JPS62136170A - Color reader - Google Patents

Abstract

PURPOSE:To discriminate an optional color, by normalizing the output signals of lien image sensors based on the level when its self-portrait is received and deciding whether or not the normalized two picture signals coincide with a level range corresponding to an aimed color to be discriminated. CONSTITUTION:Picture signals outputted from line image sensors 8 and 9 are supplied to either white waveform memories 13 and 14 or normalizing circuits 15 and 16 by means of switches 11 and 12. When a color designating key is operated, a level range corresponding to the designated color is read from a memory and the upper and lower limits of the read out level range are outputted to each reference value setter 25-28. Thus the level range is set. In corresponding with the color which is designated to be read, the level ranges of red component Kr and cyan component KC are respectively set in comparators 21 and 22 and 23 and 24. Therefore, the output signal S3 of an AND circuit 31, to which signals S1 and S2 are inputted, is led to a logic level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a color reading device that reads predetermined color information of an image.

[Prior Art] When inputting an image to a facsimile device, an image processing device, etc., it is often convenient if the color information of the image can also be determined.

For example, if a transmission document to be transmitted by a facsimile machine has red writing, a stamp, or a red underline, if this red information can be output, more effective image information transmission will be possible.

By the way, many methods have been proposed for distinguishing colors in this way, but most of them involve color separation of one color using one filter or the like.

However, when attempting to discriminate between many different colors using such conventional methods, it is necessary to provide a filter that spectrally separates each color component, and to switch the filter each time the color to be discriminated changes. is possible, but
This method has disadvantages in that the types of colors that can be discriminated are limited and the device configuration becomes extremely complicated.

[Objective] The present invention has been made to solve the above-mentioned disadvantages of the conventional technology, and an object of the present invention is to provide a color reading device that can read images of predetermined colors.

[Structure] In the present invention, an image is separated into a predetermined color and its complementary color, and photoelectrically converted by a line image sensor.

The output signals of these line image sensors are normalized based on the level when a white image is received. Then, it is determined whether the two normalized image signals match the level range corresponding to the target discrimination color, thereby making it possible to discriminate any color.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an optical system of an image reading apparatus according to an embodiment of the present invention, and in this embodiment, an image is divided into red and its complementary color, cyan.

In the figure, an image on a reading line of an original 1 to be read is illuminated by a light source 2, and the image light reflected from the reading line is reflected by a mirror 3 and guided to a lens 4. Alternatively, the beam is split into two by a beam splitting device 5 such as a prism.

The image light thus branched is separated through a red filter 6 that transmits a red component and a cyan filter 7 that transmits a cyan component, and then images are formed on line image sensors 8 and 9.

Note that the red filter 6 has a transmission limit wavelength of, for example, 580 nm, and has a characteristic of transmitting light of a wavelength longer than 580 nm.
Further, the cyan filter 7 has a transmission limit wavelength of, for example, 620 nm, and has a characteristic of transmitting light having a wavelength shorter than 620 nm.

Now, when an image is divided into red component and its complementary cyan component in this way, all colors contain these two components in a predetermined ratio, so when an image of a certain color is read, the line image sensor The output signal of 8°9 becomes a predetermined level.

That is, when a certain color C is read, the red component Kr and the cyan component Kc are within the ranges of α1 to α2 [phantom and β1 to β2 [%], respectively, as shown in FIG. In addition, in the same figure, the red component Kr and the cyan component Kc
is normalized by setting the level when reading the white part of the background of the document where the light reception level of the line image sensors 8 and 9 is the highest as 100%.

In this way, for one color C, the red component Kr and the cyan component Kc
The reason why it exhibits a certain range is because the colors that are visually recognized as the color CL include, for example, green, which has a bluish green color, and has a certain extent of spread.

And, as a matter of course, such a cyan component Kc
The level range of the red component Kr takes different values for each color C.

It goes without saying that the range of levels of the cyan component Kc and red component Kr for a given color is determined by the spectral characteristics of the red filter 6 and cyan filter 7 used.

FIG. 3 shows a color reading device according to an embodiment of the present invention, which implements the principle of the present invention described above. In addition, in the figure, line image sensors 8, which are not directly related to the present invention, are shown.
Control systems such as the drive control system 9 and the sub-scanning mechanism are omitted.

In the figure, image signals Pi and P2 output from line image sensors 8 and 9 are switched by switchers 11 and 12.

White waveform memory 13.14 or normalization circuit 15.16
can be added to either.

The switch 11.12 is switched by a control means (not shown) to select the white waveform memory 13.14 when reading a reference white image (for example, a white original). As a result, at this time, the line image sensors 8, 9
The image signals PL and P2 output from the white waveform memory 13.
14.

Moreover, the switching devices 11 and 12 are controlled by the above-mentioned control means.
When reading the image of the original document 1, the normalization circuit 15.
16 can be selected.

The normalization circuits 15 and 16 convert the image signals PL and P2 obtained when reading the original document 1 into the image signals PL and P2.
This normalization circuit 1 has a function of converting the level of the signal applied from the white waveform memory 13 and 14 as a reference and converting it into a corresponding digital signal in synchronization with the normalization circuit 1.
5.16, the difference in transmittance between the red filter 6 and the cyan filter is absorbed.

That is, the switch 11. A shading correction circuit SDI that performs shading correction on the image signal P1 outputted by the line image sensor 8 by the white waveform memory 13 and the normalization circuit 15 is connected to the line image sensor 9 by the white waveform memory 14 and the normalization circuit 16. A shading correction circuit SD2 that performs shading correction on the image signal P2 outputted by the shading correction circuit SD2 is formed respectively.

