Pixel shifting method in projection system

Abstract

A projection system for pixel offset, the projection system comprising: a light source configured to emit light; and a spatial light modulator configured to receive the light and generate modulated light. The spatial light modulator includes a plurality of micromirrors. The projection system includes a sloshing device configured to shift the modulated light by fractional pixels. The projection system includes a controller configured to, for each of a plurality of sub-cycles, control the light source to emit the light onto the spatial light modulator, and shift the modulated light by a partial pixel distance between each of the plurality of sub-cycles and with the sloshing device, the partial pixel distance is greater than the half-pixel distance.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 404,371, filed on September 7, 2022, and European Patent Application No. 22217440.1, filed on December 31, 2022, each of which is incorporated herein by reference in its entirety. Background 1. Technical Field

[0004] This application generally relates to projection systems and projection methods. 2. Background Art

[0005] Digital projection systems typically utilize a light source and an optical system to project an image onto a surface or screen. The optical system can include components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, spatial light modulators (SLMs), etc. The contrast of a projector indicates the brightest output of the projector relative to the darkest output. The contrast ratio is a quantitative measure of contrast and is defined as the ratio of the luminance of the brightest output of the projector to the luminance of the darkest output. This definition of the contrast ratio is also referred to as the "native" contrast ratio.

[0006] Some projection systems are based on an SLM that implements spatial amplitude modulation, such as a digital micromirror device (DMD) chip. The DMD can utilize a two - dimensional array of mirrors that can be controlled to create an image. If it is desired to project an image with a resolution higher than that of the DMD (e.g., an image with more pixels than the number of mirrors in the DMD), pixel offset techniques can be used. In one example of a pixel offset technique (sometimes referred to as "wobulation"), the system can be controlled to effectively offset fractional pixels of a modulator, or a device optically located after the modulator, in a set pattern to create the appearance of additional pixels. Summary of the Invention

[0007] A wobulation device is used to implement pixel offset techniques. A wobulation device or wobbler is a device that rapidly moves pixels between a set of fixed positions to create a high - resolution image. For example, a wobbler can move pixels in a square pattern to quadruple the display resolution, creating a 2×2 pixel set for each physical DMD pixel.

[0008] Transitions between each position of the shaker may cause the displayed pixels to blur, thereby reducing the potential resolution and creating artifacts within the image projected by the DMD. Specifically, for a given pixel, the observed "effective" point spread function (PSF) is the integral of the light over all instants. Thus, at least three artifacts from the shaking motion may affect the image projected by the DMD: increased pixel size, distorted pixel shape, and movement of the image centroid. The more time spent in the transition between positions, the larger the "effective" pixel provided by the shaker (e.g., the projected pixel - the pixel observed by the viewer of the projected image). Additionally, more time and distance spent away from the "ideal" pixel position causes deformation from the "ideal" pixel shape (e.g., the pixel shape when there is no motion).

[0009] Furthermore, the centroid position of each projected pixel is affected by the motion path of the shaker. This movement of the centroid of each pixel not only affects the resolution of the projected image but also creates a dependence between the position of the image pixel pattern and the shaker pixel groups. For example, depending on how a checkerboard pattern aligns with the shaker sub - pixel groups, a one - pixel checkerboard pattern (e.g., a repeating 2×2 pixel pattern) can have different projected resolutions.

[0010] The embodiments described herein provide mitigation techniques for reducing such artifacts. One mitigation technique provides: controlling the DMD to an "off" position, thereby substantially stopping the projection of light onto the shaker while the shaker moves from one position to another. Another mitigation technique provides: extending the motion path of the shaker such that the shaker moves a distance greater than half a pixel length between positions when increasing the resolution in a particular direction. This mitigation technique reduces the artifacts found in the image output from the shaker.

[0011] In an exemplary aspect of the present disclosure, a projection system with pixel offset is provided. The projection system includes: a light source configured to emit light; and a spatial light modulator configured to receive the light and generate modulated light. The spatial light modulator includes a plurality of micromirrors. The projection system includes a shaking device configured to offset the modulated light by a fractional pixel. The projection system includes a controller configured to: for each of a plurality of sub - periods, control the light source to emit the light onto the spatial light modulator, and between each of the plurality of sub - periods and using the shaking device, offset the modulated light by a partial pixel distance that is greater than half a pixel distance.

[0012] In another exemplary aspect of the present disclosure, a method for calibrating pixel offset in a projection system is provided. The method includes: emitting light using a light source; receiving the light using a spatial light modulator; and modulating the light using the spatial light modulator to generate a modulated image, where the modulated image includes a plurality of pixels. The method includes: offsetting a modulated light offset portion of a pixel distance for each pixel of the modulated image between each of a plurality of sub-periods to generate a jittered image; determining an amount of jitter artifacts in the jittered image; and adjusting the portion of the pixel distance based on the determined amount of artifacts.

[0013] In another exemplary aspect of the present disclosure, a projection method for pixel offset is provided. The projection method includes: for each of a plurality of sub-periods, controlling a light source to emit light onto a plurality of micromirrors on a spatial light modulator; receiving the light using the plurality of micromirrors and for each of the plurality of sub-periods to generate modulated light; and offsetting the modulated light by a portion of a pixel distance between each of the plurality of sub-periods, the portion of the pixel distance being greater than a half-pixel distance.

[0014] In this way, various aspects of the present disclosure provide for the display of images with high dynamic range, high contrast ratio, and high resolution, and provide effective improvements at least in technical fields such as image projection, holography, signal processing, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Reference is made to the accompanying drawings, in which these and other more detailed and specific features of various embodiments are more fully disclosed in the following description:

[0016] Figures 1A to 1B Views of an exemplary spatial light modulator in accordance with various aspects of the present disclosure are illustrated;

[0017] Figure 2 Exemplary pixel offset operations in accordance with various aspects of the present disclosure are illustrated;

[0018] Figure 3 Exemplary jitter paths of a jitter device in accordance with various aspects of the present disclosure are illustrated;

[0019] Figure 4 An exemplary checkerboard pattern in accordance with various aspects of the present disclosure is illustrated;

[0020] Figures 5A to 5B Illustrated is, in accordance with various aspects of the present disclosure, the Figure 4 exemplary jitter response of a checkerboard pattern in the case of small light spots;

[0021] Figure 6 Another exemplary checkerboard pattern in accordance with various aspects of the present disclosure is illustrated;

[0022] Figure 7 illustrates an exemplary jitter response to a Figure 6 checkerboard pattern in the case of a small light spot according to various aspects of the present disclosure;

[0023] Figure 8 illustrates an exemplary jitter response to a Figure 6 checkerboard pattern in the case of a true pixel point spread function according to various aspects of the present disclosure;

[0024] Figure 9 illustrates an exemplary jitter response to an exemplary pattern when the shaker has an instantaneous transition time according to various aspects of the present disclosure;

[0025] Figure 10 illustrates an exemplary jitter response to Figure 9 an exemplary pattern when the shaker has a non - zero transition time according to various aspects of the present disclosure;

[0026] Figure 11 illustrates an exemplary jitter response to an exemplary single - pixel high - level line pattern when the shaker has an instantaneous transition time according to various aspects of the present disclosure;

[0027] Figure 12 illustrates an exemplary jitter response to an exemplary single - pixel high - level line pattern when the shaker has a non - zero transition time according to various aspects of the present disclosure;

