JPH01248870A - Color input device - Google Patents

Abstract

PURPOSE:To read a color image without speed decrease by providing a reading means to read the image with changing an accumulating time according to a reflected light color, and successively outputting and processing the image at the accumulating time at an integer ratio or the ratio approximate to it from the color at higher comparative output sensitivity. CONSTITUTION:A reading means E is linked to respective R, G and B image sensors (a), and reads the image in a reading cycle for the same part of a color original with the help of the reflecting light color by changing the accumulating time. Following processing stages are constituted in the sequence of a switching circuit part (e), an amplifying circuit part b1, a color processing circuit part c1, a memory circuit part d1, and an I/F circuit part (f) in the same way for the R, G and B. The reading is executed in a reading cycle t1 for the same part in a reading cycle T, in which the R, G and B colors are read, at every line, in the sequence of R, G and B which is the sequence arranged from the higher comparative output sensitivity, with the accumulating time of integer ratio or the ratio approximate to it of 1:2:3.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a color input device.

(Prior Art) Conventionally, color input devices have been used to read color image sensor information such as printed matter, documents, and photographs in full color.
Several types have been commercialized.

Hereinafter, a conventional color input device (hereinafter referred to as the device) will be explained using FIGS. 3 to 9.

FIG. 3 is a block diagram of a color processing circuit including a conventional reflected light conversion means, and FIG. ) is −
FIGS. 4 to 7 are block diagrams showing cases in which the output circuit portion is shared. FIGS. green).

B (blue) light source switching system, Figure 5 shows R and G.

83-color separation method, Fig. 6 is a block diagram of each method of R, G, and 83-color filter switching method, and Fig. 7 (A) shows R, G on the image sensor.

B filters are stacked, and Fig. 7 (B) shows R and G filters.

A configuration diagram of each method of a proximity image sensor equipped with a B filter, Fig. 8 is a timing diagram in which the output timing from the image sensor is changed for each color, and Fig. 9 is a diagram showing the wavelength of light of the color filter and monochrome image sensor. 9(A) is a transmission characteristic diagram of the R, G, and B color filters with respect to the wavelength of light, and FIG. 9(B) is a diagram of the sensitivity characteristic of the monochrome image sensor with respect to the wavelength of light.

Next, in FIG. 3(A), a is a sensor section RlG, an image sensor for 83 colors, b is an amplification circuit section for R, G, and 83 colors that amplifies the signal from image sensor a, and C is an amplification circuit section for 83 colors. Color processing circuit section for R, G, 83 colors, d is R, G,
Memory circuit section that stores 83 color data, e is R, G
, f is a common switching circuit section for each of the 83 colors, and f is a 17F circuit section, and the amplification circuit section has a different amplification factor for each color of the image sensor a, and is located in front of the color processing circuit section e. The gains are the same.

Next, in FIG. 3(B), C1 is a color processing circuit section common to R, G, and 83 colors, d is a memory circuit section common to the three colors, and all amplifier circuit sections for R, G, and B are shown. A switching circuit section e is disposed after the color processing circuit section CI, a memory circuit section d, and an I/F circuit section f.

Next, 1 in Figure 4 is R (red) and G (green).

B (blue) light source, 2 is a document table, 3 is a CCD which is an image sensor, 4 is a lens, in FIG. 5, 5 is a prism that separates incident light into R, G, and B; In the figure, 6 is a filter having each of 83 colors: R and G.

Next, the operations of these conventional examples will be explained.

The device shown in Figure 4 is a light source with three types of different wavelengths: R, G, and B.
One scanning line is switched on three times (R, G) in turn.
, 83 colors) and read them sequentially. The device shown in Fig. 5 uses a prism 5 to convert the reflected light from the original into R, G, 83
The light is divided into colors, and an image sensor (CCD) 3 is provided for each color to efficiently read the three colors simultaneously. The device shown in Fig. 6 uses a solenoid (not shown) or a motor (not shown) to sequentially switch the filters 6 of R, G, and 83 colors.
The three colors are read in sequence with one CCD3.

In all of the three embodiments described above, a monochrome image sensor is used to read a color image using reflected light that is separated into R, G, and 83 colors. On the other hand, the seventh
The device shown in the figure utilizes a color image sensor 7.