The output signal RD of the normalization circuit 15 is applied to the minus input terminal of the comparator 21 and the plus input terminal of the comparator 22.
The output signal CY of the normalization circuit 16 is added to the minus input terminal of the comparator 23 and the plus input terminal of the comparator 24 by 6. The comparators 21 and 22 are used to identify the level range of the red component Kr. The upper limit of the range is set by the output signal A2 of the reference value setter 25, and the lower limit is set by the output signal A1 of the reference value setter 26.

The comparator 23 and the comparator 24 are connected to the cyan component K.
The upper limit of the range is set by the output signal 82 of the reference value setter 27, and the lower limit is set by the output signal 82 of the reference value setter 28.

The outputs of these reference value setters 25 to 28 are set by an operation display section 29 for operating this color reading device.

The operation display section 29 includes a color designation key for designating the color to be read, and a memory that stores the level ranges of the red component Kr and cyan component Kc corresponding to each color. When the color specification key is operated, the level range corresponding to the color specified at that time is read out from the memory, and the upper and lower limits of the read level range are set by each reference value setter 25 to 28.
Output to and set. Note that the operation display section 29 has various other functions, but they are not directly related to the present invention, so their explanation will be omitted.

As a result, the level range of the red component Kr is set by the comparator 2, corresponding to the color specified to be read at that time.
1 and 22, the level range of the cyan component Kc is set in comparators 23 and 24, respectively.

Therefore, when the signal RD corresponding to the image read at that time is within the level range defined by the signals At and A2, both the output signal S1 of the comparator 21 and the output signal S2 of the comparator 22 become the logic level H, and this As a result, the output signal S3 of the AND circuit 31 to which the signals S1 and S2 are input rises to the logic level H.

Similarly, the signal CY corresponding to the image read at that time
is within the level range defined by the signals Bl and B2, the output signal S3 of the comparator 23 and the output signal S4 of the comparator 24 both become a logic level H,
As a result, the output signal S3 of the AND circuit 32 to which the signals S3 and S4 are input rises to the logic level H.

As a result, the output signals S3. S4
The output signal of the AND circuit 33 to which is input rises to logic level H. The output of this AND circuit 33 is a color image signal CL that reads the color specified at that time.
It is output to an external device such as an image signal processing device.

In this way, an image of the specified color is read from the operation display section 29 and output as a color image signal CL.

By the way, the logical state of the one-color image signal CL is determined by the operation display section 29.
The signals Al, A2 . Bl, B2 and signal R
D and the signal CY, so the comparator 21
22, 23, 24 and AND circuits 31, 32, 33 can be configured by one ROM (read only memory).

Another embodiment of the present invention is shown in FIG. In this figure, the same parts and corresponding parts as in FIG. 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the figure, signals AI and A2 that set the level range of the red component Kr output from the operation display unit 29 corresponding to the designated color, signals Bl and B2 that set the level range of the cyan component Kc, and shading Correction circuit S01.
The red component signal RD and cyan component signal CY output from SO2 are added to the ROM 35.

This ROM 35 contains signals Al, A2 . Bl, B2. R
Corresponding to each value of D and CY, a color image signal CL of a corresponding logical state is stored.

Therefore, the color image signals CL of the colors designated at that time are sequentially output from the ROM 35.

In the embodiment described above, the operation display section 29 includes a color designation key and a signal AI for setting a level range for identifying the color selected by the color designation key.

A2. It is equipped with a memory that stores Bl, B2, and outputs signals AI, A2 . Although Bl and B2 are output, this configuration is not limited to this.

For example, a digital switch that switches the signal level in conjunction with the operation of a color designation key can be used.

Furthermore, in the above-described embodiment, an image is divided into colors using a red filter and a cyan filter, but the types of filters are not limited to these, and include filters that separate a predetermined color and colors that are complementary to that color. Good to have.

Furthermore, it is also possible to determine the level range corresponding to a plurality of colors for one pixel, and identify the color of the pixel.

[Effects] As explained above, according to the present invention, an image is separated into a predetermined color and its complementary color, photoelectrically converted by a line image sensor, and the output signals of these line image sensors are used to receive a white image. Normalize based on the level at that time. Then, it is determined whether the two normalized image signals match the level range corresponding to the target discrimination color, and by this, it is possible to discriminate any color. You get the advantage of being able to read images of

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the optical system of an apparatus according to an embodiment of the present invention, FIG. 2 is a grab diagram for explaining the present invention in detail, and FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 4 is a block diagram showing another embodiment of the present invention. 6...Red filter, 7...Cyan filter, 8.9
...Line image sensor, 11, 12...Switcher. 13.14... White waveform memory, 15.16... Normalization circuit. 21-24... Comparator, 25-28... Reference value setter, 29... Operation display unit, 31-33... AND circuit, 35... ROM (read only memory). Figure 1 (Additional figure) Figure 4 Bill

Claims (2)

[Claims] (1) Spectroscopy means for separating image light on a reading line into a predetermined first color and a second color complementary to the first color; Two line image sensors that receive light and output image signals corresponding to each pixel, a level range setting means that specifies a level range corresponding to the target discrimination color, and a level range setting means that sets the level of the two image signals to the level range. A color reading device comprising a discrimination color detection means for detecting the discrimination color by comparing it with a level range set by a setting means, and detecting an arbitrary color. (2) As described in claim 1, the output image signals of the two line image sensors are normalized at respective reference levels and then applied to the discrimination color detection means. color reading device.