WO2008082161A1

WO2008082161A1 - Method of measuring the pixel width of character image on display

Info

Publication number: WO2008082161A1
Application number: PCT/KR2007/006907
Authority: WO
Inventors: Se-Hyuk Song; Jae-Min Kang; Sang-Woo Lee
Original assignee: Polidigm Co., Ltd
Priority date: 2007-01-03
Filing date: 2007-12-27
Publication date: 2008-07-10
Also published as: KR100833346B1

Abstract

The present invention relates to a method of measuring the pixel width of a character image on a display, which converts a digital image, obtained by capturing a display screen such as an LCD screen, into a black and white image whose horizontal lines are removed, so that vertical pixel lines are clearly displayed. Then, a user can easily align a reference vertical line with the vertical pixel lines such that the pixel width of the character image on the original display screen can be quickly and accurately measured. According to the present invention, the pixel information of several display devices can be recognized by simply processing image data, without a complicated procedure in which the pixel information of the display devices is individually scanned by a separate sensor reading an LCD. Further, when graphic image data is processed by the pixel width through various application processors, the results can be easily applied.

Description

METHOD OF MEASURING THE PIXEL WIDTH OF CHARACTER IMAGE ON DISPLAY

Technical Field

[1] The present invention relates to a method of measuring the pixel width of a character image on a display, which converts a digital image, obtained by capturing a display screen such as a liquid crystal display (LCD) screen, into a black and white image whose horizontal lines are removed, so that vertical pixel lines are clearly displayed. Then, a user can easily align a reference vertical line with the vertical pixel lines such that the pixel width of the character image on the original display screen can be quickly and accurately measured. Background Art

[2] The size of character images on a display screen attached to general digital devices is standardized. Further, although the size of a character on a screen is adjusted, the size of the other characters is also adjusted in such a manner that the size of each character is uniformly maintained. Such a digital image is composed of pixels, and the number of pixels composing each character is uniformly maintained.

[3] However, in such a display screen as an LCD screen used in mobile phones, the size of a region occupied by a character image displayed on the display screen is not uniform. Further, when a variable font is used, the width of each character differs.

[4] Therefore, to measure the width of a character image displayed on a display screen, the number of pixels composing each character image should be counted one by one. When a person counts the number personally, the processing speed decreases, and an error is highly likely to occur. Disclosure of Invention Technical Problem

[5] An advantage of the present invention is that it provides a method of measuring the pixel width of a character image on a display, which converts a digital image, obtained by capturing a display screen such as an LCD screen, into a black and white image whose horizontal lines are removed, so that vertical pixel lines are clearly displayed. Then, a user can easily align a reference vertical line with the vertical pixel lines such that the pixel width of the character image on the original display screen can be quickly and accurately measured. Technical Solution

[6] According to an aspect of the invention, a method of measuring the pixel width of a character image on a display comprises the steps of: (a) receiving a digital image obtained by capturing a display screen whose pixel lines are shown; (b) removing horizontal lines expressed on the digital image; (c) converting the digital image, whose horizontal lines were removed, into a one-bit digital image in which the shapes of character images and vertical pixel lines displayed by the pixel are conserved; (d) displaying a user interface for setting the width of the pixel lines included in the one- bit digital image, and setting the width of the pixel lines by receiving an external input through the user interface; and (e) setting a region including one character image in the one -bit digital image by receiving the external input through the user interface, and filling the character image by the set width of the pixel lines.

Advantageous Effects

[7] According to the present invention, the pixel information of several display devices can be recognized by simply processing image data, without a complicated procedure in which the pixel information of the display devices is individually scanned by a separate sensor reading an LCD. Further, when graphic image data is processed by the pixel width through various application processors, the results can be easily applied.

Brief Description of the Drawings [8] FIG. 1 is a flow chart sequentially showing a method of measuring the pixel width of a character image on a display according to an embodiment of the invention. [9] FIG. 2 is a diagram showing a state where character images are displayed on an

LCD screen such that the pixel lines of the character images are displayed. [10] FIG. 3 is a diagram specifically showing the pixel width of a character image which is to be measured. [11] FIG. 4 is a diagram showing a digital image obtained by capturing the LCD screen, on which the image characters are displayed by the pixel, using a digital camera. [12] FIG. 5 is a diagram showing the digital image whose horizontal pixel lines are removed by a horizontal pixel line removing algorithm. [13] FIG. 6 is a flow chart showing step S30 in which the digital image whose horizontal pixel lines are removed is converted into a one-bit digital image.