In FIG. 7(A), red, green, and blue filters are sequentially stacked for every three pixels on an image sensor array 7a for three colors and three times the density. Therefore, simultaneous reading of three colors is possible at one time. However, the reading location is slightly off depending on the color. Similarly, in FIG. 7(B), three image sensors 7 are arranged close to each other, and filters of different colors are arranged respectively. Shikaru and others! To read three colors at one location, buffer memory for the shifted lines is required. Further, each of these conventional examples requires a lighting device.

However, whether it is a light source of 83 colors such as R, G, or a white light source, the intensity of light of wavelength corresponding to each color is different.

FIG. 9(A) is a diagram showing the transmission characteristics of the color filters FL, G, and B with respect to the wavelength of light, and the horizontal axis represents the incident wavelength (μm);
The vertical axis indicates relative output, and R2O and B indicate red, green, and blue characteristic curves, respectively. FIG. 9(B) is a sensitivity characteristic diagram of the monochrome image sensor with respect to the wavelength of light, where the horizontal and vertical axes indicate the incident wavelength (μm) and relative output, respectively.

As shown in Figure 9 (A), the filter also has different light transmittance and stickiness depending on the wavelength, and although the same monochrome image sensor is used, as shown in Figure 9 (B), the image sensor The output characteristics of each color also differ depending on the wavelength.

From this, naturally, the combined sensitivity output of the above three factors differs depending on the color.

Therefore, the reflected light from the color original illuminated by a light source is imaged on an image sensor, accumulated for a certain period of time (hereinafter referred to as accumulation time), and converted into an electrical signal by the reflected light conversion means, which reads the full color of the color original. If -
It was necessary to read by adjusting the reading cycle to colors for which Chikara Kagawa has low sensitivity.

Next, the advantages and disadvantages of the conventional color processing circuit will be explained with reference to the block diagram of FIG. 3 and the timing diagram of FIG. 8.

In the circuit system shown in FIG. 3(A), R up to the memory circuit section d
, G, and B, which is expensive. Therefore, as shown in Fig. 3 (B), in order to make the circuit common, a switching circuit section e is arranged after the amplifier circuit section, and the latter circuit section is made common.Three colors are available. They have to be processed in order, which takes three times as long.

Therefore, as shown in FIG. 8, a method has been adopted in which the output timing from the image sensor is changed for each color and processing is performed sequentially.

In FIG. 8, 1 indicates a shift in output timing from the image sensor for R, G, and 83 colors, and 2 indicates a shift in processing timing.

This method makes the timing relationship a little more complicated, but
After reading, there is no speed reduction due to sequential processing. However, the reading location may be slightly shifted depending on the color, and the process when restarting after a temporary stop is complicated.

[Three problems to be solved by the invention] As explained above, in the conventional example, each of the above processing methods is expensive or takes about three times as long.
Another problem is that the reading location may shift slightly depending on the color, complicating processing when restarting.

This invention was made to solve the above-mentioned problems.It is inexpensive, has no problem with the reading location and reading timing depending on the color, reads each color and performs color processing within the same reading cycle, and reduces speed reduction. It is an object of the present invention to provide a color input device that enables reading of color images that are not available.

(Means for Solving the Problems) Therefore, in the present invention, reflected light from a color original illuminated by a light source is imaged on an image sensor,
In a color input device having a reflected light converting means for accumulating a certain period of time and converting it into an electric signal, a reading means (E) is provided for reading the reflected light while changing the accumulation time depending on the color of the reflected light within a reading cycle of the same location. This aims to achieve the above objective.

(Function) The color input device of the present invention uses a reading means, for example, to sequentially output and process colors starting from a color with a high relative output sensitivity with an accumulation time of an integer ratio or a ratio close to it, so that the color of reflected light can be adjusted at the same location. Within the reading cycle, the storage time is changed depending on the color of the reflected light.

(Example〕 Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of an electric circuit having a reading means (E) which is an embodiment of the present invention.
, G, and B image sensors a, and reads the same part of a color document within the reading cycle, changing the accumulation time depending on the color of the reflected light (details will be described later).
. The subsequent processing steps include switching circuit section e, amplifier circuit section b19 color processing circuit section CI + memory circuit section a I +1
/F circuit section f is commonly configured for R, G, and B in the order,
The circuits after the switching circuit section e are the same as those in the conventional example, so repeated explanation will be omitted.

