JPS62104390A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain a device which has high resolution and good color reproducibility and is less in the generation of a false signal by providing a means which generates a low-band luminance component for obtaining a luminance signal and a color difference signal from a main horizontal line. CONSTITUTION:The arrangement figure of a color separation filter shows respective horizontal lines by n1, n2,..., odd-numbered fields 01, 02,... indicate respective horizontal scanning lines in the odd-numbered fields, and horizontal lines n1 and n2 are processed simultaneously on, for example, the horizontal scanning lines 01, thereby obtaining the luminance signal and chrominance components. Even-numbered fields are also the same. An R filter and a B filter are arranged alternately at intervals of one horizontal line. The luminance signal is formed of W signals of two horizontal lines by said simultaneous processing of each horizontal line and the color filter arrangement, and the color difference signal is formed of the chrominance component and W signal of each horizontal line. Further, low-frequency luminance components of the luminance signal and color difference signal are formed from odd-numbered horizontal lines as main horizontal lines in odd-numbered fields and from even-numbered horizontal lines as main horizontal lines in even-numbered fields.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device that forms luminance signals and color difference signals from a plurality of horizontal lines.

[Conventional technology]

FIG. 8 is a layout diagram of a conventional color separation filter.

In the figure, nl I n, I ns...
means each horizontal scanning line, and 01,02
03... means each horizontal scanning line in an odd field. The luminance signal and color signal of each horizontal scanning line are formed using the vertical correlation of the two horizontal scanning lines.

First, when pixel signals of two horizontal scanning lines are respectively added, W+G=R+2G+B and Ye+CY=R+2G+B, both of which become R+2G+B, which is simply referred to as the luminance signal Y.

Next, by taking the difference between the signals of the two horizontal scanning lines, W-G is R
+B, and since Y8-CY is R-B, R can be obtained by adding the two, and B can be obtained by subtracting them.

As described above, the above method can obtain the luminance signal Y and the color signals R and B by addition and subtraction, so the resolution is good despite the simple signal processing, and even though a complementary color filter is used, there is no false color signal. Occurrence is rare.

[Problem that the invention seeks to solve]

In the conventional signal processing method using color separation filters, the low-range luminance signal is obtained from two horizontal lines, so the vertical resolution is not very good, and when imaging a subject with poor vertical correlation, the first problem is Since pixels in the horizontal direction are repeated every 4 pixels, the sampling frequency decreases due to the large sampling interval and line crawl occurs within the image band.Secondly, by performing complementary color subtraction processing, false There were problems such as a large signal being generated.

In the conventional imaging device as described above, IL-CCIM
With OS-type sensors, when interlace readout is used, the vertical correlation distance is long, so moiré and false signals increase, and IH delay lines are often used, which increases the size of the peripheral circuitry, which increases costs. There were some problems.

Also, in order to reduce frame afterimage with IL-COD,
When using field accumulation mode, color reproducibility deteriorates because the imaging method is a modulation method, vertical resolution deteriorates because two horizontal lines are added and read out, and color difference signals deteriorate. Since it can only be obtained line-sequentially, there are problems such as generation of false signals due to the difference between the low-frequency components of the color-difference signals and the low-frequency components of the luminance signal when synchronizing the color difference signals.

The present invention aims to solve the above-mentioned conventional problems, and aims to provide an imaging device with high horizontal and vertical resolution and good color reproducibility with few false signals.

[Means for solving problems]

The imaging device according to the present invention is provided with means for forming a low-range luminance component from a main horizontal line for obtaining a luminance signal and a color difference signal.

An imaging device according to another invention of this application is provided with means for forming a color signal from each horizontal line and forming a low-range luminance component for obtaining a luminance signal and a color difference signal from a plurality of horizontal lines.

[For production]

In this invention, a means is provided for forming a low-frequency luminance component from a main horizontal line to obtain a luminance signal and a color difference signal, so that the low-frequency components of the color difference signal and the luminance signal are obtained as the same signal.

Further, in another invention of this application, a color signal is formed from each horizontal line, and a means is provided for forming a low-range luminance component from a plurality of horizontal lines for obtaining a luminance signal and a color difference signal. It is obtained from a color separation filter to obtain pure colors, and the luminance signal band is obtained from two horizontal lines.

〔Example〕

FIG. 1 is a diagram showing the arrangement of color separation filters according to an embodiment of the present invention. In the figure, n1ln! ,... indicate each horizontal line, and odd fields 01゜02,...
・indicates each horizontal scanning line in an odd field; for example, in horizontal scanning line 01, horizontal lines n1 and n2
is processed simultaneously to obtain a luminance signal and a chrominance signal. Similarly, even field el, e2...
also means each horizontal scan line in an even field. Further, the horizontal scanning line here means one horizontal scanning line of the television, and the horizontal line means one row of pixels arranged in a matrix in the horizontal direction.