[0028] Figure 13 and Figure 14 illustrates an exemplary jitter response to an exemplary pattern when the shaker has an instantaneous transition time according to various aspects of the present disclosure;

[0029] Figure 15 and Figure 16 illustrates an exemplary jitter response to an exemplary pattern when the shaker has a non - zero transition time according to various aspects of the present disclosure;

[0030] Figure 17 illustrates Figure 13 and Figure 14 the superposition of the jitter responses;

[0031] Figure 18 illustrates Figure 15 and Figure 16 the superposition of the jitter responses;

[0032] Figure 19 illustrates an exemplary jitter path for implementing a blanking reduction method according to various aspects of the present disclosure;

[0033] Figure 20A illustrates an exemplary jitter path along the x - axis according to various aspects of the present disclosure;

[0034] Figure 20B Illustrates an exemplary shake path along the y-axis according to various aspects of the present disclosure;

[0035] Figure 21 Illustrates the shake response to an exemplary checkerboard pattern when the shaker is implementing a blanking mitigation method according to various aspects of the present disclosure;

[0036] Figure 22 Illustrates the shake response to an exemplary checkerboard pattern when the shaker is not implementing a mitigation method according to various aspects of the present disclosure;

[0037] Figure 23 Illustrates an exemplary process flow of an exemplary pixel offset method including blanking according to various aspects of the present disclosure;

[0038] Figure 24 Illustrates an exemplary extended shake path according to various aspects of the present disclosure;

[0039] Figure 25 Illustrates the shake response to an exemplary checkerboard pattern when the shaker is configured with an unextended shake path according to various aspects of the present disclosure;

[0040] Figure 26 Illustrates the shake response to an exemplary checkerboard pattern when the shaker is configured with an extended shake path according to various aspects of the present disclosure;

[0041] Figure 27 Illustrates an exemplary process flow for calibrating a shake path according to various aspects of the present disclosure;

[0042] Figure 28 Illustrates a block diagram of an exemplary projector display system according to various aspects of the present disclosure;

[0043] Figure 29 Illustrates the optical configuration of an exemplary projector system according to various aspects of the present disclosure; and

[0044] Figure 30 Illustrates an exemplary projection lens according to various aspects of the present disclosure. Detailed Description

[0045] The present disclosure and its various aspects can be implemented in various forms, including: hardware, devices or circuits controlled by computer-implemented methods, computer program products, computer systems and networks, user interfaces and application programming interfaces; and hardware-implemented methods, signal processing circuits, memory arrays, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc. The foregoing summary is only intended to give a general idea of the various aspects of the present disclosure and does not limit the scope of the present disclosure in any way.

[0046] In the following description, numerous details such as optical device configurations, timing, operations, etc. are set forth to provide an understanding of one or more aspects of the present disclosure. It will be apparent to those skilled in the art that these specific details are merely exemplary and are not intended to limit the scope of the present application.

[0047] In addition, although the present disclosure mainly focuses on examples of using various circuits in digital projection systems, it should be understood that this is merely an example of an implementation. Further, it should be understood that the disclosed systems and methods can be used in any device that requires projection of light; for example, theater projection systems, consumer projection systems, and other commercial projection systems, head-up displays, virtual reality displays, etc.

[0048] Pixel shift

[0049] The optics of a projection system using a spatial light modulator (SLM) can generally be divided into two parts: the optics on the illumination side (i.e., optically upstream of the SLM) and the optics on the projection side (i.e., optically downstream of the SLM). The SLM itself includes a plurality of modulation elements arranged in, for example, a two-dimensional array. Each modulation element receives light from the illumination optics and transmits the light to the projection optics. In some examples, the SLM can be implemented as a digital micromirror device (DMD) chip; this will be discussed in more detail below. However, generally, a DMD includes a two-dimensional array of reflective elements (micromirrors or simply referred to as "mirrors") that selectively reflect light towards the projection optics or discard light based on the position of each reflective element.

[0050] Figures 1A to 1B Various views of an exemplary DMD 100 according to aspects of the present disclosure are illustrated. In particular, Figure 1A a plan view of the DMD 100 is illustrated, and Figure 1B a partial cross-sectional view of the DMD 100 taken along line I-B illustrated in Figure 1A is illustrated. The DMD 100 includes a plurality of square micromirrors 102 arranged in a two-dimensional rectangular array on a substrate 104. In some examples, the DMD 100 can be a digital light processor (DLP) device. Each micromirror 102 can correspond to a pixel of the final projected image and can be configured to tilt about a rotation axis 108 (which is shown for a particular subset of the micromirrors 102) due to electrostatic or other actuation means. Each micromirror 102 has a width 112 and is arranged with a gap 110 between the micromirrors. The micromirrors 102 can be coated with or formed of any highly reflective material such as aluminum or silver so as to specularly reflect light. The gap between the micromirrors 102 can be absorptive such that incident light entering the gap is absorbed by the substrate 104.

[0051] AlthoughFigure 1A Only some representative micromirrors 102 are explicitly shown, but in fact, the DMD 100 may include more individual micromirrors. The resolution of the DMD 100 refers to the number of micromirrors in the horizontal and vertical directions. In some examples, the resolution may be 2K (2048×1080), 4K (4096×2160), 1080p (1920×1080), consumer-grade 4K (3840×2160), etc. Additionally, in some examples, the micromirrors 102 may be rectangular and arranged in a rectangular array; they may be hexagonal and arranged in a hexagonal array, etc. Additionally, although Figure 1A the illustrated axis of rotation 108 extends in an inclined direction, in some embodiments, the axis of rotation 108 may extend vertically or horizontally.

[0052] As Figure 1B can be seen, each micromirror 102 may be connected to the substrate 104 through a yoke 114, and the yoke is rotatably connected to the micromirror 102. The substrate 104 includes a plurality of electrodes 116. Although only two electrodes 116 are visible for each micromirror 102 in the Figure 1B cross-sectional view, each micromirror 102 may actually include additional electrodes. Although not specifically illustrated in Figure 1B , the DMD 100 may further include a spacer layer, a support layer, hinge components for controlling the height or orientation of the micromirrors 102, etc. The substrate 104 may include electronic circuits associated with the DMD 100, such as CMOS transistors, memory elements, etc.

[0053] Depending on the specific operation and control of the electrodes 116, the individual micromirrors 102 can switch between an "on" position, an "off" position, and an unactuated or neutral position. If the micromirror 102 is in the on position, it is actuated to an angle of, for example, -12° (i.e., rotated counterclockwise 12° relative to the neutral position) to specularly reflect the input light 106 into the on-state light 118. If the micromirror 102 is in the off position, it is actuated to an angle of, for example, +12° (i.e., rotated clockwise 12° relative to the neutral position) to specularly reflect the input light 106 into the off-state light 120. The off-state light 120 can be directed towards a light collector that absorbs the off-state light 120. In some instances, the micromirrors 102 may be unactuated and parallel to the substrate 104. In Figures 1A to 1B the specific angles illustrated and described herein are merely exemplary and not restrictive. In some embodiments, the on-position angle and the off-position angle may be between ±12 degrees and ±13 degrees (including the endpoints), respectively.

