JP3321583B2 - Image processing method for separating and reading information on the front and back of translucent paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method for separating and independently reading information on the front and back of translucent paper by a reflection type image scanner.

[0002]

2. Description of the Related Art A method of converting image information on the front and back of a translucent paper into a multi-tone histogram is as shown in FIG.
As shown in FIG. 3A, translucent paper 2 having image information on the front and back sides is set between the carriage surface 1 of the scanner and the document cover 3, and the translucent paper 2 is irradiated with light from the carriage surface 1. . The image information of the translucent paper 2 includes reflected light from ink or toner 6 on the front surface of the translucent paper, reflected light from ink or toner 5 on the back surface of the translucent paper, or reflected light from document cover 3. Is converted to a multi-tone histogram by the pattern FIG. 3B is a multi-tone histogram of image information of translucent paper obtained by a conventional technique. In FIG. 3B, B is reflected light from the ink or toner 6 on the front surface of the translucent paper, A is reflected light from the ink or toner 5 on the back surface, and C is the original cover 3.
, Ie, a portion of the translucent paper having no ink or toner. In a reflection type image scanner according to the prior art, a white original cover 3 is usually used.

[0003]

When reading the information on the front and back of translucent paper such as Mylar paper with a reflection type image scanner, reading in the normal state, compared with the gradation difference between C, A and B, Since the gradation difference between A and B is small, A and B cannot be separated with multi-gradation resolution, and information on the front and back sides is read simultaneously. Separate the information on the front and back sides
In order to perform independent reading, a skilled operator is required to perform processing using functions such as "contrast adjustment" and "brightness adjustment" of the image scanner. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the related art, and has as its object to provide an image processing method for easily and independently reading information on the front and back of translucent paper.

[0004]

The document cover 3 'of the reflection type image scanner is placed on the back surface of the translucent paper (document cover side).
The data is read by a scanner that has been replaced with the same color as that of the ink or toner 5 and has been subjected to highlighting and gamma correction. The dynamic range is expanded and reflected by the "auto gain control (hereinafter referred to as AGC)" function of the image scanner. The gradation difference between the light patterns is widened, and the information on the front and back of the translucent paper 2 is separated and read independently.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image processing method according to the present invention will be described with reference to FIG. In FIG. 1A, the color of the original cover 3 ′ of the scanner is replaced with the same color (for example, black) as the ink or toner 5 on the back surface of the translucent paper 2. B is the reflected light from the ink or toner 6 on the surface of the translucent paper 2, A is the reflected light from the ink or toner 5 on the back of the translucent paper 2, and C is the reflection from the document cover 3 '. Light, that is, a portion having no ink or toner on the translucent paper.

FIG. 2 shows a change in the histogram of the read data caused by changing the original cover from white to black. When the original cover 3 is replaced with a black cover, the pattern of the reflected light from the original cover 3 'shifts from C at the time of the white cover to C' when the black cover is used.
', The gradation difference between A and B is reduced, and the dynamic range is reduced from 0.0 to 1.0 to 0.0 to 0.8. In order to enhance the contrast of the image, it is necessary to extend the gradation distribution of the pattern so as to cover the whole range.
FIG. 1B shows an enlarged view from 0.8 to 0.0 to 1.0. In FIG. 1B, not only the gradation difference between C 'and A and B is enlarged, but also the gradation difference between A and B is enlarged. Information can be easily identified.

The image processing method according to the present invention will be described with reference to the flowchart of FIG. The original cover of a general-purpose reflection type image scanner is replaced with the same color as the ink or toner on the back surface of the translucent paper (step S1), and the translucent paper having image information on the front and back is set on the scanner (step S2). . The image information on the front and back of the translucent paper is read from the scanner which has been subjected to the highlight and the gamma correction (step S3). The read data is converted into a multi-tone histogram (step S4). Next, the scanner A
The tone difference of the multi-tone histogram is extended by the GC function (step S5). A threshold is set so that the information on the back side disappears (step S6), and binarization is performed (step S7). The same process is performed with the translucent paper turned over (step S8), and information on the front and back of the translucent paper is separated and read independently (step S9).

[0008]

As described above, according to the image processing method for translucent paper according to the present invention, the original cover of the reflection type image scanner is replaced with the same color as the ink or toner on the back surface, and the highlight and gamma correction are applied. The image information was read from a scanner, and the read data was converted into a multi-tone histogram, and the threshold was set so that the tone difference of the histogram was expanded by the AGC function, the image separation ability was enhanced, and the information on the back side disappeared. Then, binarization processing is performed. With the above operation, the information on the front and back of the translucent paper can be separated without the need for a skilled operator such as processing using functions such as `` contrast adjustment '' and `` brightness adjustment '' of the conventional image scanner. It became possible to become independent. For example, when reading map information or the like, this technology uses a background (such as geographic information)
In addition, the present invention can be applied to image processing of map information, such as easily separating information (for example, symbols, characters, and the like) on the surface.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an image processing method according to the present invention.

FIG. 2 shows a change in a histogram of read data caused by changing a document cover from white to black.

FIG. 3 is an explanatory diagram showing an image processing method according to the related art.

FIG. 4 is a flowchart of an image processing method according to the present invention.

[Description of Signs] 1 Scanner carriage surface 2 Translucent paper 3 Conventional scanner document cover (white) 3 ′ Scanner document cover according to the present invention (black) 5 Ink or toner on the back of semitransparent paper 6 half Ink or toner on the surface of transparent paper

Continuing from the front page (72) Inventor Masahiro Ishikawa 1-9-9 Motohongo-cho, Hachioji-shi, Tokyo Central Electronics Co., Ltd. (72) Inventor Mitsuhiro Aoki 1-9-9 Motomotogo-cho, Hachioji-shi, Tokyo Central Inside Electronic Co., Ltd. (72) Inventor Koki Ito 1-9-9 Motohongo-cho, Hachioji-shi, Tokyo Central Electronics Co., Ltd. (56) References JP-A-8-289145 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H04N 1/40-1/409

Claims (1)

(57) [Claims] 1. A translucent paper having information on both sides thereof is set between a carriage surface of a reflection type image scanner and a document cover, and image information is multi-gradated from a pattern of reflected light of light emitted from the carriage surface. By converting to a histogram and setting an appropriate threshold for the histogram,
In the image processing method for converting into a value, the color of the document cover of the scanner is replaced with the same color as the ink or toner on the back surface of the translucent paper (document cover side), and image information from the scanner which has been subjected to highlight and gamma correction read, read and convert the data into multi-gradation histogram spread tone difference to expand the dynamic range by "automatic gain control" function of the image scanner of the histogram, between the patterns of reflected light
Information on the front and back of translucent paper by widening the gradation difference
The image processing method and, by setting the threshold value so that the information on the back side disappears binarized, and wherein the reading by separate and independent information on the front and back of the translucent paper.