CN105049833B - A kind of stereopsis inspection method and device using symmetrical adjustable backlight structure - Google Patents

Abstract

A stereoscopic inspection device adopting a symmetrical adjustable backlight structure, including a symmetrical adjustable backlight device, a pupil position tracking module, a synchronous signal extraction module, a signal processing module, and an image display screen; the symmetrical adjustable backlight device includes a symmetrical adjustable optical component , addressable light source assembly; wherein, the symmetrically adjustable optical assembly includes a light guide module and a symmetrically adjustable imaging module, the light guide module includes: a condenser lens, a light guide device and a triangular prism, and the symmetrically adjustable imaging module ( M) includes: a lens, a lens switching device, a refracting mirror, a beam splitter and a refracting mirror; the signal processing module controls the addressable light source components in the adjustable backlight structure according to the received pupil position information and video synchronization signal. While displaying the left image, the signal processing module lights up the corresponding light-emitting unit according to the position information of the pupil of the left eye to realize the convergence of light at the pupil of the left eye; while displaying the right image, the signal processing module The corresponding light-emitting unit lights up to realize the convergence of light at the pupil of the right eye.

Description

Stereo vision inspection method and device using symmetrical adjustable backlight structure

1. Technical field

The invention relates to the technical field of information display, in particular to a stereoscopic inspection device using a symmetrical adjustable backlight structure.

2. Background technology

Stereopia is the lack of stereo vision. The three-dimensional sense of a person is established in this way: both eyes look at an object at the same time, and the eyes of both eyes cross at one point, called the fixation point, and the light points reflected from the fixation point back to the retina correspond to each other. Compose a complete image of an object. Not only can you see this point clearly, but you can also distinguish the distance, depth, convexity, etc. between this point and the surrounding objects. The image formed in this way is a three-dimensional image. This kind of vision is called stereoscopic vision. Once people's binocular vision function is impaired and lacks stereo vision, the depth and distance of the scenery in the external space cannot be judged. Such a disease is called stereo blindness (the incidence rate of stereo blindness is 2.6%, and the stereo vision abnormality is as high as 30%) . Stereoscopic blindness is an eye disease discovered by biologists in the past ten years. It is a more serious eye disease than night blindness, color blindness and color weakness. People with stereo blindness cannot work as pilots or locomotive drivers. Color blindness is a congenital disorder of color vision. Color blind patients cannot distinguish various colors or certain colors in the natural spectrum; those who have poor ability to distinguish colors are called color weakness. Color-blind patients, although they can see the colors that normal people see, but their ability to recognize colors is slow or poor.

The traditional detection methods of stereo blindness include stereo vision meter inspection method, stereo vision inspection chart inspection method, solid mirror inspection method, and polarized light experimental inspection method. At present, there are some inspection charts for stereo detection blind detection, such as Chinese patent CN102529470A. The above-mentioned test methods all have problems such as single detection samples, limited detection distance, and monocular clues.

The existing three-dimensional display implementation methods mainly include parallax stereo, volume stereo and holographic stereo. Among them, volumetric stereo and holographic stereo have the problem of monocular clues, while parallax stereo is to project two different pictures into the left and right eyes of people respectively, and form stereoscopic vision through the fusion of the brain, so parallax stereo has its unique advantages. Detection of stereoblindness. Traditional vision examination methods, such as myopia vision test, color weakness and color blindness test, require multiple examination equipment and are poor in portability. Stereo-blind detection needs to overcome the deficiencies in the above-mentioned techniques.

3. Contents of the invention

The object of the present invention is to propose a multi-distance viewing stereo vision inspection device using a symmetrical adjustable backlight structure in order to solve the problems of single detection samples, limited detection distance, and monocular clues in the stereo blind detection process. . The present invention is realized through the following technical means. The pupil position tracking module obtains the pupil position information of the viewer. After receiving the pupil position information and the video synchronization signal, the signal processing module controls the symmetrical adjustable backlight structure to project the corresponding left and right images to the left and right pupils of the viewer, so that the viewer's The left eye can only see the left image on the image display, and the right eye can only see the right image on the image display.

