本帖最後由 WCYue 於 2022-7-14 20:31 編輯
Description translated from Method and system for stereoscopic vision of a celestial observation scene
Image Display - First Embodiment
On the , the telescope 1 incorporates a viewing device formed by two eyepieces, respectively a first eyepiece 100D and a second eyepiece 100G, installed on the tube 10. The first eyepiece 100D is the right eyepiece, in front of which the observer places his right eye OD. The second eyepiece 100G is the left eyepiece, in front of which the observer places his left eye OG.
By referring to the , each eyepiece 100D, 100G is provided with a display screen, respectively a first 101D and a second screen 101G. The processing unit 13 is suitable for displaying the first images I1A1, I1A2, I1A3 on the first screen 101D and displaying the second images I2A1, I2A2, I2A3 on the second screen 101G. The first images I1A1, I1A2, I1A3 being shifted from the second images I2A1, I2A2, I2A3, the observer obtains a stereoscopic vision of the scene S when he positions his eyes OD, OG in front of each of the eyepieces 100D, 100G.
According to one embodiment, the screens 101D, 101G are flat screens, for example polychrome LCD (for Liquid Crystal Display) or OLED (for Organic Light-Emitting Diode) liquid crystal screens. The active face of each screen 101D, 101G emerges at the level of an opening or window made in the corresponding eyepiece 100D, 100G to be accessible to the eye of the user. “ Active face ” means the face on which the images are displayed.
According to another embodiment, the two eyepieces 100D, 100G each equipped with a screen, are integrated into a display device which is remote from the telescope 1. immersive helmet, helmet-screen or helmet HMD for the English acronym of head-mounted display) of the type described in the patent document EP3400474 (GOOGLE). The connection between the head-mounted display and the telescope 1, and more particularly with the processing unit 13, can be made via a wired link (for example by means of a USB cable) or via a wireless link, for example according to a proximity communication protocol, such as, by way of non-limiting example, the Bluetooth®, Wifi®, ZigBee® protocol.
Image Display - Second Embodiment
In this embodiment, the first images I 1A1 , I 1A2 , I 1A3 and the second images I 2A1 , I 2A2 , I 2A3 are displayed in the form of an anaglyph image. An anaglyph image includes two colored images that are filtered differently at each viewer's eye. The latter can visualize the image thus formed through anaglyphic filters placed in front of each eye. Anaglyph filters can be of different colors (for example, chromatically opposite colors). For example, the anaglyph image of scene S may include a first red filtered image and a second cyan filtered image. A red color filter can be placed in front of the observer's right eye to allow him to view the red filtered image. And a cyan color filter can be placed in front of the viewer's left eye to allow them to view the cyan filtered image. Filters of other colors can be used.
Referring to Figures 5 and 6, the processing unit 13 displays on a screen 100, the anaglyph image I of the scene S in the form of two images superimposed and offset from each other. The first image is formed by the first images I1A1, I1 TO 2, I1A3stars A1, A2, A3 and the second image is formed by the second images I2A1, I2A2, I2A3of the said stars. The first images I1A1, I1 TO 2, I1A3and the second images I2A1, I2A2, I2A3are shifted as previously described. The first image (containing the first images I1A1, I1 TO 2, I1A3) is generated by the processing unit 13 by applying to it a first filter (for example a cyan filter) and the second image (containing the second images I2A1, I2A2, I2A3) by applying another filter of chromatically opposite color to it (for example a red filter).
For observation, analytic filters FD, FG are placed in front of the eyes OD, OG of the observer. These filters FD, FG can for example be worn by glasses. The right filter FD placed in front of the right eye OD is for example a cyan color filter to allow viewing of the first image filtered in cyan. And the left filter FG placed in front of the left eye OG is for example a red color filter to allow viewing of the second image filtered in red. The image seen by the right eye OD is thus separated from that seen by the left eye OG. The observer's brain then recombines the two images to obtain a relief view of the scene S.
According to one embodiment, the images are displayed simultaneously on the screen 100. According to a variant embodiment, the two images are displayed successively alternately at high frequency on the screen 100. The observer is in this case equipped with glasses (provided with filters FD, FG) which, at the frequency of alternating images, alternately mask the view of the right eye OD and of the left eye OG according to the image displayed.
According to another embodiment, the anaglyph image I is displayed on a screen of a head-mounted display of the type described in the aforementioned patent document EP3400474. According to another embodiment, each colored image of the anaglyph image I is displayed on a screen of an eyepiece of a head-mounted display with two eyepieces of the type described in the aforementioned patent document EP3400474.
According to another embodiment illustrated in the , the anaglyph image I is displayed on a screen 100 of a mobile terminal T, for example the screen of a Smartphone (smart telephone) or of a touch pad. The connection between the processing unit 13 and the screen 100 can be made via a wired link (for example by means of a USB cable) or via a wireless link, for example according to a proximity communication protocol, such as by way of non-limiting example, the Bluetooth®, Wifi®, ZigBee® protocol.
