the luminance signal Y. Therefore, the luminance signal reproduction matrix circuit 3 alternately outputs w+c _y and g+y _e for each picture element.
The signal obtained by the addition is output as a luminance signal Y to the output terminal 5.

On the other hand, in the color signal reproduction matrix circuit 4, the respective signals obtained at the output terminals 2W, 2G, 2C _Y , 2Y _e are subjected to processing such as sample and hold as necessary, and the signals are alternately outputted for each element by w- The following calculations are performed: c _y =(r+g+b)-(g+b)=r and y _e -g=(g+r)-g=r, and these are added to obtain the r signal at the output terminal ₆₁ . Also, alternately for each picture element, perform the calculations w-y _e = (r + g + b) - (g + r) = b and c _y -g = (g + b) - g = r, and add these to obtain the b signal. so that it is obtained at the output terminal 6d.

In the above manner, the luminance signal Y is sent to the output terminal 5.
However, the r signal is sent to the output terminal 6 ₁ , and the r signal is also sent to the output terminal 6 ₂
b signal is obtained.

By the way, in such an imaging device, the resolution of the luminance signal Y in the horizontal direction is equal to the number of pixels in the horizontal line, but in the vertical direction, if the horizontal line is scanned in the same way for each field, By adding the signals obtained from two adjacent horizontal lines, the number of horizontal lines is reduced to 1/2. Therefore, in order to increase the resolution in the vertical direction, if scanning is performed as described above during a certain feed time (hereinafter referred to as an odd field), in the next field time (hereinafter referred to as an even field), the horizontal lines scanned simultaneously are Try to shift only the horizontal line. That is, for odd fields, scanning is performed as described above, but for even fields, horizontal lines l ₂ and l ₃ are simultaneously scanned in the first scan, and output terminals 2W, 2G, 2C _Y , 2Y _e
to obtain w, g, c _y , y _e signals respectively,
In the second scan, horizontal lines l _{4 and} l ₅ are scanned simultaneously,
Similarly, signals are obtained so that two horizontal lines are simultaneously scanned one after another.

As described above, by shifting the two horizontal lines scanned simultaneously for odd and even fields, a pseudo-interlaced color television signal can be obtained. An operation is performed.
In a strict sense, this pseudo-interlacing does not prevent the deterioration of the vertical resolution or improve the resolution as described above, but the interpolation operation described above
The outline of the image on the drawing of the television receiver, especially the outline in the diagonal direction, is displayed smoothly, resulting in the effect of improving the visual resolution.

The above is the operation of the imaging device in moving image capturing in the two-line simultaneous readout direction. It is also possible to reduce the number of output lines of the sensor 1 by obtaining different signals by time division multiplexing, and the configurations of the drive scanning circuit 7, the luminance signal reproduction matrix circuit 3, and the color signal reproduction matrix circuit 4 can be reduced by obtaining the various signals by time division multiplexing. However, the basic configuration of the imaging device remains the same.

By the way, when obtaining a still image by capturing the instantaneous state of a moving subject (hereinafter, such capturing is referred to as a still image), a shutter is combined with the imaging device, and the shutter instantly exposes the light-receiving surface of the sensor. However, the exposed light-receiving surface is scanned to generate a signal, which is recorded on a recording medium and reproduced repeatedly to obtain a still image without blur.

However, when the above-described still image is captured using the above-mentioned two-line simultaneous readout imaging apparatus, the following problems arise.

That is, during the first field time after exposure of the shutter, the above-mentioned desired signal is obtained by scanning, but in the next field time, the necessary signal cannot be obtained because the shutter remains closed and no exposure is performed. Therefore, even if the above-mentioned signals are recorded on the recording medium for two field periods, the second field time signal is not recorded. Therefore, during playback, the recording medium will record the above-mentioned first field time signal and the above-mentioned signal. The signal of the second field time will be repeatedly scanned for reproduction alternately with the unrecorded portion, and therefore not only will it not be possible to obtain the visual resolution improvement effect of pseudo-interlacing, but the television receiver will Well then,
At every vertical synchronization signal period, that is, every 1/60 second, a captured image and a dark screen on which nothing is displayed appear alternately and repeatedly, which causes a screen flicker phenomenon and significantly deteriorates the image quality of the reproduced screen.

Therefore, in order to eliminate this surface flicker phenomenon, the signal obtained within the first field time is repeatedly reproduced from the recording medium in synchronization with the vertical synchronization signal and displayed on the television receiver. So-called field image reproduction is performed in which the second field time is interpolated by the signal obtained in the first field time. However, in such field image reproduction, since the odd and even fields are formed by the same image, it is not possible to expect an improvement in resolution due to pseudo-interlacing as in the case of video imaging, and The vertical resolution in image reproduction decreases, leading to deterioration of image quality. This means that even if the same process is used during recording, that is, directly interpolating and generating the next field image from the field image once generated, only the signal deterioration in the recording/playback system will be removed. Deterioration of image quality cannot be prevented.

SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging device that eliminates the drawbacks of the prior art described above and is capable of obtaining still images with improved vertical resolution.

In order to achieve this objective, the present invention provides a light receiving section of a sensor that is momentarily exposed to light by a shutter.
A desired signal is obtained by scanning the field over a period of time, and based on the signal, odd and even field signals forming pseudo-interlacing are formed and recorded on a recording medium, and the odd and even field signals are alternately transmitted from the recording medium. The feature is that it can be played repeatedly.

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

FIG. 2 is a block diagram showing an embodiment of the imaging device according to the present invention, in which 1 is a sensor, 2 and 2' are output terminals of the sensor, 3 and 3' are luminance signal reproduction matrix circuits, and 4 and 4' are sensor output terminals. is a color signal reproduction matrix circuit, 5 is an output terminal of a luminance signal reproduction matrix circuit, 6 is an output terminal of a color signal reproduction matrix circuit, 7 is a drive scanning circuit, 8 and 8' are signal processing circuits, and 9 and 9' are 0.5 H delay circuit (however, H is 1 horizontal period), 10 is 1H delay circuit, 11, 11', 12,
12' is a recording/reproducing means, and 13 is a switching button.

Next, the operation of this embodiment will be explained.

In the figure, color filters (not shown) are arranged in a predetermined order in the reception section of the sensor 1 for each horizontal line l ₁ , l ₂ , l ₃ , l ₄ , . . . . The switching button 13 instructs moving image and still image capturing by operating the switch button 13, controls the drive scanning circuit 7, and defines the scanning of the sensor 1.

Therefore, first, when video imaging is instructed by the switching button 13, a signal from the drive scanning circuit 7 causes the
As explained with reference to FIG. 1, the sensor 1 performs pseudo-interlace scanning in odd and even fields separated by one horizontal line, and outputs predetermined signals to output terminals 2 and 2'. The signals obtained by scanning the odd-numbered horizontal lines l ₁ , l ₃ , . . . are output to the output terminal 2, and the signals obtained by scanning the even-numbered horizontal lines l ₂ ,
The signal obtained by scanning l ₄ , ... is output.
Note that the color filter arrangement can be set as appropriate as described above, and since it targets signals read from odd-numbered horizontal lines and even-numbered horizontal lines that are scanned simultaneously, the sensor 1 has only two output terminals 2,
2' is shown.

The respective signals obtained at the output terminals 2 and 2' are supplied to the signal processing circuit 8, and in the signal processing circuit 8, the luminance signal reproduction matrix circuit 3 and the color signal reproduction matrix circuit 4 output the signals to the output terminals 5 and 6. Output terminal 5, from which a luminance signal and a color signal can be obtained, respectively;
The luminance signal and chrominance signal from 6 are supplied to an external circuit (not shown) to form a pseudo-interlaced moving image color television signal.

Next, when still image capturing is instructed by the switching button 13, a shutter (not shown) instantaneously exposes the light receiving part of the sensor 1, and a signal from the drive scanning circuit 7 causes the sensor 1 to be used as an odd field in moving image capturing. Perform scanning using the same procedure. That is, in the first horizontal scan, horizontal lines l ₁ and l ₂ are scanned simultaneously,
The signal read from the horizontal line l1 is output to the output terminal ₂ , and the signal read from the horizontal line l2 is output to the output terminal ₂ '. In the next horizontal scan, horizontal lines l ₃ and l ₄ are scanned simultaneously, and the output terminal 2
The signal read from the horizontal line _l3 is output to the output terminal 2', and the signal read from the horizontal line _l4 is output to the output terminal 2'. Thereafter, two horizontal lines are scanned in the same way, and the signal read from the odd-numbered horizontal line is obtained at output terminal 2, and the signal read from the even-numbered horizontal line is obtained from output terminal 2'. . This scanning is performed for one feed time, and all horizontal lines of the entire light receiving section are scanned. This scanning may be performed over the entire light-receiving section only once for one feed time, but it is not limited to one feed time and may be repeated multiple times. However, even if this is repeated a plurality of times, a signal can only be obtained from the sensor 1 during the first scan of one feed time.

Respective signal processing circuits 8 from output terminals 2 and 2'
In the signal processing circuit 8, a luminance signal Y for one field time is formed in the luminance signal reproduction matrix circuit 3, a color signal for one feed time is formed in the color signal reproduction matrix circuit 4, and a 0.5H delay circuit 9, 9', each is delayed by 0.5H and the recording/reproducing means 1
1 and 12, respectively.