FIG. 2 is a timing diagram showing the reading and one-color processing timing of a color input device which is an embodiment of the present invention.
Figure 2 (A) is a timing diagram showing the reading 0 color processing timing, and Figure 7 (B) is a timing diagram showing the timing when reading only one color. In Figure 2 (A), T is R
, G, the reading cycle for each line to read 83 colors, tl is the reading cycle of the same part of the reading cycle T, Tr, Tg, and Tb are the images of the reflected light from the color document illuminated by the light source on the image sensor. Then, each accumulation timing is s3& to the reflected light conversion means that accumulates for a certain period of time and converts it into an electric signal, rt I gt * b
2 indicates the color processing time for each color of R, G, and B, respectively.

Next, in FIG. 2(B), T is a reading cycle when reading only G (green) color, for example, and t2 is a reading cycle T.
, Tg is the accumulation timing of G color, gl is the accumulation time of G color, Cg & t is the color processing timing of G color, and gt is the color processing time of G color.

In each figure, the same or equivalent components as those in the conventional example are represented by the same reference numerals, and repeated explanation will be omitted.

Next, an experiment for measuring R, G, and B photoelectric conversion sensitivity ratios will be described.

The measurement conditions for this experiment were to use a BASIS image sensor as a monochrome image sensor, a light source A as a light source, a commercial standard product (manufactured by Dai Nippon Printing Co., Ltd.) as a color filter, and an accumulation time of approximately 1.2 ms. The same conditions were used. The results of experiments and measurements under the same conditions as above are red (R) and green (G).

The photoelectric conversion sensitivity ratio of blue (B) is R:G:B 1:0
．． 65:0.37. If this is B Mi 1, then R:
G:B=2.7:1.7:1. In this case, R:G
:B = 3:2:1, which is an approximately integer ratio, the slight deviation from the above ratio can be compensated for by arranging three amplifiers separately as in the conventional example shown in FIGS. 3(A) and 3(B). Even if you do not correct it, the first
Figure.

As shown in FIG. 2, with one amplifier, in addition to AE correction, shading correction, etc., it is possible to simultaneously perform necessary corrections for each color. Therefore, R has the same output sensitivity as B with an accumulation time of approximately 1/3 of B, and G with approximately 2/3 of B.

In this embodiment, the BASIS image sensor is used as described above, but since the photoelectric conversion section of the CCD image sensor is composed of a similar silicon phototransistor, it exhibits similar sensitivity characteristics.

Next, based on the above results, we will discuss the timing of the reading means (E) which reads the same location within the reading cycle by changing the storage time for each color of R, G, and B, as shown in Figure 2 (A
) and (B).

In FIG. 2(A), the reading cycle Tk for each line for reading R, G, and 83 colors is shown in the reading cycle 1. Among them, R and G are in descending order of relative output sensitivity.
. That is, each of the accumulation timings Tr, 'rg, and 'rb is read at the same location at a reading cycle of 1. Inside” ert :gt :tl
It outputs at an accumulation time of l = 1:2:3 or a ratio close to this, and the color processing timings Cr, Cg, and Cb from the switching circuit section e to the I/F circuit section f in Fig. 1 are each of the same length. Within the reading period t, color processing is performed for r2°gz and b* in the same processing time.

In this way, by utilizing the difference in output sensitivity of R, G, and B that is approximately an integer ratio, it is possible to read the same location within the reading period by changing the accumulation time depending on the color.

As mentioned above, each process of a Nf in Fig. 1 is explained in Fig. 2 (A
) R, G at the timing shown.

By sequentially overlapping color processing using different storage times and processing timings for each of the 83 colors, color images can be created using a simple circuit configuration that sequentially processes all three colors using a circuit for one color without reducing reading speed. Can be read and processed.

Regarding the R, G, and H output sensitivity characteristics, the light sources actually used are white fluorescent lamps, halogen lamps, etc., and their spectral characteristics are different from the light source A used in this example. , R,G.

The output sensitivity characteristics of B are different. However, basically, it is possible to deal with the problem as described above by changing the correction value for each color or changing the amplifier gain or the like to make the sensitivity ratio of each color an integer ratio.

