JPS63107361A - Picture reader - Google Patents

Abstract

PURPOSE:To attain picture processing while the part of reduced luminous quantity is takes as a white level by bringing the part of the reduced luminous quantity near a reference white board to be equal to a detection level of the said reference white board. CONSTITUTION:In an example of detection where an original without any picture is read, an area A of addresses 80-90 corresponds to the part of reduced luminous quantity and an area B of addresses 90-95 is a part of detection of a reference white board 7, and an area C is a reference white level by the reference white board 7. A picture processing circuit calls the detection data of the addresses 90-95 being a detection data of the reference white board to the addresses 80-90 set in advance while estimating the luminous quantity reduction and transfers the detection data of the said addresses 90-95 to the said addresses 80-90. Then a conventional picture processing is applied. That is, the data corresponding to the reduced luminous quantity at the addresses 80-90 is subject to picture processing while regarding the reference white board of addresses 90-95 as a white level.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image reading device such as a facsimile machine that optically reads images, and particularly to an image reading device capable of reading images such as photographs having shading.

Prior Art and Problems> As a method for reading images with shading, a reference white plate serving as a white reference is provided in the image reading window located in the front of the document, and
A method has been proposed in which a reference white plate is also read along with the original during image reading, and the read image is divided into gradations based on the detection level of the reference white plate. However, in the above method, the reference white is white (see Figure 4 (a)), and a shadow of the reference white plate is generated on the document due to the irradiation of the fluorescent light, and the document surface near the reference white plate is A decrease in the amount of reflected light occurred.

Therefore, since there is a shadow even though the data is actually white, the shadow portion on the document is detected as black data.

In view of the above-mentioned problems, it is an object of the present invention to perform image processing by treating the portion where the light amount decreases near the reference white plate as white.

Means for Solving the Problems> The present invention provides a light source for irradiating a document with light, an image reading window provided in the front of the document being conveyed, and a light source provided within the document reading range of the image reading window. A reference white plate provided, a charging conversion element that performs photoelectric conversion upon receiving reflected light from the original, and outputting an image signal corresponding to the density of the original based on an output signal from the photoelectric conversion element. In the image reading device capable of reading grayscale images, the image processing circuit converts the output wart signals around the signal portion corresponding to the reference white board among the output wart signals from the charge conversion element into the This image reading device is characterized in that image processing is performed in the same way as a signal portion corresponding to a reference white plate.

Effects> According to the present invention, by making the portion where the amount of light decreases near the reference white plate the same as the detection level of the reference white plate, the portion where the amount of light decreases is regarded as white and image processing is performed.

Embodiment> FIG. 1 is a perspective view schematically showing an image reading apparatus according to an embodiment of the present invention. 1 is an original, 2 is a fluorescent lamp that irradiates light onto the original 1, 3 is a mirror that deflects the light reflected from the original 1, 4 is a lens that focuses the polarized light, and 5 is the focused light. A CCD image sensor detects light and converts it photoelectrically, 6 is a back plate provided on the back side of the original 1, and 7 is an image reading window provided on the front side of the original. Reference numeral 8 denotes a reference white plate according to the present invention, which is provided using a part of the document reading range of the CCD image sensor 5, and is assigned as reference white data of a part of the image signal to be read. That is, the light emitted from the fluorescent lamp 2 is reflected by the original 1 and then reflected by M, 3.
be deflected. The polarized light is collected by a lens 4 and detected by a CCD image sensor 5. At this time, the reference white plate 8 is also irradiated with the light of the fluorescent lamp 2, and the image data is
It is read by the CD image sensor 5. FIG. 2 is a block diagram of an image reading device according to the present invention. 9 is fluorescent light 2
10 is an image reading circuit for reading an image signal read by the CCD image sensor 5 and A/D converted, and is equipped with an image memory. Reference numeral 11 denotes a document feed control circuit for controlling a drive motor 12 connected to a document feed roller (not shown). Reference numeral 13 denotes an image processing circuit that divides the image data read by the image reading circuit 10 into several gradations corresponding to the shading of the original according to the level thereof, and sends out a predetermined image signal. In the present invention, the detection level of the reference white plate 8 is regarded as the reference white, and other detection levels are determined based on that level; ! It is meant to be divided.

14 is a main control circuit that controls a series of these image reading operations.

FIGS. 3(a) and (1]) show CCDs of the conventional and the present invention.
This is an example of detection by the image sensor 5. Areas A and A in the diagram
' is a light intensity decreasing part, area B is a detection part of the reference white plate 7, and 6C is a reference white level by the reference white plate 7. That is, in the present invention, as shown in FIG. 3(b), the portion where the amount of light decreases is processed as the level B, which is the same as the reference white level, and the image processing is performed by regarding the portion where the amount of light decreases as white. Fourth
The figures show specific embodiments of the present invention. Figure 4(a) shows an example of detection when reading an unambiguous original, and addresses 80 to 9 are shown.
Area A of 0 is a reduced light amount area, area B of addresses 90 to 95 is a detection area of the reference white plate 7, and C is the reference white level by the reference white plate 7. FIG. 4(b) is a 70-chart of the part of the present invention in image processing. First, the main control circuit 14 starts calling the detection data (30
1). When the retrieval is started, the detected data is retrieved from the image memory in the image reading circuit 10, and the detected data is retrieved from the image memory in the image reading circuit 10.
The called detection data is at address 80, which was set by the operator in anticipation of the area where the light intensity decreases.
A determination is made as to whether it is part 90 (302). If the determined address is between 80 and 90, the image processing circuit 1
3 is address 90~ which is the detection data of the reference white plate part.
95 is called (303), and the detected data at addresses 90-95 is transferred to the portion of addresses 80-90 (304). After that, normal image processing is performed. That is, image processing is performed on the data of the reduced light amount portions at addresses 80 to 90, with the reference white @ portions at addresses 90 to 95 being white.

<Effects> As described above, according to the present invention, the light J[
::By making the reduced portion the same as the detection level of the reference white plate, the reduced light amount portion is regarded as white and image processing is performed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a block diagram of the image reading device shown in FIG. 1, FIG. 3 is a diagram showing an example of detection by a COD image sensor, and FIG. ) is a diagram showing an example of detection when a non-image original is read, and Figure 14 (b
) is a flowchart in image processing. 1... Original 2... Fluorescent light 5... COD image sensor 6... White back plate 7... Image reading window
8... Reference white plate 9... Fluorescent lamp drive circuit 10.
...Image reading circuit 13 Image processing circuit 14...Main control circuit Agent Patent attorney Takeshi Sugiyama (and 1 other person) Figure 1 6 Kuno
tb head 13 -v Figure 2 (b) Figure 4

Claims (1)

[Claims] A light source for irradiating the original with light, an image reading window provided in front of the transported original, a reference white plate provided within the original reading range of the image reading window, and reflected light from the original. and an image processing circuit for outputting an image signal corresponding to the density of the original document based on the output signal from the photoelectric conversion element. In the apparatus, the image processing circuit performs image processing by making an output signal around a signal portion corresponding to the reference white plate the same as a signal portion corresponding to the reference white plate in the output signal from the photoelectric conversion element. An image reading device characterized by