TWI431547B - Method of reducing black amount in an image - Google Patents

Description

Method for reducing black content in digital images

SUMMARY OF THE INVENTION The present invention is directed to a method of reducing the black content of a digital image such that the digital image can completely or substantially reduce black ink (or toner) after the digital image is printed by the printer.

The commercially available printer will automatically judge the image delivered by the user's computer, and achieve the printing grayscale effect by mixing black ink (toner) to save the consumption of color ink (toner) and achieve better. Dark details of the effect. However, some applications do not want the printer to print images with black ink (toner), such as the use of a light pen (also known as OID Pen, OID: Optical Index / Optical Identification, such as reference http://www.giga .com.tw/english/productpen.htm)Read the print code for reading voice overlaid on a certain image (mostly very fine two-dimensional barcode), and the print code for reading voice is basically black. If the image has many black parts, it will affect the reading success rate of the stylus.

The previous solution was to convert the RGB format image into CMYK format in the image processing software and remove or minimize the K value. However, an RGB value can correspond to a combination of multiple CMYKs, so after the transfer to the print end, the printing system will still process the remaining CMY values: the K value is incorporated to achieve the shadow effect. The image will also be removed due to the K value (dark part) of the original image, and the bright part will not be changed, making the printed image look top-heavy.

Therefore, it is necessary to provide a method of completely bypassing the K-value conversion mechanism of the printing system, allowing the user to print a print that does not contain or reduce black ink (toner).

The applicant applied for the above-mentioned question and applied for the Republic of China patent (Case No. 098139978). However, in the previous application, the pixel needs to be increased by 4 times or 9 times, so the resolution is poor and the operation is time consuming. The method can further improve the previously proposed method.

The primary object of the present invention is to provide a method of reducing the black content in a digital image, and the present invention comprises the following steps:

(A) reading a raw digital image 30, wherein the original digital image includes P original pixels, wherein 3 ≦ P ≦ 9,000,000,000, each original pixel includes three color information, respectively R, G and B, where R Represents a red value, G represents a green value, and B represents a blue value, and:

0≦R≦F, 0≦G≦F, 0≦B≦F, where

2 ⁴ -1≦F≦2 ³² -1; and

(B) converting each P original pixels into corresponding P transition pixels, wherein each transition pixel includes three color information, respectively R', G' and B', wherein R' represents a red value, and G' represents The green value, and B' represents the blue value, and:

0≦R’≦F,0≦G’≦F,0≦B’≦F;

The P transition pixels have the following characteristics: P transition pixels have N sets of transition pixels, where N is an integer and 1 ≦ N ≦ P / 3, wherein each set of transition pixels includes 3 adjacent transition pixels, the 3 Each of the adjacent transition pixels and the three adjacent transition pixels respectively have the following characteristics: characteristic R1: one of the transition pixels is incremented by the R value of the corresponding original pixel such that the R' value of the transition pixel is greater than or Corresponding to the R value of the corresponding original pixel, and the R' value interval of the transition pixel is: 0.8×F≦R′≦F, and according to the embodiment R′=F; the characteristic G1: one of the transition pixels is corresponding The G value of the original pixel is increased such that the G' value of the converted pixel is greater than or equal to the G value of the corresponding original pixel, and the G' value interval of the converted pixel is: 0.8×F≦G′≦F, and according to the implementation Example G'=F; and characteristic B1: one of the transition pixels is incremented by the B value of the corresponding original pixel such that the B' value of the transition pixel is greater than or equal to the B value of the corresponding original pixel, and the transition pixel The B' value interval is: 0.8 × F ≦ B ' ≦ F, and according to the real Example B '= F.

In order to enable the reviewing committee to better understand the technical contents of the present invention, a preferred embodiment will be described below.

Please refer to FIG. 1 for a schematic diagram of the first embodiment of the use environment.

The user performs the method of the present invention through the personal computer 10. The computer 10 mainly includes a processor 11 and a memory 12. The memory 12 stores an application 20. The present invention executes the application 20 through the processor 11 to generate the steps of the present invention.

The computer 10 is connected to a printer 16 by wire or wirelessly. The function of the printer 16 is to print the documents.

Figure 2 is a schematic illustration of a second embodiment of the environment in which the present invention is used. The user uses a near-end computer 81 to connect to a computer 10a (web server) via a network 80 (such as the Internet), so that the near-end computer 81 can use the application 20 of the web server 10a. In the second embodiment, the printer 16 is connected to the near-end computer 81 in a wired or wireless manner. The focus of the two different embodiments is that the user can use the computer to execute the application 20 and then print the file on the printer 16.