[14] FIG. 7 is a diagram showing the digital image from which a red channel is removed.

[15] FIG. 8 is a diagram showing the digital image whose luminance information is only maintained. [16] FIG. 9 is a diagram showing a one-bit digital image obtained when a set critical value is too large. [17] FIG. 10 is a diagram showing a one-bit digital image obtained when the set critical value is too small. [18] FIG. 11 is a diagram showing a one-bit digital image obtained when the set critical value is proper. [19] FIG. 12 is a flow chart showing step S40 in which the width of the pixel lines included in the one-bit digital image is set. [20] FIG. 13 is a diagram showing the user interface on which a plurality of vertical lines for setting the width of the pixel lines are displayed. [21] FIG. 14 is a diagram showing the user interface after the distance between the plurality of vertical lines are properly adjusted by an external input from a user in accordance with the width of the pixel lines. [22] FIG. 15 is a flow chart showing step S50 in which the pixel width of a character image is calculated. [23] FIG. 16 is a diagram showing the result of measuring the pixel width of the character image by increasing the number one by one while the character image is filled by the width of the pixel lines.

Best Mode for Carrying Out the Invention [24] Hereinafter, a method of measuring the pixel width of a character image on a display according to the present invention will be described. [25] FIG. 1 is a flow chart sequentially showing a method of measuring the pixel width of a character image on a display according to an embodiment of the invention. [26] As shown in FIG. 1, a digital image obtained by capturing a display screen, whose pixel lines are shown, is provided (step SlO). The display screen indicates an LCD screen of a mobile phone or the like, on which a character image is displayed by the pixel. The feature of the invention is to measure the pixel width of a character image displayed on the LCD screen of a mobile phone or the like. This will be described in more detail by referring to FIGS. 2 and 3. [27] FIG. 2 is a diagram showing a state where character images are displayed on an

LCD screen such that the pixel lines of the character images are displayed. [28] As shown in FIG. 2, the LCD screen attached on digital communication devices such as mobile phones and so on display characters and figures by the pixel. [29] FIG. 3 is a diagram specifically showing the pixel width of a character image which is to be measured. [30] As shown in FIG. 3, RGB pixels compose one pixel on a color display. The character image 'A' exemplified in FIG. 3 has 8-pixel width. [31] The pixel width of the character image displayed on the LCD display may be measured by checking the pixel width with the naked eye. In this case, however, when the number of pixels is counted by a person, the processing speed is low, and an error is highly likely to occur. Therefore, the LCD screen on which the image character is displayed is processed into a digital image by an imaging device such as a digital camera or the like. [32] FIG. 4 is a diagram showing a digital image obtained by capturing the LCD screen, on which the image characters are displayed by the pixel, using a digital camera.

[33] As shown in FIG. 4, it can be found that the digital image is created in such a manner that the pixel lines of the character images are displayed. In this case, the size of the pixels on the original LCD screen is not identical to that of the pixels composing the digital image created by the imaging device. In general, a number of pixels on the digital image compose pixels lines on the LCD screen.

[34] As such, when the digital image is created by capturing the LCD screen, the pixel lines are created in both the horizontal and vertical directions. However, to measure the width of the character image, only the vertical pixel lines are needed, and the horizontal pixel lines may be an obstacle to measuring the width of the character image. Therefore, after the digital image is created, a process of removing the horizontal pixel lines expressed on the digital image is performed (step S20). FIG. 5 is a diagram showing the digital image whose horizontal pixel lines are removed by a horizontal pixel line removing algorithm.

[35] After the horizontal pixel lines are removed, the digital image is converted into a one -bit digital image in which the shapes of the character images and the vertical pixel lines displayed by the pixel are conserved (step S30). The process of converting the digital image into a one-bit digital image can be roughly divided into three steps. FIG. 6 shows the process in detail.

[36] FIG. 6 is a flow chart showing step S30 in which the digital image whose horizontal pixel lines are removed is converted into a one-bit digital image.

[37] First, as shown in FIG. 6, a red channel among RGB channels of the digital image, whose horizontal pixel lines are removed, is removed (step S31). In the digital image obtained by capturing the LCD screen, the red channel is more prominent among RGB channels. When the red channel is removed, the width of the pixels can be checked more clearly. FIG. 7 is a diagram showing the digital image from which the red channel is removed.

