CN110967166B - Detection method, detection device and detection system of near-eye display optical system - Google Patents
Detection method, detection device and detection system of near-eye display optical system Download PDFInfo
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Abstract
The detection method, the detection device and the detection system of the near-eye display system are characterized in that the detection method comprises the following steps: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit to form a first detection light path, acquiring an image of a first test image formed on the first display unit; processing the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system; acquiring an image of a second test image formed on the first display unit while maintaining the inspection camera in a first inspection optical path; and processing the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system. Thus, a plurality of detection indexes of the near-eye display optical system are obtained by using test images with different test patterns through one detection optical path.
Description
Technical Field
The invention relates to the field of near-eye display optical systems, in particular to a detection method, a detection device and a detection system of a near-eye display optical system.
Background
In recent years, near-eye visual optical systems such as virtual reality and augmented reality have created a rich visual experience for humans. Before the optical product is put into service, various detection indexes of the near-eye display optical product need to be measured so as to check the product quality.
The existing method for detecting the near-eye display optical product is mainly based on manual detection of an optical detection device. More specifically, different detection light paths are built corresponding to different detection indexes, and the corresponding detection indexes are obtained by combining active observation of human eyes. Those skilled in the art will know that the number and types of detection indexes of the near-eye display optical product are many, and taking the AR head-mounted display device as an example, the key detection indexes thereof include: angle of view, distortion, resolving power, ghosting, luminance uniformity, transmittance, interpupillary distance, eye box size, virtual image distance, binocular fusion accuracy, and the like. Therefore, in order to obtain different detection index items, different testing instruments (such as a collimator, a reflector, a photometer and the like) are used for constructing a specific detection light path.
Although the manual detection based on the optical detection device can realize the detection of the near-eye display optical system, on one hand, the detection process is complex, the efficiency is low, and the cost is high; on the other hand, because of relying on subjective reading of people, human errors certainly exist, and the requirement of automatic detection is difficult to meet.
On the basis of manual detection based on an optical detection device, an automatic detection method based on camera images is also gradually developed. However, the existing camera image-based automatic detection method is not mature in development, and most of the existing camera image-based automatic detection methods can only detect a few detection indexes. A few automatic detection devices capable of covering most detection indexes have more and complex detection light paths. Moreover, because the detection camera is used for replacing the observation of human eyes, most automatic detection results cannot reflect the real feeling of the human eyes.
Therefore, a demand for a detection method and a detection system thereof capable of improving the detection efficiency of the near-eye display optical system and reducing the detection cost is urgent.
Disclosure of Invention
The invention mainly aims to provide a detection method, a detection device and a detection system of a near-eye display optical system, wherein the detection method can realize automatic detection of a detection index of the near-eye display optical system.
Another object of the present invention is to provide a detection method, a detection device and a detection system for a near-eye display optical system, wherein the detection method can automatically detect each detection index of the near-eye display optical system.
Another objective of the present invention is to provide a detection method, a detection apparatus, and a detection system for a near-eye display optical system, wherein the detection method utilizes one detection optical path to achieve automatic detection of multiple detection indexes of the near-eye display optical system. Therefore, the optical system of the detection system constructed based on the detection method is relatively simple in design, and the detection process is relatively simplified.
Another object of the present invention is to provide a method, an apparatus and a system for detecting a near-eye display optical system, wherein during the detection of the near-eye display optical system by the near-eye display optical system detection system, each detection index is automatically generated without depending on manual observation, thereby effectively eliminating the influence of unstable manual factors and reducing the labor cost.
Another object of the present invention is to provide a method, an apparatus and a system for detecting a near-eye display optical system, wherein during the detection of the near-eye display optical system, the entrance pupil surface of the detection camera is controlled to simulate the actions of the human eye (including the rotation of the eyeball and the contraction of the pupil), so that the automatic detection result can reflect the real feeling of the human eye.
Another objective of the present invention is to provide a method, an apparatus and a system for detecting a near-eye display optical system, wherein during the process of detecting the near-eye display optical system, an entrance pupil plane of the detection camera is adjusted to coincide with a central cross section of an eye box region of the near-eye display optical system, so as to optimize an observation angle of the detection camera, thereby improving detection accuracy of each detection index.
Another object of the present invention is to provide a detection method, a detection device, and a detection system for a near-eye display optical system, in which the detection method can measure binocular fusion accuracy of the near-eye display optical system.
Other advantages and features of the invention will become apparent from the following description and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve at least one of the above objects or advantages, the present invention provides a detection method of a near-eye display optical system including a first display unit and a second display unit, wherein the detection method includes: when an entrance pupil surface of a detection camera is positioned in an eye box area of the first display unit to form a first detection optical path, acquiring an image of a first test image formed on the first display unit, wherein the first test image is provided with a first test pattern; processing the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system; acquiring an image of a second test image formed on the first display unit while maintaining the inspection camera in a first inspection optical path, wherein the second test image has a second test pattern; and processing the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system.
In an embodiment of the present invention, before acquiring the image of the first test image formed on the first display unit, the method includes: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and controlling a motion platform to adjust the inspection camera entrance pupil surface based on the pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with the central section of the eye box area of the first display unit, wherein the motion platform is used for moving the inspection camera.
In an embodiment of the present invention, the third test pattern includes a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a central area of the third test pattern, and the cell detection areas are located in four corner areas of the third test pattern.
In an embodiment of the present invention, processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil plane of the detection camera includes: determining the angle adjustment signal of the detection camera entrance pupil plane based on the pose of the feature pattern located in the central region of the third test pattern; determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and determining a position adjustment signal of the entrance pupil plane of the detection camera based on relative position information between the center position of the eye box region of the first display unit and the feature pattern located in the center region of the third test pattern.
In an embodiment of the present invention, before acquiring the image of the first test image formed on the first display unit, the method further includes: controlling the motion platform to move an entrance pupil plane of the inspection camera away from or close to a center cross-section of a cell area of the first display unit while the entrance pupil plane of the inspection camera is maintained aligned with the center cross-section of the cell area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an embodiment of the invention, the second test pattern includes at least one texture region, and the at least one texture region is used for detecting the second detection index of the near-eye display optical system, where the second detection index is any one or a combination of several selected from a group consisting of a modulation transfer function curve, a resolution, and a contrast.
In an embodiment of the present invention, processing the second test pattern in the image of the second test image to obtain a second detection indicator of the near-eye display optical system includes: extracting the at least one texture region of the second test pattern in the image of the second test image; and processing the at least one texture region in the test image with an optical model to obtain the second detection index of the visual optical system.
In an embodiment of the present invention, the detecting method further includes: controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the first display unit; obtaining an image of the second test image formed on the first display unit at different rotation angles; and processing the second test pattern in the image of the second test image to obtain the second detection index of the near-eye display optical system at different rotation angles.
In an embodiment of the invention, the first test pattern is a pure white pattern, and the pure white pattern is used for detecting the first detection index of the near-eye display optical system, where the first detection index is any one or a combination of several selected from a group consisting of an angle of view, distortion, curvature of field, luminance, chrominance, luminance uniformity, and chrominance uniformity.
In an embodiment of the present invention, processing the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system includes: obtaining the gray value of the image of the first test image; and determining a brightness value in the first detection index of the near-eye display optical system based on a gray value of an image of the first test image and an exposure value of the detection camera which is pre-calibrated, and a corresponding relationship between a brightness value of a calibration target and a gray value of the calibration target image formed by the detection camera.
In an embodiment of the present invention, the detecting method further includes: controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the first display unit; obtaining an image of the first test image formed on the first display unit at different rotation angles; and processing the first test pattern in the image of the first test image to obtain the first detection index of the near-eye display optical system at different rotation angles.
In an embodiment of the present invention, the inspection camera includes a liquid lens, wherein the inspection method further includes: adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera; detecting the imaging definition of the detection camera under different focal lengths; and determining a virtual image distance index of the near-eye display system based on a function of a distance and a voltage between the detection camera and a detected image constructed by the imaging definition of the detection camera in response to the imaging definition of the detection camera being a highest value, wherein the virtual image distance index represents a distance between a test image formed on the display unit and the detection camera.
In an embodiment of the present invention, the process of obtaining the virtual image distance index of the near-eye display system is performed after obtaining a second detection index of the near-eye display optical system, wherein the test image is the second test image.
