KR101195018B1 - Electronic pen for capturing an image, and method thereof - Google Patents

Abstract

The present invention emits LEDs at the same time each time a vertical synchronous signal that starts an image frame is generated in an electronic pen using a CMOS-type image sensor to obtain a still image. The present invention relates to an image acquisition electronic pen and an image acquisition method thereof capable of acquiring an image for one frame in such a manner that light emission is maintained for a predetermined time.
According to an aspect of the present invention, there is provided an electronic pen for acquiring an image, the electronic pen comprising: a vertical synchronization generator configured to generate a vertical synchronization (Vsync) signal related to a frame of the image; A horizontal sync generator for generating a horizontal sync signal (Hsync) associated with at least one line included in the frame and controlling an exposure time of the horizontal sync signal for the line; An LED driver which exposes the LED light when the vertical synchronization signal is generated, and drives the LED so that the exposed LED light is maintained until the start of the next vertical synchronization signal; A control unit which controls the image to be acquired until the driving of the LED is terminated; And an image sensor for acquiring the image.

Description

Electronic pen for capturing an image, and method

The present invention relates to an image capturing electronic pen and an image capturing method thereof, and more particularly, to an image pen in an electronic pen using a complementary metal-oxide semiconductor (CMOS) type image sensor to obtain a still image. It relates to obtaining an image for one frame by instantaneously emitting an LED whenever a starting vertical synchronization signal is generated.

Inputting a document using a single electronic pen on a paper (or printed matter) on which a code containing information of coordinates is printed enables natural handwriting input through fast image acquisition. The user freely writes and inputs a letter or picture using an electronic pen, and the electronic pen converts and recognizes a letter or picture written by the user into data. As described above, in order to obtain printed information, the electronic pen uses an image sensor, which is an element that receives light and converts it into an electrical signal.

The image sensor is a solid-state image sensor (CCD) type image sensor and a complementary metal-oxide semiconductor (CMOS) type image sensor according to a method in which an electron hole forms a signal and is transmitted to an output part. It can be distinguished.

The CCD image sensor and the CMOS image sensor have a light receiving part which receives light and converts it into an electric signal in common. The CCD image sensor transfers this electrical signal through the CCDFMF and converts it to voltage at the last stage. On the other hand, a CMOS image sensor converts a signal from each pixel to a voltage and sends the signal to the outside.

In terms of image acquisition, the above-described image sensor is applied to a frame exposure method in which a CCD-type image sensor acquires image data through frame-by-frame exposure. A line exposure method is used for acquiring image data by means of.

The image acquisition method by the line exposure method of the CMOS image sensor has the advantage of lower power consumption than the frame exposure method of the CCD image sensor, and has the advantage of convenience in manufacturing the sensor. For this reason, the demand or use is increasing.

Despite the increasing demand, CMOS image sensors must have a high frame rate in order to obtain high speed image data. However, the definition of high-speed frame rate varies depending on which application is applied, and CMOS image sensors that satisfy all high-speed image acquisition applications are very expensive or have low power consumption for battery-based applications. There are many problems.

An object of the present invention for solving the above problems is to start an image frame in an electronic pen using a CMOS image sensor to obtain an accurate still image of a photographing surface in a fast moving device such as writing or drawing with a pen. To provide an image acquisition electronic pen and an image acquisition method thereof, the LED can be instantaneously emitted every time a vertical synchronization signal is generated, so that one frame can acquire an accurate still image.

According to an aspect of the present invention, there is provided an electronic pen for acquiring an image, comprising: a vertical synchronization generator configured to generate a vertical sync (Vsync) signal related to a frame of the image; A horizontal sync generator for generating a horizontal sync signal (Hsync) associated with at least one line included in the frame and controlling an exposure time of the horizontal sync signal for the line; An LED driver which exposes the LED light when the vertical synchronization signal is generated, and drives the LED so that the exposed LED light is maintained until the start of the next vertical synchronization signal by the amount of photon charge of the CMOS image sensor; A control unit which controls the image to be acquired until the driving of the LED is terminated; And an image sensor for acquiring the image.

The image sensor is a complementary metal oxide semiconductor (CMOS) type image sensor.

In addition, the horizontal synchronization generating unit controls the exposure time of the horizontal synchronization signal for each line in accordance with the brightness state of the image formed on the image sensor.

In addition, the LED driver emits the LED light at the instant of generating the vertical synchronization signal to drive the image blur in a situation where the photon of the CMOS image sensor moves at high speed.

The LED driver controls at least one of driving start time, light quantity, driving current value, and driving end time for the LED according to the brightness of the image formed on the image sensor.

