JPS6031384A - Single board color camera - Google Patents

Abstract

PURPOSE:To compensate electrically the drift of transfer efficiency by providing a sample hold circuit and an adder between an image pickup element and an amplifier. CONSTITUTION:The sample hold circuits 14, 15, 16, 17 and the adders 18, 19 are provided between the image pickup element and the amplifiers 2, 3. The sampling position of the circuits 14, 15 is taken as (e), (f) in Fig. A. Thus, the output waveform of the circuits 14, 15 is respectively as shown in Figs. B and C to an output of the image pickup element 1 as shown in Fig. A. In Fig., (b1) is the first read signal, (b2) is a read signal close to the end and a leak signal (c) is generated near the (b2). In adding the outputs of the circuits 14, 15 shown in Figs. B, C by the adder 18, the waveform is as shown in Fig. D and the effect of the leak signal to the idle bits of a horizontal register H. CCD is corrected as shown in (d) and the reduction in the read signal due to the incomplete transfer of the image pickup element during a horizontal scanning period is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a single-chip color camera using a solid-state image sensor.

Conventional configuration and problems Regarding this type of camera, for example, NATIO-NA
L TEGHN'ICAL REPORT VOL, 2
8.

It is introduced in detail on pages 33 to 42 of Nα2 (APR, 1982). The configuration will be explained below with reference to FIG. 1.The CPD image sensor 1 has two output terminals t+.
, i2, and the relationship with the pixels is such that every other pixel in the horizontal direction is read into the upper and lower horizontal registers H1COD every other bit.

Here, Oy, Ye, Mg, and G are color filters arranged on the light receiving part of the CPD image sensor 1. Therefore, the two output terminals t1. From t2 to amplifier 2 respectively
The signals amplified through .degree. 3 are added by an adder 4, and then passed through a low pass filter (LPF) 5 to obtain a luminance signal. In addition, the color difference signal is obtained by subtracting the signals from these two output terminals t1 + t2 through amplifiers 2 and 3 through an LPF 6.7 with a cassette off frequency of 500 KHz using a subtracter 8. -C color difference signals are sequentially obtained every horizontal period. These signals are basically synchronized by a 1H3W circuit 10 consisting of a 1H period delay line (1HDL) g and a switch, and are converted into Gy -Ye.
and Mg-G color difference signals, which are converted into NTSC signals by an encoder 11 along with a luminance signal. Here, 13 is a luminance signal correction circuit, 13 is a white balance correction circuit, FDA is a horizontal register H, a reading peak part of COD is p, and CPT is a priming transfer part.

In this way, the upper and lower horizontal registers H, CC; D for each pixel
When the transfer efficiency of the horizontal register H1CCD is incomplete, that is, when the transfer efficiency is not 100, the amount of signal leakage to the empty bits is 1H period. The closer it gets to the final stage, the larger it gets.

For example, projecting a uniform white pattern, horizontal register H9CO
The output signal when the reading peak part FDA on the output side of D is driven with a reset pulse for each bit is as shown in FIG. In the figure, a is recent noise, b is a signal, and C is a leakage signal to empty bits.

Therefore, luminance shading occurs in the luminance signal. Furthermore, when the transfer efficiency of the upper and lower horizontal registers H1COD is the same, the amount of color signals will be different on the left and right sides of the screen, and when they are different, color shading will occur.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks and provides a single-chip color camera that electrically compensates for drift in transfer efficiency.

Structure of the Invention In order to achieve the above object, the present invention provides a sample-and-hold circuit and an adder between an image sensor and an amplifier.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will now be described with reference to FIG. In the figure, 1, 2.3 are 1.2. , Q.C.
Equivalent to. Therefore, from the output terminal t1tt2, as shown in Fig. 4 (
As shown in (b), a signal with zero leakage in the empty bits is output as in the conventional example. Reference numerals 14 and 15 are sample and hold circuits, and 18 is an adder. Here, the same hold circuit 14.
The sampling positions of 16 are designated as e and f shown in FIG. 4(a). Therefore, the output waveforms of the sample and hold circuits 14 and 15 for the output of the image sensor 1 shown in FIG. 4(a) become as shown in FIG. 4(b) and (c), respectively.

Now, to explain about FIG. 4, (a) shows the signal from the terminal t1, bl is the first read signal, b
2 is a readout signal near the end, and a leakage signal C is generated near bz. (b) is the output of the sample and hold circuit 14, and b+ and bz correspond to b< and b2. e→ is the output of the sample hold circuit 15 υ
c/ is to compensate for the leakage C. When the outputs of the sample and hold circuits 14 and 15 shown in (b) and (c) are added by the adder 18, the result is as shown in (d), and the leakage signal to the empty bits of the horizontal registers H, CC:D is obtained as shown in d. The influence of this can be corrected, and the drop in the readout signal due to incomplete transfer of the image sensor during the horizontal scanning period can be corrected. Note that although the signal from terminal t1 has been explained centering around the sample and hold circuits 14+16, 16, 17.19 are
If the same sample-hold circuit and adder as in 18 are used, it is easy to understand that the signal from the terminal t2 is also corrected in the same manner as described above, so a description thereof will be omitted.

Effects of the Invention As explained above with reference to embodiments, according to the present invention, the image sensor can be made into a form of perfect transfer, so good image quality can be obtained, while freedom in adjusting the amplitude, phase, etc. of the transfer pulse of the image sensor is achieved. 0, where the degree increases.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional single-chip color camera, Fig. 2 is an output waveform diagram of an image sensor, Fig. 3 is a block diagram of main parts of a single-chip color camera according to an embodiment of the present invention, and Fig. 4 is a block diagram of a conventional single-chip color camera. It is an output waveform diagram. 1... Image sensor, 2, 3... Magnifier,
14,15゜16.17...Sample/hold times] 18゜19...Adder.

Claims (1)

[Claims] an image sensor in which color filters are arranged in a light receiving part, and signals from the light receiving part are read in every other bit in horizontal registers for every other pixel in a horizontal scanning direction; and an image sensor is provided on the output side of the image sensor. A single-chip color camera Φ consisting of sample hold circuits each having a different sample position and an adder that adds the outputs of the sample hold circuits.