In an embodiment of the present invention, the detecting method further includes: controlling the motion platform to move the inspection camera such that an entrance pupil plane of the inspection camera is located within an eye box region of the second display unit based on a distance between the first display unit and the second display unit; obtaining an image of a second test image formed on the second display unit; and obtaining binocular fusion accuracy of the near-eye display optical system based on an image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the first display unit and an image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the second display unit.
According to another aspect of the present invention, there is also provided a detection camera pose adjustment method for adjusting a relative positional relationship between an entrance pupil plane of a detection camera and a center cross-section of an eye box region of a first display unit of a near-eye display optical system, including: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and controlling a motion platform to adjust the inspection camera entrance pupil surface based on the pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with the central section of the eye box area of the first display unit, wherein the motion platform is used for moving the inspection camera.
In an embodiment of the present invention, the pose adjustment method further includes: controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an embodiment of the present invention, the third test pattern includes a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a central area of the third test pattern, and the cell detection areas are located in four corner areas of the third test pattern.
In an embodiment of the invention, the characteristic pattern is a cross-hair pattern.
In an embodiment of the present invention, processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil plane of the detection camera includes: determining the angle adjustment signal of the detection camera entrance pupil plane based on the pose of the feature pattern located in the central region of the third test pattern; determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and determining a position adjustment signal of the entrance pupil plane of the detection camera based on relative position information between the center position of the eye box region of the first display unit and the feature pattern located in the center region of the third test pattern.
According to another aspect of the present invention, there is also provided a method for detecting a virtual image distance index of a near-eye display optical system including a first display unit and a second display unit, including: acquiring an image of a second test image formed on the first display unit while an entrance pupil plane of a detection camera is maintained to coincide with a central cross section of an eye box region of the first display unit, wherein the second test image includes at least one texture region, wherein the detection camera includes a liquid lens; adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera; detecting the imaging sharpness of the image of the second test image at different focal lengths; and determining a virtual image distance index of the near-eye display system based on a distance between the detection camera and the image to be detected, which is constructed by the imaging sharpness of the detection camera, and a voltage function in response to the imaging sharpness of the image of the second test image being a highest value, wherein the virtual image distance index represents a distance between the test image formed on the display unit and the detection camera.
In an embodiment of the present invention, before acquiring the image of the first test image formed on the first display unit, the method includes: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera; controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an embodiment of the present invention, the third test pattern includes a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a central area of the third test pattern, and the cell detection areas are located in four corner areas of the third test pattern.
In an embodiment of the invention, the characteristic pattern is a cross-hair pattern.
In an embodiment of the present invention, processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil plane of the detection camera includes: determining the angle adjustment signal of the detection camera entrance pupil plane based on the pose of the feature pattern located in the central region of the third test pattern; determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and determining a position adjustment signal of the entrance pupil plane of the detection camera based on relative position information between the center position of the eye box region of the first display unit and the feature pattern located in the center region of the third test pattern.
According to another aspect of the present invention, there is also provided a method for detecting binocular fusion accuracy of a near-eye display optical system, wherein the near-eye display optical system includes a first display unit and a second display unit, including: acquiring an image of a second test image formed on the first display unit while an entrance pupil plane of a detection camera is maintained to coincide with a central cross section of an eye box region of the first display unit, wherein the second test image includes at least one texture region; controlling a motion platform to move the inspection camera such that an entrance pupil plane of the inspection camera is located within an eye box area of the second display unit based on a distance between the first display unit and the second display unit, wherein the motion platform is used to move the inspection camera; obtaining an image of the second test image formed on the second display unit; and obtaining the binocular fusion accuracy of the near-eye display optical system based on the image of the second test image obtained when the entrance pupil plane of the detection camera coincides with the central cross section of the eye box area of the first display unit and the image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the second display unit.
In an embodiment of the present invention, before acquiring the image of the second test image formed on the first display unit, the method further includes: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera; controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
According to another aspect of the present invention, the present invention also provides a detection apparatus for a near-eye display optical system, comprising: an image acquisition module, configured to acquire an image of a first test image formed on the first display unit when an entrance pupil plane of the inspection camera is located in an eye box area of the first display unit to form a first inspection optical path, wherein the first test image has a first test pattern, and acquire an image of a second test image formed on the first display unit when the inspection camera is maintained in the first inspection optical path, wherein the second test image has a second test pattern; a first detection index obtaining module, configured to process the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system; and the second detection index acquisition module is used for processing the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system.
In an embodiment of the present invention, the detecting apparatus further includes a posture adjustment module, configured to: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and controlling a motion platform to adjust the inspection camera entrance pupil surface based on the pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with the central section of the eye box area of the first display unit, wherein the motion platform is used for moving the inspection camera.
In an embodiment of the present invention, the pose adjustment module is further configured to: controlling the motion platform to move an entrance pupil plane of the inspection camera away from or close to a center cross-section of a cell area of the first display unit while the entrance pupil plane of the inspection camera is maintained aligned with the center cross-section of the cell area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an embodiment of the present invention, the detection apparatus further includes a virtual image distance index obtaining module, configured to: adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera; detecting the imaging definition of the detection camera under different focal lengths; and determining a virtual image distance index of the near-eye display system based on a function of a distance and a voltage between the detection camera and a detected image constructed by the imaging definition of the detection camera in response to the imaging definition of the detection camera being a highest value, wherein the virtual image distance index represents a distance between a test image formed on the display unit and the detection camera.
In an embodiment of the present invention, the first detection index obtaining module is further configured to: obtaining the gray value of the image of the first test image; and determining a brightness value in the first detection index of the near-eye display optical system based on a gray value of an image of the first test image and an exposure value of the detection camera which is pre-calibrated, and a corresponding relationship between a brightness value of a calibration target and a gray value of the calibration target image formed by the detection camera.
In an embodiment of the present invention, the second detection index obtaining module is further configured to: extracting the at least one texture region of the second test pattern in the image of the second test image; and processing the at least one texture region in the test image with an optical model to obtain the second detection index of the visual optical system.
In an embodiment of the present invention, the pose adjustment module is further configured to: controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the first display unit; and controlling the motion platform to rotate the inspection camera so that an entrance pupil plane of the inspection camera rotates around the center of the center section of the eye box area of the second display unit.
In an embodiment of the present invention, the first detection index obtaining module is further configured to: the first detection index obtaining module is further configured to: obtaining an image of the first test image formed on the first display unit at different rotation angles; and processing the first test pattern in the image of the first test image to obtain the first detection index of the near-eye display optical system at different rotation angles.
In an embodiment of the present invention, the second detection index obtaining module is further configured to: obtaining an image of the second test image formed on the first display unit at different rotation angles; and processing the second test pattern in the image of the second test image to obtain the second detection index of the near-eye display optical system at different rotation angles.
In an embodiment of the present invention, the detection apparatus further includes a binocular fusion precision obtaining module, configured to: controlling the motion platform to move the inspection camera such that an entrance pupil plane of the inspection camera is located within an eye box region of the second display unit based on a distance between the first display unit and the second display unit; obtaining an image of a second test image formed on the second display unit; and obtaining binocular fusion accuracy of the near-eye display optical system based on an image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the first display unit and an image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the second display unit.
The present invention also provides a detection system for a near-eye display optical system, comprising: a detection camera for acquiring a test image formed on a first display unit or/and a second display unit of the near-eye display optical system; a motion platform for moving the detection camera; and, a calibration apparatus, wherein the calibration apparatus comprises: a processor; and a memory, wherein computer program instructions are stored in the memory, which computer program instructions, when executed by the processor, cause the processor to perform the detection method as described above.
According to another aspect of the present invention, there is also provided a computer readable storage medium having stored thereon computer program instructions operable to, when executed by a computing device, perform the detection method as described above.
Further objects and advantages of the invention will be fully apparent from the ensuing description and drawings.
These and other objects, features and advantages of the present invention will become more fully apparent from the following detailed description, the accompanying drawings and the claims.
Drawings
Fig. 1 illustrates a flowchart of a detection method of a near-eye display optical system according to a preferred embodiment of the present invention.
Fig. 2 is a perspective view illustrating an AR head-mounted display device detected in the detection method according to the preferred embodiment of the invention.
Fig. 3 is a perspective view illustrating the visual effect of the augmented reality of the detected AR head-mounted display device in the detection method according to the preferred embodiment of the invention.
