CN106933376B - A kind of scaling method of smooth projected keyboard - Google Patents

Abstract

The invention discloses a calibration method for a light projection keyboard, comprising the following steps: step 1, obtaining image coordinate data of all keys of the reference keyboard; step 2, obtaining image coordinate data of four vertex keys located on the keyboard to be calibrated; step 3. Use affine transformation to obtain the image coordinate data of the other keys of the keyboard to be calibrated except for the four vertex keys; Step 4, use the internal parameters, distortion and external parameters of the calibration camera and the image coordinates of all the keys of the light projection keyboard to be calibrated to obtain The keyboard position coordinate information of all keys of the light projection keyboard to be calibrated; step 5, storing the keyboard position coordinate information in the memory to complete the calibration of the light projection keyboard. The calibration method of the optical projection keyboard of the present invention has high speed and high efficiency, is suitable for batch calibration, and solves the problem of manually determining the image coordinate data of all keys of the keyboard to be calibrated, repeated operations, and heavy labor for manual calibration of the optical projection keyboard.

Description

A Calibration Method for Optical Projection Keyboard

technical field

The invention belongs to the technical field of optical projection keyboards, in particular to a calibration method for optical projection keyboards.

Background technique

The keyboard is one of the most commonly used input devices for electronic equipment, and it is widely used in computers, electronic instruments and various terminal equipment. The keyboard is the most commonly used and most important input device, through which English letters, numbers, punctuation marks, etc. can be input into the computer, so as to issue commands and input data to the computer.

In order to solve the problems that the traditional physical keyboard is too large, difficult to carry and place, easy to absorb dust and difficult to clean, and easy to be damaged by excessive use, the equipment manufacturer has developed a virtual laser keyboard (Virtual LaserKeyboard). The virtual laser keyboard hardware mainly consists of 3 parts. Composition, that is, camera, keyboard projection module and infrared laser transmitter. The function of the keyboard projection module is to project the laser keyboard to the desktop, the infrared laser emitter is to project infrared light parallel to the desktop or at a certain angle with the desktop, and the function of the camera is to collect the position information of the fingers. When a person's finger presses the keyboard projected by the keyboard projection module to the keyboard on the desktop, the camera shoots the infrared light projected on the finger by the infrared laser emitter. When the virtual laser keyboard leaves the factory, each key coordinate of the keyboard projected by the keyboard projection module on the desktop needs to be stored in the memory, so that when a person's finger presses the keyboard key projected by the keyboard projection module on the desktop, the camera will shoot To the spot information projected by the infrared laser transmitter to the human finger, and calculate the corresponding spot position coordinates, so that according to the coordinate information collected by the camera compared with the button information we stored in the memory before, it will be determined that the user specifically pressed Which key was pressed. At present, the method of obtaining the coordinates of each key is manually completed, requiring the user to determine the positions of all keys on the keyboard, which is highly repetitive and prone to errors or mistakes.

Contents of the invention

The purpose of the present invention is to provide a method for calibrating an optical projection keyboard, so as to solve the problems of low calibration efficiency and long time consumption in manual calibration of an optical projection keyboard, and prone to calibration errors.

The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a method for calibrating an optical projection keyboard, comprising the following steps:

Step 1, use the calibration camera to obtain the reference keyboard photo of the reference light projection keyboard prototype, process the reference keyboard photo to obtain the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys;

Step 2, using the calibration camera to obtain the photo of the keyboard to be calibrated for the light projection keyboard to be calibrated, and processing the photo of the keyboard to be calibrated to obtain the image coordinate data of the four vertex keys located on the keyboard to be calibrated;

Step 3, based on the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys, and the image coordinate data of the four vertex keys of the keyboard to be calibrated, use affine transformation to obtain the keyboard to be calibrated except for the four vertex keys The image coordinate data of the other buttons of ;

Step 4, using the internal parameters, distortion and external parameters of the calibration camera and the image coordinates of all the keys of the light projection keyboard to be calibrated to obtain the first world coordinate data of all the keys of the light projection keyboard to be calibrated; The first world coordinate data of all keys is used as the keyboard position coordinate information;

Step 5, storing the coordinate information of the keyboard position into the memory to complete the calibration of the light projection keyboard.

In the calibration method of the optical projection keyboard as described above in the present invention, preferably, the optical projection keyboard includes: a keyboard projection module, an infrared laser emitter, a device camera, a memory, and a processor; the keyboard projection module is used to The operating surface projects a virtual keyboard; the infrared laser emitter is used to project infrared rays covering the virtual keyboard area; the device camera is used to collect infrared images of the virtual keyboard area and transmit the images to the processor; the The memory is used to store the coordinate information of the keyboard position; the processor is used to process the infrared image collected by the camera of the device to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image; and combine the coordinate information with the keyboard position prestored in the memory The coordinate information is compared to confirm the content of the information input by the user.