The technical scheme of the present invention: a free three-dimensional test device for multi-distance viewing with a symmetrical adjustable backlight structure, including a symmetrical adjustable backlight device, a pupil position tracking module, a synchronous signal extraction module, a signal processing module, and an image display screen; The adjustable backlight device includes a symmetrical adjustable optical component and an addressable light source component; among them, the symmetrical adjustable optical component includes a light guide module and a symmetrical adjustable imaging module. The light guide module includes: a condenser lens, a light guide device and a triangle Prism; symmetrical adjustable imaging module (M) (including: lens, lens switching device, refracting mirror, beam splitter and refracting mirror); the signal processing module controls the adjustable backlight according to the received pupil position information and video synchronization signal The addressable light source component in the structure. While displaying the left image, the signal processing module lights up the corresponding light-emitting unit according to the position information of the pupil of the left eye to realize the convergence of light at the pupil of the left eye; while displaying the right image, the signal processing module The corresponding light-emitting unit lights up to realize the convergence of light at the pupil of the right eye; the invention is a multi-distance free stereoscopic test device with a symmetrical adjustable backlight structure.

A light guide module is used to realize the transmission of light. The light emitted from the addressable light source module passes through the light guide module composed of a condenser lens, a light guide device, and a triangular prism; the light emitted from the light guide module passes through a beam splitter. The separation of the light, half of the light is projected to the upper refracting mirror, and half of the split light is reflected and converged by the refracting mirror; the other half of the light is projected to the lower refracting mirror to reflect and converge; the light emitted by the light guide module The vertical position of the optical path is fixed with two to five lenses or lens groups with different focal lengths and a lens switching device. Through the lens switching device, different lenses are placed in the optical path of the light beam; the symmetrical adjustable imaging module realizes the lens corresponding to different distances combination. The application of the lens switching device achieves different optical effects and realizes that the viewer can watch the three-dimensional effect at different distances.

Use a symmetrical backlight structure to gather the light emitted by the addressable light source components into a viewing window at a certain distance; at different viewing distances, the viewing window width and the length of the light-emitting unit are in a fixed proportional relationship, and the proportionality constants are β ₁ , β ₂ , β ₃ , which represent proportionality constants for different distances;

In the above formula, W represents the width of the viewing window, w represents the width of the light emitting unit, T represents the distance between two viewing windows, and t represents the distance between two light emitting units.

In order to achieve a good stereoscopic display effect, the width W of the viewing window and the distance T between the two viewing windows need to be kept within a certain range, so when β changes, the lens switching device in the symmetrical adjustable imaging module needs to be Perform lens switching.

The device adopts a symmetrical adjustable backlight structure to provide synchronous backlight for the image display screen. By adjusting the lens switching device in the symmetrical adjustable optical component, different lens combinations in the symmetrical adjustable imaging module are realized. With the light emitted by the addressable light source component, after passing through the symmetrical adjustable optical component, convergence and A viewing window is formed so that the viewer can watch the stereoscopic effect at different distances. The light guide module is used to realize the transmission of light. The light emitted from the addressable light source module passes through the light guide module composed of a condenser lens, a light guide device, and a triangular prism, which effectively increases the optical path. The light guide device applies the principle of total reflection, which effectively reduces the divergence angle and transmission loss of light, and improves the utilization rate of light.

The combination of multiple lenses achieves the effect of converging light at different distances. The light emitted by the addressable light source component is combined with the lens switching device to realize the convergence of the light at different distances after being combined by the multi-lens, thereby realizing the three-dimensional effect.

Adopt synchronous signal extraction module. After the synchronous signal of the video is extracted, the signal is sorted and denoised. In order to realize the interconnection of modules, the signal amplitude is limited, and at the same time, the signal quality is further improved, and the stability of the system is improved.

Addressable light source components are used. After receiving the pupil position information from the pupil position tracking module, the signal processing module lights up the light emitting unit at the corresponding position in the addressable light source assembly. The signal processing module receives the synchronous signal of the image display screen from the synchronous signal extraction module, and lights up the light-emitting units in the addressable light source module in time division. When displaying the right image, only the light-emitting unit corresponding to the right eye of the viewer is lit, that is, the viewer can only see the right image; similarly, when the left image is displayed, only the light-emitting unit corresponding to the left eye of the viewer is lit , that is, the viewer sees only the left image.

The beneficial effect of the present invention is: the present invention provides a kind of autostereoscopic test device that adopts symmetrical adjustable backlight structure and can be viewed at multiple distances Compared with the prior art, its remarkable advantages are:

1. The symmetrical adjustable backlight structure is adopted, which greatly enhances the uniformity and brightness of the backlight;

2. By adjusting the lens switching device, the three-dimensional effect can be seen at different distances;

3. Using synchronous signal extraction module and symmetrical adjustable backlight structure, it has good imaging quality and greatly reduces the three-dimensional cross shadow;

4. Adopt light guide device, compact structure, small size, easy to carry;

5. Using the pupil position tracking module, no need to wear auxiliary equipment;

6. The playback source is high-definition video with left and right images with parallax. The display image has no resolution reduction and has a strong three-dimensional effect;

7. Freely switch between 2D and 3D, with strong applicability. Rich detection samples, multi-distance viewing, compact structure, high-definition, etc.