Fig. 4 is a schematic diagram illustrating an implementation of the third test pattern in the detection method according to the preferred embodiment of the invention.
Fig. 5 is a flowchart illustrating a pose adjustment process of the inspection camera in the inspection method according to the preferred embodiment of the present invention.
Fig. 6 illustrates a block diagram of a detection apparatus for a near-eye display optical system according to a preferred embodiment of the present invention.
FIG. 7 illustrates a perspective view of a detection system for a near-eye display optical system according to a preferred embodiment of the present invention.
Detailed Description
The following description is provided to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention.
It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced devices or components must be constructed and operated in a particular orientation and thus are not to be considered limiting.
It is understood that the terms "a" and "an" should be interpreted as meaning "at least one" or "one or more," i.e., that a quantity of one element may be one in one embodiment, while a quantity of another element may be plural in other embodiments, and the terms "a" and "an" should not be interpreted as limiting the quantity.
Summary of the application
As described above, before the optical product is put into service in the near-eye display mode, various indexes of the optical product need to be detected to check the product quality. The method of inspecting near-eye display optical products has undergone a development process from manual inspection based on optical inspection devices to automated inspection based on camera images.
The automatic detection is an inevitable trend of industrial development instead of manual detection, is favorable for liberating manpower, eliminates errors caused by human factors, and has higher stability and efficiency. However, the existing camera image-based automatic detection method is not developed well. In essence, most camera image-based automated detection methods are also in the initial stage of simply replacing human eye observation with a detection camera and processing with a background algorithm to obtain corresponding detection indexes.
More specifically, the existing camera image-based automatic detection method needs to build a plurality of detection light paths for detecting a plurality of detection indexes. For example, in order to detect indexes related to luminance and chrominance, the detection camera needs to specially acquire a colorimeter image for calibrating the indexes related to chrominance and luminance, and process the colorimeter image by using a corresponding algorithm to obtain detection indexes such as chrominance, luminance, chrominance uniformity and luminance uniformity. When other detection indexes (such as a field angle, distortion and the like) of the near-eye display optical device need to be detected, another detection optical path needs to be additionally established for the detection camera, so that the detection camera can acquire different test images and analyze the test images to obtain other detection indexes.
Those skilled in the art will appreciate that in order to improve the detection accuracy of certain detection indexes, different types of detection cameras should preferably be configured for different detection indexes. For example, in order to improve the detection accuracy of the detection index relating to luminance and chromaticity, the detection camera preferably has a small angle of view; however, in detecting the detection index such as the angle of view, curvature of field, or the like, the detection camera preferably has a relatively large angle of view. The requirements of different detection indexes on the configuration of the detection camera (even contradictory configuration requirements) cause that the balance between the complexity of the automatic detection based on the camera image and the detection precision of each index is difficult to achieve.
Furthermore, in camera image based automatic detection processes, the detection camera is typically placed in a fixed position instead of being viewed by the human eye. However, when a human eye observes an object naturally, the field of view and the observation angle are continuously adjusted, that is, the eyeball of the human eye performs various movements, such as rotating the eyeball and adjusting the size of the pupil. That is, the detection camera is used to replace the observation of human eyes, and the obtained detection result cannot reflect the real feeling of human eyes. This is a drawback to be overcome by existing camera image-based automated inspection systems.
Also, most of the existing camera image-based automatic detection apparatuses can detect only a few detection indexes. That is, the detection integration of most existing camera image-based automatic detection apparatuses is not high in general. The reasons for this are roughly: firstly, when more detection indexes need to be covered, a more complex detection light path needs to be constructed, and the complex detection light path directly causes the rising of the detection cost; second, for some detection indicators (e.g., virtual image distance, eye box size, etc.), it is necessary to detect that the camera is at a specific location to enable measurement. However, an adjustment algorithm for detecting the position and posture of the camera is a technical problem.
In order to solve the technical problem, the basic concept of the present invention is to first adjust the position of the entrance pupil surface of the inspection camera by a specific inspection camera pose adjustment method, so that the entrance pupil surface of the inspection camera is located in the eye box region of the near-eye display optical system to form a first inspection optical path; and acquiring images of different test images by the detection camera on the premise of keeping the detection camera in the first detection light path so as to obtain multiple detection indexes. In addition, for a detection item which can be measured only when the detection camera is at a specific position, the position of the detection camera can be adjusted through a specific detection camera pose adjustment algorithm to perform corresponding measurement. Furthermore, the motion of the human eyes can be simulated through the detection camera pose adjustment algorithm, so that the final detection result can reflect the real feeling observed by the human eyes.
Based on this, the invention provides a detection method of a near-eye display optical system, which first acquires an image of a first test image formed on a first display unit when an entrance pupil plane of a detection camera is located in an eye box area of the first display unit to form a first detection optical path, wherein the first test image has a first test pattern; further, the first test pattern in the image of the first test image is processed to obtain a first detection index of the near-eye display optical system; then, while maintaining the inspection camera in the first inspection optical path, acquiring an image of a second test image formed on the first display unit, wherein the second test image has a second test pattern; and processing the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system. In this way, multiple detection indexes of the near-eye display optical system are measured with high integration through one detection optical path and by using test images with different test patterns, so as to balance the complexity of the detection optical path and the detection precision and efficiency.
Having described the general principles of the present invention, various non-limiting embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
Exemplary imaging quality testing method
Fig. 1 illustrates a flowchart of a detection method of a near-eye display optical system according to a preferred embodiment of the present invention. As shown in fig. 1, the method for detecting a near-eye display optical system according to the preferred embodiment of the invention includes: s110, when an entrance pupil surface of a detection camera is positioned in an eye box area of the first display unit to form a first detection light path, acquiring an image of a first test image formed on the first display unit, wherein the first test image is provided with a first test pattern; s120, processing the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system; s130, when the detection camera is kept in the first detection light path, acquiring an image of a second test image formed on the first display unit, wherein the second test image has a second test pattern; and S140, processing the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system.
Here, for ease of understanding and explanation, a detection process of the near-eye display optical system using the detection method is described by taking the near-eye display optical system as an example for realizing Augmented Reality (AR), and more specifically, by taking the AR head-mounted display device as an example.
Fig. 2 is a perspective view illustrating an AR head-mounted display device detected in the detection method according to the preferred embodiment of the invention. As shown in fig. 2, the AR head-mounted display device includes two display units 13 (a first display unit 131 and a second display unit 132) and an image source (not shown in the figure), wherein the image source is used to generate a virtual image on the first display unit 131 and/or the second display unit 132, wherein the display unit 13 has a special performance, after the user wears the head-mounted display device, the user can see not only real objects in the real world through the display unit 13, but also the virtual image projected by the head-mounted display device on the display unit 13, so as to bring a special visual experience of virtual objects existing in the real space to the user, and the effect of the special visual experience can be schematically referred to fig. 3. In a specific implementation, the image source may be implemented as an oled (organic Light Emitting display) screen or an led (Light Emitting display) screen, and the display unit 13 is implemented as an AR lens (i.e., the first display unit 131 is a left AR lens, and the second display unit 132 is a right AR lens).
In step S110, when the entrance pupil plane of the detection camera is located in the eye box region of the first display unit to form a first detection optical path, an image of a first test image formed on the first display unit is acquired, wherein the first test image has a first test pattern. Here, the entrance pupil plane of the detection camera refers to a common entrance plane of the detection camera where the light beams emitted from all points on the object plane enter, that is, the entrance plane of the detection camera where the external light can enter. In particular, the entrance pupil surface of the detection camera is arranged in front in the application, namely, the entrance pupil surface is arranged at the front end of the lens structure of the detection camera, so that unnecessary interference in the detection process is prevented, and the detection precision is ensured. The eye box region of the first display unit refers to a region where a user can observe a virtual image formed on the first display unit. Therefore, when the entrance pupil surface of the inspection camera is located in the eye box area of the first display unit, the inspection camera can capture the image of the first test image formed on the first display unit.
Test images with different test patterns are provided corresponding to different detection indexes. In particular, the first test pattern is a pure color pattern (e.g., a pure white pattern) for detecting the first detection index of the near-eye display optical system, wherein the first detection index is any one or a combination of several selected from the group consisting of field angle, distortion, curvature of field, luminance, chrominance, luminance uniformity, and chrominance uniformity.