[0054] In some embodiments, the resolution of the DMD 100 may be lower than the desired resolution of the projected image. For example, it may be desired to project an image with 4K resolution, but a DMD with 4K resolution may have limited commercial availability or no commercial availability, high cost, etc. In such an embodiment, the DMD 100 with a relatively low resolution can be controlled to effectively display additional pixels in the projected image. For example, a 2K mirror array can be controlled to display a 4K projected image, or a 1080p mirror array can be controlled to display a consumer 4K projected image. Pixel offset techniques can be used to effect such control.

[0055] An exemplary pixel offset technique (wobulation) uses some method (e.g., an optical method) to effectively offset the DMD 100 by a fractional pixel in a set pattern to display additional pixels. In Figure 2 an example of such a pixel offset technique is illustrated. In Figure 2 the pixel offset technique of, the frame display period T (usually one divided by the projector frame rate) is divided into four sub - periods, each with a duration of T / 4. At time t 0 (which corresponds to the start of the first sub - period and thus the start of the frame display period T), the image is projected onto the screen. In Figure 2 only a 2×2 subset of the pixels in the first resulting image 201 is shown; however, the resolution of the first resulting image 201 actually corresponds to the relatively low resolution of the DMD 100. At time t 1 (which corresponds to the start of the second sub - period), the image is offset to the right by half a pixel, thereby generating a second resulting image 202 on the screen. At time t 2 (which corresponds to the start of the third sub - period), the image is offset down by half a pixel, thereby generating a third resulting image 203 on the screen. At time t 3 (which corresponds to the start of the fourth sub - period), the image is offset to the left by half a pixel, thereby generating a fourth resulting image 204 on the screen. At the end of the frame display period T, the image can be offset up by half a pixel, thereby corresponding to the original position for starting to display the next frame. As can be seen from Figure 2 each offset increases the effective display resolution (e.g., the resolution observed by the viewer of the image). The direction of the offset is not limited to the column and row directions (i.e., up, down, left, and right) of the pixel array, but may be along a skew direction (e.g., diagonal). Additionally, while Figure 2 illustrates a pixel offset technique that offsets the image in two dimensions, in some embodiments, the pixel offset may occur only in one dimension in a back - and - forth manner.

[0056] In some instances, a wobbling device performs pixel shifting on the output of the DMD 100 such that the superimposed output of the DMD 100 can be observed as a higher resolution output. The wobbling device is optically located after the DMD 100 such that the output of the DMD 100 is received as the input to the wobbling device. The wobbling device can shift in a single direction (e.g., doubling only the vertical resolution or only the horizontal resolution), or can shift along multiple axes (such as a 2×2 position setting which doubles the resolution along two axes and effectively quadruples the number of output pixels).

[0057] Figure 3 A diagram according to one example is provided that illustrates the movement of the wobbling device between four positions. In Figure 3 this, the wobbler shifts between a first position 300, a second position 305, a third position 310, and a fourth position 315. For example, at time t 0 (which corresponds to the start of the first sub-cycle and thus corresponds to the start of the frame display period T), the wobbling device is at the first position 300. At time t 1 (which corresponds to the start of the second sub-cycle), the wobbler shifts from the first position 300 to the right to the second position 305. At time t 2 (which corresponds to the start of the third sub-cycle), the wobbler shifts from the second position 305 down to the third position 310. At time t 3 (which corresponds to the start of the fourth sub-cycle), the wobbler shifts from the third position 310 to the left to the fourth position 315. At the end of the frame display period T, the wobbler shifts from the fourth position 315 up to the first position 300. Each "dot" in the diagram represents the position of the wobbler within the display period T. As Figure 3 seen in this, as described in more detail below, when the wobbler transitions between each position, a small amount of light can "spread" along the travel path.

[0058] Figure 4 An example wobbling output in response to an example checkerboard pattern 400 is provided. The checkerboard pattern 400 includes four "checks", where each check is a basic 2×2 checkerboard pattern. Each "check" in the checkerboard pattern consists of 'on' pixels in the upper left and lower right corners and 'off' pixels in the upper right and lower left corners. This pattern results in two pixels (along the diagonal) being active within each "check".

[0059] Figures 5A to 5B An example wobbling response to an input checkerboard pattern 300 is provided. In Figures 5A to 5BIn the example jitter responses, as well as the other example responses provided herein, the point-source pixels are analyzed rather than the pixels with a typical point spread function (PSF) (which are reflected on each micromirror 202 in DMD 100). A typical pixel PSF covers an area that is at least as large as the pixel itself (e.g., as large as each micromirror 202). Figures 5A to 5B Eight pixels are provided for each jittered output pixel.

[0060] In Figure 5A , the jitter remains near the corners of each square for a relatively large portion of the entire sub-pixel cycle. The brightness of the shown pixels is related to the transition time between each position (e.g., between each corner). In Figure 5B , for comparison, the jitter path is the same, but more time is spent on the transition compared to Figure 5A . Therefore, in Figure 5B , more light is found outside the corner positions along the path, and the corners are less bright compared to the corners found in Figure 5A .

[0061] Pixel offset artifacts

[0062] To illustrate example artifacts on the effective (or projected) pixels, a reduced test pattern of two separate checkerboards is used, shown in Figure 6 . In Figure 6 , the leftmost checkerboard 600 is aligned and fully contained within a 2×2 jitterer sub-pixel grid. Specifically, each of the four pixels within the leftmost checkerboard 600 is created by the same jitterer offset between four different positions. However, the rightmost checkerboard 605 spans two separate 2×2 sub-pixel grids. The two left pixels within the rightmost checkerboard 605 are created by jittering the first pixel (e.g., offsetting the first pixel with a jitterer), and the two right pixels within the rightmost checkerboard 605 are created by jittering the second pixel.

[0063] Figure 7 Illustrates example jitter responses of the leftmost checkerboard 600 and the rightmost checkerboard 605 of Figure 6 using artificial small pixels (for ease of visualization). Specifically, the leftmost jitter response 700 corresponds to the leftmost checkerboard 600, and the rightmost jitter response 705 corresponds to the rightmost checkerboard 605. The effective pixels observed in each jitter response are the integral of the light over the entire path of the jitter device. As Figure 7As seen, the transition time differently affects the leftmost shake response 700 and the rightmost shake response 705. For the leftmost shake response 700, since the checkerboard pattern is within a single 2×2 shake grid, the effect on the valid pattern causes each pixel to move towards the center of the 2×2 shake grid and come closer together. For the rightmost shake response 705, since the checkerboard pattern is placed across two separate shake grids, the valid pattern causes each pixel to move away from each other relative to the x-axis (while still moving towards the center of the 2×2 shake grid).

[0064] Figure 8 Illustrates the same shake response in the case of actual-size pixel PSF. In Figure 8 the light has different shapes in response to two identical checkerboard input patterns. Specifically, compared to the checkerboard on the left, the checkerboard on the right is further apart, and the valleys between the pixels are lower. Thus, the shake artifacts depend on the phase of the input pattern and on the shake grid itself.

[0065] The artifacts present in the shake output can be further observed within a recurring pattern. For example, Figure 9 illustrates the shake response to an exemplary pattern when the shaker has an ideal shake motion. As mentioned herein, a shaker characterized by an ideal shake motion can be a shaker with an instantaneous transition time. For comparison, Figure 10 illustrates the shake response to Figure 9 the exemplary pattern when the shaker has a non-ideal shake motion or a non-zero transition time. In Figure 10 due to the phase of the checkerboard relative to the 2×2 shaker pixel cluster, different artifact orientations are shown on the left and right sides of the pattern. In Figure 9 the checkerboard pattern is clearly visible. However, in Figure 10 due to the non-ideal shaker motion affecting the size, shape, and position of the valid output pixels, there is a distinct artifact pattern.

