Display levels and calibration of display levels

Abstract

A system and method for calibrating a display level created using a dual-modulation digital micromirror device. In one example, the multi-modulation display system includes a light source, a first modulator, and a second modulator. The first modulator includes a first plurality of mirrors for modulating light from the light source, and the second modulator includes a second plurality of mirrors for modulating light from the first modulator. A first image is captured when the first modulator is off and the second modulator is on, thereby creating a first display level. A second image is captured when both the first and second modulators are on, thereby also creating the same first display level. The difference between the first and second images is determined, and a control signal for controlling the second modulator can be adjusted based on this difference.

Description

[0001] background 1. Cross-references to related applications This application claims priority to U.S. Provisional Application Serial No. 63 / 605,841, filed December 4, 2023; U.S. Provisional Application Serial No. 63 / 556.167, filed February 21, 2024; and European Patent Application No. EP 24165364.1, filed March 21, 2024, each of which is incorporated herein by reference in its entirety. 2. Technical Field This application generally relates to bit sequences for dual-modulation display systems, and particularly to the calibration of display levels created using dual-modulation digital micromirror devices. 3. Background Technology Digital projection systems typically use light sources and optical systems to project images onto a surface or screen. Optical systems include components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, digital micromirror devices (DMDs), spatial light modulators (SLMs), and phase light modulators (PLMs). Bit ordering modes control the time periods during which the DMD micromirrors are on and off. The modulator can switch multiple times within a single frame. Image levels are specified by the video signal, which has code values ​​that specify these levels. For example, the video signal can be encoded with perceptual quantizer (PQ) coding to encode image levels so that the code values ​​indicate the light intensity levels on the image. Summary of the Invention

[0004] Various aspects of this disclosure relate to apparatus, systems, and methods for projection displays. One example embodiment provides a method for calibrating a multimodulation display system. The multimodulation display system includes: a light source; a first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator illuminated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator. The method includes: sending a first control signal to the first modulator such that the first plurality of mirrors are controlled to be in an off position during the first time period; sending a second control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during the first time period; and capturing a first image of the light modulated by the second modulator during the first time period. The method further includes: sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to modulate light during the second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during the second time period; and capturing a second image of the light modulated by the first modulator and the second modulator during the second time period. The method includes determining a difference between the first image and the second image.

[0005] Another example embodiment provides a method for calibrating a multimodulation display system. The multimodulation display system includes: a light source; a first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator illuminated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator. The method includes: sending a first control signal to the first modulator such that the first plurality of mirrors are controlled to be in a closed position during all sub-intervals of a first time period; sending a second control signal to the second modulator such that the second plurality of mirrors are controlled to be in an open position during a first portion of the sub-intervals of the first time period; and capturing a first image of the light modulated by the second modulator during the first time period. The method further includes: sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to be in an open position during a second portion of the sub-intervals of a second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during a third portion of the sub-intervals of the second time period; and capturing a second image of the light modulated by the first modulator and the second modulator during the second time period. The method includes determining a difference between the first image and the second image.

[0006] Another example embodiment provides an apparatus for calibrating a multimodulation display system, the multimodulation display system comprising: a light source; a first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator illuminated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator. The apparatus includes an electronic processor configured to perform operations including: sending a first control signal to the first modulator such that the first plurality of mirrors are controlled to be in a closed position during all sub-intervals of a first time period; sending a second control signal to the second modulator such that the second plurality of mirrors are controlled to be in an open position during a first portion of the sub-intervals of the first time period; and capturing a first image of the light modulated by the second modulator during the first time period. These operations include: sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to be in an open position during a second portion of the sub-intervals of a second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during a third portion of the sub-intervals of the second time period; and capturing a second image of the light modulated by the first modulator and the second modulator during the second time period. These operations include determining the differences between the first image and the second image.

[0007] Another example embodiment provides an apparatus for calibrating a multimodulation display system, the multimodulation display system comprising: a light source; a first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator illuminated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator. The apparatus includes an electronic processor configured to perform operations including: sending a first control signal to the first modulator such that the first plurality of mirrors are controlled to be in a closed position during all sub-intervals of a first time period; sending a second control signal to the second modulator such that the second plurality of mirrors are controlled to be in an open position during a first portion of the sub-intervals of the first time period; and capturing a first image of the light modulated by the second modulator during the first time period. These operations include: sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to be in an open position during a second portion of the sub-intervals of a second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during a third portion of the sub-intervals of the second time period; and capturing a second image of the light modulated by the first modulator and the second modulator during the second time period. These operations include determining the differences between the first image and the second image.

[0008] Another example embodiment provides a non-transitory computer-readable storage medium having instructions recorded thereon that can be executed by a device to perform a method comprising: sending a first control signal to a first modulator such that a first plurality of mirrors are controlled to be in an off position during a first time period; sending a second control signal to a second modulator such that a second plurality of mirrors are controlled to modulate light during the first time period; and capturing a first image of the light modulated by the second modulator during the first time period. The method further comprises: sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to modulate light during a second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during the second time period; and capturing a second image of the light modulated by the first modulator and the second modulator during the second time period. The method includes determining a difference between the first image and the second image.

[0009] Another example embodiment provides a non-transitory computer-readable storage medium having instructions recorded thereon that can be executed by a device to perform a method comprising: sending a first control signal to a first modulator such that a first plurality of mirrors are controlled to be in a closed position during all sub-intervals of a first time period; sending a second control signal to a second modulator such that a second plurality of mirrors are controlled to be in an open position during a first portion of the sub-intervals of the first time period; and capturing a first image of light modulated by the second modulator during the first time period. The method further comprises: sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to be in an open position during a second portion of the sub-intervals of a second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during a third portion of the sub-intervals of the second time period; and capturing a second image of light modulated by the first and second modulators during the second time period. The method includes determining a difference between the first image and the second image.