[38] Second, the digital image from which the red channel is removed is converted into a gray digital image whose luminance information is only maintained (step S32). In this step, the digital image from which the red channel is removed is converted in an HSL (Hue Saturation Luminance) image including hue, saturation, and luminance. Then, the channel information of the hue and saturation included in the converted HSL image is removed so as to maintain only the channel information of the luminance. As a result, the digital image is converted into a gray digital image whose luminance information is only maintained, as shown in FIG. 8.

[39] Third, the gray digital image is converted into a one-bit digital image in which the shapes of the character images and the vertical pixel lines displayed by the pixel are conserved (step S33). In this step, when a critical value is adjusted by an external input from a user, the gray digital image is converted into a one-bit digital image referring to the selected critical value. At this time, the critical value should be set in such a manner that the shape of each character image can be conserved. FIGS. 9 and 10 shows examples of the one-bit digital image depending on critical values.

[40] FIG. 9 is a diagram showing a one-bit digital image obtained when the set critical value is too large.

[41] As shown in FIG. 9, when the critical value is too large, the distinction between the character images and the background is clarified, but the vertical pixel lines are not clearly shown.

[42] FIG. 10 is a diagram showing a one-bit digital image obtained when the set critical value is too small.

[43] As shown in FIG. 10, when the critical value is too small, the vertical pixel lines are clearly shown, but the character images and the vertical pixel lines overlap each other such that the character images cannot be recognized clearly.

[44] FIG. 11 is a diagram showing a one-bit digital image obtained when the set critical value is proper.

[45] As shown in FIG. 11, when a proper critical value is selected, the shapes of the respective character images are reliably conserved, and simultaneously, the vertical pixel lines are clearly shown. Therefore, the width of the pixel lines can be clearly recognized.

[46] As described above, after the red channel is removed and the digital image is converted into the gray digital image by the process from step S31 to step S33, the one-bit digital image in which the shapes of the character images and the vertical pixel lines are conserved is created. Then, a user interface for setting the width of the pixel lines included in the one-bit digital image is displayed, and an external input is received through the user interface to set the width of the pixel lines (step S40). That is, the width of the pixel lines is set by an input means such as a keyboard or mouse.

[47] FIG. 12 is a flow chart showing step S40 in which the width of the pixel lines included in the one-bit digital image is set.

[48] First, a plurality of vertical lines are displayed, between which the distance is uniformly adjusted by an external input through the user interface (step S41).

[49] Then, when the external input is received through the user interface, the distance between the vertical lines is set in accordance with the external input, and the width of the pixel lines is set to the same value as the distance between the vertical lines (step S42).

[50] Referring to FIGS. 13 and 14, step S40 will be described in more detail.

[51] FIG. 13 is a diagram showing the user interface on which a plurality of vertical lines for setting the width of the pixel lines are displayed.

[52] As shown in FIG. 13, the user interface is composed of a rectangular cursor and vertical lines displayed in green and red. The distance between the green and red vertical lines can be adjusted by an external input from a user. For example, when a left bracket '<' is pressed, the distance is narrowed. Further, when a right bracket '>' is pressed, the distance is widened.

[53] FIG. 14 is a diagram showing the user interface after the distance between the plurality of vertical lines are properly adjusted by an external input from a user in accordance with the width of the pixel lines.

[54] As shown in FIG. 14, once a user sets the distance between the vertical lines such that the distance corresponds to the width of the pixel lines of the digital image, the width of the pixel lines is recognized referring to the distance between the vertical lines.

[55] At this time, although the distance between the vertical lines is adjusted by an external input, the position of any one of the vertical lines included in the user interface is not changed in the one-bit digital image. In FIGS. 13 and 14, the vertical line corresponds to a vertical line displayed in red in the central upper end of the rectangular cursor. When the distance between the vertical lines is adjusted after the red vertical line is aligned with the vertical pixel lines, the distance between the vertical lines can be effectively adjusted to the distance between the vertical pixel lines.

[56] After the width of the pixel lines is determined by the external input from the user, an external input is received through the user interface so as to set a region including one character image in the one-bit digital image. Further, as the character image is filled by the width of the pixel lines, the pixel width of the character image is calculated (step S50).

[57] FIG. 15 is a flow chart showing step S50 in which the pixel width of the character image is calculated.

