A method for realizing automatic calibration of a projection keyboard by utilizing external cameras

An external camera and projection keyboard technology, applied in image enhancement, image analysis, image data processing, etc., can solve the problems of large calibration errors, time-consuming and labor-intensive problems, save labor costs, avoid manual operations, and facilitate automatic installation and calibration Effect

CN107657642AActive Publication Date: 2018-02-02哈尔滨拓博科技有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2018-02-02

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Abstract

The invention provides a method for realizing automatic calibration of a projection keyboard by utilizing external cameras, relates to an automatic calibration method of a projection keyboard, and isto solve the problem of waste of time and energy and the problem of large calibration errors of a conventional calibration method. The method is characterized by shooting pictures of an LED calibration plate through a jig top camera and an identification camera, and calculating an inner parameter matrix, an outer parameter matrix and distortion coefficients of the cameras; shooting a reference keyboard picture through the jig top camera; according to a reference keyboard and a projection keyboard to be calibrated, obtaining an affine transformation relationship and obtaining an image coordinate of a reference point on the keyboard to be calibrated; calculating the coordinate of the reference point of the keyboard to be calibrated in a camera coordinate system according to the inner parameter matrix of the cameras and obtaining a correction coordinate according to a camera distortion model; and then, calculating a world coordinate of the reference point of the keyboard to be calibratedand calculating corresponding key coordinates according to the world coordinate of each reference point of the keyboard to be calibrated. The method is suitable for automatic calibration of the projection keyboard.
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Description

technical field

[0001] The invention relates to an automatic calibration method for a projection keyboard. Background technique

[0002] Input devices (keyboards, mice) are important tools for human-computer interaction of computer devices or other smart devices. With the miniaturization of computer devices or wearable smart devices, many products in the electronic field will miniaturize or even miniaturize input devices. , but the smaller the input device, the trouble of inconvenient input is caused to people, but it still cannot meet the needs of mobility and portability. At present, some computer devices or wearable smart devices have adopted projection keyboards as input devices.

[0003] However, there are still many problems in the calibration of the projection keyboard. At present, manual calibration is basically used for the calibration of the projection keyboard. In the actual calibration process, due to the consistency of the installation of the recognition camera ...

Examples

specific Embodiment approach 1

[0047] Specific implementation mode one: combine Figure 4 To describe this embodiment,

[0048] An automatic calibration method for projecting a keyboard using an external camera, comprising:

[0049] Step 1. Camera calibration:

[0050] The camera calibration is divided into two parts, namely, the camera calibration on the top of the jig and the calibration of the recognition camera. The camera on the top of the jig is provided with the projection keyboard calibration jig and is used to measure the size of the projection keyboard; the projection of the recognition camera and the projection keyboard The device is integrated and used for fingertip area identification and positioning;

[0051] The calibration uses a customized LED small light board with known distribution size as the LED calibration board, and uses the LED calibration board to calibrate the internal and external parameters and distortion coefficients of the camera on the top of the fixture, which is used for th...

specific Embodiment approach 2

[0063] An automatic calibration method for projecting a keyboard using an external camera, comprising:

[0064] Step 1. Camera calibration:

[0065] The camera calibration is divided into two parts, namely, the camera calibration on the top of the jig and the calibration of the recognition camera. The camera on the top of the jig is provided with the projection keyboard calibration jig and is used to measure the size of the projection keyboard; the projection of the recognition camera and the projection keyboard The device is integrated and used for fingertip area identification and positioning;

[0066] The calibration uses a customized LED small light board with known distribution size as the LED calibration board, and uses the LED calibration board to calibrate the internal and external parameters and distortion coefficients of the camera on the top of the fixture, which is used for the later calculation of the projection keyboard; the recognition camera calibration also us...

specific Embodiment approach 3

[0082] The specific process of calculating the corresponding button coordinates according to the world coordinates of each reference point of the keyboard to be calibrated described in step 5 of this embodiment includes the following steps:

[0083] According to the keyboard reference point to be calibrated corresponding to the projected keyboard keys, the projected keyboard key coordinate description is based on the world coordinates of the upper left corner vertex of each key (corresponding to the keyboard reference point to be calibrated), and the projected keyboard key coordinates are obtained according to the width and length of the keys.

[0084] Other steps and parameters are the same as those in Embodiment 1 or 2.