Please refer to FIG. 3 for a schematic diagram of techniques and steps for reducing the black content in a digital image according to the present invention. The present invention basically processes each of three adjacent pixels as a group, taking three adjacent pixels 61, 62, 63 as an example, and the values of the three color information RGB are as follows (where R represents a red value, G Represents a green value, and B represents a blue value, with a value of 255 as the full value:

Pixel 61 (RGB) = (0, 150, 200),

Pixel 62 (RGB) = (10, 155, 100),

Pixel 63 (RGB) = (20, 150, 255).

Then, for 3 pixels, respectively: "R value is added", "G value is added" and "B value is added". In this embodiment, the value of R, G or B is directly added to the full value (such as 255). After adding value, please see three adjacent pixels 61a, 62a, 63a, and the values of the three color information RGB are as follows:

Pixel 61a (RGB) = (255, 150, 200),

Pixel 62a (RGB) = (10, 255, 100),

Pixel 63a (RGB) = (20, 150, 255).

It should be noted that each pixel is only incremented for one of the color values. For example, the pixel 61 only adds value to the R value, and does not add value to the G value or the B value. The colors added by the three adjacent pixels are different from each other.

In addition, since the B value of the pixel 63 is originally a full value (255), the pixel 63a has no space to add value to the B value, so the RGB value of the pixel 63a is the same as the pixel 63, so in this specification In the case of color "value added", the meaning of "value added" means that if "color is full value", it is no longer increasing the value of full value.

The above-mentioned pixels 61, 62, 63 or pixels 61a, 62a, 63a are represented by RGB values in the format of general file recording, or color information expressed when presented on the screen 81. As shown in Figure 2, when printed on printer 16 (or other printer), the printing system (or computer) will convert RGB to CMY system printing. CMY is actually a complementary color of RGB. Please continue to refer to Figure 3, which prints pixels 61b, 62b, 63b in CMY:

Pixel 61b (CMY) = (0, 105, 55),

Pixel 62b (CMY) = (245, 0, 155),

Pixel 63b (CMY) = (235, 105, 0).

The CMY value algorithm subtracts the RGB value from the "full value" (eg 255). Since at least one color value (R, G, or B) of the pixels 61a, 62a, 63a is a full value (255), each of the pixels 61b, 62b, 63b has a CMY value of "0", so when the pixel When 61b, 62b, 63b are printed, no black ink will be printed.

In order to further understand the present invention, please refer to FIG. 4 for a flow chart of the present invention, and please refer to FIGS. 1 to 2 and FIGS. 5 to 7 to understand the present invention.

Step 401:

A raw digital image 30 is read.

The original digital image 30 includes P original pixels 31, of which 1 ≦ P ≦ 9,000,000,000. Pixel (pixel) is the smallest unit that constitutes a digital image (dotmap). In the case of an 800x600 image, it consists of 800 grid points in the horizontal direction and 600 grid points in the vertical direction. Therefore, the length and width are 800x600. The size of the digital image contains a total of 480,000 grid points (800x600 = 480,000). The size of P can theoretically be infinite, but for current and future applications, P should be set to a maximum of 9 billion to cover the vast majority of digital images.

For example, if a user obtains a digital image from his or her computer or website, it is read by the application 20. It should be noted that the format of the original digital image may not be recorded in bitmap (such as jpg compression file), then it must be converted to a file described in pixels. The original digital image 30 described in step 401 may be a processed digital image, such as processed by a digital image of another format, or reduced or increased by pixel processing, and the like.

Each of the original pixels 31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h, 31i (taking the first column of FIG. 5 as an example) includes values of three color information RGB. At present, the general color information is expressed in octets, and the value of each color information is at least 0 and the maximum is 255. At present, it is generally expressed in four bits, octet representation, or sixteen digits, and in the future it may be represented by 32 bits, so:

0≦R≦F, 0≦G≦F, 0≦B≦F, where 2 ⁴ -1≦F≦2 ³² -1.

Step 402:

Taking 3 adjacent pixels as a group, the R value is added for each of the 3 pixels, the G value is added, and the B value is added.

Step 402 is as described above in the manner of FIG. 3. Taking the first column of FIG. 5 as an example, each of the original pixels 31a to 31i performs R value, G value, and value of B value in three cycles, as shown in FIG. 6. Shown: For example, the first three adjacent original pixels: original pixel 31a: adding value to R, original pixel 31b: adding value to G, original pixel 31c: adding value to B.

Next, the next set of adjacent original pixels is added: original pixel 31d: adding value to R, original pixel 31e: adding value to G, and original pixel 31f: adding value to B.

Then, the next set of adjacent original pixels is added: original pixel 31g: adding value to R, original pixel 31h: adding value to G, and original pixel 31i: adding value to B.

Of course, the value of R', G' and B' (where R' stands for red value, G' stands for green value, and B' stands for blue value) of any transition pixel after adding value must still be between 0 and full value. That is: 0≦R'≦F, 0≦G'≦F, 0≦B'≦F.

