CN109873920B - Projection grating modeling method and device based on rolling shutter - Google Patents
Projection grating modeling method and device based on rolling shutter Download PDFInfo
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- CN109873920B CN109873920B CN201910112254.5A CN201910112254A CN109873920B CN 109873920 B CN109873920 B CN 109873920B CN 201910112254 A CN201910112254 A CN 201910112254A CN 109873920 B CN109873920 B CN 109873920B
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Abstract
The invention discloses a projection grating modeling method and a device based on a rolling shutter, wherein the projection grating modeling method comprises the following steps: after the trigger signal is sent out, the projector projects grating images of a plurality of continuous projection periods; the camera shoots the grating image after receiving the trigger signal to obtain a modeling image, the camera is a rolling shutter camera, the single-line exposure duration of the camera is longer than N projection periods, and N is an integer larger than 0; and obtaining a model according to the modeling image. The projection grating modeling method based on the rolling shutter has low cost and high running speed, can realize the synchronization of the projector and the camera, can accelerate the synchronization process, improves the use efficiency of projection grating modeling, and improves the projection effect.
Description
Technical Field
The invention relates to a projection grating modeling method and device based on a rolling shutter.
Background
Three-dimensional reconstruction refers to the establishment of a mathematical model suitable for computer representation and processing of a three-dimensional object, is the basis for processing, operating and analyzing the properties of the three-dimensional object in a computer environment, and is also a key technology for establishing virtual reality expressing an objective world in a computer.
The three-dimensional reconstruction of the grating projection is a three-dimensional reconstruction mode, the grating is respectively projected to a reference plane and the surface of a measured object, and the reference grating projected to the reference plane is not deformed because the reference plane is a horizontal plane; when the grating is projected on the surface of the measured object, the grating can generate deformation of different degrees because the projected grating is modulated by the height of the surface of the measured object. The heights of the placed measured objects are different, the phase change degrees of the gratings are different, and the phase change of the two-dimensional plane deformation stripes carries three-dimensional shape information of the surfaces of the objects. Therefore, by obtaining the phase change value, the height of the object at the corresponding point can be obtained, and the contour shape of the three-dimensional object can be obtained.
The existing grating projection has the defects of expensive equipment, unsynchronized projector and camera and low synchronization efficiency in the process of three-dimensional reconstruction.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects that the equipment is expensive, the projector and the camera are asynchronous and the synchronization efficiency is low in the prior art, and provide the projection grating modeling method and the projection grating modeling device based on the rolling shutter, which have the advantages that the cost is low, the synchronization of the projector and the camera can be realized, the synchronization process can be accelerated, the use efficiency of projection grating modeling is improved, and the projection effect is improved.
The invention solves the technical problems through the following technical scheme:
a projection grating modeling method based on a rolling shutter is characterized by comprising the following steps:
after the trigger signal is sent out, the projector projects grating images of a plurality of continuous projection periods;
the camera shoots the grating image after receiving the trigger signal to obtain a modeling image, the camera is a rolling shutter camera, the single-line exposure duration of the camera is longer than N projection periods, and N is an integer larger than 0;
and obtaining a model according to the modeling image.
Preferably, before the projector projects the raster image of a plurality of consecutive projection periods after the trigger signal is sent out, the method includes:
after the trigger signal is sent out, the projector projects a gray image with preset gray;
the camera shoots the gray image after receiving the trigger signal so as to obtain a shot image;
acquiring an error value of the camera according to the gray value, the preset gray value and the exposure duration of the camera in the shot image;
and adjusting the projector and the camera to be synchronous according to the error value.
Preferably, before the projector projects the raster image of a plurality of consecutive projection periods after the trigger signal is sent out, the method includes:
after a trigger signal is sent out, projecting a gray image of a first preset gray by a projector, wherein the gray value of the first preset gray is 255;
the camera shoots the gray image after receiving the trigger signal so as to obtain a first shot image;
after the trigger signal is sent out, the projector projects a gray image with a second preset gray level, wherein the gray value of the second preset gray level is 127 or 128;
the camera shoots the gray image after receiving the trigger signal so as to obtain a second shot image;
and obtaining an error value of the camera according to the first row gray value, the first preset gray value, the second preset gray value and the single-row exposure duration of the camera of the first shot image and the second shot image.
Preferably, the adjusting the projector and the camera synchronization according to the error value comprises:
adjusting the time length from the moment when the trigger signal is sent to the moment when the projector starts to project the grating image according to the error value;
sending out a trigger signal, and projecting a grating image by a projector after the trigger signal is adjusted in duration;
and the camera shoots the grating image after receiving the trigger signal so as to obtain a modeling image.
Preferably, the adjusting the projector and the camera synchronization according to the error value comprises:
after sending out a trigger signal, projecting a grating image by a projector;
the camera shoots the grating image after receiving the trigger signal so as to obtain a modeling image;
and adjusting the modeling image according to the error value to obtain a synchronous image.