On the other hand, the image acquisition method of the electronic pen according to the present invention for achieving the above object, the image acquisition of the electronic pen having a complementary metal oxide semiconductor (CMOS) image sensor, a vertical synchronization (Vsync) generating unit and the LED light emitting unit A method, comprising: (a) generating a Vsync signal at the start of a line in a frame of an image and emitting an LED; (b) maintaining the image by the complementary metal oxide semiconductor (CMOS) type image sensor due to the light emission of the LED until the start of the next vertical synchronization signal; And (c) acquiring the image through the image sensor until the driving of the LED is terminated.

In addition, the step (c) may control one or more of driving start time, light amount, driving current value and driving end time of the LED according to the brightness of the image formed on the image sensor.

In addition, the step (c) may adjust the output speed of the image according to the amount of light for the LED and the brightness of the image.

In the step (b), the LED driver which emits the LED at the moment of generating the vertical synchronization signal ends the driving at the time when the image scanning operation for the last line of the image frame is finished.

The step (b) is repeated for each line included in the image frame from the time of generating the horizontal synchronization signal to the end of each line, and the horizontal synchronization signal is generated and terminated at the last line of the image frame. The emission of LEDs is also gradually reduced to prevent unnecessary images from being acquired.

According to the present invention, by acquiring an image by one LED light emission operation for each line in a frame forming an image, power consumption according to LED driving can be reduced by shortening the LED driving time and reducing the number of driving. In addition, as the number of LED driving for image acquisition is reduced, the LED life can be extended. The maximum amount of light at the moment the LED is turned on can be used.

1 is a block diagram schematically illustrating a functional block of an image capturing electronic pen according to an embodiment of the present invention.
2 is a flowchart illustrating an image acquisition method of an electronic pen according to an embodiment of the present invention.
3 is a diagram illustrating a relationship between a vertical synchronization signal, a horizontal synchronization signal, LED light emission, and a light amount holding time of an image capturing electronic pen according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically illustrating a functional block of an image capturing electronic pen according to an embodiment of the present invention.

Referring to FIG. 1, the image acquisition electronic pen 100 according to the present invention may include a vertical synchronization generator 110, a horizontal synchronization generator 120, an LED driver 130, a controller 140, and an image sensor 150. ), And the like.

The vertical synchronizing generator 110 generates a vertical synchronizing signal (Vsync) signal related to a frame of an image. That is, the vertical synchronization generator 110 generates a vertical synchronization signal (Vsync) at each start of each line in the frame of the image.

The horizontal synchronizing generator 120 generates a horizontal synchronizing signal (Hsync) signal related to one or more lines included in the frame, and controls the exposure time of the horizontal synchronizing signal for each line. In addition, the horizontal synchronization generating unit 120 controls the exposure time of the horizontal synchronization signal for each line according to the brightness of the image formed on the image sensor 150.

The LED driver 130 exposes the LED light when the vertical synchronization signal is generated, and drives the LED so that the exposed LED light is maintained for a certain time during the effective period of the horizontal synchronization signal for each line.

In addition, the LDE driver 130 emits LED light at the instant of the generation of the vertical synchronization signal to terminate the driving of the LED before or after the time when the horizontal synchronization signal for the last line of the frame ends.

In addition, the LED driver 130 emits LED light at the instant of vertical synchronization signal generation, before the horizontal synchronization signal for each line is terminated, and within a time period during which the photon of the CMOS image sensor can maintain an appropriate amount of light. Terminate the drive for the LED.

The LED driver 130 may control at least one of driving start time, light amount, driving current value, and driving end time for the LED according to the brightness of the image formed on the image sensor 150.

The controller 140 controls the image to be acquired through the image sensor 150 after the driving of the LED is finished.

The image sensor 150 acquires an image. Here, the image sensor is an element that receives light and converts it into an electric signal, and a solid-state image pickup device (CCD) type image sensor and line related to the frame exposure method according to a method in which an electron hole forms and outputs a signal. Complementary Metal-Oxide Semiconductor (CMOS) -type image sensor related to the exposure method can be classified, the image sensor for the image acquisition method of the electronic pen according to the present invention may be included in the image acquisition electronic pen 100. And a processor for controlling the CMOS image sensor.

In addition, although not shown in FIG. 1, the image acquisition electronic pen 100 according to the present invention supplies power required for the operation of the LED, the image sensor 150, and the LED driver 130 driven by the LED driver 130. The apparatus may include a power supply device and a memory capable of storing a still image acquired by the image sensor 150, and may include a communication interface capable of transmitting the obtained still image by wire or wirelessly.

2 is a flowchart illustrating an image acquisition method of an electronic pen according to an embodiment of the present invention.

Referring to FIG. 2, the image capturing electronic pen 100 according to the present invention generates a Vsync signal at the start of a line in a frame of an image and emits an LED (S210).