Next, a mode will be described in which a characteristic single color, for example, only green (G) is read at a reading cycle corresponding to the storage time of the single color G.

As shown in Figure 2 (B), when reading with only green (G), the green (G) accumulation time g+ (Figure 2 (A))
If the reading period t2 is configured with only R, G in color,
, cycle 1 when reading all 83 colors. It takes 2/3 of the time compared to the conventional method, and can be read at high speed. Also, red (R
) When reading in one color (not shown), use 1/1 color in the same way.
High-speed reading is possible in 3 hours.

As explained above, according to this embodiment, it is possible to sequentially perform color processing for three colors using a circuit for one color by utilizing the difference in sensitivity of the image sensor depending on the color that constitutes visible light. , other highly sensitive colors can be processed during the accumulation timing (time) of the least sensitive color,
Does not require special processing time. In addition, by taking advantage of the fact that the difference in sensitivity between colors is close to an integer ratio, it is possible to simplify the timing circuit and processing routine, and when reading with only one color with high output sensitivity, the It is possible to read faster by using a read cycle that matches the storage timing.

(Effects of the Invention) As explained above, according to the present invention, reflected light conversion is performed in which reflected light from a color document illuminated by a light source is imaged on an image sensor, accumulated for a certain period of time, and converted into an electrical signal. In a color input device having a color input device, by providing a reading means (E) that changes the storage time and reads the same location according to the color of the reflected light within the reading cycle of the same location, it is inexpensive and can read the location according to the color of the reflected light. There is no problem with the reading timing, each color is read and processed within the same reading cycle, and the effect is that it is possible to read color images without slowing down.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a processing circuit having a reading means according to an embodiment of the present invention, and FIG. 2 is a timing diagram showing color processing timing according to an embodiment of the present invention.
) is a timing diagram showing the reading processing timing for one color, FIG. 2(B) is a timing diagram showing the timing when reading only one color, and FIG. 3 is a block diagram of a color processing circuit including a conventional reflected light conversion means. Yes, and Fig. 3 (A) shows that when R, G, and 83 circuit parts are arranged up to the memory circuit part, Fig. 3 (A)
B) is a block diagram showing a case where some circuit parts are shared, and FIGS. 4 to 7 are block diagrams of a device that is a conventional reflected light conversion means. , 83-color filter switching method, Figure 5 is a separation method into R, G, and 83 colors, Figure 6 is a configuration diagram of each method of R, G, and 83-color filter switching method, and Figure 7 (A) 7(B) is a configuration diagram of a proximity image sensor method with R, G, and B filters arranged on the image sensor, and FIG. 8 is a configuration diagram of each method for each color. A timing diagram with different output timing from the image sensor. Figure 9 is a characteristic diagram of the color filter and the monochrome image sensor with respect to the wavelength of light. Figure 9 (A) is a diagram showing the wavelength of light of the color filters R, G, and B. Transmission characteristic diagram for Fig. 9 (B
) is a sensitivity characteristic diagram of a monochrome image sensor with respect to the wavelength of light. 1------Light source 3---CCD 6---------Filter T---Reading cycle 1, . 1.・・・・・・Reading cycle

Claims (5)

[Claims] (1) In a color input device that has a reflected light conversion means that images reflected light from a color original illuminated by a light source on an image sensor, accumulates it for a certain period of time, and converts it into an electrical signal, within the reading cycle of the same location. A color input device characterized in that the color input device is provided with a reading means that changes the accumulation time and reads the reflected light depending on the color of the reflected light. (2) The color input device according to claim 1, wherein the reading means sequentially outputs and processes the colors starting from the colors with the highest relative output sensitivity at an accumulation time of an integer ratio or a ratio close to the integer ratio. (3) The reading means selects the colors with the highest relative output sensitivity in order of red (R
), green (G), and blue (B). (4) The reading means is characterized in that the ratio of accumulation times in the order of red (R), green (G), and blue (B) within the reading cycle of the same location is approximately 1:2:3. 4. A color input device according to claim 1, 2 or 3. (5) The color input device according to claim 1, further comprising a mode in which when reading a specific single color, the reading is performed at a reading cycle corresponding to the storage time of the single color.