Reference plane
To improve the perception of relief of stars A1, A2, A3, it is advantageous to define a reference plane. It is thus possible to produce an emergence or springing effect for the stars identified located in front of this reference plane. The observer will perceive these stars as floating in front of the screen or coming out of the screen on which the images are displayed. Conversely, for the identified stars located behind this reference plane, the observer will perceive them in retreat, with a depth effect.
Thus, for an identified star Ai located behind the reference plane, the processing unit 13 will shift the first image I 1Ai and the second image I 2Ai so that said images have a positive parallax. For an identified star Ai located in front of the reference plane, the processing unit 13 will shift the first image I 1Ai and the second image I 2Ai so that said images have a negative parallax. And for an identified star located in the reference plane, the processing unit 13 will not shift the first image I 1Ai from the second image I 2Ai so that said images have zero or zero parallax.
According to one embodiment, the reference plane Pref is defined at infinity. Therefore, for each identified star Ai, the processing unit 13 shifts the first image I 1Ai and the second image I 2Ai so that said images have a negative parallax. The observer then perceives the stars A1, A2, A3 as emerging or springing from the observed scene.
According to another embodiment illustrated in the , the reference plane Pref coincides with an identified star, here star A3. For this star A3, the processing unit 13 does not shift the first image I1A3 from the second image I2A3 so that said images have zero or zero parallax. The observer will perceive this star as located in the plane of the display screen or of the observed scene. For the star(s) A2 located behind this plane Pref, i.e. for the star(s) A2 whose estimated distance LA2 is greater than the estimated distance LA3 of the reference star A3, then the unit of processing 13 shifts the first image I1A2 and the second image I2A2 so that said images have a positive parallax. The observer perceives this or these stars A2 set back, with a depth effect. And for the star(s) A1 located in front of this plane Pref, i.e. for the star(s) A1 whose estimated distance LA1 is less than the estimated distance LA3 of the reference star A3, then the unit processing 13 shifts the first image I1A1 and the second image I2A1 so that said images have a negative parallax. The observer perceives this or these stars A1 as emerging or springing from the observed scene.
In this embodiment, the choice of the reference plane Pref, and therefore of the reference star A2, can be chosen by the observer, for example by means of a dedicated user interface, for example from an integrated touch screen in the telescope 1 or from a mobile user terminal, such as an intelligent telephone (Smartphone) or a touch pad, connected to the processing unit 13. According to another embodiment, in the case where the observer selects a recording of a star in the database 18, this selected star can be considered as the reference star by the processing unit 13. According to yet another embodiment, the reference star is automatically selected by the processing unit 13 taking as selection criterion the evaluated distances L A1 , L A2 , L A3 . For example, the processing unit 13 can select as reference star the one whose evaluated distance is closest to the average of all the evaluated distances. The processing unit 13 can also select as reference star the one whose evaluated distance is the greatest or, on the contrary, the shortest.
The illustrates the images displayed in each of the 100D, 100G eyepieces of the telescope of the , when the reference plane Pref coincides with the star A3 ( ). The center of each star identified A1, A2, A3, as they appear on the image of the scene S acquired by the sensor 12, is referenced respectively CA1, CA2, CA3.
For the body A2 located behind the reference plane Pref, the positive parallax can be obtained by shifting the first image I 1A2 to the right in the right image (i.e. the image displayed on the screen 101D of the right eyepiece OD) and shifting the second I 2 A2 image to the left in the left image (i.e. the image displayed on the screen 101G of the left eyepiece OG ). The binocular focal plane is then behind the display. The shift of the first image I 1A2 and of the second image I 2A2 with respect to the center C A2 can be 1/2×D A2 so that the total shift between the two images is D A2 . It is also possible to obtain positive parallax by shifting the first image I 1A2 only to the right by a distance D A2 in the right-hand image and by not shifting the second image I 2A2 in the left-hand image. Similarly, the positive parallax can be obtained by shifting the second image I 2A2 only to the left by a distance D A2 in the left image and by not shifting the first image I 1A2 in the right image.
For the star A1 located in front of the reference plane Pref, the negative parallax can be obtained by shifting the first image I 1A 1 to the left in the right image and by shifting the second image I 2A 1 to the right in the image on the left, so that the binocular focal point is then in front of the display. As explained previously, the shift of the first image I 1A 1 and of the second image I 2A 1 with respect to the center C A 1 can be 1/2xD A 1 so that the total shift between the two images is D A 1 . It is also possible to obtain the negative parallax by only shifting the first image I 1A1 to the left by a distance D A 1 in the right image and by not shifting the second image I 2A2 in the left image. Similarly, the negative parallax can be obtained by only shifting the second image I 2A1 to the right by a distance D A 1 in the left image and by not shifting the first image I 1A 1 in the right image .
For the star A3 located in the reference plane, the first image I 1A3 and the second image I 2A3 are not shifted from the center C A3 so as to obtain zero or zero parallax. The binocular focal plane is on the display.
