KR100269747B1 - Reduced color image scanner - Google Patents

Abstract

PURPOSE: A lens reduction type color image scanner is provided to reduce a manufacturing cost by decreasing the number of device for processing an analog video signal. CONSTITUTION: A timing control portion provides one or more clock control signal to each color CCD(Charge Coupled Device) image sensor. Each color CCD image sensor is controlled by the provided clock control signal. A sensor amplification portion amplifies output signals of each color CCD image sensor. A multiplexing portion multiplexes a signal outputted from the sensor amplification portion and transfers the multiplexed signal to an ADC.

Description

Reduced Color Image Scanner

1A and 1B are unit cell configuration and input / output signal timing diagram of a single output type CCD sensor.

2A and 2B are unit cell configuration and input / output signal timing diagram of a multiple output CCD sensor.

3A and 3B are unit cell configuration and input / output signal timing diagram of a combined output type CCD sensor.

Figure 4 shows the configuration of a single color CCD sensor, Figure 4a is a sensor consisting of a single CCD, Figure 4b is a sensor consisting of a plurality of CCD, Figure 5 is a view showing the configuration of the color CCD sensor according to the present invention and its driving circuit .

6A and 6B are a block diagram and a signal timing diagram of a color image scanner according to the present invention.

* Explanation of symbols for main parts of the drawings

100: color CCD image sensor 110: oscillator

120: system control pulse generator 130: CCD pulse driver

The present invention relates to a color image processing apparatus, and more particularly, to a lens reduction type color image scanner.

An image scanner using a Charge Coupled Device (CCD) image sensor can be roughly divided into a compact image scanner and a close type image scanner. The former allows the reflected light of a light source corresponding to a read document to pass through the reduced optical lens. The original is read out by being provided in a minute photo cel1, and the latter does not have a reduction optical system, and the resolution of the photocell is read in a 1: 1 resolution.

As a well-known technique related to a miniature image scanner, Japanese Patent Publication No. 63-290063 discloses a clock pulse after sequentially passing through a photodiode and a transfer gate, which are light receiving elements of a CCD sensor constituting a scanner. Is transferred to a CCD analog register, and then converted into a shaped wave by a reset pulse in a pre-amplifier and outputted.

The CCD sensor can be constructed in three well-known ways, the first of which is a single output method as shown in FIG. 1, the second of which is a multiple output method as shown in FIG. It is a complex output method like the one shown.

In FIGS. 1A and 1B showing the configuration of the short output type CCD sensor and its operation timing, respectively, reference numeral 1 denotes an input terminal of a transfer pulse øT provided from a pulse driving circuit (not shown), 2 denotes an input terminal of the clock pulse?, 3 an input terminal of the reset pulse? R, and 4 an output terminal of the video data signal. Reference numeral 5 denotes a photodiode, 6 a photogate, 7 a transfergate, 8 a CCD analog register, and 9 a preamplifier.

The optical data reflected from the image is converted into an electrical signal by the photodiode 5, passes through the photogate 6, stays in the transfer gate 7, and is controlled by a transfer pulse øT to control the CCD analog register 8. Is provided.

Light provided to the photodiode 5 in the time from the rising edge of the transfer pulse øTn to the rising edge of the next pulse øTn to the rising edge of the next pulse øTn + 1. Only data is accumulated as electric charges and output as electric signals.

The electrical data signals obtained by the predetermined number n of light receiving elements, i.e., photodiodes 5 are stored in parallel transfer to the CCD analogograph 8 of predetermined bits n.

The predetermined bit of data stored in the CCD analog register 8 is serially transferred to the preamplifier 9 in synchronization with the clock pulse ø.

The preamplifier 9 samples and amplifies the data corresponding to each bit of the CCD analog register 8 in synchronization with the reset pulse? R and outputs the result.

The above data processing timing is shown in FIG. 1B.

2A and 2B show the configuration and operation timing of the multi-output CCD sensor, respectively, and the same reference numerals and reference numerals are given to the same input / output signals and elements that perform the same functions as the components of FIG. Each component is marked in a column so that they can be distinguished from each other by subscript.