More preferably, the specific process for the processor to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is: the processor uses the internal parameters, distortion and external parameters of the device camera to convert the image of the light spot reflected by the user's finger to The coordinates are converted into first world coordinates, and the first world coordinates are compared with the keyboard position coordinate information prestored in the memory to confirm the information input by the user.

In the method for calibrating a light projection keyboard as described above in the present invention, preferably, step 4 further includes: using a transformation matrix to convert the first world coordinate data into second world coordinate data; the plane where the first world coordinate is located is a horizontal plane , the angle between the plane where the second world coordinates are located and the horizontal plane is between zero degrees and five degrees; the second world coordinate data of all keys of the light projection keyboard to be calibrated is the keyboard position coordinate information.

More preferably, the specific process for the processor to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is: the processor uses the internal parameters, distortion and external parameters of the device camera to convert the image of the light spot reflected by the user's finger to The coordinates are transformed into the first world coordinates, and the transformation matrix is used to convert the first world coordinates into the second world coordinates; the second world coordinates are compared with the keyboard position coordinate information pre-stored in the memory to confirm the information input by the user.

The beneficial effects of the present invention are:

Using the method of the present invention to calibrate the light projection keyboard only needs to use the calibration camera to obtain the reference keyboard photo of the reference light projection keyboard prototype, and process the reference keyboard photo to obtain the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys; This data can be reused for the same batch of light projection keyboards. For the light projection keyboard to be calibrated, it is only necessary to obtain the image coordinate data of the four vertex keys located on the keyboard to be calibrated, which solves the problem of manual calibration of the light projection keyboard, which requires manual determination of the image coordinate data of all the keys of the keyboard to be calibrated, repeated operations, and a large amount of labor. , the problem that batch calibration of optical projection keyboards cannot be performed.

Description of drawings

The above and/or other aspects and advantages of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, which are only schematic and do not limit the present invention, wherein:

Fig. 1 is a schematic flow chart of a calibration method of an optical projection keyboard according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of an optical projection keyboard according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of key positions of an optical projection keyboard according to the first embodiment of the present invention;

Fig. 4 is a schematic diagram of keys of the light projection keyboard according to the second embodiment of the present invention.

In the accompanying drawings, the list of parts represented by each label is as follows:

1. Optical projection keyboard, 2. Keyboard projection module, 3. Infrared laser transmitter, 4. Equipment camera, 5. Memory, 6. Processor.

Detailed ways

Hereinafter, embodiments of the calibration method of the light projection keyboard of the present invention will be described with reference to the accompanying drawings.

The examples described here are specific specific implementations of the present invention, and are used to illustrate the concept of the present invention. They are all explanatory and exemplary, and should not be construed as limiting the implementation of the present invention and the scope of the present invention. In addition to the embodiments described here, those skilled in the art can also adopt other obvious technical solutions based on the claims of the application and the contents disclosed in the description, and these technical solutions include adopting any obvious changes made to the embodiments described here. Replacement and modified technical solutions.

The accompanying drawings in this specification are schematic diagrams, which assist in explaining the concept of the present invention, and schematically represent the shapes of various parts and their interrelationships. Please note that in order to clearly show the structures of the components in the embodiments of the present invention, the drawings are not drawn in the same scale. The same reference numerals are used to designate the same parts.

Example 1

A method for calibrating an optical projection keyboard according to an embodiment of the present invention is described in conjunction with FIG. 1 and FIG. 2. The optical projection keyboard 1 includes: a keyboard projection module 2, an infrared laser emitter 3, a device camera 4, a memory 5 and a processor 6; the keyboard projection module 2 is used to project a virtual keyboard to the operation surface; the infrared laser emitter 3 is used to project infrared rays covering the virtual keyboard area; the device camera 4 is used to collect the virtual keyboard area The infrared image and transmit the image to the processor 6; the memory 5 is used to store the coordinate information of the keyboard position; The coordinate information of the reflected light spot; and compare the coordinate information with the keyboard position coordinate information pre-stored in the memory 5 to confirm the information input by the user.

