JPH04252658A - Color image input device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image input device using a line sensor or the like, and specifically relates to a color separation method.

0002

2. Description of the Related Art Conventionally, several methods have been studied as means for inputting color images in image input devices using line sensors such as CCDs.

For example, as shown in FIG. 2, three lighting devices 1b, 1c, and 1d that emit specific wavelengths of RGB are sequentially turned on,
The document surface 3 placed on the document table glass 2 is illuminated to obtain color-separated document surface reflected light 7, and mirrors 4a, 4b, 4
The light reflected from the original surface is guided to the imaging system 5 by c, and color-separated RGB images are sequentially formed on the photoelectric conversion element 6d.

In another example, as shown in FIG. 3, an illumination device 1a using a white light source illuminates a document surface 3 placed on a document table glass 2, and the reflected light 7 is transmitted to mirrors 4a, 4b, 4.
c, the light is guided to the imaging system 5 and imaged on the photoelectric conversion element 6d. Color separation is then performed by sequentially inserting RGB filters 10 between the document surface and the imaging system of the above-mentioned apparatus.

[0005]

[Problem to be Solved by the Invention] In the above-mentioned image input device, when trying to obtain full color for each line, R
In the method using three GB lighting devices, the three lighting devices are blinked for each line, but it is necessary to synchronize the blinking. In addition to the actual lighting time, the time required for the light intensity to stabilize after the lighting device is turned on, and the time for the afterglow to disappear after the lighting device is turned off, are required, and there is a limit to the reading speed.

[0006] Furthermore, when using RGB three-color filters, a mechanism is required to operate the filters, and as mentioned above, a mechanism is required.
It is necessary to synchronize filter insertion for each line. Apart from the above method of obtaining full color for each line,
In the method of reading the required document range separately for each color and then combining the document images of each color to obtain full color, RG
In both cases where three B illumination devices are used and when three RGB color filters are used, one round trip is required to read each of the RGB colors, and a total of three round trips are required, so there is still a limit to the reading speed.

[0007] Furthermore, in the conventional color separation method, information for each color is given in chronological order, so in order to perform color correction processing that requires full-color information, for example, the data for each color must be temporarily stored. Memory was required to hold it.

[0008] The prior art had the above-mentioned problems. The present invention is intended to solve these problems, and its purpose is to enable high-speed reading, eliminate the complicated control required for color separation, and retain data for each color. This eliminates the need for memory for

[0009]

[Means for Solving the Problems] In order to solve the above problems, a color image input device of the present invention is provided with a document table glass, an illumination device using a white light source, a photoelectric conversion element, and an imaging system, In an image input device in which the light reflected from the illuminated document surface is imaged onto a photoelectric conversion element by an imaging system, at least two Equipped with two semi-transparent mirrors, the semi-transparent mirror branches the original image into different directions, and a color separation filter is installed individually at each branch destination to perform color separation. It is characterized by forming an image on a photoelectric conversion element.

0010

[Operation] According to the above structure of the present invention, by branching the original image into multiple directions and installing a color separation filter at each branch destination, the color-separated image is simultaneously subjected to individual photoelectric conversion. Since the image is formed on the element, high-speed reading is possible, and there is no need to insert a filter or synchronize the blinking of the illumination device.

[0011]

Embodiments will be explained below based on the drawings.

FIG. 1 is a sectional view in the sub-scanning direction of a color image input device according to the present invention. A document surface 3 placed above a document surface 2 is illuminated by a white light illumination device 1a, and the generated document surface reflected light 7 is guided to an imaging system 5 by mirrors 4a, 4b, and 4c. Then, two semi-transparent mirrors 8a and 8 are installed in the back focus of the imaging system 5, and the original image is split into three directions and formed onto photoelectric conversion elements 6a, 6b, and 6c, respectively. In addition, R filters 9a and 6b are provided in front of the photoelectric conversion element 6a.
G filter 9b on the front of 6c, B filter 9c on the front of 6c
is installed, and an image decomposed into R elements is formed on the photoelectric conversion element 6a, an image decomposed into G elements is formed on the photoelectric conversion element 6b, and an image decomposed into B elements is formed on the photoelectric conversion element 6c, respectively.

[0013]

As described above, the color image input device according to the present invention includes two semi-transparent mirrors installed in the back focus, three photoelectric conversion elements, and a color image input device installed in front of the photoelectric conversion element. Since it is possible to obtain color-separated images at the same time using the RGB filters, high-speed color image reading is possible, and there is no need to synchronize lighting device blinking and filter insertion, making control easier. Furthermore, full color information can be obtained at the same time, and there is no need for memory for color correction processing.

Another possible method is to use a dichroic mirror to perform color separation in the same manner as in the present apparatus, but a semi-transparent mirror is cheaper and easier to produce than a dichroic mirror.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view in the sub-scanning direction of a main optical system of a color image input device according to the present invention.

FIG. 2 is a cross-sectional view in the sub-scanning direction of a conventional color image input device that performs color separation by blinking illumination.

FIG. 3 is a cross-sectional view in the sub-scanning direction of a conventional color image input device that performs color separation by sequentially inserting filters.

[Explanation of symbols]

1a White light source lighting device 1b R color lighting device 1c G color lighting device 1d B color lighting device 2　　　Original table glass 3　　　　Manuscript surface 4a 1st mirror 4b Second mirror 4c 3rd mirror 5 Imaging system 6a First photoelectric conversion element 6b Second photoelectric conversion element 6c Third photoelectric conversion element 6d Photoelectric conversion element 7. Light reflected from the original surface 8a First semi-transparent mirror 8b Second semi-transparent mirror 9a R filter 9b G filter 9c B filter 10 RGB filter

Claims (1)

[Claims] Claim 1: A document platen glass, an illumination device using a white light source, a photoelectric conversion element, and an imaging system. In a color image input device that forms an image on a photoelectric conversion element, a semitransparent mirror is installed between the imaging system and the photoelectric conversion element, and the semitransparent mirror branches the original image in different directions. 1. A color image input device comprising means for first installing color separation filters to perform color separation, and for forming each color-separated image on a plurality of photoelectric conversion elements.