It should be noted that, in step S110, before the image of the first test image is captured by the inspection camera, the pose of the inspection camera should be adjusted to ensure that the entrance pupil plane of the inspection camera is located within the eye box region of the first display unit. In other words, before the inspection camera obtains the image of the first test image formed on the first display unit, the relative position relationship between the inspection camera and the first display unit needs to be adjusted to ensure that the inspection camera can capture the image of the test image formed on the first display unit. It will be appreciated by those skilled in the art that there is an optimum image capture position when capturing an image of a test image formed on the first display unit using the inspection camera: an entrance pupil plane of the detection camera coincides with a central cross section of the eye box area of the first display unit.
When the entrance pupil surface of the detection camera coincides with the central cross section of the eye box area of the first display unit, on one hand, the detection camera can observe a test image formed on the first display unit at the maximum viewing angle; on the other hand, in this position, the posture of the detection camera can be adjusted at will, and the test image formed on the first display unit can be observed completely at all times at a relatively large observation angle. Also, when the entrance pupil plane of the detection camera is at this position, detection of detection items (such as a virtual image distance, an eye box size, and the like) that require the detection camera to be at a specific position for measurement becomes also practicable.
Therefore, preferably, in this embodiment of the present application, before performing step S110, the position of the entrance pupil plane of the detection camera should be adjusted so that the entrance pupil plane of the detection camera coincides with the central cross section of the eye box region of the first display unit. In particular, in this embodiment of the present application, the position of the entrance pupil surface of the inspection camera is adjusted using a specific pose adjustment algorithm, again without human intervention.
More specifically, in the embodiment of the present application, the process of adjusting the position of the entrance pupil plane of the detection camera so as to coincide with the central cross section of the eye box region of the first display unit using a specific pose adjustment algorithm includes the following steps.
First, the entrance pupil plane of the inspection camera is placed substantially in the eye box region of the first display unit, and here, whether or not the entrance pupil plane of the inspection camera is located in the eye box region of the first display unit can be determined based on whether or not the inspection camera can observe the test image formed on the first display unit.
Furthermore, when the entrance pupil surface of the detection camera is located in the eye box area of the first display unit, an image of a third test image formed on the first display unit is acquired, wherein the third test image has a third test pattern.
Further, the third test pattern in the image of the third test image is processed to obtain a pose adjustment signal of the detection camera entrance pupil surface. That is, in this embodiment of the present application, the inspection camera pose adjustment algorithm takes an image of the third test image as data input, and processes the third test pattern in the third test image to obtain a pose adjustment signal of the inspection camera entrance pupil surface. Here, the position and orientation adjustment signal of the detection camera entrance pupil surface includes an angle adjustment signal of the detection camera entrance pupil surface and a position adjustment signal of the detection camera entrance pupil surface, wherein the angle adjustment signal is used to adjust an inclination angle of the entrance pupil surface of the detection camera with respect to a center cross section of the eye box region of the first display unit, and the position adjustment signal is used to adjust a positional relationship between the entrance pupil of the detection camera and the center cross section of the eye box region of the first display unit.
More specifically, in the embodiment of the present application, the third test pattern includes a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a central area of the third test pattern, and the at least 4 cell detection areas are located in four corner areas of the third test pattern. In the subsequent data processing, the feature pattern located in the central region of the third test pattern functions to: determining an angle adjustment signal for the detection camera entrance pupil surface based on the pose of the feature pattern in the image of the third test image. The eye box detection areas located at the four corner areas of the third test pattern function to: determining a boundary and a center position of the eye box region of the first display unit, and determining a position adjustment signal of the entrance pupil plane of the detection camera based on relative position information between the center position of the eye box region and the feature region.
Fig. 3 is a schematic diagram illustrating an implementation of the third test pattern in the detection method according to the preferred embodiment of the invention. In this implementation, the feature pattern is implemented as a "cross-hair" pattern, and 4 of the eye-box detection regions are located at four corner regions of the third test pattern, respectively, as shown in fig. 3. Thus, in the subsequent data processing, the angle adjustment signal of the entrance pupil plane of the detection camera is determined based on the posture (including the rotation angle, the pitch angle, and the like) of the "crosshair pattern" in the image of the third test image. Meanwhile, the position boundary of the eye box detection area in the image of the third test image is obtained through a traversal method, so that the boundary of the eye box area of the first display unit is obtained through solving. Accordingly, the center position of the eye box region of the first display unit can also be known. Further, a position adjustment signal of the detection camera entrance pupil plane may be determined based on position information between the center position of the eye box region and the "cross-hair" pattern.
It is worth mentioning that in other embodiments of the present application, the feature pattern located at the center of the third test pattern may be selected as a feature pattern having other shapes, for example, a turbo pattern, or a black and white checkerboard pattern, etc. And is not intended to limit the scope of the present application.
After processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the inspection camera entrance pupil surface, further, based on the pose adjustment signal of the inspection camera entrance pupil surface, controlling a motion platform to adjust a relative positional relationship between the inspection camera entrance pupil surface and a central cross section of the eye box region of the first display unit, and finally aligning the entrance pupil surface of the inspection camera with the central cross section of the eye box region of the first display unit.
More specifically, the motion platform is controlled to rotate or tilt the inspection camera entrance pupil surface based on an angle adjustment signal in a pose adjustment signal of the inspection camera entrance pupil surface such that the entrance pupil surface of the inspection camera is parallel to a center cross section of the eye box region of the first display unit. Accordingly, the motion platform is controlled to translate the entrance pupil surface of the inspection camera based on the position adjustment signal in the pose adjustment signal of the entrance pupil surface of the inspection camera so that the center of the entrance pupil surface of the inspection camera is aligned with the center of the center cross section of the eye box region of the first display unit.
It is worth mentioning that, in the process of specifically adjusting the relative position relationship between the inspection camera entrance pupil surface and the central cross section of the eye box region of the first display unit based on the pose adjustment signal of the inspection camera entrance pupil surface, the motion platform may be controlled to rotate or tilt the inspection camera entrance pupil surface based on the angle adjustment signal in the pose adjustment signal, so that the entrance pupil surface of the inspection camera is parallel to the central cross section of the eye box region of the first display unit; and then, based on a position adjusting signal in the position and posture adjusting signal of the entrance pupil surface of the detection camera, controlling the motion platform to translate the entrance pupil surface of the detection camera so that the center of the entrance pupil surface of the detection camera is aligned with the center of the central section of the eye box area of the first display unit. It is also possible that the motion platform may be first controlled to translate the entrance pupil surface of the inspection camera based on a position adjustment signal in the pose adjustment signal of the entrance pupil surface of the inspection camera such that the center of the entrance pupil surface of the inspection camera is aligned with the center of the center cross-section of the eye box region of the first display unit; then, based on the angle adjusting signal in the pose adjusting signal, the motion platform is controlled to rotate or tilt the inspection camera entrance pupil surface, so that the entrance pupil surface of the inspection camera is parallel to the central section of the eye box area of the first display unit. And is not intended to limit the scope of the present application.
After the entrance pupil surface of the inspection camera is adjusted to be aligned with the central cross section of the eye box area of the first display unit, further, the motion platform is controlled to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera is far away from or close to the eye box area of the first display unit. Here, it should be appreciated that when the relative positional relationship between the entrance pupil plane of the detection camera and the eye box region of the first display unit is changed, the area of the overlapping region between the entrance pupil plane of the detection camera and the eye box region of the first display unit will be changed. In particular, when the area of the overlapped region between the two reaches the maximum value, the entrance pupil plane of the detection camera is located at a position overlapped with the central section of the eye box region of the first display unit.
Fig. 4 is a flowchart illustrating a pose adjustment process of the inspection camera in the inspection method according to the preferred embodiment of the present invention. As illustrated in fig. 4, the pose adjustment process of the detection camera includes: s210, when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; s220, processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; s230, controlling a motion platform to adjust the entrance pupil surface of the detection camera based on the pose adjustment signal of the entrance pupil surface of the detection camera so that the entrance pupil surface of the detection camera is aligned with the central section of the eye box area of the first display unit, wherein the motion platform is used for moving the detection camera; s240, when the entrance pupil surface of the detection camera is kept aligned with the central section of the eye box area of the first display unit, controlling the motion platform to move the entrance pupil surface of the detection camera so that the entrance pupil surface of the detection camera moves along the Z-axis direction set by the detection camera to be far away from or close to the eye box area of the first display unit; s250, detecting the size of a superposition area between the entrance pupil surface of the detection camera and the eye box area of the first display unit at different positions; and S260, in response to the size of the overlapping area between the entrance pupil surface of the detection camera and the eye box area of the first display unit being the maximum value, maintaining the entrance pupil surface of the detection camera at a position where the size of the overlapping area between the entrance pupil surface of the detection camera and the eye box area of the first display unit is the maximum value, so that the entrance pupil surface of the detection camera overlaps with the central cross section of the eye box area of the first display unit.