Preferably, before the projector projects the raster image of a plurality of consecutive projection periods after the trigger signal is sent out, the method includes:
the projector projects a plurality of frames of gray level images according to a preset rule, wherein the preset rule is that the projector projects a frame of gray level image with preset gray level after a trigger signal is sent out;
the camera shoots the gray image after receiving the trigger signal every time to obtain a shot image;
for the gray image of each frame, acquiring a single error value of the camera according to the gray value of the first row in the shot image, the preset gray value and the exposure duration of the camera;
obtaining an average error value according to all the single error values;
and adjusting the projector and the camera to be synchronous according to the average error value.
The invention also provides a projection grating modeling device based on the rolling shutter, which is characterized by comprising a triggering module, an obtaining module and a modeling module,
the trigger module is used for calling the projector to project the grating images with a plurality of continuous projection periods after sending out a trigger signal;
the acquisition module is used for shooting the grating image to acquire a modeling image after receiving the trigger signal through a camera, the camera is a rolling shutter camera, the single-line exposure time of the camera is longer than N projection periods, and N is an integer larger than 0;
the modeling module is used for obtaining a model according to the modeling image.
Preferably, the projection grating modeling apparatus includes a calculation module and a synchronization module,
the trigger module is also used for sending a trigger signal and then projecting a gray image with preset gray by the projector;
the acquisition module is further used for acquiring a shot image by shooting the gray image after receiving the trigger signal through the camera;
the calculation module is used for acquiring an error value of the camera according to the gray value, the preset gray value and the exposure duration of the camera in the shot image;
the synchronization module is used for adjusting the synchronization of the projector and the camera according to the error value.
Preferably, the first and second liquid crystal films are made of a polymer,
the trigger module is used for sending a trigger signal and then projecting a gray image of a first preset gray level by the projector, wherein the gray value of the first preset gray level is 255;
the acquisition module is used for shooting the gray-scale image after receiving the trigger signal through a camera to acquire a first shot image;
the trigger module is further configured to send a trigger signal and then project a gray image of a second preset gray level by the projector, where the gray value of the second preset gray level is 127 or 128;
the acquisition module is further used for shooting the gray-scale image after receiving the trigger signal through a camera to acquire a second shot image;
the calculation module is used for acquiring the error value of the camera according to the first row gray value, the first preset gray value, the second preset gray value and the single-row exposure duration of the camera of the first shot image and the second shot image.
Preferably, the first and second liquid crystal films are made of a polymer,
the synchronization module is used for adjusting the time length from the moment when the trigger signal is sent to the moment when the projector starts to project the grating image according to the error value;
the trigger module is also used for sending out a trigger signal and projecting a grating image by the projector after the adjusted duration;
the acquisition module is further used for shooting the raster image after receiving the trigger signal through a camera so as to acquire a modeling image.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The positive progress effects of the invention are as follows:
the projection grating modeling method based on the rolling shutter can realize the synchronization of the projector and the camera, accelerate the synchronization process, improve the use efficiency of projection grating modeling and improve the projection effect.
Drawings
Fig. 1 is a flowchart of a projection grating modeling method according to embodiment 1 of the present invention.
Fig. 2 is a signal diagram of the projector according to embodiment 1 of the present invention.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
Example 1
The embodiment provides a projection grating modeling device based on a rolling shutter. The projection grating modeling device comprises a triggering module, an obtaining module and a modeling module.
The trigger module is used for calling the projector to project the grating images with a plurality of continuous projection periods after sending out a trigger signal;
the acquisition module is used for shooting the grating image to acquire a modeling image after receiving the trigger signal through a camera, the camera is a rolling shutter camera, the single-line exposure time of the camera is longer than N projection periods, and N is an integer larger than 0;
the modeling module is used for obtaining a model according to the modeling image.
Due to the progressive scanning of the rolling camera (rolling shutter camera), in a single projection period, the projection grating cannot completely capture an image, the projector repeatedly projects the grating, the camera spans several projection periods, each line can capture an integral multiple of the projection grating in time, and thus the image captured by each line is a complete projection grating image.
The projection grating modeling device of the embodiment can also synchronize the camera and the projector, can accelerate the synchronization process, improves the service efficiency of projection grating modeling, and improves the projection effect
Specifically, the projection grating modeling device further comprises a calculation module and a synchronization module.
The trigger module is also used for sending a trigger signal and then projecting a gray image with preset gray by the projector;
the acquisition module is further used for acquiring a shot image by shooting the gray image after receiving the trigger signal through the camera;
the calculation module is used for acquiring an error value of the camera according to the gray value, the preset gray value and the exposure duration of the camera in the shot image;
the synchronization module is used for adjusting the synchronization of the projector and the camera according to the error value.