The color filters in this embodiment include gold transmission filters (W) arranged in a checkerboard pattern, and red transmission filters (R) and blue transmission filters (B) arranged line sequentially every two pixels.

That is, R filters and B filters are alternately arranged for each horizontal line.

Due to the above-described simultaneous processing of each horizontal line and color filter arrangement, a luminance signal is formed from the W signal of two horizontal lines, and a color difference signal is formed from the color signal and W signal of each horizontal line.

Furthermore, the low-band luminance components of the luminance signal and color difference signal are formed from odd horizontal lines as main horizontal lines in odd fields, and from even horizontal lines as main horizontal lines in even fields.

Note that another horizontal line read out at the same time is defined as a sub-horizontal line.

Figure 2 is a schematic diagram of the sensor drive, where R, B, and W represent each pixel and the color filter on the pixel, V and SR are vertical shift registers, H-8R is a horizontal shift register,
φV-R8 and φH-R8 indicate the vertical charge refresh pulse and the charge refresh pulse for each bit, respectively.

In the signal wiring method of this embodiment, two horizontal lines are simultaneously read out, and the R and B color signals are alternately read out pixel by pixel from the output S2, and the W signal is successively read out pixel by pixel from the output 81.

FIG. 3 is a sampling timing chart of signals read out by the sensor of FIG. 2. The R and B point sequential signals of S2 are separated into R and B at the timing shown in the diagram, and the W and W point sequential signals of S1 are separated into W signals from the horizontal line where R exists in odd fields, and in even fields. The W signal from the horizontal line where B exists is separated and used as a low-band luminance component of a luminance signal and a color difference signal.

FIG. 4 is a signal processing block diagram, and in the figure, 10
is a non-destructively readable image sensor (hereinafter referred to as SIT),
20 is a clock generator, 40° 70a, 70b are sample and hold circuits (S/H), 50.80a, 80
b is a low pass filter (LPF), 60 is a band pass filter (BPF), and 90a.

90b is a white balance circuit, 100 is a process circuit, and 110 is an adder.

In the device configured as described above, when two adjacent horizontal lines are read out simultaneously, the W signals of the two horizontal lines are read out alternately and dot-sequentially from the output line S1 of 5ITIO, and from the output line S2. The R and B dot sequential signals are read out alternately. The luminance signal is formed from the SIT output S1 mentioned above. First, since the SIT output S1 is directly used as the high-band luminance signal, a high-resolution band is secured.

That is, the repetition frequency of the W signal from Sl is, for example, 5IT.
If the number of horizontal pixels of the IO is 510 pixels, the readout frequency will be approximately 9.5 MH2, and therefore, if this is taken as the Nyquist frequency, the luminance band will be approximately 4.7 MHZ.

In that case, the band of BPF60 is approximately IMH2~4.7MH
2 bandpass characteristics.

Next, the low frequency component for luminance, the low frequency component for color difference, and the color signal are sampled and held by a sample hold circuit 40 e 70 a *70
It is separated from the SIT outputs SL and S2 by b. 1st
To explain with reference to the figure, in the 01 horizontal scanning line of the odd field, the W signal and R signal corresponding to horizontal line n1 are separated, and the W signal and B signal corresponding to horizontal line n2 are separated. Further, the low-band luminance signal is formed from the W signal of the nl line. In the next 02 horizontal scanning lines, the W signal and R signal corresponding to horizontal line n3 are separated, and the W signal and B signal corresponding to line n4 are separated, and the low-range luminance signal is formed from the W signal of line n3. be done. Further, in an odd field, a low-band luminance signal is formed from the odd-numbered horizontal lines of each horizontal line, and in an even-numbered field, a low-band luminance signal is formed from the even-numbered horizontal lines of each horizontal line. Therefore, there is no deterioration in vertical resolution.

The low-band luminance signal and color signal obtained as described above are band-limited to approximately IMH2 by the next stage LPF 50, 80a, and 80b. The color signal is further subjected to a white balance operation using a load roll voltage (not shown) that is controlled line-sequentially by white balance circuits 90a and 90b at the next stage. The white-balanced R and B line-sequential color signals and the low-range luminance signal YI are subjected to γ processing in the process circuit 100 to produce a low-range luminance signal Y and a line-sequential color difference signal R'-Y.
formula.

B/7/ is output. and low-range luminance signal YL'
is added to the high-frequency luminance signal YH by an adder 110 to form a Y signal, which is input to the encoder 200.

By performing the signal processing as described above, color signals are obtained from pure color filters, so color reproducibility is good, and the error of one vertical pixel between R and B is not a problem in terms of the color signal band.

Further, the band of the luminance signal is wide because W of two horizontal lines is added.

Furthermore, since the low frequency components of the color difference signal and the luminance signal are the same signal, when returning to the original primary color signal, no false color signal due to luminance error is generated.