After the entrance pupil plane of the inspection camera is adjusted to an optimal image capture position (the entrance pupil plane of the inspection camera coincides with the center cross-section of the eye box region of the first display unit) by the inspection camera pose adjustment algorithm described above, an image of a first test image formed on the first display unit is captured by the inspection camera. It will be appreciated that in this position, the image quality of the first test image captured by the inspection camera is higher, which is beneficial to improving inspection accuracy.
In step S120, the first test pattern in the image of the first test image is processed to obtain a first detection index of the near-eye display optical system. Here, a process of processing the pure white pattern in the image of the first test image to obtain the first detection index of the near-eye display optical system will be described by taking a solution of the luminance index in the first detection index as an example.
Firstly, obtaining a gray value of an image of the first test image, and further determining a brightness value in the first detection index of the near-eye display optical system based on the gray value of the image of the first test image and an exposure value of the detection camera which is pre-calibrated, and a corresponding relationship between a brightness value of a calibration target and the gray value of the calibration target image formed by the detection camera. In other words, in the preferred embodiment of the present application, before the brightness measurement is performed, the inspection camera needs to be calibrated in advance to obtain the exposure value of the inspection camera, and the corresponding relationship between the brightness value of the calibration target and the gray-level value of the calibration target image formed by the inspection camera is calibrated.
It should be noted that, corresponding to the specific detection item in the first detection index, the processing procedure of the image of the first test image is specifically adjusted. Since this technique is well known, it will not be described here.
In steps S130 and S140, while maintaining the inspection camera in the first inspection optical path, an image of a second test image formed on the first display unit is acquired, wherein the second test image has a second test pattern, and the second test pattern in the image of the second test image is processed to obtain a second inspection index of the near-eye display optical system. In other words, the second detection index of the near-eye optical display is measured while keeping the relative position of the detection camera and the first display unit unchanged.
In particular, in the preferred embodiment of the present invention, the second test pattern of the second test image includes at least one texture region for detecting the second detection index of the near-eye display optical system, wherein the second detection index is any one or a combination of several selected from the group consisting of modulation transfer function curve, resolution and contrast.
Fig. 5 is a schematic diagram illustrating an implementation of the second test pattern in the detection method according to the preferred embodiment of the invention. As shown in fig. 5, the second test pattern is implemented as a striped region (i.e., the textured region) alternating between black and white. Here, it should be understood by those skilled in the art that, in other embodiments of the present application, the second test pattern may be specifically adjusted according to a specific detection item in the second detection index. And is not intended to limit the scope of the present application.
In one embodiment, the processing of the image of the first test image includes the following steps. Firstly, identifying and extracting the at least one texture region of the first test pattern; further, the at least one texture region in the test image is processed with an optical model to obtain the first detection index of the visual optical system.
It is worth mentioning that the optical model integrates a correlation algorithm for processing the texture region, and is configured to process and analyze the at least one texture region to obtain the corresponding first detection index. As mentioned above, the first detection index is any one or a combination of several selected from the group consisting of modulation transfer function curve, resolution and contrast. In particular, the algorithm into which the optical model is integrated will make specific adjustments for specific different first detection indicators.
It should be noted that, in the preferred embodiment of the present application, the first test pattern and the second test pattern are different types of test patterns, which are used to obtain different types of the first detection index and the second detection index. In other words, on the premise of keeping the detection camera in the first detection optical path, by switching different test images, a plurality of detection indexes of the near-eye display optical system can be automatically and integrally obtained. Meanwhile, in the process of measuring the first detection index and the second detection index of the near-eye display optical system, the relative position relationship between the detection camera and the first display unit is kept unchanged, namely, the detection camera is always in the first detection optical path. In other words, in the application, the detection method realizes automatic detection of multiple detection indexes of the near-eye display optical system by constructing one detection optical path.
Further, as described above, when the entrance pupil plane of the inspection camera coincides with the central cross section of the eye box region of the first display unit, the posture of the inspection camera can be arbitrarily adjusted, and the inspection camera can always observe the test image formed on the first display unit at the maximum angle of view in different postures. Based on this characteristic, the detection camera can be further controlled to move in a particular pattern to simulate the effect observed by the human eye.
For example, in the preferred embodiment of the present application, after step S120, the detection camera may be further controlled to imitate a human eye rotation effect, so as to obtain the first detection index of the near-eye display optical system at different rotation angles. More specifically, in this process, the motion platform is first controlled to rotate the inspection camera so that the entrance pupil plane of the inspection camera rotates around the center of the center cross section of the eye box region of the first display unit; further, under different rotation angles, obtaining an image of the first test image formed on the first display unit; then, the first test pattern in the image of the first test image is processed to obtain the first detection index of the near-eye display optical system at different rotation angles.
Similarly, in the preferred embodiment of the present application, after step S140, the detection camera may be further controlled to imitate the human eye rotation effect to obtain the second detection index of the near-eye display optical system at different rotation angles. More specifically, in this process, the motion platform is first controlled to rotate the inspection camera so that the entrance pupil plane of the inspection camera rotates around the center of the center cross section of the eye box region of the first display unit; further, under different rotation angles, obtaining an image of the second test image formed on the first display unit; then, the second test pattern in the image of the second test image is processed to obtain the second detection index of the near-eye display optical system at different rotation angles.
In order to simulate the pupil zooming process of the human eye, in the preferred embodiment of the present application, the detecting camera may be configured with an iris to simulate different pupil sizes of the human eye by changing the aperture of the iris. In this way, by repeating the above-described process of detecting the first detection index and the second detection index for different entrance pupil sizes, a series of the first detection index and the second detection index for different entrance pupil sizes can be obtained.
Further, as described above, when the entrance pupil plane of the detection camera coincides with the central cross section of the eye box region of the first display unit, detection of detection items (for example, virtual image distances) that require the detection camera to be in a specific position for measurement also becomes practicable. Here, in the preferred embodiment of the present application, when the entrance pupil plane of the detection camera coincides with the central cross section of the eye box region of the first display unit, the detection method further includes measuring a virtual image distance index of the near-eye display optical system, where the virtual image distance index refers to a distance between a test image formed on the display unit and the detection camera.
In one embodiment, in order to measure the virtual image distance index of the near-eye display optical system, the detection camera is specially configured with a liquid lens, wherein the liquid lens has different focal powers under different voltages. In other words, the detection cameras have different focal lengths at different voltages.
Accordingly, in the preferred embodiment of the present application, the process of obtaining the virtual image distance index of the near-eye display optical system includes the following steps. Firstly, adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera; further, detecting the imaging definition of the detection camera under different focal lengths; and when the imaging definition of the detection camera is the highest value, determining a virtual image distance index of the near-eye display system based on a function of the distance and the voltage between the detection camera and the detected image, which is constructed through the imaging definition of the detection camera. In other words, the detection camera is calibrated to establish the corresponding relation between the distance of the object to be detected and the voltage through the image definition degree. In the virtual image distance measurement, the focal length of an imaging system is changed by changing the voltage so as to find a corresponding voltage value when the imaging is clearest, and then the virtual image distance is reversely deduced according to a pre-calibrated result.
It should be noted that, in the preferred embodiment of the present application, the process of obtaining the virtual image distance index of the near-eye display system may be performed after obtaining a second detection index of the near-eye display optical system, where the test image is the second test image, that is, the second test image is kept unchanged. Of course, those skilled in the art will readily appreciate that in implementations, the process of obtaining a virtual image index of the near-eye display system may be performed in any process, and that entirely new test images may be used, which need only include at least one texture region. And is not intended to limit the scope of the present application.
After the measurement of the detection indexes of the first display unit is completed by the detection method, the detection camera can be moved to the second display unit by the motion platform, so as to repeat the detection process to obtain the measurement of the detection indexes of the second display unit on the one hand, and obtain the detection items needing to participate in the first display unit and the second display unit together on the other hand, for example, the binocular fusion precision of the near-eye display optical system.