[58] First, a region range including one character image in the one-bit digital image is set by an external input (step S51). This is achieved by adjusting and setting the size and position of the rectangular cursor shown in FIGS. 13 and 14 such that one character image is included therein. For example, the width of the rectangular cursor is adjusted using left and right arrows, and the length of the rectangular cursor is adjusted using upper and lower arrows. As such, the size of the rectangular cursor should be adjusted by an external input from a user such that one character image is sufficiently covered by the rectangular cursor. However, a region range including one character image may be set.

[59] Further, when the selection for a specific position within the region range is received through an external input, a region having the same bit value as the specific position within the region range is recognized as the character image (step S52). That is, when a black region corresponding to the character image is selected by a mouse click, all black portions within the rectangular cursor are recognized as one character image.

[60] Next, while the character image is filled by the width of the pixel lines set in step

S40, a vertical line and a number are displayed by the width of the pixel lines (step S53). When the character image is completely filled, the number of fillings performed by the width of the pixel lines is counted so as to be set to the pixel width of the character image (step S54). The results of steps S53 and S54 will be described in more detail with reference to FIG. 16.

[61] FIG. 16 is a diagram showing the result of measuring the pixel width of the character image by increasing the number one by one while the character image is filled by the width of the pixel lines.

[62] As shown in FIG. 16, the region occupied by the character image is filled in red color, and red vertical lines are sequentially displayed from the leftmost side of the character image by the calculated width of the pixel lines. Further, a number is marked on each of the vertical lines, thereby indicating how many pixels the width of the character image is composed of. This is achieved by measuring the pixel width of the character image through the flood- fill algorithm to obtain the pixel width of the region occupied by the character image. Further, the above-described process is repeated for the next character image such that the measurement of the pixel width is achieved.

[63] While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications in form and detail may be made therein without departing from the scope of the present invention as defined by the following claims.

Claims

[1] A method of measuring the pixel width of a character image on a display, comprising: a 10th step of receiving a digital image obtained by capturing a display screen whose pixel lines are shown; a 20th step of removing horizontal lines expressed on the digital image; a 30th step of converting the digital image, whose horizontal lines were removed, into a one -bit digital image in which the shapes of character images and vertical pixel lines displayed by the pixel are conserved; a 40th step of displaying a user interface for setting the width of the pixel lines included in the one-bit digital image, and setting the width of the pixel lines by receiving an external input through the user interface; and a 50th step of setting a region including one character image in the one-bit digital image by receiving the external input through the user interface, and filling the character image by the set width of the pixel lines.

[2] The method according to claim 1, wherein the 30th step includes: a 31st step of removing a red channel among RGB channels of the digital image whose horizontal lines were removed; a 32nd step of converting the digital image, from which the red channel was removed, into a gray digital image whose luminance information is only maintained; and a 33rd step of converting the gray digital image into a one -bit digital image in which the shapes of character images and vertical pixel lines displayed by the pixel are conserved.

[3] The method according to claim 2, wherein the 33rd step comprises a step of converting the gray digital image into a one-bit digital image referring to a critical value set by an external input.

[4] The method according to claim 3, wherein the 32nd step includes: a step of converting the digital image from which the red channel was removed into an HSL (Hue Saturation Luminance) image including hue, saturation, and luminance; and a step of removing the channel information of the hue and saturation which included in the converted HSL image such that only the luminance information is maintained.

[5] The method according to any one of claims 1 to 4, wherein the 40th step includes: a 41st step of displaying a plurality of vertical lines between which the distance is unif orally adjusted by an external input through the user interface; and a 42nd step of setting, when an external input is received through the user interface, the distance between the vertical lines in accordance with the external input, and setting the width of pixel lines to the same value that of the distance between the vertical lines.

[6] The method according to claim 5, wherein the 41st step includes a step of displaying one vertical line whose position is fixed within the one -bit digital image, and wherein the 42nd step includes a step of changing the distance between the plurality of vertical lines in accordance with the external input referring to the fixed vertical line.

[7] The method according to claim 6, wherein the 50 step includes: a 51st step of setting a region range including one character image in the one-bit digital image in accordance with the external input; a 52nd step of recognizing a region as a character image, when a selection for a specific position within the region range is received through an external input, which region has the same bit value as the specific position within the region range; a 53rd step of displaying a vertical line and a number by the width of the pixel lines set in the 40th step, while filling the character image by the width of the pixel lines; and a 54th step of counting, when the character image is completely filled, the number of fillings performed by the width of the pixel lines so as to set the width of the character image by the number of fillings.