4. Description of drawings

Figure 1 is a side view of the overall structure of an implementation example, the dotted line part M is a symmetrical adjustable imaging module;

Fig. 2 is a perspective view of the principle of the free-stereoscopic testing device;

Figure 3 is a schematic diagram of a symmetrical adjustable backlight structure that can be viewed from multiple distances;

Fig. 4 is the schematic diagram of condenser;

Fig. 5 is a schematic diagram of the light guide device;

Fig. 6 is a schematic diagram of a triangular prism;

Figure 7 is a schematic diagram of a Fresnel lens;

Fig. 8 is a schematic diagram of a lens switching device;

Fig. 9 is a schematic diagram of a beam splitter;

Fig. 10 is a schematic diagram of a refracting mirror;

Figure 11 is a schematic diagram of an addressable light source component;

Fig. 12 is a block diagram of a signal processing module.

5. Specific implementation

In Fig. 1, the autostereoscopic test device for multi-distance viewing of the symmetrical adjustable backlight structure includes a light-emitting unit 1, a condenser lens 2, a light guide device 3, a triangular prism 4, a triangular prism 5, a light guide device 6, a triangular prism 7, and a lens switch Device 8, lens 9, lens 10, lens 11, beam splitter 12, refracting mirror 13, refracting mirror 14, lens 15, lens 16, refracting mirror 17, refracting mirror 18, LCD display 20; Fig. 3 Symmetrical adjustable backlight structure Schematic diagram that can be viewed at multiple distances; Figure 7 Fresnel lens schematic diagram; Figures 3 and 7: symmetrical adjustable imaging module M, light emitting unit width w, light emitting unit array center distance t, observation window width W, observation window width distance T, viewer position A, viewer position B, distance U from the light-emitting unit to the symmetrical adjustable backlight structure, optimal viewing distance V(A), optimal viewing distance V(B), virtual image object distance V'.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The basic idea of the present invention is to use the time-division principle to realize the three-dimensional effect. It is necessary to point out here that the following examples are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Those skilled in the art make some non-essential improvements and improvements to the present invention according to the above-mentioned content of the invention. Adjustment still belongs to the protection scope of the present invention.

An autostereoscopic test device with a symmetrical adjustable backlight structure capable of multi-distance viewing, the whole device is composed of a symmetrical adjustable backlight structure, a viewer position tracking module, a synchronous signal extraction module and an image display screen. In this implementation example, the image display screen is an LCD (120HZ) display. The symmetrical adjustable backlight structure includes a symmetrical adjustable optical component and an addressable light source component. Among them, the symmetrical adjustable optical components include light guide modules (including: condenser mirrors, light guide devices and triangular prisms) and symmetrical adjustable imaging modules (including: lenses, lens switching devices, refracting mirrors, beam splitters and refracting mirrors) ).

The principle of system arrangement is as follows: the signal processing module receives the video synchronization signal from the synchronization signal extraction module, and at the same time when the left image is displayed, lights up the light-emitting unit corresponding to the left image in the addressable light source module to provide a synchronous backlight for the image; When the right image is displayed, the light emitting unit corresponding to the right image in the addressable light source module is turned on to provide synchronous backlight for the image. The signal processing module receives the eye position information from the pupil position tracking module, and lights up the corresponding light emitting unit in the addressable light source module. After obtaining the information of the left eye, the light-emitting unit corresponding to the left eye in the addressable light source module is turned on, and after passing through the symmetrical adjustable backlight structure, the light converges at the position of the left eye to form an observation window. Similarly, after obtaining the right eye information, light up the light-emitting unit corresponding to the right eye in the addressable light source module. After the light passes through the symmetrical adjustable backlight structure, the right eye is converged to form an observation window, as shown in Figure 2. The lens switching device in the symmetrical adjustable imaging module can realize the combination of different lenses, and cooperate with the light-emitting unit in the addressable light source module to realize the convergence of light at different distances, so that the viewer can watch the three-dimensional effect at different distances .

Addressable light source components are used. After receiving the pupil position information from the pupil position tracking module, the signal processing module lights up the light emitting unit at the corresponding position in the addressable light source assembly. The signal processing module receives the synchronous signal of the image display screen from the synchronous signal extraction module, and lights up the light-emitting units in the addressable light source module in time division. When displaying the right image, only the light-emitting unit corresponding to the right eye of the viewer is lit, that is, the viewer can only see the right image; similarly, when the left image is displayed, only the light-emitting unit corresponding to the left eye of the viewer is lit , that is, the viewer sees only the left image.

