JPH01205659A - Line sensor for color reading - Google Patents

Abstract

PURPOSE:To attain reading of stable color picture by adopting red or blue color filters for all color filters of a line sensor where color filters are arranged periodically adjacent to other line sensor. CONSTITUTION:One picture element consists of R, G, B in this order, a transmission filter coated onto one-chip CCD sensor starts from the R(red) filter in the order of R, G(green) and B(blue) and the B filter comes finally. The arrangement of the filters is adopted to arrange the G filter transmitting a light most stimulus to human eyes to the center of one picture element and to avoid one picture element from being bridged over two sensor chips. Since the color filters of the line sensor arranged with the color filters periodically in this way adjacent to other line sensor are all red or blue color filters, the deterioration in the output picture is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a color image reading line sensor that reads an image of an object as image information having color information using an image sensor made of a COD or the like.

(Prior Art) With the development of electronic technology, various image processing devices are becoming popular. In this type of device, a part that converts an image of an object into an electrical signal, that is, an image sensor, a so-called line sensor, is essential. In addition, as a line sensor for color image reading, generally a plurality of light receiving elements having different spectral sensitivities (for example, red) are arranged on the light receiving element array.

Line sensors with a configuration in which green, blue) filters are applied to each light-receiving element in sequence are often used, especially in recent years.
In order to read wide lines, devices have appeared in which multiple line sensors are arranged in a staggered manner.

, FIG. 8(a) is a schematic diagram showing the above-mentioned staggered color reading line sensor.

R (red) and G (green) on the photodetector array.

Color filters or line sensors 801 arranged periodically as B (blue), R (red), G (green), B (blue), etc.
802, 803, 804, and 805 are each fixed to the substrate 806 in a staggered manner. In such a sensor,
Since the characteristics of each sensor are not completely the same, Figure 8 (b)
Two line sensors (for example, 803 and 80
4) When configuring one pixel (R, G, B) across the two pixels, when performing operations such as masking operations performed in image processing, the calculation error for one pixel in the connecting portion will be magnified. This will adversely affect the output image.

(Summary of the Invention) An object of the present invention is to eliminate the drawbacks of the conventional line sensors described above and to provide a color reading line sensor that can stably read color images.

The above-mentioned object of the present invention is to provide a color reading line sensor in which a plurality of line sensors in which red, green, and blue color filters are arranged periodically are arranged continuously in the direction in which the color filters are arranged. This is achieved by using red or blue color filters for all of the color filters in the portions of the line sensors arranged in the same direction that are adjacent to other line sensors.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic diagram showing a copying machine equipped with a color reading line sensor of the present invention.

In FIG. 1, 1 is a document, 2 is an illumination system, 3 is an imaging optical system, and 4 is a sensor of the present invention.

By pressing a switch (not shown), the above-mentioned 2
~4 optical units scan in the U direction.

FIG. 2(a) shows a line sensor for color reading according to the present invention, in which 62.5
pm (1/16 mm) as one pixel, 1024 pixels, that is, 1 pixel is 3 in R, G, B in the main scanning direction as shown in the figure.
Since it is divided, the total number of effective pixels is 1024x3=3072.

A connecting portion between each of the chips 58 to 62 is shown in FIG. 82(b). One pixel is composed of R, G, and B in that order, and the transmission filter coated on the l-chip CCD sensor is R.
(Red).

G (green) and B (blue) are applied in this order, starting with R (red) and ending with a B (blue) filter. This arrangement of filters is to place the G (green) filter, which transmits light that is most stimulating to the human eye, at the center of each pixel, and one pixel has two
This is to prevent it from straddling the book's sensor chip. In addition, each chip 58 to 62 is formed on the same ceramic substrate, and the 1st, 3rd, and 5th sensors (58, 60, 62) are connected to the same line sensor, and the 2nd and 4th sensors are connected to LA for 4 lines (62 , 5gmX4=250gm), and scans in the direction of arrow AL force when reading a document. Each of the five CCDs is connected to the drive pulse group 0DRV518 for the 1°3.5th drive pulse group and tEDRV5 for the 2.4th drive pulse group.
19, Jl:') are driven independently and synchronously.

oφIA, Oφ2A, ORS included in 0DRV518
and EφIA, Eφ2A, ER included in EDRV519
3 has a charge transfer lock and a charge reset pulse within each sensor, and due to mutual interference and noise limitations between the 1st and 3.5th fIt and the 2nd and 4th, they are completely synchronized so that there is no jitter between them. is generated.