After processing three adjacent original pixels each time, if other pixels have not been processed (step 403), then step 402 is continued until all the original pixels have undergone value-added processing, and finally the converted digital image 50 is completed (step 404).

Since the present invention performs color value-adding processing on every three adjacent pixels, in the case of P pixels, there are at most three adjacent pixels in the "P/3" group, and if N represents several groups of three adjacent pixels. Then, the relationship between N and P can be expressed as follows: N is an integer and 1≦N≦P/3.

After the processing in step 402, according to the above embodiment (including the description of FIG. 3), it can be summarized as follows: the number of pixels of the converted digital image (P transition pixels) still retains 30 pixels of the original digital image (P original pixels) The number of).

P transition pixels have N sets of transition pixels, where N is an integer and 1 ≦ N ≦ P / 3, wherein each set of transition pixels includes 3 adjacent transition pixels, the 3 adjacent transition pixels and the 3 Adjacent transition pixels have the following characteristics:

Characteristic R1:

One of the transition pixels is incremented by the R value of the corresponding original pixel such that the R' value of the transition pixel is greater than or equal to the R value of the corresponding original pixel, and the R' value interval of the transition pixel is: 0.8×F ≦R'≦F.

The G value of the original pixel corresponding to the G' value of the transition pixel is as follows: 0.9G ≦ G' ≦ 1.1 G ≦ F; the B value of the original pixel corresponding to the R' value of the transition pixel is as follows: 0.9B ≦ B' ≦1.1B≦F; take pixel (RGB)=(0,150,200) as an example: R value is added, G, B keeps close:

Pixel (R'G'B') = (204~255, 135~165, 180~220)

R' is at least close to the full value F (e.g., 255) and at least greater than R because the C value for R' turning to printing is small, so the black content is very low. R' is recommended to have a full value of F to ensure no black content.

G'B' is close to G, B can try to maintain the original color, the best suggestion is still G'=G, B'=B.

Characteristic G1:

One of the transition pixels is incremented by the G value of the corresponding original pixel such that the G' value of the transition pixel is greater than or equal to the G value of the corresponding original pixel, and the G' value interval of the transition pixel is: 0.8×F ≦G'≦F.

The B value of the original pixel corresponding to the B' value of the transition pixel is as follows: 0.9B≦B'≦1.1B≦F; the R value of the original pixel corresponding to the B' value of the transition pixel is as follows: 0.9 R≦R' ≦1.1 R≦F; take pixel (RGB)=(0,150,200) as an example: G value increases, B, R stays close:

Pixel (R'G'B') = (0, 204~255, 180~220)

G' should be at least close to the full value F (e.g., 255) and at least greater than G, because the M value when G' is converted to printing is small, so the black content is very low. G' is recommended to have a full value of F to ensure no black content.

B'R' is close to B, and R can maintain the original color as much as possible. The best suggestion is still B'=B, R'=R.

Characteristic B1:

One of the transition pixels is incremented by the B value of the corresponding original pixel such that the B' value of the transition pixel is greater than or equal to the B value of the corresponding original pixel, and the B' value interval of the transition pixel is: 0.8×F ≦B'≦F.

The R value of the original pixel corresponding to the R' value of the transition pixel is as follows: 0.9 R ≦ R' ≦ 1.1 R ≦ F; the G value of the original pixel corresponding to the G' value of the transition pixel is as follows: 0.9 G ≦ G ' ≦ 1.1 G≦F; take pixel (RGB) = (0, 150, 200) as an example: B value is added, R, G stays close:

Pixel (R'G'B') = (0, 135~165, 204~255)

B' is at least close to the full value F (e.g., 255) and at least greater than B because the F value for B' to be printed is small and therefore the black content is very low. B' is recommended to have a full value of F to ensure no black content.

R'G' should be close to R, and G can maintain the original color as much as possible. The best suggestion is still R'=R, G'=G.

In the above-mentioned FIG. 6, the R values, the G values, and the B values are added in a sequential manner by the original pixels 31a to 31i (of course, other sequential methods such as GBR, GRB, RBG, BRG, BGR, etc.) may be added. However, according to the experiment, the effect of not necessarily in a fixed order is also very good, as long as three adjacent original pixels are assigned value-added R value, G value and B value, as shown in FIG. 7, the original pixel 31a~ 31c adds value to RGB, respectively, but the next set of three original pixels 31d~31f respectively add value to GBR (not in RGB order), and the next set of three original pixels 31g~31i respectively to BGR (also not in RGB) The order) adds value.

After the above steps, the original digital image 30 is lowered in black or completely removed to K. After the digital image 50 is converted, for example, the printed document can be used by a light pen 90. The light pen 90 is also called OID Pen (OID: Optical Index/Optical Identification, for example, refer to http://www.giga.com.tw/english/productpen.htm). Since the hardware is a known device, it will not be described here. . Referring to FIG. 8, the voice print code 70 and the transition digital image 50 are printed at the same position. Although the read voice print code 70 is black, the light pen 90 reads the success rate of the voice print code 70. greatly increase.