In particular, in the preferred embodiment of the present application, the process of obtaining binocular fusion accuracy of the near-eye display optical system includes the following steps. Firstly, based on the distance between the first display unit and the second display unit, controlling the motion platform to move the detection camera so that the entrance pupil surface of the detection camera is positioned in the eye box area of the second display unit; further, obtaining an image of a second test image formed on the second display unit; then, the binocular fusion accuracy of the near-eye display optical system is obtained based on the image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the first display unit and the image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the second display unit. It should be appreciated that in obtaining the binocular fusion accuracy, the test image may be selected to have any test pattern, which only needs to include at least one texture region. And is not intended to limit the scope of the present application.
In summary, the detection process for the AR head-mounted display device using the above detection method is clarified, wherein, in the detection process, the first detection index (including field angle, distortion, curvature of field, luminance, chromaticity, luminance uniformity, chromaticity uniformity, and the like), the second detection index (including modulation transfer function curve, resolution, and contrast), the eye box area size of the display unit (including the first display unit and the second display unit), the virtual image distance, the binocular fusion precision, and other series of indexes can be integrally and automatically determined.
It is worth mentioning that although the detection method is used in the AR head-mounted display device as an example, those skilled in the art will readily understand that the detection method disclosed in the present invention can be used in other types of AR near-eye optical display devices as well, and even VR near-eye optical display devices. And is not intended to limit the scope of the present application.
According to another aspect of the present invention, the present invention further provides a method for detecting a camera pose adjustment, comprising the steps of: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and controlling a motion platform to adjust the inspection camera entrance pupil surface based on the pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with the central section of the eye box area of the first display unit, wherein the motion platform is used for moving the inspection camera.
In an embodiment of the present invention, the method for adjusting the pose of the detection camera further includes: controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an embodiment of the present invention, the third test pattern includes a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a central area of the third test pattern, and the cell detection areas are located in four corner areas of the third test pattern.
In an embodiment of the present invention, processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil plane of the detection camera includes: determining the angle adjustment signal based on a pose of the feature pattern located in a central region of the third test pattern; determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and determining a position adjustment signal of the entrance pupil plane of the detection camera based on relative position information between the center position of the eye box region of the first display unit and the feature pattern located in the center region of the third test pattern.
According to another aspect of the present invention, the present invention also provides a method for detecting a virtual image distance index of a near-eye display optical system, including: acquiring an image of a second test image formed on the first display unit while an entrance pupil plane of a detection camera is maintained to coincide with a central cross section of an eye box region of the first display unit, wherein the first test image has a second test pattern having at least one texture region, wherein the detection camera includes a liquid lens; adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera; detecting the imaging sharpness of the image of the second test image at different focal lengths; and determining a virtual image distance index of the near-eye display system based on a distance between the detection camera and the image to be detected, which is constructed by the imaging sharpness of the detection camera, and a voltage function in response to the imaging sharpness of the image of the second test image being a highest value, wherein the virtual image distance index represents a distance between the test image formed on the display unit and the detection camera.
In an embodiment of the present invention, before acquiring the image of the second test image formed on the first display unit, the method includes: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera; controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an embodiment of the present invention, the third test pattern includes a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a central area of the third test pattern, and the cell detection areas are located in four corner areas of the third test pattern.
In an embodiment of the present invention, processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil plane of the detection camera includes: determining the angle adjustment signal based on a posture of the feature pattern located in a central region of the third test pattern; determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and determining a position adjustment signal of the entrance pupil plane of the detection camera based on relative position information between the center position of the eye box region of the first display unit and the feature pattern located in the center region of the third test pattern.
According to another aspect of the present invention, the present invention also provides a method for detecting binocular fusion accuracy of a near-eye display optical system, comprising: acquiring an image of a second test image formed on the first display unit while an entrance pupil plane of a detection camera is maintained to coincide with a central cross section of an eye box region of the first display unit; controlling a motion platform to move the inspection camera such that an entrance pupil plane of the inspection camera is located within an eye box area of the second display unit based on a distance between the first display unit and the second display unit, wherein the motion platform is used to move the inspection camera; obtaining an image of the second test image formed on the second display unit; and obtaining the binocular fusion accuracy of the near-eye display optical system based on the image of the second test image obtained when the entrance pupil plane of the detection camera coincides with the central cross section of the eye box area of the first display unit and the image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the second display unit.
In an embodiment of the present invention, before acquiring the image of the first test image formed on the first display unit, the method further includes: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera; controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit. .
Schematic detection device
Fig. 6 illustrates a block diagram of a detection apparatus for a near-eye display optical system according to a preferred embodiment of the present invention.
As shown in fig. 6, the detecting device 600 according to the preferred embodiment of the present invention includes: an image obtaining module 610, configured to obtain an image of a first test image formed on the first display unit when an entrance pupil plane of the inspection camera is located in an eye box area of the first display unit to form a first inspection optical path, wherein the first test image has a first test pattern, and obtain an image of a second test image formed on the first display unit when the inspection camera is kept in the first inspection optical path, wherein the second test image has a second test pattern; a first detection index obtaining module 620, configured to process the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system; and a second detection index obtaining module 630, configured to process the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system.
In an example, in the above detecting apparatus 600, a position adjustment module 640 is further included for: when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern; processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and controlling a motion platform to adjust the inspection camera entrance pupil surface based on the pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with the central section of the eye box area of the first display unit, wherein the motion platform is used for moving the inspection camera.
In one example, in the above detection apparatus 600, the pose adjustment module 640 is further configured to: controlling the motion platform to move an entrance pupil plane of the inspection camera away from or close to a center cross-section of a cell area of the first display unit while the entrance pupil plane of the inspection camera is maintained aligned with the center cross-section of the cell area of the first display unit; detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and in response to the size of a region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the region of overlap between the entrance pupil surface of the inspection camera and the eye box region of the first display unit is a maximum value, such that the entrance pupil surface of the inspection camera coincides with a central cross section of the eye box region of the first display unit.
In an example, in the above detection apparatus 600, the detection apparatus further includes a virtual image distance index obtaining module 650, configured to: adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera; detecting the imaging definition of the detection camera under different focal lengths; and determining a virtual image distance index of the near-eye display system based on a function of a distance and a voltage between the detection camera and a detected image constructed by the imaging definition of the detection camera in response to the imaging definition of the detection camera being a highest value, wherein the virtual image distance index represents a distance between a test image formed on the display unit and the detection camera.
In an example, in the above detection apparatus 600, the first detection index obtaining module 620 is further configured to: obtaining the gray value of the image of the first test image; and determining a brightness value in the first detection index of the near-eye display optical system based on a gray value of an image of the first test image and an exposure value of the detection camera which is pre-calibrated, and a corresponding relationship between a brightness value of a calibration target and a gray value of the calibration target image formed by the detection camera.
In an example, in the above detection apparatus 600, the second detection index obtaining module 630 is further configured to: extracting the at least one texture region of the second test pattern in the image of the second test image; and processing the at least one texture region in the test image with an optical model to obtain the second detection index of the visual optical system.
In an example, in the above detection apparatus 600, the pose adjustment module 640 is further configured to: controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the first display unit; and controlling the motion platform to rotate the detection camera so that an entrance pupil surface of the detection camera rotates around the center of the center section of the eye box area of the second display unit.
In an example, in the above detection apparatus 600, the first detection index obtaining module 620 is further configured to: obtaining an image of the first test image formed on the first display unit at different rotation angles; and processing the first test pattern in the image of the first test image to obtain the first detection index of the near-eye display optical system at different rotation angles.
In an example, in the above detection apparatus 600, the second detection index obtaining module 630 is further configured to: obtaining an image of the second test image formed on the first display unit at different rotation angles; and processing the second test pattern in the image of the second test image to obtain the second detection index of the near-eye display optical system at different rotation angles.
In an example, in the above detection apparatus 600, the detection apparatus 600 further includes a binocular fusion precision obtaining module 660, configured to: controlling the motion platform to move the inspection camera such that an entrance pupil plane of the inspection camera is located within an eye box region of the second display unit based on a distance between the first display unit and the second display unit; obtaining an image of a second test image formed on the second display unit; and obtaining binocular fusion accuracy of the near-eye display optical system based on an image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the first display unit and an image of the second test image obtained when the entrance pupil plane of the detection camera is located in the eye box area of the second display unit.