[0066] Another example pattern affected by non-ideal shaker motion is the pattern of a single-pixel high horizontal line. Figure 11 Illustrates the ideal shaker response to a horizontal line. For comparison, Figure 12 illustrates the non-ideal shaker response to a horizontal line. As Figure 12 seen in

[0067] compared to the ideal straight-line output, the shaker motion causes horizontal modulation of the line. Figure 11 and Figure 12 The modulation of Figure 12 can be further examined by observing small light spots instead of the full PSF pixels of Figure 13 Illustrates a single-pixel high horizontal line in the case of small light spots for an ideal shaker (i.e., a shaker without a transition time).Figure 14 illustrates the wobble output in the actual PSF case corresponding to Figure 13 the horizontal line of

[0068] However, once an actual wobbler with non - zero transition time between positions is used, modulation appears in the output. Figure 15 illustrates the single - pixel high - level horizontal line in the case of a small light spot for an actual wobbler with non - zero transition time. Figure 16 illustrates the wobble output in the actual PSF case corresponding to Figure 15 the horizontal line of

[0069] The superposition of the wobble responses further illustrates the artifacts generated during the wobbler movement. For example, Figure 17 illustrates the superposition of the wobble responses when the wobbler has an instantaneous transition time Figure 13 and Figure 14 For comparison, Figure 18 shows the superposition of the wobble responses when the wobbler has a non - instantaneous transition time Figure 15 and Figure 16 The superposition of Figure 18 shows the "bump" in the line generated by the actual wobbler movement.

[0070] Mitigation method

[0071] To mitigate the artifacts generated by the movement of the wobbler between positions, a mitigation method proposed herein includes "blanking" (e.g., turning off) the light projected by the DMD 100 during the transition time of the modulator device. Figure 19 A figure is provided according to an example that illustrates the movement of the wobble device between four positions and simultaneously implements "blanking". Specifically, the wobble device is offset between a first position 1900, a second position 1905, a third position 1910, and a fourth position 1915. When transitioning between each position, the DMD 100 controls a plurality of micromirrors 102 to the "off" position for at least a portion of the transition time between positions, thus directing the light away from the wobble device and towards the light collector. Accordingly, the light previously observed during the transition between each position (such as the positions shown in Figure 3 ) is removed.

[0072] Figure 20A and Figure 20B illustrate example movements of the wobble device. Figure 20A illustrates the movement of the modulator device along the x - axis, and Figure 20B illustrates the movement of the modulator device along the y - axis. The period during which "blanking" of the light occurs is indicated by "B" and occurs during the transition period between each position.

[0073] InFigure 21 An example checkerboard pattern of a wobbling device implementing "blanking" is provided. For comparison, in Figure 22 an example checkerboard pattern of a wobbling device not implementing "blanking" is provided. In Figure 21 the example of

[0074] Figure 23 there are fewer artifacts. Although "blanking" provides removal of artifacts, "blanking" also results in light loss to the light collector. Figure 23 A specific example method 2300 for implementing "blanking" mitigation techniques is provided. Figure 28 The method 2300 of

[0075] can be executed by a controller or control circuit associated with the control of the DMD 100 and the wobbling device (such as the controller 2816 described with respect to Figure 2 ), and can be implemented using hardware, software, firmware, or a combination thereof. In some examples, the method 2300 is implemented as instructions stored in a non-transitory computer-readable medium (such as a hard disk, or other storage media included in or associated with the projection system).

[0075] In method 2300, a series of images are displayed using image data including a series of frames. The image data is divided into a plurality of frame periods, each frame period corresponding to the duration T of a frame; for example, a 60 Hz display has a frame period T of (1 / 60) seconds. At operation 2301, the frame period is divided into N sub-periods, where N is an integer greater than 1. Preferably, N is four to implement a pixel offset pattern similar to Figure 2 shown and a wobbling device movement pattern similar to Figure 3 shown; however, in other embodiments, N can be six or other numbers other than four. At operation 2302, a counter I is initialized to 1. Subsequently, at operation 2303, for the I-th sub-period, an image is projected by the DMD 100 and through the wobbling device. Operation 2303 may include sub-operations such as causing the light source of the projection system to emit light, controlling a spatial light modulator (e.g., the DMD 100 of FIG. 1) to modulate the light and form an image, etc. The image is maintained for a duration of T / N. In the example of a 60 Hz display using four sub-periods per frame, the sub-period duration is (1 / 240) seconds.

[0076] At operation 2304, at the end of the sub-period, the counter I is compared with N to determine whether the sub-period is the last sub-period of the frame. If the counter I is not equal to N, then at operation 2305 the counter I is incremented by 1. At operation 2306, the micromirror 102 of the DMD 100 is turned to the "off" position to provide "blanking" of the wobbling device. At operation 2307, the wobbling device is offset so that the pixels are offset. Four sub-periods are provided per frame (as Figure 19as shown) and the pixel offset follows Figure 2 In the example of the square pattern in, this corresponds to an offset of half a pixel. Alternatively, four sub - periods can be provided per frame, and the pixel offset can follow a diamond or rectangular pattern; six sub - periods can be provided per frame, and the pixel offset can follow a rectangular or hexagonal pattern; three sub - periods can be provided per frame, and the pixel offset can follow a triangular pattern; two sub - periods can be provided per frame, and the pixel offset can follow a linear (back - and - forth) pattern; and so on. In some embodiments, the number of sub - periods can be in the dozens (or greater), and the pixel offset can approximate a circular pattern or a complex shape. Once the wobbling device is close to the new position, at operation 2308, the micromirror 102 of the DMD 100 is turned to the "on" position. The duration of the blanking of the wobbling device (e.g., the duration of operations 2306 to 2308) can be, for example, 5% of the duration of a sub - period, 10% of the duration of a sub - period, 25% of the duration of a sub - period, etc.

[0077] Thereafter, operation 2303 is repeated for the next sub - period until the counter I is equal to N. At this point, at operation 2309, the frame is incremented, and method 2300 returns to operation 2302. Operations 2302 to 2309 are repeated during the duration of the image display, and these operations can continue until the end point of the media content has been reached, a pause or stop instruction has been issued by the operation, etc.

[0078] Another artifact mitigation method disclosed herein provides an extended wobbling path for the movement of the wobbling device. Traditionally, each position of the wobbler corresponds to a quadrant or corner of the micromirror 102 because the wobbling device represents each micromirror 102 as four "pixels" (e.g., effective pixels). Thus, each "effective" pixel is evenly spaced along the micromirror 102, and the offset of the wobbling device is a distance of half a pixel (0.5).

