JPS63232763A - Image pickup device - Google Patents

Abstract

PURPOSE:To execute the expanding reading of an above-mentioned part by driving a part of an image at a low speed for an effective period and driving other part at a high speed for a blanking period. CONSTITUTION:In a vertical scanning, the high speed scanning of a horizontal line equivalent to unnecessary parts (d) and (f) is executed for the vertical blanking period and in an expanding part (e), the low speed driving is executed. In the horizontal scanning of the expanding part (e), a starting pulse phiS1 is inputted during the horizontal blanking period, and a shift register 107 is driven by a horizontal transfer frequency 3fS of three times. During a first period, an OB signal is outputted, and a clamping circuit 106 sets a black reference level with a clamping pulse CP. Namely, for the clamping pulse, the timing is changed at the time of the usual reading and at the time of the expanding reading. Next, after an unnecessary part (a) is transferred at a high speed by an above-mentioned transfer frequency 3fS, the expanding part is transferred at a low speed by 1/2fS in the effective period. Next, a remaining unnecessary part C is transferred at a high speed by the frequency 3fS in a next blanking period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an imaging device, and particularly to an imaging device having an enlargement/reduction function.

[Prior art and its problems] There are two methods of enlarging or reducing an image: a method of optically changing the image formation using a zoom lens, and a method of performing electrical processing using an image memory etc. .

However, the method using a zoom lens has the problem that the lens body is large and heavy, and the method using an image memory or the like requires a complicated image processing system.

An object of the imaging device according to the present invention is to provide an imaging element with an ability to enlarge or reduce.

[Means for solving problems] An imaging device according to the present invention is:

In an imaging device that sequentially reads photoelectrically converted image information, a first mode in which a desired portion of the image information is read at a frequency different from other portions and processed as a read-out valid image, and a second mode in which a desired portion of the image information is read at the same frequency and processed as a read-out valid image. It has two modes, and is characterized in that at least the clamp timing is changed depending on the first and second modes.

[Operation] By reading at different frequencies, for example, by driving a part of the image at low speed during the effective period and driving the other part at high speed during the blanking period, it is possible to perform enlarged reading of a part. At this time, by changing at least the clamp timing depending on the mode, it is possible to clamp an accurate black reference signal, for example.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of enlarged reading according to the present invention.

In the same figure, part B of the image formed on the image sensor lO1
In order to enlarge and display it on the display, it is necessary to read out the enlarged portion B during the television's active period, and to process the rest within the horizontal and vertical blanking periods.

For example, in horizontal scanning 102, the optical black OB, unnecessary portions a and C signals are transferred at high speed during the horizontal blanking period, and the enlarged portion signals are transferred at low speed in accordance with the effective period of the television. Similarly, in vertical scanning, the enlarged portion e is driven at low speed according to the valid period, and the unnecessary portions d and f are driven at high speed within the six-shift blanking period.

The horizontal transfer frequency varies depending on the magnification ratio (zoom ratio).If the horizontal transfer frequency during normal readout is fs, for example, in the case of 2x magnification, low-speed transfer is performed at a frequency of f s / 2, and for other parts High-speed transfer is performed at 3 fs in consideration of reading optical black OB. When other transfers are performed within the horizontal blanking period, the data may be transferred at an even higher speed.

FIG. 2 is a schematic circuit diagram of an embodiment of an imaging device according to the present invention.

In the figure, an image sensor 101 is composed of mXn light conversion cells 103. The outputs a1 to an of each horizontal line of the image sensor 101 are each connected to a transistor Qs.
The signals are sequentially taken out to an output line 104 via an amplifier 105 and serially output to a clamp circuit 106.

Here, it is assumed that several bits from the output a1 correspond to the optical black OB signal. Therefore, the clamp circuit 106 clamps the signal level of the first few bits at the timing of the clamp pulse CP, and sets the black reference level.

Horizontal scanning pulses φh1 to φhn are input from the horizontal shift register 107 to each gate electrode of the transistor Qs. Shift register 107 receives start pulse φS1 and outputs horizontal scanning pulses in synchronization with pulses φ1 and φ2. Therefore, by controlling the frequencies of pulses φ1 and φ2, the horizontal transfer frequency can be changed.