The calibration method of the optical projection keyboard includes the following steps:

Step 1, use the calibration camera to obtain the reference keyboard photo of the reference light projection keyboard 1 prototype, process the reference keyboard photo to obtain the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys;

In one embodiment, the image coordinate data is an image plane coordinate value, and the image area corresponding to each button is calculated and determined according to the image coordinate data of all buttons. As shown in Figure 3, the keyboard keys are adjacent to each other, and the image coordinate data of the key is determined to be (x, y), where x is the abscissa of the vertex of the upper left corner of a certain key, and y is the ordinate of the vertex of the upper left corner of the key ;.

In another embodiment, as shown in FIG. 4 , the image coordinate data includes an image plane coordinate value and a set of length and width values. As shown in Figure 4, there is a certain gap between the keys of this keyboard, and the image coordinate data of the determined keys are (x, y), (a, b), where x is the abscissa of the vertex of the upper left corner of a certain key, and y is the ordinate of the top left corner of the button; a is the length of each button, and b is the height of each button.

Step 2, using the calibration camera to obtain the photo of the keyboard to be calibrated of the light projection keyboard 1 to be calibrated, and processing the photo of the keyboard to be calibrated to obtain the image coordinate data of the four vertex keys located on the keyboard to be calibrated;

Step 3, based on the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys, and the image coordinate data of the four vertex keys of the keyboard to be calibrated, use affine transformation to obtain the keyboard to be calibrated except for the four vertex keys The image coordinate data of the other buttons of ;

Step 4, using the internal parameters, distortion and external parameters of the calibration camera and the image coordinates of all the keys of the light projection keyboard 1 to be calibrated to obtain the first world coordinate data of all the keys of the light projection keyboard 1 to be calibrated; the light projection to be calibrated The first world coordinate data of all keys of the keyboard 1 is used as the keyboard position coordinate information;

Step 5, storing the coordinate information of the keyboard position in the memory 5 to complete the calibration of the light projection keyboard 1 .

In a preferred embodiment, the specific process for the processor 6 to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is: the processor 6 uses the internal parameters, distortion and external parameters of the device camera 4 to convert the user's finger The image coordinates of the reflected light spots are converted into first world coordinates, and the first world coordinates are compared with the keyboard position coordinate information pre-stored in the memory 5 to confirm the information input by the user.

Example 2

A method for calibrating an optical projection keyboard according to an embodiment of the present invention is described in conjunction with FIG. 1 and FIG. 2. The optical projection keyboard 1 includes: a keyboard projection module 2, an infrared laser emitter 3, a device camera 4, a memory 5 and a processor 6; the keyboard projection module 2 is used to project a virtual keyboard to the operation surface; the infrared laser emitter 3 is used to project infrared rays covering the virtual keyboard area; the device camera 4 is used to collect the virtual keyboard area The infrared image and transmit the image to the processor 6; the memory 5 is used to store the coordinate information of the keyboard position; The coordinate information of the reflected light spot; and compare the coordinate information with the keyboard position coordinate information pre-stored in the memory 5 to confirm the information input by the user. In a preferred embodiment, the specific process for the processor 6 to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is: the processor 6 uses the internal parameters, distortion and external parameters of the device camera 4 to convert the user's finger The image coordinates of the reflected light spots are converted into first world coordinates, and the first world coordinates are compared with the keyboard position coordinate information pre-stored in the memory 5 to confirm the information input by the user.

The calibration method of the optical projection keyboard includes the following steps:

Step 1, use the calibration camera to obtain the reference keyboard photo of the reference light projection keyboard 1 prototype, process the reference keyboard photo to obtain the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys;

Step 2, using the calibration camera to obtain the photo of the keyboard to be calibrated of the light projection keyboard 1 to be calibrated, and processing the photo of the keyboard to be calibrated to obtain the image coordinate data of the four vertex keys located on the keyboard to be calibrated;

Step 3, based on the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys, and the image coordinate data of the four vertex keys of the keyboard to be calibrated, use affine transformation to obtain the keyboard to be calibrated except for the four vertex keys The image coordinate data of the other buttons of ;

Step 4, using the internal parameters, distortion and external parameters of the calibration camera and the image coordinates of all the keys of the light projection keyboard 1 to be calibrated to obtain the first world coordinate data of all the keys of the light projection keyboard 1 to be calibrated; the light projection to be calibrated The first world coordinate data of all keys of the keyboard 1 is used as the keyboard position coordinate information; in the present embodiment, step 4 also includes: using the transformation matrix to convert the first world coordinate data into the second world coordinate data; the first world The plane where the coordinates are located is a horizontal plane, and the angle between the plane where the second world coordinates is located and the horizontal plane is between zero degrees and five degrees; the second world coordinate data of all keys of the light projection keyboard 1 to be calibrated is the keyboard position coordinate information.