In particular, the amount of the solvent to be used,
the trigger module is used for sending a trigger signal and then projecting a gray image of a first preset gray level by the projector, wherein the gray value of the first preset gray level is 255;
the acquisition module is used for shooting the gray-scale image after receiving the trigger signal through a camera to acquire a first shot image;
the trigger module is further configured to send a trigger signal and then project a gray image of a second preset gray level by the projector, where the gray value of the second preset gray level is 127 or 128;
the acquisition module is further used for shooting the gray-scale image after receiving the trigger signal through a camera to acquire a second shot image;
the calculation module is used for acquiring the error value of the camera according to the first row gray value, the first preset gray value, the second preset gray value and the single-row exposure duration of the camera of the first shot image and the second shot image.
In this embodiment, the gray value of the preset gray of the 8-bit projected gray image is 127 (or 128), the signal of the 127 gray value after PWM modulation is composed of signals of gray value 0 and gray value 225, the length of the gray value when the gray value is a certain value can be obtained by obtaining the gray value, so as to obtain the delay, and the second gray value may refer to an average gray value.
Referring to fig. 2, for a Pattern (225), assuming the snapshot gray level is Lev1, for the Pattern (127) snapshot gray level value Lev2, the synchronization error can be calculated for a given camera exposure time value.
The delay, i.e., the error value, can be calculated by the relationship that the ratio of the gray values of the first captured image and the second captured image is equal to the ratio of the exposure time.
After the error value is obtained, the synchronization module is used for adjusting the time length from the moment when the trigger signal is sent to the moment when the projector starts to project the grating image according to the error value;
the trigger module is also used for sending out a trigger signal and projecting a grating image by the projector after the adjusted duration;
the acquisition module is further used for shooting the raster image after receiving the trigger signal through a camera so as to acquire a modeling image.
With the projection grating modeling apparatus, the embodiment further provides a projection grating modeling method, with reference to fig. 1, including:
102, after sending a trigger signal, projecting a gray image with a second preset gray level by a projector, wherein the gray value of the second preset gray level is 127;
103, shooting the gray image by the camera after receiving the trigger signal to acquire a second shot image;
and 104, acquiring an error value of the camera according to the first-row gray value, the first preset gray value, the second preset gray value and the single-row exposure duration of the camera of the first shot image and the second shot image.
The first row of gray values refers to gray values of images acquired by the first row of sensors of the rolling shutter camera, and the first row of gray values of the second shot images can also refer to average gray values.
And 105, adjusting the projector and the camera to be synchronous according to the error value.
106, after sending a trigger signal, projecting a grating image with a plurality of continuous projection periods by a projector;
and 107, shooting the raster image to acquire a modeling image after the camera receives the trigger signal, wherein the camera is a rolling shutter camera, the single-line exposure time of the camera is longer than N projection periods, and N is an integer larger than 0.
The single line exposure duration in this embodiment is two projection periods.
And 108, acquiring a model according to the modeling image.
Wherein, the step 106 is specifically: adjusting the time length from the moment when the trigger signal is sent to the moment when the projector starts to project the grating image according to the error value;
and after the trigger signal is sent out and the adjusted time length is passed, the projector projects a grating image.
The projection grating modeling method based on the rolling shutter can realize synchronization of the projector and the camera, accelerate the synchronization process, improve the use efficiency of projection grating modeling and improve the projection effect.
Example 2
This embodiment is substantially the same as embodiment 1 except that:
by using the projection grating modeling device, the projection grating modeling method of the embodiment sequentially includes:
the projector projects a plurality of frames of gray level images according to a preset rule, and the preset rule is that the projector projects a frame of gray level image with preset gray level after sending a trigger signal.
And the camera shoots the gray-scale image after receiving the trigger signal every time to acquire a shot image.
And for the gray image of each frame, acquiring a single error value of the camera according to the gray value of the first line in the shot image, the preset gray value and the exposure duration of the camera.
An average error value is obtained from all the individual error values.
And after the trigger signal is sent out, the projector projects a grating image.
The camera shoots the grating image after receiving the trigger signal so as to obtain a modeling image;
and adjusting the modeling image according to the average error value to obtain a synchronous image.
While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that these are by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.