The multiple output CCD sensor is separated into two photogates 6a and 6b, transfer gates 7a and 7b, and CCD analog registers 8a and 8b, respectively, which are output from a plurality of photodiode 5 data. After that, the output gate 10 is reached.

In this way, the output of the light receiving element reaching the output gate 10 is multiplexed by the output gate 10 and then sampled in the preamplifier 9.

The clock pulse ø is provided to the input terminal 2a of the CCD analog register 8a, and the inverted clock pulse (b) is applied to the input terminal 2b of the CCD analog register 8b. ) Is provided.

The operation principle of this multi-output CCD sensor is the same as that of the short-output CCD sensor described above, and this method is mainly used for a sensor having a data processing capacity of about 2K bits.

This multiple output method can reduce the data transmission time by half compared to the above-described short output method.

3A and 3B show the configuration of the combined output type CCD sensor and its operation timing, respectively.

This method separates and processes data provided from each photodiode of odd and even columns in the same way as the multiple output method. ) Is a two-output system that has (9b) independently. That is, the data Da and Db of the radix and even columns are respectively output from the preamplifiers 9a and 9b of FIG. 3.

If the CCD sensor is configured as shown in Fig. 4a or arranged in a single row as shown in Fig. 4b, it becomes a monochromatic image sensor, but as shown in Fig. 5, three rows, that is, R (red), G (green), and B When the CCD image sensor is configured in three rows to correspond to the three columns of the (blue) filter, it becomes a color image sensor.

In order to increase the scan speed of the color image sensor and to increase the width of the signal pulse, each sensor of the R, G, and B columns is generally configured with a complex output method.

Japanese Laid-Open Patent Publication No. 02-254866 discloses a reduced type image scanner in which three color image sensors 100 are configured in five rows.

As described above, even if the CCD image sensor arranged to correspond to the R, G, and B filters drives the reduced-size image scanner composed of a plurality of columns in any of the three driving methods described above, the independent driving of the output signal There was a problem that the signal processing scale was large and its configuration was complicated.

The present invention is to solve the above problems of the prior art, to provide a miniaturized image scanner that is reduced in signal processing scale and simplified configuration.

As a technical means for achieving the above object, the present invention provides a timing control means for controlling the three sensors to be driven independently by providing at least one control signal to the R image sensor, G image sensor and B image sensor, respectively; And amplifying means for amplifying the output signals of the three sensors to a predetermined level, and multiplexing means for dividing the output signals of the amplifying means into R, G, and B groups and providing the same to the ADC means.

Another characteristic feature of the present invention is that a low pass filtering means is additionally configured between the multiplexing means and the ADC means.

In another aspect of the present invention, the multiplexing means is constituted by an analog multiplexer.

According to still another feature of the present invention, as a configuration method of the color image sensors, the data provided from the light-receiving elements of each column is processed separately and a complex output method having two outputs is adopted.

According to another feature of the present invention, the color image sensors are driven by a pulse signal generated from one reference oscillation source in order to prevent the generation of noise and jitter.

The present invention will now be described in detail with reference to FIGS. 5 and 6.

Figure 6a shows the configuration of a reduced color image scanner according to the present invention, the reference numeral 100 denotes a color CCD image sensor, 200 is an emitter follower (300), an amplifier follower, 400 is a multiplexer, 500 represents a filter unit, and 600 represents an A / D (analog to digital) change unit, respectively.

The light reflected from the document irradiated by the exposure lamp (light source: not shown) is color-separated and amplified by the color CCD image sensor 100, and then amplified by the amplifier 300 through the emitter follower 200. Is amplified to the level of.

The configuration and driving circuit of the color CCD image sensor (hereinafter, abbreviated as 'color sensor') 1000 according to the present invention are as shown in FIG.

In FIG. 5, 110 is an oscillator, 120 is a system control pulse generator, 130a to 130c are R sensors 101, G sensors 102, and B sensors 103 of the color sensor 100. Are shown respectively.

The color sensor 100 according to the present invention has 2500 pixels in the main scanning direction (horizontal direction) with a read width of 14 μm as a pixel, and the R image sensor 101 and the B image sensor 102 and The G image sensor 103 is configured at intervals of 168 mu m.