Step 5, storing the coordinate information of the keyboard position in the memory 5 to complete the calibration of the light projection keyboard 1 .

In this embodiment, the specific process for the processor 6 to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is as follows: the processor 6 uses the internal parameters, distortion and external parameters of the device camera 4 to obtain the coordinate information of the user's finger The image coordinates of the reflected light spot are converted into the first world coordinates, and the transformation matrix is used to convert the first world coordinates into the second world coordinates; the second world coordinates are compared with the keyboard position coordinate information prestored in the memory 5 to confirm the use of information entered by the user.

A device for calibrating an optical projection keyboard, the device includes a hollow box inside; a calibration camera installed in the box, the calibration camera is located on the top of the box; a fixing device, the fixing device is used for The optical projection keyboard to be calibrated is fixed on the bottom plate of the box body; the camera parameter calibration board is equipped with a plurality of infrared LED lights, and the infrared LED lights are arranged in rows and columns perpendicular to each other. The spacing is equal (such as 15mm), and the column spacing is equal (such as 15mm). In a preferred embodiment, the infrared lamp has a wavelength of 850nm.

The function of the calibration camera is to obtain the reference keyboard photo of the reference light projection keyboard prototype, and obtain the to-be-calibrated keyboard photo of the light projection keyboard to be calibrated. The function of the camera parameter calibration board is to combine the calibration camera to obtain the internal parameters, distortion and external parameters of the calibration camera, as well as the internal parameters, distortion and external parameters of the equipment camera.

The technical features disclosed above are not limited to the disclosed combination with other features, and those skilled in the art can also make other combinations among the technical features according to the purpose of the invention, so as to achieve the purpose of the present invention.

Claims (5)

1. A calibration method for an optical projection keyboard, comprising the following steps: Step 1, use the calibration camera to obtain the reference keyboard photo of the reference light projection keyboard prototype, process the reference keyboard photo to obtain the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys; Step 2, using the calibration camera to obtain the photo of the keyboard to be calibrated for the light projection keyboard to be calibrated, and processing the photo of the keyboard to be calibrated to obtain the image coordinate data of the four vertex keys located on the keyboard to be calibrated; Step 3, based on the image coordinate data of the four vertex keys of the reference keyboard and the image coordinate data of other keys, and the image coordinate data of the four vertex keys of the keyboard to be calibrated, use affine transformation to obtain the keyboard to be calibrated except for the four vertex keys The image coordinate data of the other buttons of ; Step 4, using the internal parameters, distortion and external parameters of the calibration camera and the image coordinates of all the keys of the light projection keyboard to be calibrated to obtain the first world coordinate data of all the keys of the light projection keyboard to be calibrated; The first world coordinate data of all keys is used as the keyboard position coordinate information; Step 5, storing the coordinate information of the keyboard position into the memory to complete the calibration of the light projection keyboard. 2. The calibration method of the optical projection keyboard according to claim 1, wherein the optical projection keyboard comprises: a keyboard projection module, an infrared laser transmitter, a device camera, a memory and a processor; the keyboard projection module The group is used to project a virtual keyboard to the operation surface; the infrared laser emitter is used to project infrared rays covering the virtual keyboard area; the device camera is used to collect infrared images of the virtual keyboard area and transmit the images to the processing The memory is used to store the coordinate information of the keyboard position; the processor is used to process the infrared image collected by the camera of the device to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image; and the coordinate information is combined with the memory The pre-stored keyboard position coordinate information is compared to confirm the information input by the user. 3. The calibration method of the light projection keyboard according to claim 2, wherein the specific process for the processor to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is: the processor uses the internal Parameters, distortion and external parameters Convert the image coordinates of the light spots reflected by the user's fingers into the first world coordinates, and compare the first world coordinates with the keyboard position coordinate information pre-stored in the memory to confirm the information input by the user content. 4. The method for calibrating a light projection keyboard according to claim 1 or 2, wherein step 4 further comprises: using a transformation matrix to convert the first world coordinate data into the second world coordinate data; the first world The plane where the coordinates are located is a horizontal plane, and the angle between the plane where the second world coordinates are located and the horizontal plane is between zero degrees and five degrees. 5. The calibration method of light projection keyboard according to claim 4, characterized in that, the specific process for the processor to obtain the coordinate information of the light spot reflected by the user's finger in the infrared image is: the processor uses the internal Parameters, distortion and external parameters Convert the image coordinates of the light spots reflected by the user's fingers into the first world coordinates, and use the transformation matrix to convert the first world coordinates into the second world coordinates; The coordinate information of the keyboard position is compared to confirm the information input by the user.