On the other hand, the signal obtained at the output terminal 2 and the signal obtained at the output terminal 2' and delayed by 1H in the 1H delay circuit 10 are supplied to the signal processing circuit 8'. In the signal processing circuit 8', similarly to the signal processing circuit 8, a luminance signal Y for one field time is formed in the luminance signal matrix circuit 3', and a color signal for one field time is formed in the color signal reproduction matrix circuit 4'. ,
The information is recorded by recording and reproducing means 11' and 12', respectively.

Here, the recording/reproducing means 11, 12, 11', 1
The luminance signal and color signal recorded by 2' will be explained in more detail.

First, regarding the luminance signal and color signal recorded in the recording/reproducing means 11 and 12, these signals are formed by signals obtained simultaneously at the output terminals 2 and 2'. That means sensor 1
is formed by signals read from two simultaneously scanned horizontal lines. On the other hand, the luminance signal and color signal recorded in the recording/reproducing means 11' and 12' are obtained at the output terminal 2' and are 1H
Signal delayed by 1H in delay circuit 10 and output terminal 2
Since they are formed by the signals obtained during the period of adjacent scanning,
It is formed by signals obtained from two horizontal lines separated by 1H.

In other words, the luminance signal and color signal recorded and reproduced by the recording and reproducing means 11 and 12 are the combined information content of the horizontal lines l ₁ and l ₂ of the sensor 1, and the combined information content of the horizontal lines l ₃ and l ₄ of the sensor 1. In contrast, the luminance signal and color signal recorded by the recording/reproducing means 11' and 12' are horizontal lines l ₂ and l _{3 .}
Because it has the synthesized information content of...
After all, the luminance signals and color signals recorded by the recording and reproducing means 11 and 12 are, for example, odd fields, and the luminance signals recorded by the recording and reproducing means 11' and 12' are, for example, even field signals. , pseudo-interlaced odd and even field signals are obtained. In this case, these odd and even field signals are also limited simultaneously within the field time.

Therefore, the luminance signal and color signal recorded by the recording and reproducing means 11 and 12, and the recording and reproducing means 11',
The luminance signal and color signal recorded at 12' are
A pseudo-interlaced still image is displayed by alternately reproducing the field time and supplying it to a television receiver (not shown). The 0.5H delay circuits 9 and 9' of the signal processing circuit 8 eliminate the discontinuity of the horizontal synchronizing signal in odd and even fields, and smooth the jumping of horizontal lines in the drawings of television receivers in odd and even fields. This is to prevent the occurrence of skew at the top of the drawing, and if the skew is tolerable,
In particular, the 0.5H delay circuits 9 and 9' are not required.

Further, recording/reproducing means 11, 12, 11', 1
For example, a magnetic disk or a magnetic tape is used as a recording medium for recording the luminance signal and color signal by 2', and each signal is recorded on a separate recording track. However, it is not necessarily necessary to record each signal on a separate recording track;
The luminance signal from the signal processing circuit 8 and the luminance signal and the chrominance signal from the signal processing circuit 8' may be multiplexed and recorded, for example, by means of multiple frequencies.

As described above, a pseudo-interlaced still image is obtained, and the vertical resolution of the still image is greatly improved. As is clear from the above explanation, this still image is obtained even when shooting a video, so it goes without saying that it can be recorded on magnetic tape, etc., and by playing it back, it can be used as an interface. Still images of frames with significantly improved vertical resolution can be obtained continuously while maintaining the race.

In the above embodiment, the type and arrangement order of the color filters provided in the sensor 1 were not specified.Next, a specific example of the arrangement order of the color filters shown in FIG. 1 will be explained. .

FIG. 3 is a block diagram showing one such example, in which 10' is a 1H delay circuit, and FIGS.
Parts corresponding to the figures are given the same reference numerals.

Next, the operation of this specific example will be explained.

In FIG. 3, when video imaging is instructed by the switching button 13, the scanning in the sensor 1, the signals obtained at the output terminals 2W, 2G, 2C _Y , 2Y _e ,
The signal processing in the luminance signal reproduction matrix circuit 3 and color signal reproduction matrix circuit 4 applied to the signal processing circuit 8 is the same as that shown in _FIG . ₂ , color signals r and b are obtained, and these luminance signal Y and color signals r and b form a pseudo-interlace.

Next, when a still image is specified using the switching button 13, the light receiving part of the sensor 1 is momentarily exposed to light by a shutter (not shown), and then horizontal lines l ₁ and l ₂ ,
It is the same as the case shown in FIG. 2 that l ₃ and l ₄ , . . . are sequentially scanned. As a result, the w signal from the odd-numbered horizontal lines scanned simultaneously is output to the output terminal 2W, the g signal to the output terminal 2G, and the C _y signal from the even-numbered horizontal line is output to the output terminal 2C _y. Then, the y _e signals are output to the output terminal 2Y _e , respectively.