In addition, a transistor Q is provided in each horizontal line of the image sensor 101.
A driving pulse φr is applied through the transistor Qvb, and vertical scanning pulses φv1 to φvn are input from the vertical shift register 108 to each gate electrode of the transistor Qvb. That is, only the cell 103 of the water moline to which the vertical scanning pulse from the vertical shift register 10B has been output is driven, and the signal al''an of that line is read out.

Vertical shift register 108 receives start pulse φS2 and outputs a vertical scanning pulse in synchronization with pulses φ3 and φ4. Therefore, by controlling the frequencies of pulses φ3 and φ4, the vertical scanning speed can be changed.

Pulses φ1 to φ4, φs1, φs2 . for driving the shift register, photoelectric conversion cell, and clamp circuit. φ
r and the clamp pulse CP are also supplied to the driver 109, and their timing etc. are controlled by the control unit 110.

Next, the operation of this embodiment will be explained using a timing chart.

FIG. 3 is a timing chart for explaining an example of the operation of this embodiment.

First, in the case of 1 normal readout (upper stage of the same timing chart), a start pulse φS1 is input within the horizontal blanking (HBLK) period, and the shift register 107 is driven at the frequency fs by pulses φ1 and ≠2. As a result, the signals a1 to an of one horizontal line are sequentially transferred.

The clamp circuit 106 sets a black reference level from the first several bits of the OB multiplied signal at the timing of the clamp pulse CP, and accurately fixes and outputs the black level of subsequent line signals.

The above horizontal scanning is performed for each horizontal line selected by the vertical shift register 108, and all pixel signals are read out.

Next, with reference to the lower part of the timing chart in FIG. 3, the enlarged readout operation will be explained using a double zoom as an example.

First, in vertical scanning, a horizontal line corresponding to an unnecessary portion d is scanned at high speed during a vertical blanking period, and while horizontal scanning, which will be described later, is performed during an enlarged portion e, driving is performed at a low speed to match the vertical effective period. When the low-speed driving of the enlarged portion e is completed, high-speed scanning of horizontal lines corresponding to unnecessary molecules is performed in the next vertical blanking period.

In the horizontal scanning of the enlarged portion e, the start pulse φS1 is input within the horizontal blanking period, and the shift register 107
is driven at a frequency of 3fs. OB in the period tab
The clamp circuit 106 outputs the doubled signal and the clamp pulse C
The black reference level is set by P. That is, it is necessary to change the timing and pulse width of the clamp pulse CP between normal readout and enlarged readout.

Further, during period ta, unnecessary portion a is transferred at high speed and removed.

Subsequently, the enlarged portion is set at a frequency f s / 2 for an effective period +
111 th.

Then, in the next horizontal blanking period, the remaining unnecessary part C
is removed by high-speed transfer at a frequency of 3 fs.

By controlling the transfer speed as described in 1 above, it is possible to enlarge and read out a desired image portion.

Note that the present invention is not limited to the above embodiments,
The present invention can be applied to a configuration in which an interlace circuit is provided in the vertical scanning section, or a color separation mosaic filter is provided on the image sensor, and color signals are output from a plurality of output lines.

[Effects of the Invention] As explained in detail below, the imaging device according to the present invention reads out at different frequencies, for example, drives a part of the image at a low speed during the effective period, and drives the other part during the blanking period. By driving at high speed, enlarged reading of a portion can be performed. At this time, by changing at least the clamp timing depending on the mode, for example, it is possible to accurately clamp the black reference signal.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of enlarged readout according to the present invention, FIG. 2 is a schematic circuit diagram of an embodiment of an imaging device according to the present invention, and FIG. 3 is a diagram for explaining an example of the operation of the present embodiment. This is a timing chart. 101...Image sensor 103...Photoelectric conversion cell 104-group/Output line 106...Clamp circuit 107.108...Shift register 109...Driver 110...Fist control unit

Claims (1)

[Claims] (1) In an imaging device that sequentially reads photoelectrically converted image information, there is a first mode in which a desired portion of the image information is read out at a frequency different from other portions and processed as a readout valid image, and a first mode in which a desired portion of the image information is read out at a frequency different from other portions and processed as a readout valid image; Second to process
What is claimed is: 1. An imaging device having a first mode and a second mode, and changing at least clamp timing depending on the first and second modes.