Here, it can be understood by those skilled in the art that the specific functions and operations of the respective units and modules in the above-described inspection apparatus 600 have been described in detail in the imaging quality test method for a visual optical system described above with reference to fig. 1 to 5, and thus, a repetitive description thereof will be omitted.
As described above, the detection apparatus according to the embodiment of the present application can be implemented in various terminal devices, such as a server of a detection system for a near-eye display optical system. In one example, the detection apparatus according to the embodiment of the present application may be integrated into the terminal device as a software module and/or a hardware module. For example, the detection means may be a software module in the operating system of the terminal device, or may be an application developed for the terminal device; of course, the detection means may also be one of a plurality of hardware modules of the terminal device.
Alternatively, in another example, the detecting device and the terminal device may be separate terminal devices, and the detecting device may be connected to the terminal device through a wired and/or wireless network and transmit the interaction information according to an agreed data format.
Exemplary calibration System
FIG. 7 illustrates a perspective view of a detection system for a near-eye display optical system according to a preferred embodiment of the present invention.
As shown in fig. 7, the detection system 700 for the near-eye display optical system according to the preferred embodiment of the present invention includes: a detection camera 710, the detection camera 710 for capturing a test image formed on a first display unit or/and a second display unit of the near-eye display optical system; a motion platform 720 for moving the detection camera; and a calibration apparatus 730. The calibration device 730 includes: a processor 731; and a memory 732 in which the memory 732 has stored computer program instructions that, when executed by the processor 731, cause the processor 731 to perform the detection method as described above.
Illustrative computer program product
In addition to the above-described methods and apparatus, embodiments of the present application may also be a computer program product comprising computer program instructions which, when executed by a processor, cause the processor to perform the steps in the detection method of a ocular optical system according to various embodiments of the present application described in the "exemplary methods" section of this specification above.
The computer program product may be written with program code for performing the operations of embodiments of the present application in any combination of one or more programming languages, including an object oriented programming language such as Java, C + + or the like and conventional procedural programming languages, such as "r" or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device, or entirely on the remote computing device or server.
Furthermore, embodiments of the present application may also be a computer-readable storage medium having stored thereon computer program instructions which, when executed by a processor, cause the processor to perform the steps in the detection method of a ocular optical system according to various embodiments of the present application described in the "exemplary methods" section above in the present description.
The computer-readable storage medium may take any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may include, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
The foregoing describes the general principles of the present application in conjunction with specific embodiments, however, it is noted that the advantages, effects, etc. mentioned in the present application are merely examples and are not limiting, and they should not be considered essential to the various embodiments of the present application. Furthermore, the foregoing disclosure of specific details is for the purpose of illustration and description and is not intended to be limiting, since the foregoing disclosure is not intended to be exhaustive or to limit the disclosure to the precise details disclosed.
The block diagrams of devices, apparatuses, systems referred to in this application are only given as illustrative examples and are not intended to require or imply that the connections, arrangements, configurations, etc. must be made in the manner shown in the block diagrams. These devices, apparatuses, devices, systems may be connected, arranged, configured in any manner, as will be appreciated by those skilled in the art. Words such as "including," "comprising," "having," and the like are open-ended words that mean "including, but not limited to," and are used interchangeably therewith. As used herein, the words "or" and "refer to, and are used interchangeably with, the word" and/or, "unless the context clearly dictates otherwise. The word "such as" is used herein to mean, and is used interchangeably with, the phrase "such as but not limited to".
It should also be noted that in the devices, apparatuses, and methods of the present application, the components or steps may be decomposed and/or recombined. These decompositions and/or recombinations are to be considered as equivalents of the present application.
The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing description has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit embodiments of the application to the form disclosed herein. While a number of example aspects and embodiments have been discussed above, those of skill in the art will recognize certain variations, modifications, alterations, additions and sub-combinations thereof.
It will be appreciated by persons skilled in the art that the embodiments of the invention described above and shown in the drawings are given by way of example only and are not limiting of the invention. The objects of the invention have been fully and effectively accomplished. The functional and structural principles of the present invention have been shown and described in the examples, and any variations or modifications of the embodiments of the present invention may be made without departing from the principles.
Claims (25)
1. A method for inspecting a near-eye display optical system, wherein the near-eye display optical system includes a first display unit and a second display unit, the method comprising:
when an entrance pupil surface of a detection camera is positioned in an eye box area of the first display unit to form a first detection light path, acquiring an image of a first test image formed on the first display unit, wherein the first test image has a first test pattern;
processing the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system;
acquiring an image of a second test image formed on the first display unit while maintaining the inspection camera in a first inspection optical path, wherein the second test image has a second test pattern; and
processing the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system;
wherein, before acquiring an image of a first test image formed on the first display unit, it comprises:
when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern;
processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and
controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera;
wherein the third test pattern comprises a feature pattern and at least 4 cell detection areas, wherein the feature pattern is located in a center area of the third test pattern, and the cell detection areas are located in four corner areas of the third test pattern;
wherein processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the detection camera entrance pupil surface comprises:
determining an angle adjustment signal of the detection camera entrance pupil plane based on the pose of the feature pattern located in the central region of the third test pattern;
determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and the number of the first and second groups,
determining a position adjustment signal of the detection camera entrance pupil surface based on relative position information between a center position of the eye box region of the first display unit and the feature pattern located in a center region of the third test pattern.
2. The inspection method according to claim 1, wherein before acquiring the image of the first test image formed on the first display unit, further comprising:
controlling the motion platform to move an entrance pupil plane of the inspection camera away from or close to a center cross-section of a cell area of the first display unit while the entrance pupil plane of the inspection camera is maintained aligned with the center cross-section of the cell area of the first display unit;
detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and
in response to the size of the area of coincidence between the entrance pupil surface of the inspection camera and the eye box area of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the area of coincidence between the entrance pupil surface of the inspection camera and the eye box area of the first display unit is a maximum value such that the entrance pupil surface of the inspection camera coincides with the central cross-section of the eye box area of the first display unit.
3. The detection method according to claim 1 or 2, wherein the second test pattern comprises at least one texture region for detecting the second detection index of the near-eye display optical system, wherein the second detection index is any one or a combination of several selected from the group consisting of modulation transfer function curve, resolution and contrast.
4. The inspection method of claim 3, wherein processing the second test pattern in the image of the second test image to obtain a second inspection index for the near-eye display optical system comprises:
extracting the at least one texture region of the second test pattern in the image of the second test image; and
processing the at least one texture region in the test image with an optical model to obtain the second detection index of the near-eye display optical system.
5. The detection method of claim 4, further comprising:
controlling the motion platform to rotate the inspection camera so that an entrance pupil surface of the inspection camera rotates around the center of the center section of the eye box area of the first display unit;
obtaining an image of the second test image formed on the first display unit at different rotation angles; and
and processing the second test pattern in the image of the second test image to obtain the second detection index of the near-eye display optical system under different rotation angles.
6. The detection method according to claim 1 or 2, wherein the first test pattern is a pure white pattern for detecting the first detection index of the near-eye display optical system, wherein the first detection index is any one or a combination of several selected from the group consisting of field angle, distortion, curvature of field, luminance, chromaticity, luminance uniformity, and chromaticity uniformity.
7. The inspection method of claim 6, wherein processing the first test pattern in the image of the first test image to obtain a first inspection index of the near-eye display optical system comprises:
obtaining the gray value of the image of the first test image; and
and determining a brightness value in the first detection index of the near-eye display optical system based on a gray-scale value of the image of the first test image and an exposure value of the pre-calibrated detection camera, and a corresponding relationship between a brightness value of a calibration target and a gray-scale value of a calibration target image formed by the detection camera.
8. The detection method of claim 7, further comprising:
controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the first display unit;
obtaining an image of the first test image formed on the first display unit at different rotation angles; and
processing the first test pattern in the image of the first test image to obtain the first detection index of the near-eye display optical system at different rotation angles.
9. The inspection method of claim 1, wherein the inspection camera includes a liquid lens, wherein the inspection method further comprises:
adjusting the working voltage of the liquid lens of the detection camera to change the focal length of the detection camera;
detecting the imaging definition of the detection camera under different focal lengths; and
determining a virtual image distance index of the near-eye display optical system based on a distance and voltage function between the detection camera and a detected image constructed by the imaging definition of the detection camera when the imaging definition of the detection camera is a highest value, wherein the virtual image distance index refers to the distance between the detection camera and the detected image and the voltage function
The mark indicates a distance between a test image formed on the display unit and the inspection camera.