[0079] However, by offsetting the wobbling device by more than half a pixel distance, the wobbling device compensates for the pixel position offset caused by the non - instantaneous transition time (see, for example, the discussion related to Figure 7 and Figure 8 regarding how some wobbling artifacts shift the effective center of a sub - pixel towards or away from the center of the four sub - pixels) and thus removes some artifacts without light loss. Figure 24 Illustrates an example extended wobbling path compared to the "traditional" wobbling path. In Figure 24In the example, the extended jitter path is 0.55 pixel distances (or 1.1 times the distance of the "conventional" jitter path). However, the extended jitter path can be any value greater than half a pixel distance (e.g., greater than 50% pixel distance) that can remove artifacts from the jitter output image. In some embodiments, the extended jitter path is between 50.1% pixel distance and 60% pixel distance. In other embodiments, the extended jitter path is greater than 60% of the pixel distance, such as values in the range from 60% to 70%, values in the range from 70% to 80%, values in the range from 80% to 90%, and values in the range from 90% to 100%.

[0080] In Figure 25 an exemplary checkerboard pattern of a jitter device implementing a "conventional" jitter path is provided. For comparison, in Figure 26 an exemplary checkerboard pattern of a jitter device implementing an extended jitter path is provided. In Figure 26 there are fewer artifacts present in the example.

[0081] Figure 27 A specific example method 2700 for calibrating the jitter path of a jitter device is provided. Method 2700 can be executed during the initial setup of a projection system implementing the DMD 100 and the corresponding jitter device.

[0082] At operation 2701, the DMD 100 is controlled to project a modulated image. For example, the DMD 100 can be controlled to project a test image, such as Figure 9 a checkerboard image of Figure 11 or a horizontal line image of

[0083] The modulated image can be projected onto a screen such that an operator performing the calibration can observe the modulated image. In some instances, the DMD 100 initially projects an image with a "normal" pixel size PSF. At operation 2702, the size of the pixels included in the modulated image is adjusted. In some embodiments, an aperture is added to the projection system to reduce the pixel size during calibration, thereby making artifacts more easily observable during calibration.

[0084] In some instances, artifacts depend on the frame rate of the display. Thus, method 2700 can be performed for a frame rate corresponding to the frame rate of the respective display, and this frame rate remains constant during the duration of the calibration method 2700. In some instances, when operating at a frame rate higher than a relatively low frame rate (e.g., 120 Hz), it may be necessary to expand the jitter path more greatly to sufficiently mitigate jitter artifacts (e.g., at 120 Hz, a jitter path of 0.60 pixel size can be useful for mitigating artifacts, while at 60 Hz, a jitter path of 0.50 pixel size may be sufficient to avoid jitter artifacts).

[0085] Additionally, although method 2700 has been described with respect to an operator calibrating the jitter path, in some instances, a controller or control circuitry associated with the control of DMD 100 and the jitter device (such as the controller 2816 described with respect to Figure 28 described) and method 2700 can be implemented using hardware, software, firmware, or a combination thereof. In some examples, method 2700 is implemented as instructions stored on a non-transitory computer-readable medium (such as a hard disk, or other storage medium included in or associated with the projection system). For example, controller 2816 can store a model that indicates the desired output modulation image or ideal jitter path for a given frame rate. Then, controller 2816 selects the jitter path based on this model.

[0086] Although the "blanking" mitigation described in method 2300 and the extended jitter path mitigation described in method 2700 have been described separately, in some instances, these mitigation methods are complementary and implemented simultaneously. The amount of each technique can be adjusted based on the jitter device used to balance the benefits of artifact mitigation with light loss.

[0087] Although the examples described herein mainly relate to doubling the resolution, in some instances, jitter techniques can be used to increase the resolution of DMD 100 to more than double, such as tripling or quadrupling the resolution of DMD 100. In an embodiment where the resolution is tripled, the image is offset by approximately one-third (1 / 3) pixel distance instead of a half-pixel distance. Thus, in the extended jitter path mitigation method, the jitter path is adjusted to be greater than one-third pixel distance. In an embodiment where the resolution is quadrupled, the image is offset by approximately one-fourth (1 / 4) pixel distance. Thus, in the extended jitter path mitigation method, the jitter path is adjusted to be greater than one-fourth pixel distance.

[0088] Projector system

[0089] Figure 28Illustrated is one possible embodiment of a suitable image projector display system that implements the described mitigation techniques. In the illustrated embodiment, the projector display system is configured as a dual / multi-modulator projection system 2800. The projection system 2800 employs a light source 2802 that supplies the desired illumination to the projector system such that the final projected image will be bright enough for the intended viewer of the projected image. The light source 2802 can include any suitable light source, such as but not limited to xenon lamps, lasers, coherent light sources, and partially coherent light sources. Additionally, the optical systems described herein can implement optical fibers to transmit light from the light source 2802 to the optical components within the optical system. Although the light source and the optical fiber can be separately mentioned, it should be understood that the optical fiber is a component of the light source. Thus, a mere mention of the light source does not exclude the optical fiber.

[0090] In some embodiments, the optical fiber is a rectangular optical fiber or a rectangular optical fiber array that has an aspect ratio that matches a downstream modulator (such as the first modulator 2806 and / or the second modulator 2810).

[0091] Light 2804 from the light source 2802 can illuminate the first modulator 2806, which can then illuminate the second modulator 2810 via an optional set of optical components 2808. The light from the second modulator 2810 can be projected by a projection lens 2812 (or other suitable optical component) to form the final projected image on a screen 2814. In some instances, a wobbling device is implemented within the projection lens 2812. In other instances, the wobbling device can be optically located between the second modulator 2810 and the projection lens 2812.

[0092] The first modulator 2806 and the second modulator 2810 can be controlled by a controller 2816. The controller 2816 can receive input image and / or video data and can perform certain image processing algorithms, color gamut mapping algorithms, or other such suitable processing on the input image / video data and output control / data signals to the first modulator 2806 and the second modulator 2810 in order to achieve the desired final projected image on the screen 2814. Additionally, in some projector systems, the light source 2802 can be modulated depending on the light source (control lines not shown) in order to achieve additional control over the image quality of the final projected image.

[0093] The light recycling module 2803 is depicted as a dashed box in Figure 28 and can be placed in the optical path from the light source 2802 to the first modulator 2806. It should be understood that light recycling can be inserted into the projector system at various points within the projector system. For example, the light recycling can be placed between the first modulator 2806 and the second modulator 2810. Additionally, the light recycling can be placed at more than one point in the optical path of the display system.

[0094] Although Figure 28 the embodiments are presented in the context of a dual - modulation, multi - modulation projection system, it should be understood that the techniques and methods of the present application will be applicable to single - modulation or other dual - modulation, multi - modulation display systems. For example, a dual - modulation display system including a backlight, a first modulator (e.g., LCD, etc.) and a second modulator (e.g., LCD, etc.) can employ suitable optical components as well as image - processing methods and techniques to affect the performance and efficiency discussed herein in the context of a projection system. It should also be understood that even Figure 28 a two - stage or dual - modulator display system is depicted, the methods and techniques of the present application can also be applied to a display system having only one modulator or a display system having three or more modulators (multi - modulator). The scope of the present application encompasses these different alternative embodiments.

[0095] Figure 29 FIG. 2900 illustrates another example projection system. Projection system 2900 includes an illumination assembly 2904 (e.g., illumination optics) that receives light from a fiber optic input 2902 and feeds the light into a modulation assembly 2906. The modulation assembly 2906 includes a prism 2908 and a modulator 2910 (e.g., a reflector device). The modulator 2910 can be configured as a digital light processing (DLP) device, a DMD, etc.