That is, the image capturing electronic pen 100 generates a vertical sync (Vsync) signal indicating the start of each line of the image frame through the vertical sync generator 110 and emits LEDs through the LED driver 130. . At this time, depending on the sensitivity of the commercially available CMOS sensor, the LED driving time may be operated a little earlier or later than the vertical sync (Vsync) signal.

Subsequently, the light emission of the LED through the LED driver 130 is maintained only for a time enough to acquire a single image (S220).

3 is a diagram illustrating a relationship between a vertical synchronization signal, a horizontal synchronization signal, LED light emission, and a light amount holding time of an image capturing electronic pen according to an embodiment of the present invention.

In addition, the LED driver 130 repeats the same form for all the lines included in the image frame, from the generation of the horizontal synchronization signal to the end of each line, through which the image frame is continuously obtained. It becomes possible. As shown in FIG. 3, the amount of light according to the light emission of the LED becomes maximum at the start of the vertical synchronization signal and gradually decreases to near zero at the time of the start of the next vertical synchronization signal.

Subsequently, the image acquisition electronic pen 100 acquires an image for each line through the image sensor 150 until the driving of the LED is terminated (S230).

In addition, the image capturing electronic pen 100 may control at least one of a driving start time, a light amount, a driving current value, and a driving end time of the LED according to the brightness of the image formed on the image sensor 150.

In addition, the image capturing electronic pen 100 may adjust the output speed of the image according to the amount of light for the LED and the brightness of the image.

As described above, according to the present invention, when the vertical synchronous signal starting the image frame is generated in the electronic pen using the CMOS image sensor to acquire a still image, LEDs are simultaneously emitted so that the image acquisition operation of all the lines for the frame is performed. An image capturing electronic pen and an image capturing method thereof can be realized in such a manner that an image for one frame can be obtained in such a manner that the light emission of the LED is maintained so that it can be terminated.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. Only. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

The present invention can be applied to an electronic pen having a writing instrument shape and capable of drawing various types of images.

In addition, the present invention can be applied to any electronic device that uses LED light to acquire an image.

100: image acquisition electronic pen 110: vertical synchronization generating unit
120: horizontal synchronization generating unit 130: LED driving unit
140: control unit 150: image sensor

Claims (10)

In the electronic pen for obtaining an image,
A vertical synchronization generator for generating a vertical synchronization signal (Vsync) related to the frame of the image;
A horizontal sync generator for generating a horizontal sync signal (Hsync) associated with at least one line included in the frame and controlling an exposure time of the horizontal sync signal for the line;
An LED driver which exposes the LED light when the vertical synchronization signal is generated, and drives the LED so that the exposed LED light is maintained until the start of the next vertical synchronization signal by the amount of photon charge of the CMOS image sensor;
A control unit which controls the image to be acquired until the driving of the LED is terminated; And
An image sensor for acquiring the image;
Including,
And the LED driver controls a driving start time, an amount of light, a driving current value, or a driving end time for the LED according to the brightness of an image formed on the image sensor.
The method of claim 1,
The LED driver exposes the LED light when the vertical synchronization signal is generated, and drives the LED such that the exposed LED light is maintained for a predetermined time during the effective period of the horizontal synchronization signal for each line. .
The method of claim 1,
And the horizontal synchronization generating unit controls the exposure time of the horizontal synchronization signal for each line according to the brightness of the image formed on the image sensor.
The method of claim 1,
The LED driver acquires the LED light at the instant of generation of the vertical synchronization signal to terminate driving of the LED before or after the time when the horizontal synchronization signal for the last line of the frame ends. Electronic pen.
delete An image acquisition method of an electronic pen having a complementary metal oxide semiconductor (CMOS) type image sensor, a vertical synchronization (Vsync) generator, and an LED light emitter,
(a) generating a Vsync signal at the start of a line in the image frame and emitting an LED;
(b) maintaining the image by the complementary metal oxide semiconductor (CMOS) type image sensor due to the light emission of the LED until the start of the next vertical synchronization signal; And
(c) acquiring the image through the image sensor until the driving of the LED is terminated;
Including,
In the step (c), the driving start time, the amount of light, the driving current value, or the driving end time of the LED is controlled according to the brightness of the image formed on the image sensor.
delete The method according to claim 6,
In the step (c), the output speed of the image is adjusted according to the amount of light of the LED and the brightness of the image.
The method according to claim 6,
In the step (b), the LED driver which emits the LED at the moment of generating the vertical synchronization signal ends the driving at the time when the image scanning operation for the last line of the image frame is finished. Image Acquisition Method.
The method according to claim 6,
Step (b) is repeated for all the lines included in the image frame from the time of generating the horizontal synchronization signal to the end of each line, generating the horizontal synchronization signal at the last line of the image frame and ending the next vertical line. The image acquisition method of the electronic pen, characterized in that the still image is maintained by the light emission of the LED until the synchronization signal starts.

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