10. The detection method according to claim 9, wherein the process of obtaining the virtual image distance index of the near-eye display optical system is performed after obtaining a second detection index of the near-eye display optical system, wherein the test image is the second test image.
11. The detection method of claim 1, further comprising:
controlling the motion platform to move the inspection camera such that an entrance pupil plane of the inspection camera is located within an eye box region of the second display unit based on a distance between the first display unit and the second display unit;
obtaining an image of a second test image formed on the second display unit; and
and obtaining the binocular fusion precision of the near-eye display optical system based on the image of the second test image obtained when the entrance pupil surface of the detection camera is located in the eye box area of the first display unit and the image of the second test image obtained when the entrance pupil surface of the detection camera is located in the eye box area of the second display unit.
12. A detecting camera pose adjusting method for adjusting a relative positional relationship between an entrance pupil plane of a detecting camera and a center cross-section of an eye box region of a first display unit of a near-eye display optical system, comprising:
when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern;
processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and the number of the first and second groups,
controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera;
the method for adjusting the pose of the detection camera further comprises the following steps:
controlling the motion platform to move the entrance pupil surface of the inspection camera so that the entrance pupil surface of the inspection camera moves along the Z-axis direction set by the inspection camera to be far away from or close to the eye box area of the first display unit when the entrance pupil surface of the inspection camera is kept aligned with the central cross section of the eye box area of the first display unit;
detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and
in response to the size of the area of coincidence between the entrance pupil surface of the inspection camera and the eye box area of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the area of coincidence between the entrance pupil surface of the inspection camera and the eye box area of the first display unit is a maximum value such that the entrance pupil surface of the inspection camera coincides with the central cross-section of the eye box area of the first display unit.
13. The inspection camera pose adjustment method of claim 12, wherein the third test pattern comprises a feature pattern and at least 4 eyebox detection areas, wherein the feature pattern is located in a center area of the third test pattern and the eyebox detection areas are located in four corner areas of the third test pattern.
14. A detection camera pose adjustment method according to claim 13, wherein said feature pattern is a cross-hair pattern.
15. The inspection camera pose adjustment method of claim 14, wherein processing the third test pattern in the image of the third test image to obtain the pose adjustment signal of the inspection camera entrance pupil plane comprises:
determining an angle adjustment signal of the detection camera entrance pupil plane based on the pose of the feature pattern located in the central region of the third test pattern;
determining a boundary and a center position of the eye box region of the first display unit based on the eye box detection regions located at four corner regions of the third test pattern; and the number of the first and second groups,
determining a position adjustment signal of the detection camera entrance pupil surface based on relative position information between a center position of the eye box region of the first display unit and the feature pattern located in a center region of the third test pattern.
16. A detection apparatus for a near-eye display optical system, comprising:
the image acquisition module is used for acquiring an image of a first test image formed on a first display unit when an entrance pupil surface of a detection camera is positioned in an eye box area of the first display unit to form a first detection light path, wherein the first test image is provided with a first test pattern, and acquiring an image of a second test image formed on the first display unit when the detection camera is kept in the first detection light path, wherein the second test image is provided with a second test pattern;
a first detection index obtaining module, configured to process the first test pattern in the image of the first test image to obtain a first detection index of the near-eye display optical system; and
a second detection index obtaining module, configured to process the second test pattern in the image of the second test image to obtain a second detection index of the near-eye display optical system;
wherein the detection device further comprises a posture adjusting module for:
when the entrance pupil surface of the detection camera is positioned in the eye box area of the first display unit, acquiring an image of a third test image formed on the first display unit, wherein the third test image has a third test pattern;
processing the third test pattern in the image of the third test image to obtain a pose adjustment signal of the entrance pupil surface of the detection camera; and
controlling a motion platform to adjust the inspection camera entrance pupil surface based on a pose adjustment signal of the inspection camera entrance pupil surface so that the entrance pupil surface of the inspection camera is aligned with a central cross section of the eye box region of the first display unit, wherein the motion platform is used for moving the inspection camera;
wherein, the pose adjusting module is further configured to:
controlling the motion platform to move an entrance pupil surface of the inspection camera away from or close to a center cross section of a cell area of the first display unit while the entrance pupil surface of the inspection camera is kept aligned with the center cross section of the cell area of the first display unit;
detecting the size of a coincidence region between an entrance pupil surface of the detection camera and an eye box region of the first display unit at different positions; and
in response to the size of the area of coincidence between the entrance pupil surface of the inspection camera and the eye box area of the first display unit being a maximum value, maintaining the entrance pupil surface of the inspection camera at a position where the size of the area of coincidence between the entrance pupil surface of the inspection camera and the eye box area of the first display unit is a maximum value such that the entrance pupil surface of the inspection camera coincides with the central cross-section of the eye box area of the first display unit.
17. The detection apparatus of claim 16, further comprising a virtual image distance indicator obtaining module configured to:
adjusting the working voltage of a liquid lens of the detection camera to change the focal length of the detection camera;
detecting the imaging definition of the detection camera under different focal lengths; and
and when the imaging definition of the detection camera is the highest value, determining a virtual image distance index of the near-eye display optical system based on a function of the distance and the voltage between the detection camera and the detected image, which is constructed by the imaging definition of the detection camera, wherein the virtual image distance index represents the distance between the test image formed on the display unit and the detection camera.
18. The detection apparatus according to claim 17, wherein the first detection index obtaining module is further configured to:
obtaining the gray value of the image of the first test image; and
determining a brightness value in the first detection index of the near-eye display optical system based on a gray value of the image of the first test image and an exposure value of the pre-calibrated detection camera, and a corresponding relationship between a brightness value of a calibration target and a gray value of a calibration target image formed by the detection camera.
19. The detection apparatus according to claim 18, wherein the second detection index obtaining module is further configured to:
extracting at least one texture region of the second test pattern in the image of the second test image; and
processing the at least one texture region in the test image with an optical model to obtain the second detection index of the near-eye display optical system.
20. The detection apparatus of claim 19, wherein the pose adjustment module is further configured to:
controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the first display unit; and
controlling the motion platform to rotate the inspection camera such that an entrance pupil plane of the inspection camera rotates about a center of a center cross section of an eye box region of the second display unit.
21. The detection apparatus according to claim 20, wherein the first detection index obtaining module is further configured to:
obtaining an image of the first test image formed on the first display unit at different rotation angles; and
processing the first test pattern in the image of the first test image to obtain the first detection index of the near-eye display optical system at different rotation angles.
22. The detection apparatus according to claim 20, wherein the second detection index obtaining module is further configured to:
obtaining an image of the second test image formed on the first display unit at different rotation angles; and
and processing the second test pattern in the image of the second test image to obtain the second detection index of the near-eye display optical system under different rotation angles.
23. The inspection apparatus of claim 16, further comprising a binocular fusion accuracy acquisition module for:
controlling the motion platform to move the inspection camera so that an entrance pupil plane of the inspection camera is located within an eye box area of the second display unit based on a distance between the first display unit and the second display unit;
obtaining an image of a second test image formed on the second display unit; and
and obtaining the binocular fusion precision of the near-eye display optical system based on the image of the second test image obtained when the entrance pupil surface of the detection camera is located in the eye box area of the first display unit and the image of the second test image obtained when the entrance pupil surface of the detection camera is located in the eye box area of the second display unit.
24. A detection system for a near-eye display optical system, comprising:
a detection camera for acquiring a test image formed on a first display unit or/and a second display unit of the near-eye display optical system;
a motion platform for moving the detection camera; and
calibration apparatus, wherein the calibration apparatus comprises:
a processor; and
a memory having stored therein computer program instructions which, when executed by the processor, cause the processor to perform the detection method of any one of claims 1-11.
25. A computer readable storage medium having computer program instructions stored thereon, which, when executed by a computing device, are operable to perform the detection method of any one of claims 1-11.
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Application publication date: 20200407 Assignee: Zhejiang Shunwei Technology Co.,Ltd. Assignor: SUNNY OPTICAL (ZHEJIANG) RESEARCH INSTITUTE Co.,Ltd. Contract record no.: X2024330000055 Denomination of invention: Detection methods, detection devices, and detection systems for close eye display optical systems Granted publication date: 20220701 License type: Common License Record date: 20240515 |