[0096] In some instances, the light from the fiber optic input 2902 is a white - light input and the prism 2908 is a white - light prism. In such instances, the prism 2908 includes a number of prism parts. For example, a spectral filter such as a yellow notch filter can be provided in the prism 2908. Additional parts can be used as TIR prisms. In some embodiments, the modulation assembly 2906 includes three modulators 2910 (e.g., 3 - chip) for modulating the received white light. The prism 2908 splits the white light into a number of color beams (e.g., three color channels), one color beam for each modulator 2910. A controller (such as controller 2816) can be coupled to each modulator 2910 to control the modulation of each color beam. Then, the modulator 2910 modulates its corresponding color beam and then combines the modulated color beams in the prism 2908. In other embodiments, the modulator 2910 directly modulates the white light. In both of these embodiments, the modulation assembly 2906 then relays the output beam to the projection optics 2914 of the projection system 2900. In some embodiments, the projection optics 2914 are included in the projection lens. In other embodiments, a part or section of the projection optics 2914 is included in the projection lens. In some instances, the projection optics 2914 include a wobbling device.

[0097] In other instances, the projection system 2900 includes a number of fiber optic inputs 2902 from a number of color channels such as a red channel, a blue channel, and a green channel. In such an instance, the illustrated illumination assembly 2904 that receives the fiber optic inputs 2902 corresponds only to a monochromatic channel for the prism 2908. A number of illumination assemblies 2904 may be included to direct light from the fiber optic inputs to the prism 2908. In such an instance, the prism 2908 is a color light prism that receives each fiber optic input 2902 and redirects each color channel to a corresponding modulator 2910. After modulation, the modulated color channels are combined and directed toward the projection optics 2914.

[0098] In some instances, the fiber optic input 2902 is a high etendue light source. Etendue is a measure of the product of the emission area and the solid angle, and is related to terms such as mm 2 *sr (steradian), M 2 factor, or beam parameter product (BPP). More specifically, the etendue can be provided as: π * area * NA 2 . Thus, the light projected by a single fiber optic input has a lower etendue than the light projected by a cluster of fiber optic inputs (such as Figure 7 the multiple inner fibers 710). A high etendue light source can have, for example, an etendue in the range of 0.2 mm 2 *sr to 50 mm 2 *sr. A single fiber having a diameter of about 450 microns disclosed herein can have an etendue of approximately 0.024 mm 2 *sr. A fiber having a diameter of about 100 microns can have an etendue of approximately 0.0012 mm 2 *sr.

[0099] In some instances, the illumination assembly 2904 achieves a high f-number with a narrow illumination angle while maintaining the uniformity of the light incident on the modulator 2910. The f-number (denoted as f / #) is the ratio of the focal length of the system to the diameter of the aperture. The f / # of the light incident on the prism 2908 can be in the range of f / 10 and f / 20.

[0100] In some embodiments, the projection optics 2914 are provided within the projection lens architecture. Figure 30FIG. 0 is an exploded view of an exemplary projection lens system 3000 in accordance with various aspects of the present disclosure. The projection lens system 3000 has a modular design. The projection lens system 3000 includes a Fourier section 3001 (e.g., a Fourier lens assembly), an aperture 3002, and a zoom section 3003 (also referred to as a zoom lens assembly), where the Fourier section is configured to form a Fourier transform of an object at an exit pupil. The spatial Fourier transform applied by the Fourier section 3001 converts the propagation angle of each diffraction order of the modulated light into a corresponding spatial position on the Fourier plane. The Fourier section 3001 is thus able to select desired diffraction orders and reject undesired diffraction orders by performing spatial filtering at the Fourier plane. The spatial Fourier transform of the modulated light at the Fourier plane is equivalent to the Fraunhofer diffraction pattern of the modulated light.

[0101] The Fourier section 3001 includes a first attachment segment 3004, which may include threads, fasteners, etc. The zoom section 3003 includes a second attachment segment 3005, which may include complementary threads, fasteners, etc., to allow mating with the first attachment segment 3004. In one example, the first attachment segment 3004 includes a portion with external threads, and the second attachment segment 3005 includes a portion with internal threads, and vice versa. In another example, the first attachment segment 3004 and the second attachment segment 3005 are configured for a friction fit, in which case one or more fastening elements, such as screws, cams, flanges, etc., may be provided. In yet another example, the first attachment segment 3004 may include one or more radial pins, and the second attachment segment 3005 may include a corresponding number of L-shaped slots, and vice versa, such that a bayonet connection is used to connect the Fourier section 3001 to the zoom section 3003. By these examples, the Fourier section 3001 may be removably attached to the zoom section 3003 to provide a modular assembly.

[0102] Although Figure 30 the Fourier section 3001 and the zoom section 3003 are illustrated as being fully separable, the present disclosure is not limited thereto. In some embodiments, the Fourier section 3001 and the zoom section 3003 are only partially separable, for example, by providing an access portion in one of the Fourier section 3001 and the zoom section 3003. The access portion may be a slot, door, window, etc., through which an operator may access and / or replace the aperture 3002. In such embodiments, the Fourier section 301 and the zoom section 3003 may be bonded (e.g., via an adhesive on the first attachment segment 3004 and / or the second attachment segment 3005) to prevent full separation. Alternatively, the Fourier section 3001 and the zoom section 3003 may be provided with an integral housing including attachment portions.

[0103] The aperture 3002 is configured to block a portion of the light (e.g., the modulated light corresponding to one or more diffraction orders) in the projection lens system 3000 (e.g., the modulated light provided via the modulation component 2906). As Figure 30 illustrated, the aperture 3002 is a square opening having sides, for example, 6 mm in length. Figure 30 The optical axis 3010 of the projection lens system 3000 is also illustrated. After assembly, the Fourier section 3001 and the zoom section 3003 are substantially coaxial with each other and substantially coaxial with the optical axis 3010. In some embodiments (e.g., depending on the illumination angle), the aperture 3002 is further substantially coaxial with the optical axis 3010. However, in other embodiments, the aperture 3002 may not be substantially coaxial with the optical axis 3010. In some instances, the aperture 300 is selected to achieve a desired "small spot" at operation 2702 of the calibration method 2700.

[0104] The projection lens system 3000 may include or be associated with one or more non-optical elements, the one or more non-optical elements including heat dissipation devices such as heat sinks (or cooling fins), one or more adhesives (or fasteners), etc. In some embodiments, the aperture 3002 may block and thus absorb approximately 15% of the incident light, and thus the heat sink or cooling fin may be positioned and configured to dissipate heat from the aperture 3002 appropriately. In some embodiments, the aperture 3002 is thermally isolated from other parts of the projection lens system 3000.

[0105] The Fourier section 3001 and the aperture 3002 together operate as a Fourier lens with a spatial filter, which Fourier lens may also be used as a fixed projection projection lens. Figure 30 The zoom section 3003 illustrated therein may be one zoom lens assembly of a series of zoom lens assemblies configured to be attached to the Fourier section 3001, thereby producing a series of projection zoom lens systems and accommodating different theaters. In other words, the Fourier section 3001 and the aperture 3002 may be applicable to any theater setup, while the zoom section 3003 provides a specific projection light pattern customized for a particular theater. Thus, by selecting a specific zoom section 3003 from a series of zoom lens assemblies and attaching the selected zoom section 3003 to the Fourier section 3001 and the aperture 3002, a projection lens system 3000 suitable for a particular theater can be achieved. Additionally, both the Fourier section 3001 and the zoom section 30 may include a plurality of individual lens elements.