FIG. 3(a) shows 0DRV518. FIG. 3(b) is a timing chart of the circuit block that generates the EDRV519. The clock KO335, which is a frequency-divided original clock CLKφ generated from a single reference oscillation source 0SC58', is 0.
Reference signal 5 that determines the generation timing of DRV and EDRV
This is the clock that generates YNC2, 5YNC3, and 5Y
NC2, 5YNC3 is the signal line 5 connected to the CPU bus
Presettable counter 64°6 set by 39
The output timing is determined according to the setting value of 5YN
C2,5YNC3 initializes the frequency divider 66.67 and the drive pulse generator 68.69. That is, with HSYNC515 input to this block as a reference, all oscillation sources O8C
Since it is generated by CLKφ output from
The respective pulse groups of 8 and EDRV519 are obtained as synchronous signals with no jitter at all, and signal disturbances due to interference between sensors can be prevented. Here they were obtained in sync with each other. Sensor drive pulse 0DRV518 is 1,3.5
The EDRV519 is supplied to the 2.4th sensor, and video signals vl to v5 are independently output from each sensor 5B, 59, 60, 61.62 in synchronization with the drive pulse, as shown in FIG. Each channel shown in a) is amplified to a predetermined voltage value by an independent amplifier circuit (not shown),
0OS in Figure 2 (C) through a coaxial cable (not shown)
At the timing of 529, the video signals Vl, V3. V5 is E
The video signal V2. The V4 signal is sent out and input to a video processing unit (not shown).

The color image signal obtained by dividing the input document into 5 parts into a video processing unit (not shown) is sent to the sample hold circuit S/H, and the color image signals are divided into R (red), G (green), and B (blue). It is separated into three colors. Therefore S/H
After that, there will be 3x5=15 signal processing systems. As shown in FIG. 4(b), the digital data A /
A timing chart obtained by D out is shown.

FIG. 4(a) shows a processing block diagram.

The analog color image signals read by the 5-chip life-size color sensor described above are divided into four channels for each of the five channels.
The signals are respectively input to the analog color signal processing circuit shown in FIG. Since circuits A to E corresponding to each channel are the same circuit, circuit A will be explained together with the waveform timing shown in FIG. 4(b). The input analog color signals are in the order of SiGA throat R→GB as shown in FIG. 4(b).
Sample and hold pulses for each color with sample and hold circuit (S/H) 250 5HR535, 5HG536, 5H
B537 converts each color in parallel. Figure 4(b) VD
RI, VDGI, VDBI (538-540) Here, the signals 538-540 separated for each color are sent to the amplifier 251.
After the offset (Fig. 4 (C) 0 characteristic) is adjusted at ~253, the low pass filter (LPF) 254~2
After cutting the band other than the signal component with 56, the amplifier 25
After gain adjustment at 7 to 259 (Fig. 4 (C) G characteristic), the pulse RS is adjusted again to multiplex into one signal system.
E.L.

MP by GSEL, BSEL (544-546)
X260 becomes one system, which is A/D converted and converted into a digital value (ADOUT547). In this configuration, MPX
After multiplexing with 260 and A/D conversion, the color signals of 15 systems in total of 5 channels of R2O and 863 colors are processed by 5 A/D converters. The same applies to the BE circuit.

The A/D converted signal is input to an image processing device.

In this way, three types of color signals that pass through the R (red), G (green), and B (blue) filters centered around the G (green) filter are converted into one pixel and output to the image processing unit. .

Next, in this embodiment, as mentioned above, 4 lines (62, 51
Since the document is read using five staggered sensors that are spaced apart (Lmx4=250pm) in the sub-scanning direction and divided into five areas in the main-scanning direction, the pre-scanning is performed as shown in Figure 5(a). channels 2 and 4 and the remaining l.

In 3.5, the reading position is off. Therefore, in order to connect this correctly, we use memory for multiple lines. FIG. 5(b) shows the memory configuration of this embodiment, with 7
Memories 0 to 74 each store a plurality of lines, and have a FiFo configuration. That is, 70°72.7
4 is 5 lines with l line 1024 pixels, 71.7
3 has a capacity for 15 lines, Lite Point WPO
Data is written one line at a time from the point indicated by 75 and WPE76, and when writing for one line is completed, wpo or WPE is incremented by 1.

WPO75 is common to channels 1 and 3.5, WPE76
is common to 2 and 4.