Claims (6)
1. A projection grating modeling method based on a rolling shutter is characterized by comprising the following steps:
after the trigger signal is sent out, the projector projects grating images of a plurality of continuous projection periods;
the camera shoots the grating image after receiving the trigger signal to obtain a modeling image, the camera is a rolling shutter camera, the single-line exposure duration of the camera is longer than N projection periods, and N is an integer larger than 0;
obtaining a model according to the modeling image;
the step of sending out the trigger signal and then projecting the grating image with a plurality of continuous projection periods by the projector comprises the following steps:
after the trigger signal is sent out, the projector projects a gray image with preset gray;
the camera shoots the gray image after receiving the trigger signal so as to obtain a shot image;
acquiring an error value of the camera according to the gray value, the preset gray value and the exposure duration of the camera in the shot image;
adjusting the projector and the camera to be synchronous according to the error value;
the step of sending out the trigger signal and then projecting the grating image with a plurality of continuous projection periods by the projector comprises the following steps:
after a trigger signal is sent out, projecting a gray image of a first preset gray by a projector, wherein the gray value of the first preset gray is 255;
the camera shoots the gray image after receiving the trigger signal so as to obtain a first shot image;
after the trigger signal is sent out, the projector projects a gray image with a second preset gray level, wherein the gray value of the second preset gray level is 127 or 128;
the camera shoots the gray image after receiving the trigger signal so as to obtain a second shot image;
and obtaining an error value of the camera according to the first row gray value, the first preset gray value, the second preset gray value and the single-row exposure duration of the camera of the first shot image and the second shot image.
2. The projection grating modeling method of claim 1, wherein the adjusting projector and the camera synchronization based on the error value comprises:
adjusting the time length from the moment when the trigger signal is sent to the moment when the projector starts to project the grating image according to the error value;
sending out a trigger signal, and projecting a grating image by a projector after the trigger signal is adjusted in duration;
and the camera shoots the grating image after receiving the trigger signal so as to obtain a modeling image.
3. The projection grating modeling method of claim 1, wherein the adjusting projector and the camera synchronization based on the error value comprises:
after sending out a trigger signal, projecting a grating image by a projector;
the camera shoots the grating image after receiving the trigger signal so as to obtain a modeling image;
and adjusting the modeling image according to the error value to obtain a synchronous image.
4. The projection grating modeling method of claim 1, wherein said triggering signal is issued prior to the projector projecting the grating image for a plurality of successive projection periods, comprising:
the projector projects a plurality of frames of gray level images according to a preset rule, wherein the preset rule is that the projector projects a frame of gray level image with preset gray level after a trigger signal is sent out;
the camera shoots the gray image after receiving the trigger signal every time to obtain a shot image;
for the gray image of each frame, acquiring a single error value of the camera according to the gray value of the first row in the shot image, the preset gray value and the exposure duration of the camera;
obtaining an average error value according to all the single error values;
and adjusting the projector and the camera to be synchronous according to the average error value.
5. A projection grating modeling device based on a rolling shutter is characterized by comprising a triggering module, an obtaining module and a modeling module,
the trigger module is used for calling the projector to project the grating images with a plurality of continuous projection periods after sending out a trigger signal;
the acquisition module is used for shooting the grating image to acquire a modeling image after receiving the trigger signal through a camera, the camera is a rolling shutter camera, the single-line exposure time of the camera is longer than N projection periods, and N is an integer larger than 0;
the modeling module is used for acquiring a model according to the modeling image;
the projection grating modeling device also comprises a calculation module and a synchronization module,
the trigger module is also used for sending a trigger signal and then projecting a gray image with preset gray by the projector;
the acquisition module is further used for acquiring a shot image by shooting the gray image after receiving the trigger signal through the camera;
the calculation module is used for acquiring an error value of the camera according to the gray value, the preset gray value and the exposure duration of the camera in the shot image;
the synchronization module is used for adjusting the synchronization of the projector and the camera according to the error value;
the trigger module is used for sending a trigger signal and then projecting a gray image of a first preset gray level by the projector, wherein the gray value of the first preset gray level is 255;
the acquisition module is used for shooting the gray-scale image after receiving the trigger signal through a camera to acquire a first shot image;
the trigger module is further configured to send a trigger signal and then project a gray image of a second preset gray level by the projector, where the gray value of the second preset gray level is 127 or 128;
the acquisition module is further used for shooting the gray-scale image after receiving the trigger signal through a camera to acquire a second shot image;
the calculation module is used for acquiring the error value of the camera according to the first row gray value, the first preset gray value, the second preset gray value and the single-row exposure duration of the camera of the first shot image and the second shot image.
6. The projection grating modeling apparatus of claim 5,
the synchronization module is used for adjusting the time length from the moment when the trigger signal is sent to the moment when the projector starts to project the grating image according to the error value;
the trigger module is also used for sending out a trigger signal and projecting a grating image by the projector after the adjusted duration;
the acquisition module is further used for shooting the raster image after receiving the trigger signal through a camera so as to acquire a modeling image.
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| CN103727898A (en) * | 2014-01-21 | 2014-04-16 | 成都天拓众成科技有限公司 | Rapid three-dimensional measurement system and method for correcting nonlinear distortion through lookup tables |
| CN105095894A (en) * | 2015-08-06 | 2015-11-25 | 磐纹科技（上海）有限公司 | Noncontact type book scanning equipment |
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