[0106] The systems, methods, and devices according to the present disclosure may adopt any one or more of the following configurations.

[0107] (1) A projection system with pixel offset, comprising: a light source configured to emit light; a spatial light modulator configured to receive the light and generate modulated light, wherein the spatial light modulator includes a plurality of micromirrors; a wobbling device configured to offset the modulated light by a fractional pixel; and a controller configured to: for each of a plurality of sub - cycles, control the light source to emit the light onto the spatial light modulator, and between each of the plurality of sub - cycles and using the wobbling device to offset the modulated light by a partial pixel distance, the partial pixel distance being greater than a half - pixel distance.

[0108] (2) The projection system according to (1), further comprising: a lens configured to perform a spatial Fourier transform on the modulated light; and a filter including an aperture, the filter being configured to transmit at least one diffraction order of the modulated light Fourier - transformed by the lens and block the remainder of the modulated light.

[0109] (3) The projection system according to any one of (1) to (2), wherein the plurality of sub - cycles are four sub - cycles.

[0110] (4) The projection system according to any one of (1) to (3), wherein the partial pixel distance is equal to a value in the range between 50.1% and 60% of the full - pixel distance.

[0111] (5) The projection system according to any one of (1) to (4), wherein the controller is further configured to: between the first sub - cycle and the second sub - cycle, offset the modulated light by a distance greater than a half - pixel distance in a first direction; between the second sub - cycle and the third sub - cycle, offset the modulated light by a distance greater than a half - pixel distance in a second direction perpendicular to the first direction; between the third sub - cycle and the fourth sub - cycle, offset the modulated light by a distance greater than a half - pixel distance in a third direction perpendicular to the second direction and opposite to the first direction; and after the fourth sub - cycle, offset the modulated light by a distance greater than a half - pixel distance in a fourth direction perpendicular to the third direction and opposite to the second direction.

[0112] (6) The projection system according to any one of (1) to (5), wherein the controller is configured to: for a plurality of image frames, repeatedly cause the projection system to emit the light and offset the modulated light.

[0113] (7) The projection system according to any one of (1) to (6) further includes: a prism configured to receive the light from the light source and redirect the light into a second light, and wherein the spatial light modulator receives the second light.

[0114] (8) The projection system according to any one of (1) to (7), wherein the light source is a rectangular optical fiber.

[0115] (9) A method for calibrating pixel offset in a projection system, the method comprising: emitting light using a light source; receiving the light using a spatial light modulator; modulating the light using the spatial light modulator to generate a modulated image, wherein the modulated image includes a plurality of pixels; offsetting the modulated light of each pixel of the modulated image by a partial pixel distance between each of a plurality of sub - periods to generate a wobbling image; determining the amount of wobbling artifacts in the wobbling image; and adjusting the partial pixel distance based on the determined amount of wobbling artifacts.

[0116] (10) The method according to (9), wherein adjusting the partial pixel distance includes adjusting the partial pixel distance to be greater than a half - pixel distance.

[0117] (11) The method according to any one of (9) to (10), wherein the partial pixel distance is adjusted by receiving an input from a user interface.

[0118] (12) The method according to any one of (9) to (11), wherein the frame rate of the projection system remains constant during the adjustment of the partial pixel distance.

[0119] (13) The method according to any one of (9) to (12), wherein the adjustment of the partial pixel distance depends on the frame rate of the projection system.

[0120] (14) The method according to any one of (9) to (13), wherein adjusting the partial pixel distance includes adjusting the partial pixel distance based on a model stored in a memory.

[0121] (15) A projection method for pixel offset, comprising: for each of a plurality of sub - periods, controlling a light source to emit light onto a plurality of micromirrors on a spatial light modulator; receiving the light using the plurality of micromirrors and for each of the plurality of sub - periods to generate modulated light; and offsetting the modulated light by a partial pixel distance between each of the plurality of sub - periods, the partial pixel distance being greater than a half - pixel distance.

[0122] (16) The projection method according to (15) further includes: performing a spatial Fourier transform on the modulated light by using a lens; transmitting at least one diffraction order of the modulated light that has undergone Fourier transform by the lens by using a filter including an aperture; and blocking the remaining part of the modulated light by using the filter.

[0123] (17) The projection method according to any one of (15) to (16), wherein the plurality of sub - periods are four sub - periods.

[0124] (18) The projection method according to any one of (15) to (17), wherein the partial pixel distance is equal to a value within the range between 50.1% and 60% of the full pixel distance.

[0125] (19) The projection method according to any one of (15) to (18) further includes: between the first sub - period and the second sub - period, shifting the modulated light in a first direction by a distance greater than half a pixel distance; between the second sub - period and the third sub - period, shifting the modulated light in a second direction perpendicular to the first direction by a distance greater than half a pixel distance; between the third sub - period and the fourth sub - period, shifting the modulated light in a third direction perpendicular to the second direction and opposite to the first direction by a distance greater than half a pixel distance; and after the fourth sub - period, shifting the modulated light in a fourth direction perpendicular to the third direction and opposite to the second direction by a distance greater than half a pixel distance.

[0126] (20) The projection method according to any one of (15) to (19) further includes: for a plurality of image frames, repeatedly emitting the light and shifting the modulated light.

[0127] (21) The projection method according to any one of (15) to (20) further includes: receiving the light from the light source by using a prism; redirecting the light into a second light by using the prism; and receiving the second light by using the spatial light modulator.

[0128] (22) A projection system with pixel offset, comprising: a light source configured to emit light; a spatial light modulator configured to receive the light and generate modulated light, wherein the spatial light modulator includes a plurality of micromirrors; a shaking device configured to offset the modulated light by a fractional pixel; and a controller configured to: for each of a plurality of sub - periods, control the light source to emit the light onto the spatial light modulator, and between each of the plurality of sub - periods and using the shaking device: control the plurality of micromirrors to a closed position, offset the modulated light by a partial pixel distance, and after offsetting the modulated light by the partial pixel distance, control the plurality of micromirrors to an open position.

[0129] (23) The projection system according to (22), wherein the plurality of sub - periods are four sub - periods.

[0130] (24) The projection system according to any one of (22) to (23), wherein the partial pixel distance is equal to a half - pixel distance.

[0131] (25) The projection system according to any one of (22) to (24), further comprising: a lens configured to perform a spatial Fourier transform on the modulated light; and a filter including an aperture, the filter being configured to transmit at least one diffraction order of the modulated light Fourier - transformed by the lens and block the rest of the modulated light.

[0132] (26) The projection system according to any one of (22) to (25), wherein the plurality of micromirrors are controlled in the closed position for a duration between 5% and 25% of the duration of the corresponding sub - period.

[0133] (27) The projection system according to any one of (22) to (26), wherein when in the closed position, the plurality of micromirrors are configured to direct light onto a light collector.

[0134] (28) The projection system according to any one of (22) to (27), wherein the controller is further configured to: between a first sub-period and a second sub-period, shift the modulated light in a first direction by a distance greater than a half-pixel distance; between the second sub-period and a third sub-period, shift the modulated light in a second direction perpendicular to the first direction by a distance greater than a half-pixel distance; between the third sub-period and a fourth sub-period, shift the modulated light in a third direction perpendicular to the second direction and opposite to the first direction by a distance greater than a half-pixel distance; and after the fourth sub-period, shift the modulated light in a fourth direction perpendicular to the third direction and opposite to the second direction by a distance greater than a half-pixel distance.