Based on the above basic principles, the symmetrical adjustable backlight structure (as shown in FIG. 1 ) includes a symmetrical adjustable optical component and an addressable light source component. In this implementation example, the addressable optical component is composed of a series of high-brightness LEDs closely arranged (as shown in FIG. 11 ), and cooperates with the driving circuit to realize the turning on and off of any LED. The light emitted from the high-brightness LED can be compressed in the YZ plane through the condenser lens (2). In this implementation example, a prism lens is used to compress the light (as shown in Figure 4), and the divergent light is compressed into near-parallel light. The compressed light enters the light guide devices (3, 6) in the light guide module. In this implementation example, the light guide plate is used, and the lossless transmission of light is realized by using its total reflection prism transmission principle (as shown in FIG. 5 ). The light enters the triangular prism (4, 5) from the light guide plate, realizes the reversal of the direction of the light, and finally emits from the triangular prism (7).

In this implementation example, the light emitted from the light guide module passes through the beam splitter to realize the separation of the light, half of the light is projected to the above reflector, and after the light is reversed, it is reflected by the refracting mirror to achieve the convergence of the light at a specific distance ; Similarly, half of the light is projected to the mirror below. Three lenses are fixed on the vertical mechanical structure, and different lenses can be placed in the optical path through the lens switching device. The application of the lens switching device achieves different optical effects and realizes that the viewer can watch the three-dimensional effect at different distances. The lens used for convergence is a Fresnel lens. Through the combination of two types of Fresnel lenses, the convergence of light at different distances is realized. The combination of two Fresnel lenses is equivalent to the effect of a single Fresnel lens, and the following uses a single Fresnel lens to illustrate.

A high-brightness LED (1) is placed within one focal length of the Fresnel lens to form a virtual image at a distance through the Fresnel lens. The position of the virtual image varies with the position of the LED being lit (as shown in Figure 7). The virtual image distance and the object distance U have the following relationship:

Wherein f is the focal length of Fresnel lens, in the present implementation example, the parameter of Fresnel lens 15 and Fresnel lens 16 is identical, the focal length of Fresnel lens 9, Fresnel lens 10 and Fresnel lens 11 each Are not the same. By adjusting the lens switching device (as shown in Figure 8), different Fresnel lens combinations are realized, so that the light converges at different distances to achieve the effect of multi-distance viewing. As shown in Figure 3, for the sake of brevity, two distances are used for illustration. Adjusting the lens switching device and cooperating with high-brightness LEDs realize the convergence of light at different distances.

In this implementation example, a spectroscope (prism) is used as a spectroscopic device (as shown in FIG. 9 ), which realizes the separation of light rays and improves the brightness uniformity to a great extent. The light propagates from two directions up and down, and passes through the reflectors 13, 14, Fresnel lenses 15, 16, and reflectors 17, 18 to realize the inversion of the light. Finally, the light is projected onto the refracting mirror (as shown in FIG. 10 ), and after passing through the LCD display (20), the convergence of the light is realized. For the synchronous signal extraction module circuit, reference may be made to the applicant's previous application.

In this implementation example, the pupil position tracking module is composed of software and hardware. The hardware includes three cameras with different focal lengths, corresponding to different viewing distances. The Adaboost algorithm is used to detect candidate points, and then the ASM (Active Shape Model) algorithm based on SIFT features is used to accurately locate the face. The available algorithms are as follows:

1. Face positioning. Face positioning methods include ASM face positioning based on SIFT features. The traditional ASM algorithm uses the gray information of local feature points to calculate the Mahalanobis distance, which has low fitting accuracy and poor rotation robustness. Therefore, the SIFT (Scale Invariant Feature Transform) feature is used as the local feature point of the ASM algorithm. SIFT is an image local feature description operator based on spatial scale that remains unchanged for image scaling, rotation and even affine transformation. It is very good for the state changes of faces, the environment of the scene and the characteristics of imaging equipment adaptability.

2. Pupil position tracking. Normally, the position of the pupil does not change quickly, and this feature can be used to quickly detect and predict the position of the pupil. Taking advantage of the characteristic that the pupil position does not change quickly, the detection algorithm can detect around the pupil position in the previous frame to narrow the detection range. Using the continuous position information of the pupil, the possible position of the pupil in the next frame can be predicted, which also reduces the detection range. Kalman algorithm and TLD algorithm are commonly used tracking algorithms.