The illustrates the case where the first images I1A1, I1A2, I1A3 and the second images I2A1, I2A2, I2A3 are displayed on the screen 100 in the form of an anaglyph image I. To illustrate the position of the different images, the reference plane Pref coincides with the star A3 ( ). As previously described with reference to , the center of each star identified A1, A2, A3, as they appear on the image of the scene S acquired by the sensor 12, is referenced respectively CA1, CA2, CA3.
For explanatory purposes only, it is assumed that the first images I 1A1 , I 1A2 , I 1A3 are generated by applying a cyan filter to the image acquired by the sensor 13, and the second images I 2A1 , I 2A2 , I 2A3 are generated by applying a red filter to said acquired image. The right filter FD placed in front of the right eye is a cyan color filter to enable the first images I 1A1 , I 1A2 , I 1A3 to be viewed. And the left filter FG placed in front of the left eye is a red filter to enable the second images I 2A1 , I 2A2 , I 2A3 to be viewed. Those skilled in the art will understand that other combinations of chromatically opposite colors can be envisaged.
For the star A2 located behind the reference plane Pref, the positive parallax can be obtained by shifting the first image I 1A2 to the right and by shifting the second image I 2A2 to the left. When the observer views the image I through the filters FD, FG, the binocular focal plane is then behind the screen 100. The shift of the first image I 1A2 and of the second image I 2A2 with respect to the center C A2 can be 1/2xD A2 so that the total offset between the two images is D A2 . It is also possible to obtain the positive parallax by shifting the first image I 1A2 only to the right by a distance D A2 and by not shifting the second image I 2A2 . Likewise, the positive parallax can be obtained by shifting the second image I 2A2 only to the left by a distance D A2 and by not shifting the first image I 1A2 .
For the star A1 located in front of the reference plane Pref, the negative parallax can be obtained by shifting the first image I 1A1 to the left and by shifting the second image I 2A1 to the right, so that when the observer views the image I through the filters FD, FG, the binocular focal plane is then in front of the screen 100. As explained previously, the shift of the first image I 1A1 and of the second image I 2A1 with respect to the center C A1 can be 1/2xD A1 so that the total offset between the two images is D A1 . It is also possible to obtain the negative parallax by only shifting the first image I 1A1 to the left by a distance D A1 and by not shifting the second image I 2A2 . Similarly, the negative parallax can be obtained by shifting the second image I 2A1 only to the right by a distance D A1 and by not shifting the first image I 1A1 .
For the star A3 located in the reference plane, the first image I 1A3 and the second image I 2A3 are not shifted from the center C A3 and are merged, so as to obtain zero or zero parallax. The binocular focal plane is on screen 100.
Other embodiments of the optical system of the device .
In FIGS. 1 and 7, the optical system is formed by a mirror 11 placed inside the tube 10 and centered on the optical axis.
On the , the optical system is formed by:
- a primary mirror 110 positioned in the tube 10, to reflect the light rays entering said tube,
- a secondary mirror 111 positioned in the tube 10 to reflect the light rays reflected by the primary mirror 110.
The primary 110 and secondary 111 mirrors are positioned on the same X-X optical axis. They are arranged so that the light rays reflected by said mirrors form, in a focal plane Pf, an image of the scene S, which focal plane is perpendicular to the optical axis X-X. The mirrors 110, 111 are arranged so that the focal plane Pf is located in the tube 10, between the two said mirrors. The sensor 12 is then arranged on the X-X optical axis, in the focal plane Pf, for the acquisition of the image of the observation scene.
The primary mirror 110 is preferably a concave parabolic mirror having a low focal ratio (preferably less than 5). This type of mirror eliminates spherical aberrations. The diameter of the primary mirror 110 corresponds substantially to the diameter of the tube 10.
Compared to the device of the , with equivalent diameter and focal length of the primary mirror, the fact of bringing the focal plane F between the two mirrors 110, 111 makes it possible to reduce the focal length of the optical system and the length of the telescope 1. The magnification of the stars observed is lower, but with the benefit of an increase in the visual field and an increase in image brightness. We can thus observe faint stars such as nebulae or galaxies with better image quality. The image quality of luminous bodies such as planets or stars remains very good.
The display of images to obtain stereoscopic vision is carried out according to one of the display modes described previously (display in two eyepieces, on a single screen, etc.).
The arrangement of the various elements and/or means and/or steps of the invention, in the embodiments described above, should not be understood as requiring such an arrangement in all implementations. Other variants may be provided, in particular:
- The optical system of the device does not necessarily consist of one or more mirrors, but may include one or more lenses in addition to or in substitution for said mirrors.
- Other types of sensors 12 can be envisaged. For example a sensor of the CCD, CMOS, or Foveon type, color or black and white.
Further, one or more features disclosed only in one embodiment may be combined with one or more other features disclosed only in another embodiment. Similarly, one or more features disclosed only in one embodiment may be generalized to other embodiments, even if such feature or features are described only in combination with other features. |