[0135] (29) The projection system according to any one of (22) to (28), wherein the controller is configured to: for a plurality of image frames, repeatedly cause the projection system to emit the light and shift the modulated light.

[0136] Regarding the processes, systems, methods, heuristics, etc. described herein, it should be understood that although the steps of these processes, etc. have been described as being performed in a particular ordered sequence, these processes can be practiced using the described steps executed in an order different from that described herein. Further, it should be understood that certain steps can be performed simultaneously, other steps can be added, or certain steps described herein can be omitted. In other words, the process descriptions herein are provided for the purpose of illustrating certain embodiments and should in no way be construed as limiting the claims.

[0137] Accordingly, it should be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided will be apparent upon reading the above description. The scope should not be determined with reference to the above description, but rather should be determined with reference to the appended claims and the full scope of equivalents to which those claims are entitled. It is expected and hoped that the technologies discussed herein will be developed in the future, and the disclosed systems and methods will be incorporated into such future embodiments. In summary, it should be understood that this application is capable of modification and change.

[0138] All terms used in the claims are intended to be given the broadest reasonable interpretation and ordinary meaning as understood by those who are knowledgeable about the technologies described herein, unless an express contrary indication appears herein. In particular, the use of singular articles such as "a", "the", etc. should be understood to recite one or more of the indicated elements, unless the claim recites an express contrary limitation.

[0139] A summary of the present disclosure is provided to enable a reader to quickly ascertain the nature of the technical disclosure. This summary is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Additionally, in the foregoing detailed description, it can be seen that various features are grouped together in various embodiments for the purpose of presenting the disclosure as a unified whole. The methods of the present disclosure should not be construed as reflecting an intention that the claimed embodiments incorporate more features than are expressly recited in each claim. On the contrary, as reflected by the appended claims, the inventive subject matter lies in less than all of the features of a single disclosed embodiment. Accordingly, the appended claims are hereby incorporated into the detailed description, with each claim standing on its own as a separately claimed subject matter.

Claims

1. A projection system with pixel offset, comprising: a light source configured to emit light; a spatial light modulator configured to receive the light and generate modulated light, wherein the spatial light modulator includes a plurality of micromirrors; a wobbling device configured to offset the modulated light by a fraction of a pixel; and a controller configured to: for each of a plurality of sub - periods, control the light source to emit the light onto the spatial light modulator, and between each of the plurality of sub - periods and using the wobbling device, offset the modulated light by a partial pixel distance that is greater than a half - pixel distance.

2. The projection system according to claim 1, further comprising: a lens configured to perform a spatial Fourier transform on the modulated light; and a filter including an aperture, the filter being configured to transmit at least one diffraction order of the modulated light Fourier - transformed by the lens and block the remaining part of the modulated light.

3. The projection system according to claim 1 or 2, wherein the plurality of sub - periods are four sub - periods.

4. The projection system according to any one of claims 1 to 3, wherein the partial pixel distance is equal to a value in the range between 50.1% and 60% of the full - pixel distance.

5. The projection system according to any one of claims 1 to 4, wherein the controller is configured to: between a first sub - period and a second sub - period, offset the modulated light by a distance greater than a half - pixel distance in a first direction, between the second sub - period and a third sub - period, offset the modulated light by a distance greater than a half - pixel distance in a second direction perpendicular to the first direction, between the third sub - period and a fourth sub - period, offset the modulated light by a distance greater than a half - pixel distance in a third direction perpendicular to the second direction and opposite to the first direction, and after the fourth sub - period, offset the modulated light by a distance greater than a half - pixel distance in a fourth direction perpendicular to the third direction and opposite to the second direction.

6. The projection system according to any one of claims 1 to 5, wherein the controller is configured to: for a plurality of image frames, repeatedly cause the projection system to emit the light and offset the modulated light.

7. The projection system according to any one of claims 1 to 6, further comprising: a prism configured to receive the light from the light source and redirect the light as second light, and wherein the spatial light modulator receives the second light.

8. The projection system according to any one of claims 1 to 7, wherein the light source is a rectangular optical fiber.

9. A method for calibrating pixel offset in a projection system, the method comprising: emitting light using a light source; receiving the light using a spatial light modulator; Modulating the light using the spatial light modulator to generate a modulated image, wherein the modulated image includes a plurality of pixels; shifting the modulated light of each pixel of the modulated image by a partial pixel distance between each of a plurality of sub - periods to generate a wobbled image; Determining the amount of wobbling artifacts in the wobbled image; and Adjusting the partial pixel distance based on the determined amount of wobbling artifacts.

10. The method according to claim 9, wherein, Adjusting the partial pixel distance includes adjusting the partial pixel distance to be greater than half a pixel distance.

11. The method according to claim 9 or 10, wherein, Adjusting the partial pixel distance by receiving an input from a user interface.

12. The method according to any one of claims 9 to 11, wherein, During the adjustment of the partial pixel distance, the frame rate of the projection system remains constant.

13. The method according to any one of claims 9 to 12, wherein, The adjustment of the partial pixel distance depends on the frame rate of the projection system.

14. The method according to any one of claims 9 to 13, wherein, Adjusting the partial pixel distance includes adjusting the partial pixel distance based on a model stored in a memory.

15. A projection method for pixel offset, comprising: For each of a plurality of sub - periods, controlling a light source to emit light onto a plurality of micromirrors on a spatial light modulator; Using the plurality of micromirrors and for each of the plurality of sub - periods, receiving the light to generate modulated light; and Between each of the plurality of sub - periods, shifting the modulated light by a partial pixel distance, the partial pixel distance being greater than half a pixel distance.

16. The projection method according to claim 15, further comprising: Performing a spatial Fourier transform on the modulated light using a lens; Using a filter including an aperture to transmit at least one diffraction order of the modulated light Fourier - transformed by the lens; and Using the filter to block the remaining part of the modulated light.

17. The projection method according to claim 15 or 16, wherein, The plurality of sub - periods are four sub - periods.

18. The projection method according to any one of claims 15 to 17, wherein, The partial pixel distance is equal to a value in the range between 50.1% and 60% of the full pixel distance.

19. The projection method according to any one of claims 15 to 18, further comprising: Between a first sub - period and a second sub - period, shifting the modulated light in a first direction by a distance greater than half a pixel distance; Between the second sub - period and the third sub - period, shifting the modulated light in a second direction perpendicular to the first direction by a distance greater than half a pixel distance; Between the third sub - period and the fourth sub - period, shifting the modulated light in a third direction perpendicular to the second direction and opposite to the first direction by a distance greater than half a pixel distance; and After the fourth sub-period, the modulated light is offset by a distance greater than half a pixel distance in a fourth direction perpendicular to the third direction and opposite to the second direction.

20. The projection method according to any one of claims 15 to 19, further comprising: For a plurality of image frames, repeatedly emitting the light and offsetting the modulated light.

21. The projection method according to any one of claims 15 to 20, further comprising: Receiving the light from the light source using a prism; Redirecting the light into a second light using the prism; and Receiving the second light using the spatial light modulator.

Images