Since the CCD sensor according to the present invention is composed of a complex output method, the number of pixels per chip of each of the R, G, and B sensors becomes 5000. Accordingly, this method is a two-output method that separates and processes data provided from each sensor of radix and rain column, independently of the multiple output method, without outputting radix and rain column multiplexes, respectively. ), Output Vr has output of Ro, Re, output Vg of G sensor 102 has Go, Ge output, and output Vb of B sensor 103 has Bo, Be output.

Here, the subscript 'o' of Bo, Go, and Ro means odd (odd), and the subscript 'e' of Be, Ge, and Re denotes even (even).

When reading the document, each R, G, B sensor is driven in the sub-scanning direction.

Pulse signals input to each sensor are completely synchronized so that jitter is not generated between signals for mutual interference and noise limitation.

For this purpose, pulse signals for driving each sensor are generated from one reference oscillation source (see 110 in FIG. 5).

The analog video signals Bo, Be, Go, Ge, Ro, and Re outputted from each sensor (R sensor, G sensor, B sensor) in synchronization with the driving pulse signals are respectively emitter followers 201 through. 206, or directly provided to each of the amplifiers (301 to 306) of the amplifying means (300) and amplified to a predetermined level.

Each video signal amplified by the amplifying means 300 is divided into R, G, and B groups (Ro and Re, Go and Ge, Bo and Be), and three analog multiplexers 401 to 403 which are multiplexing means 400. Are each provided.

The analog video signals input to the three analog multiplexers 401 to 403, respectively, are multiplexed by the synchronization signal SYNC provided from the system control pulse generator 120, which is a timing control means.

The analog video signals Ra, Ga, and Ba output from the multiplexing means 400 are provided to the A / D changing means 600 via respective filters 501 to 503 of the low pass filter 500. .

Each ADC 601 to 603 of the A / D converting means 600 converts the analog video signals Ba, Ga, Ra multiplexed by the multiplexers 401 to 403 of the multiplexing means 400 into digital signals, respectively. Generate color digital video signals R, G, and B of color.

As described above, the present invention, in which a single color CCD image sensor is configured in three columns to reduce the number of components, is a scanner of the prior art in which a three color CCD image sensor is configured in five rows by multiplexing an analog video signal to prevent a decrease in reading speed of the sensor. It is possible to reduce the number of devices for analog video signal processing by about half while maintaining the same data processing rate, which is a significant advantage that the production cost is much reduced compared to the prior art.

Claims (6)

In the reduced-size color image scanner in which a plurality of CCD image sensors are arranged in three rows of R, G, and B, at least one control signal is provided to each of the R image sensor, the G image sensor, and the B image sensor. Timing control means for controlling the G image sensor and the B image sensor to be driven independently, and output signals obtained by separating the odd and even columns of the R image sensor, the G image sensor, and the B image sensor, respectively; A / D conversion by combining amplification means for amplifying Re), (Go, Ge), (Bo, Be), and even-numbered output signal and even-numbered output signal for each of the R, G, and B output signals of the amplification means A reduced size color image scanner comprising multiplexing means provided by means. The reduced size color image scanner according to claim 1, further comprising a low pass filtering means configured between said multiplexing means and said A / D conversion means. 2. The reduced color image scanner according to claim 1, wherein said multiplexing means comprises three analog multiplexers (401, 402, 403). The reduced-size color image scanner according to claim 1, wherein the R image sensor, the G image sensor, and the B image sensor are each configured in a combined output method having two outputs and are spaced apart from each other by 168 mu m. . 5. The reduced color image according to claim 1 or 4, wherein the R image sensor, the G image sensor, and the B image sensor are driven by pulse signals generated from one reference oscillation source, respectively. Garner. 4. The multiplexing means according to claim 1 or 3, wherein the multiplexing means is controlled by a synchronization signal SYNC provided from the timing control means to multiplex the odd-numbered and even-numbered output signals for each of R, G and B of the amplification means. Reduced color image scanner, characterized in that.