The signal processing circuit 8 has output terminals 2W, 2G, 2
w, g, c _{y ,} y _e signals from C _Y , 2Y e are supplied,
As explained in FIG. 1, the luminance signal reproduction matrix circuit 3 forms a luminance signal by alternately adding the w signal, the g signal, the c _y signal and the y _e signal for each pixel, and generates a chrominance signal reproduction matrix. As also explained in FIG. 1, the circuit 4 generates the r signal by alternately subtracting the w signal, the c _y signal, the y _e signal, and the g signal for each pixel, and also subtracts the r signal, the w signal, the y _e signal, and the A b signal is formed by alternately subtracting _{the y} signal and the g signal for each pixel. Then, the luminance signal Y is delayed by the 0.5H delay circuit 9 and recorded by the recording/reproducing means 11, and the r and b signals are
Delayed by 0.5H delay circuit 9', recording/reproducing means 12
recorded by.

The signal processing circuit 8' receives w and g signals from output terminals 2w and 2G, and c _{y and y} e obtained at output terminals 2C _Y and 2Y _e and delayed by 1H delay circuits 10 and 10', respectively.
The luminance signals Y, r, b signals are formed and recorded by recording and reproducing means 11' and 12', respectively.

In this case, the luminance signal Y and r, b signals formed by the signal processing circuit 8 are based on signals read out from two horizontal lines simultaneously scanned by the sensor 1; The luminance signal Y and the r, b signals formed by By reproducing these odd and even field signals alternately every field time, a still image with pseudo-interlacing and improved resolution in the vertical scanning direction is created. can get.

In addition, if skew is not a problem, 0.5H
The delay circuits 9 and 9' are unnecessary, and the luminance signals by the recording and reproducing means 11, 12, 11' and 12' are
The recording method of the r and b signals, the recording medium, etc. are the same as those described in FIG. 2.

Furthermore, since the resolution of the color signal is usually a fraction of that of the luminance signal, the luminance signal Y by the luminance signal reproduction matrix circuit 3' of the signal processing circuit 8' is
The r, b signals to be combined with the r, b signals from the color signal reproduction matrix circuit 4 of the signal processing circuit 8 are
The color signal reproduction matrix circuit 4' may be omitted by using the color signal, and there is no problem in practical use since there is almost no deterioration in the image quality of still images. This is the second
The same applies to the embodiment shown in the figure.

Further, in the above embodiments and specific examples, the NTSC system has been described, but the present invention is not limited to this, and can be applied to other systems, such as the PAL system or the SECAM system.

Furthermore, all horizontal lines of the sensor are simultaneously scanned two horizontal lines at a time, and signals obtained from odd-numbered and even-numbered horizontal lines scanned simultaneously;
By using the signals obtained from even and odd horizontal lines whose scanning time is 1H apart from each other,
It is clear that the type, arrangement, etc. of the color filters in the sensor are not limited to those shown in FIG. 3, as long as pseudo-interlaced odd and even field signals can be obtained.

As explained above, according to the present invention, it is possible to obtain a color television signal for a pseudo-interlaced still image, so that the vertical resolution of the still image is greatly improved and the image quality is improved. , it is possible to provide an imaging device with excellent functions except for the drawbacks of the above-mentioned prior art.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional imaging device, FIG. 2 is a block diagram showing an embodiment of the imaging device according to the present invention, and FIG. 3 is a block diagram showing a specific example of the imaging device shown in FIG. . 1... Sensor, 3, 3'... Luminance signal reproduction matrix circuit, 4, 4'... Color signal reproduction matrix circuit, 8, 8'... Signal processing circuit, 10, 1
0'...1H delay circuit, 11, 11', 12, 1
2'...Recording and reproducing means.

Claims (1)

[Scope of Claims] It has a light-receiving surface composed of picture elements arranged in one row, and two vertically adjacent rows are simultaneously and individually read out by one horizontal scan of the light-receiving surface, and configured such that all the rows of the light receiving surface are scanned by a number of horizontal scans that is half the number of all the rows of the light receiving surface,
Furthermore, a first terminal outputs a first image signal read out from one side of the two upper and lower rows, and a second terminal outputs a first image signal read out from the other side of the two upper and lower rows.
a second terminal that outputs an image signal; a first image signal obtained at the first terminal of the image sensor; and a second image signal obtained at the second terminal of the image sensor; a first signal processing circuit that performs signal processing to generate a first video signal component for forming one field; and a second imaging signal obtained from the second terminal that is delayed by one horizontal scanning period. a second field for forming the other field by signal processing a first imaging signal obtained at the first terminal of the image sensor and a second imaging signal delayed by the delaying means; a second signal processing circuit that generates video signal components; storage means that stores the first and second video signal components; An imaging device comprising: a reading unit configured to read out and form one frame of a captured image.