0WR3T540. EWR3T541 is a signal that initializes the values of the respective write points WPO75 and WPE76 and returns them to the beginning, and 0RST542. ERSTS43
is a signal that returns the value of the read point (point at the time of reading) to the beginning. Let's take channels 1 and 2 as an example. As shown in Figure 5(a), channel 2 is ahead of channel l by 4 lines, so for the same line, for example line
Four lines after writing to the memory 71, channel 1 reads line 2. Therefore, if WPE is advanced by 4 from the write point WPO to the memory, channels 1, 3.5 and channels 2, 4 will be on the same line if they are read from the FiFo memory with the same read point value. This means that the deviation in the sub-scanning direction has been corrected. For example, in FIG. 5(b), in channel 1, WPO is on the first line 1 of the memory, and at the same time, channel 2 is pointing to WPE 5, which is the fifth line from the beginning. If you start from this point, WPo
indicates 5, WPE indicates 9, and both points are 5.
The line ■ on the manuscript is written in the area, and from then on RPO,
All you have to do is read out cyclically while advancing both RPEs (read points) in the same way. FIG. 5(C) is a timing chart for performing the above-mentioned control, and image data is sent one line at a time in synchronization with the HSYNC 515. EWR5T541.0WR3T540 is generated with a shift of 4 lines as shown in the figure, and 0R5T5
42 corresponds to the capacity of the FiFo memory 70, 72, 74, and therefore is generated every 5 lines, and ERST 543 is generated every 15 lines for the same reason. On the other hand, when reading, first read one line at a speed five times faster than channel 1, then channel 2.
Similarly, by sequentially reading out one line, then channels 3, 4, and 5, it is possible to obtain connected signals from channels 1 to 5 between IHsYNc. Figure 5(d) IRD~5RD (544~5
48) indicates the valid period signal of the read operation of each channel. Note that a control signal for controlling image splicing between channels using the wood FiFo memory is generated by a memory control circuit (not shown). The circuit is composed of a discrete circuit such as a TLL, but since this is not the gist of the present invention, a description thereof will be omitted. Further, although the memory has three colors of an image, namely, a red component, a green component, and a true component, since they have the same configuration, the explanation will be limited to only one of them.

As explained above, all of the color filters in the portions of the line sensor in which color filters are arranged periodically and adjacent to other line sensors are red or blue color filters. As a result, compared to the line sensors shown in FIGS. 8(a) and 8(b), calculation errors at the connecting portions of the line sensors are not magnified, and deterioration of the output image can be prevented.

In the above embodiment, a plurality of line sensors are arranged continuously in a staggered manner in the direction in which the color filters are arranged, but it is sufficient that the line sensors are arranged continuously in the main scanning direction of the document (image). Therefore, the following cases are possible.

FIG. 6 is a schematic diagram showing a color reading line sensor according to another embodiment of the present invention. R (red), G (green), and B (blue) on the photodetector array.

Line sensors 601, 602 in which color filters are arranged periodically like R (red), G (green), B (blue), etc.
603, 604, 605° 606, 607 are fixed to the substrate 608 in a stepwise manner continuously in the color filter arrangement direction A, and are arranged on the line sensor, the end portion adjacent to another line sensor. All color filters are red or blue color filters. Thereby, the same effect as the embodiment shown in FIG. 2(a) can be obtained.

FIG. 7 is a schematic diagram showing a color reading line sensor according to another embodiment of the present invention. B (blue), G (green), and R (red) on the photodetector array.

Line sensors 701, 702 in which color filters are arranged periodically like B (blue), G (green), R (red), etc.
703, 704, 705° 708, 707 are fixed to the substrate 708 in a line in the color filter arrangement direction A, and among the color filters arranged on the line sensor, the color filter at the end adjacent to the other line sensor is fixed to the substrate 708 in a line in the color filter arrangement direction A. All have blue or red color filters. Thereby, the same effect as the embodiment shown in FIG. 2(a) can be obtained.

(Effects of the Invention) As explained above, by using red or blue color filters as all of the color filters in the part of the line sensor in which color filters are arranged periodically and adjacent to other line sensors, it is possible to without increasing calculation errors,
Stable color image reading becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a copying machine equipped with a color reading line sensor of the present invention, FIG. 2(a) is a schematic diagram showing a color reading line sensor of the present invention, and FIG.
) is a partially enlarged view of the line sensor shown in FIG. 2(a), FIG. 2(C) is a timing chart of sensor drive pulses,
FIG. 3(a) is a block diagram of a sensor drive pulse generation circuit, FIG. 3(b) is a timing chart shown in FIG. 3(a), and FIG. 4(a) is a block diagram of an analog signal processing circuit.
FIG. 4(b) is a timing chart of the analog signal processing circuit. Figure 4(c) is a diagram showing the amplifier and offset characteristics in the analog signal processing circuit, Figure 5(a) is a schematic diagram showing the misalignment between sensor chips, and Figure 5(b) is a diagram showing the misalignment between sensor chips. FIG. 5(C) is a control timing chart for correcting misalignment between sensor chips. FIG. 5(d) is a diagram showing readout timing of misalignment correction memory between sensor chips. 7 and 7 are schematic diagrams showing a color reading line sensor according to another embodiment of the present invention, and FIGS. 8(a) and 8(b) are schematic diagrams showing a conventional color reading line sensor. be.

Claims (1)

[Claims] (1) In a color reading line sensor in which a plurality of line sensors in which red, green, and blue color filters are arranged periodically are arranged continuously in the direction in which the color filters are arranged, the color filters are arranged periodically. A line sensor for color reading, characterized in that all color filters in a portion of the line sensor adjacent to other line sensors are red or blue color filters.