In this implementation example, the signal processing module adopts an AVR single-chip microcomputer, and is interconnected with the pupil position tracking module through a serial port, and interconnected with a synchronous signal extraction module (as shown in Figure 12) through a cable. The signal processing module controls the bright LED in the addressable light source module to turn on and off according to the received pupil position information and video synchronization information. The specific system block diagram is shown in Figure 12. For specific solutions not described in detail, please refer to the following patent applications of the applicant (inventor): 201310615833.4 Pupil Positioning Method Based on Hybrid Projection, 201310627291.2 Pupil Position Filtering Method Based on Motion Correlation, 201310612559.5 Tablet Unassisted Stereoscopic Display Device and methods.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art of the present invention may make various changes and modifications without departing from the scope of the spirit of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims (4)

1. A stereoscopic inspection device adopting a symmetrical adjustable backlight structure is characterized in that it includes a symmetrical adjustable backlight device, a pupil position tracking module, a synchronous signal extraction module, a signal processing module, and an image display screen; the symmetrical adjustable backlight device includes Symmetrically adjustable optical components and addressable light source components; among them, the symmetrically adjustable optical components include a light guide module and a symmetrically adjustable imaging module. The light guide module includes: a condenser lens, a light guide device and a triangular prism. The adjustable imaging module (M) includes: lenses, lens switching devices, refracting mirrors, beam splitters and refracting mirrors; the signal processing module controls the addressable LEDs in the adjustable backlight structure according to the received pupil position information and video synchronization signals. Light source component; while displaying the left image, the signal processing module lights up the corresponding light-emitting unit according to the position information of the pupil of the left eye, so that the light converges at the pupil of the left eye; while displaying the right image, the signal processing module The position information lights up the corresponding light-emitting unit to realize the convergence of light at the pupil of the right eye; the light guide module is used to realize the transmission of light, and the light emitted from the addressable light source component passes through the condenser lens, light guide device, and triangular prism. The light guide module composed of the light guide module; the light emitted from the light guide module passes through the beam splitter to realize the separation of light, half of the light is projected to the above refraction mirror, and half of the light after splitting is reflected and converged by the refraction mirror; the other half The light projected to the refracting mirror below is reflected and converged; the vertical position of the optical path of the light emitted by the light guide module is fixed with two to five lenses or lens groups with different focal lengths and a lens switching device, through which the different lenses are in the In the optical path of the light rays; the symmetrical adjustable imaging module realizes lens combinations corresponding to different distances; Use a symmetrical backlight structure to gather the light emitted by the addressable light source components into a viewing window at a certain distance; at different viewing distances, the viewing window width and the length of the light-emitting unit are in a fixed proportional relationship, and the proportionality constants are β ₁ , β ₂ , β ₃ , which represent proportionality constants for different distances; <mrow> <mfrac> <mi>W</mi> <mi>w</mi> </mfrac> <mo>=</mo> <mfrac> <mi>T</mi> <mi>t</mi> </mfrac> <mo>=</mo> <mi>&amp;beta;</mi> </mrow> In the above formula, W represents the width of the viewing window, w represents the width of the light emitting unit, T represents the distance between two viewing windows, and t represents the distance between two light emitting units. 2. The stereoscopic inspection device adopting a symmetrical adjustable backlight structure according to claim 1, characterized in that the symmetrical adjustable backlight structure provides synchronous backlight for the image display screen; the lens in the symmetrical adjustable optical assembly is adjusted The switching device realizes the combination of different lenses in the symmetrical adjustable imaging module, and the light emitted by the addressable light source assembly realizes the convergence and forms the viewing window at different positions after passing through the symmetrical adjustable optical assembly, so the viewer can be in the The three-dimensional effect can be seen at different distances. 3. The stereoscopic inspection device adopting a symmetrical adjustable backlight structure according to claim 1, characterized in that a synchronous signal extraction module is used to extract the synchronous signal of the video, and the signal is sorted and denoised. 4. The stereoscopic inspection device adopting a symmetrical adjustable backlight structure according to claim 1, characterized in that the symmetrical adjustable backlight structure adopts addressable light source components; the signal processing module receives the pupil position information from the pupil position tracking module Afterwards, light up the light-emitting unit at the corresponding position in the addressable light source assembly; the signal processing module receives the synchronous signal of the image display screen from the synchronous signal extraction module, and lights up the light-emitting unit in the addressable light source assembly in time-sharing; image, only the light-emitting unit corresponding to the viewer’s right eye is lit, that is, the viewer can only see the right image; similarly, when the left image is displayed, only the light-emitting unit corresponding to the viewer’s left eye is lit, that is, the viewer The user can only see the left image.