To sum up, the present invention, regardless of its purpose, means and efficacy, shows its distinctive features of the prior art. You are requested to review the examination and express the patent as soon as possible. It should be noted that the various embodiments described above are merely illustrative for ease of explanation, and the scope of the invention is intended to be limited by the scope of the claims.

10,10a. . . computer

11. . . processor

12. . . Memory

16. . . Printer

20. . . application

30. . . Original digital image

50. . . Transforming digital images

70. . . Voice print code

80. . . network

81. . . Near-end computer

90. . . Light pen

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a first embodiment of an environmental schematic diagram to which the present invention is applied.

2 is a second embodiment of an environmental schematic diagram to which the present invention is applied.

3 is a schematic diagram of a technique and a step of reducing the black content in a digital image according to the present invention.

Figure 4 is a flow chart of the present invention.

Figure 5 is a schematic illustration of the original pixels of the original digital image.

Figure 6 is a schematic diagram of one embodiment of a transformed digital image.

Figure 7 is a schematic illustration of another embodiment of a transition digital image.

Fig. 8 is a schematic view showing a print code for reading a voice by a light pen.

Step 401: Read an original digital image 30.

Step 402: Adding 3 adjacent pixels as a group, adding value to the R value for each of the three pixels, adding value to the G value, and adding value to the B value.

Step 403: All pixels are processed?

Step 404: Complete the transition digital image 50.

Claims (4)

A method for reducing the black content in a digital image by processing a raw digital image into a black content or eliminating black content to obtain a converted digital image, the method comprising the following steps: (A) reading Taking the original digital image, wherein the original digital image includes P original pixels, wherein 3 ≦P ≦ 9,000,000,000, each original pixel includes three color information, respectively R, G and B, wherein R represents a red value, G Represents a green value, and B represents a blue value, and: 0≦R≦F, 0≦G≦F, 0≦B≦F, where 2 ⁴ -1≦F≦2 ³² -1; and (B) will each P original pixels are converted into corresponding P transition pixels, wherein each transition pixel includes three color information, respectively R', G' and B', wherein R' represents a red value, G' represents a green value, and B ' represents a blue value, and: 0≦R'≦F, 0≦G'≦F, 0≦B'≦F; wherein P transition pixels have the following characteristics: P transition pixels have N sets of transition pixels, wherein N is an integer and 1≦N≦P/3, wherein each set of transition pixels includes 3 adjacent transition pixels, the 3 adjacent transition pixels and the 3 adjacent The transition pixels respectively have the following characteristics: characteristic R1: one of the transition pixels is incremented by the R value of the corresponding original pixel such that the R' value of the transition pixel is greater than or equal to the R value of the corresponding original pixel, and the transition pixel The R' value interval is: 0.8×F≦R′≦F; characteristic G1: one of the transition pixels is incremented by the G value of the corresponding original pixel, so that the G′ value of the converted pixel is greater than or equal to the corresponding one. The G value of the original pixel, and the G' value interval of the transition pixel is: 0.8×F≦G′≦F; and the characteristic B1: one of the transition pixels is incremented by the B value of the corresponding original pixel, so that the transition pixel The B' value is greater than or equal to the B value of the corresponding original pixel, and the B' value interval of the transition pixel is: 0.8×F≦B′≦F. The method for reducing the black content in the digital image according to the first aspect of the patent application, wherein: the characteristic R1 further includes: the G value of the original pixel corresponding to the G′ value of the transition pixel is as follows: 0.9G≦G '≦1.1G≦F; The B value of the original pixel corresponding to the B' value of the transition pixel is as follows: 0.9B≦B'≦1.1B≦F; in the characteristic G1, it further includes: the B' value of the transition pixel corresponds to The B value relationship of the original pixel is as follows: 0.9B≦B'≦1.1B≦F; the R value of the original pixel corresponding to the R' value of the transition pixel is as follows: 0.9R≦R'≦1.1R≦F; In B1, the relationship between the R values of the original pixels corresponding to the R' value of the transition pixel is as follows: 0.9R ≦ R' ≦ 1.1R ≦ F; the G value of the original pixel corresponding to the G' value of the transition pixel is as follows: :0.9G≦G'≦1.1G≦F. A method for reducing the black content in a digital image as described in claim 2, wherein: in the characteristic R1, R' = F; in the characteristic G1, G' = F; and in the characteristic B1, B' = F. A method for reducing the black content in a digital image as described in claim 3, wherein: in the characteristic R1, G'=G, B'=B; in the characteristic G1, B'=B, R'=R; And in the characteristic B1, R'=R, G'=G.