Further, since the low frequency component of the luminance signal is formed from one horizontal line, the vertical resolution does not deteriorate.

It has the following effects.

FIG. 5 is a layout diagram of color separation filters according to a second embodiment of the present invention.

In FIG. 5(a), the signal changes from W to Y. The B signal is obtained by subtracting the signals, and the R signal is obtained by subtracting the CY signal from the W signal. The signal processing circuit block diagram at that time is the subtracter 190a.

The circuit configurations shown in FIGS. 6(a), (b), and (e) are obtained by adding 190b to the signal processing circuit block diagram of FIG. 4.

That is, in FIG. 6 ((turn)), the output I! of 5ITIO!
The point that the high-range luminance signal Y1 and the low-range luminance signal Y1 are obtained by the W signal from S1 is the same as in the case of FIG. 4, but R,
The B color signal is the line sequential color signal of Y, , CY from W from 81.
It is obtained by subtracting it from the signal.

Figure 6(b) shows the output of the luminance signal Y for Figure 6.
! The output of Sl is directly passed through a low-pass filter 210 to form the output.

In FIG. 5(b), the R signal is obtained by subtracting the G signal from the Y8 signal, and the B signal is obtained by subtracting the G signal from the CY signal. A block diagram of the signal processing circuit at that time is, for example, as shown in FIG. 6(b), and the above-mentioned subtraction processing is performed by subtracters 190C and 190d.

The brightness signal is the output S1 of SITIO as it is.

That is, Y8. Since CY is outputted point-sequentially and the G signal is outputted point-sequentially to S2, the output Ye of Sl, CY
By passing through LPF210, Y=Ye+CY=R+
200B is formed. Also, in Article 61M(c), SI
The signals of output S1 and output S2 of T are added to form a luminance signal.

In FIG. 7, the brightness signal is the output S1 of the 5ITIO as it is, and the output S1 of the S-TIO is used as the brightness signal.
2, R and B point sequential signals are obtained. Other processing is the same as in the case of FIG.

By performing the above-described signal processing, this invention makes the low-frequency components of the color difference signal and the luminance signal the same signal, so that when returning to the original primary color signal, false color signals due to luminance errors do not occur. .

Further, another invention of this application has two bands of high-frequency luminance signals.
Since the two horizontal lines W are combined, the signal is wide, and the brown signal is obtained from a filter for obtaining pure color, so the color reproducibility is good. Note that the error of one vertical pixel between R and B does not pose a problem in terms of the color signal band and can be ignored.

〔Effect of the invention〕

As described above, the present invention provides a means for forming low-range luminance components from the main horizontal line for obtaining luminance signals and color difference signals, and therefore has the effect that false color signals due to luminance errors are not generated.

Further, another invention of this application is provided with means for forming a color signal from each horizontal line and forming a low-range luminance component from a plurality of horizontal lines for obtaining a luminance signal and a color difference signal.
This has the effect that line crawl does not occur within the image band and false color signals do not occur.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the arrangement of a color separation filter according to an embodiment of the present invention, FIG. 2 is a schematic diagram of driving the sensor, and FIG. 3 is a diagram showing two samples of the output signal of the sensor in FIG. 2. Waveform diagrams, Figures 1 and 4 are signal processing block diagrams of Figure 412, Figure 5 is a color separation filter arrangement diagram of the second implementation column of 1, and Figure 6 is a block diagram of the main signal processing in the embodiment. Figure 7 is a block diagram of another processing circuit of Figure 5, and Figure 8 is a layout diagram of a conventional color separation filter. .7 Ua, 7Ub are sample and hold circuits, 50, 80a, 8υb, 21L) are U-bus filters (LPF'), and 6o is a bandpass 7 (lej(
BPF), 9L) a, 9Ub are #'7 () Bakunsu circuit, 1 (30 is 107 circuit, 11υ, 12 (j is addition: j
i#-190a, 191Jb, 191Jc, 190d. 190e, 19L) f is t'A N Q, 2 U 01
4 x > Korg. Agent: Bentoshi 1) Haruaki Kita (father: Sue L. Do) -1
'74-LD Fig. 1 52RBRBRB RBRBR 51W W W W W W Fig. 4 (a) (b) Fig. 5 Fig. 6 (a) Fig. 6 (b)

Claims (2)

[Claims] (1) Low-range luminance for obtaining luminance signals and color difference signals in an imaging device that forms luminance signals and chrominance signals using the correlation of signals of a plurality of horizontal lines consisting of a main horizontal line and a sub-horizontal line. An imaging device comprising means for forming a component from the main horizontal line. (2) In an imaging device that forms a luminance signal and a color signal using the correlation of signals of a plurality of horizontal lines consisting of a main horizontal line and a sub-horizontal line, a color signal is formed from each horizontal line, and a luminance signal is An imaging device characterized by comprising means for forming a low-range luminance component from a plurality of horizontal lines to obtain a color difference signal.