[0010] In this way, various aspects of this disclosure provide for the display of images with high dynamic range and high resolution, and provide effective improvements in at least the fields of image projection, holography, signal processing, etc. Attached Figure Description

[0011] Referring to the accompanying drawings, these and other more detailed and specific features of various embodiments are disclosed more fully in the following description, in which: Figure 1 A block diagram of an exemplary image projector display system according to various aspects of this disclosure is illustrated.

[0012] Figure 2A A plan view of an exemplary spatial light modulator used in conjunction with various aspects of this disclosure is illustrated.

[0013] Figure 2B The diagram illustrates the following: along Figure 2A The cross-sectional view taken by line IB.

[0014] Figure 3 The diagram illustrates a high-level diagram of a switching scheme that matches the bit sequence repetition pattern.

[0015] Figure 4A The illustration shows an example bit sequence of a premodulator.

[0016] Figure 4B The illustration shows an example bit sequence of the master modulator.

[0017] Figure 4C The diagram illustrates the process of... Figure 4A and Figure 4B The transmittance generated by the bit sequence.

[0018] Figure 5A Another example bit sequence of a premodulator is illustrated.

[0019] Figure 5B Another example bit sequence of the master modulator is illustrated.

[0020] Figure 5C The diagram illustrates the process of... Figure 5A and Figure 5B The transmittance generated by the bit sequence.

[0021] Figure 6A Another example bit sequence of a premodulator is illustrated.

[0022] Figure 6B Another example bit sequence of the master modulator is illustrated.

[0023] Figure 6C The diagram illustrates the process of... Figure 6A and Figure 6B The transmittance generated by the bit sequence.

[0024] Figure 7 The diagram illustrates the bit sequence levels for various PQ code values.

[0025] Figure 8 The illustration shows the gradient image levels for various PQ code values.

[0026] Figures 9A to 9C The illustration shows an example premodulator off state level for color channels normalized for a white image.

[0027] Figure 10 The diagram illustrates the process of... Figure 1A block diagram of an example method for an image projector display system. Detailed Implementation

[0028] This disclosure and its 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; as well as hardware-implemented methods, signal processing circuits, memory arrays, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc. The foregoing description is intended only to give a general idea of ​​the various aspects of this disclosure and does not limit the scope of this disclosure in any way.

[0029] In the following description, numerous details, such as optical device configuration, timing, and operation, are set forth to provide an understanding of one or more aspects of this 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 this application.

[0030] Furthermore, while this disclosure focuses primarily on examples of using various circuits in digital projection systems, it should be understood that this is merely one example of an implementation. It should also be understood that the disclosed systems and methods can be used in any device that requires the projection of light; for example, cinema projection systems, consumer projection systems and other commercial projection systems, head-up displays, virtual reality displays, etc.

[0031] Projector system Figure 1 A possible embodiment of a suitable image projector display system is illustrated. In the illustrated embodiment, the projector display system is configured as a dual / multi-modulator projection system 100. The projection system 100 employs a light source 102 that supplies the projector system with the desired illumination such that the final projected image will be sufficiently bright for the intended viewer. The light source 102 may include any suitable light source, such as, but not limited to, a xenon lamp, multiple lasers, coherent light sources, and partially coherent light sources. Additionally, the optical system described herein may incorporate optical fibers to transmit light from the light source 102 to optics within the optical system.

[0032] Light 104 from light source 102 can illuminate a first modulator 106 (e.g., a premodulator), which in turn can illuminate a second modulator 110 (e.g., a master modulator) via a set of optional optical components 108. Light from the second modulator 110 can be projected by a projection lens 112 (or other suitable optical components) to form a final projected image on screen 114. In some instances, the projection lens 112 includes filters for filtering the light from the second modulator 110, as described in more detail below. The first modulator 106 and the second modulator 110 can be controlled by a controller 116. The controller 116 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 106 and the second modulator 110 to achieve the desired final projected image on screen 114. In addition, in some projector systems, the light source 102 (control lines not shown) can be modulated depending on the light source in order to achieve additional control over the image quality of the final projected image.

[0033] The controller 116 may include electrical components such as an electronic processor and memory to perform the methods and operations described herein. The electronic processor may be implemented as a microprocessor with a separate memory or as a microcontroller with memory on the same chip. The electronic processor may be implemented using multiple processors and may be implemented partially or wholly as, for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). The memory of the controller 116 includes non-transitory computer-readable memory that stores instructions received and executed by the electronic processor of the controller 116 to perform the functions of the projection system 100 described herein. The memory may include, for example, a combination of different types of memory, such as read-only memory and random access memory.

[0034] Light recycling module 103 in Figure 1 The light recovery point is depicted as a dashed box and can be placed in the optical path from the light source 102 to the first modulator 106. It should be understood that the light recovery point can be inserted into the projector system at various points within the projector system. For example, the light recovery point can be placed between the first modulator and the second modulator. Alternatively, the light recovery point can be placed at more than one point in the optical path of the display system.

[0035] although Figure 1The embodiments depict a single optical channel; however, it should be understood that the first and second modulators can be replicated for each of a series of color channels within the projector, such that each color channel includes two optically offset reflective modulators. The series of color channels may include a red channel, a green channel, and a blue channel. The light source may include, for example, multiple colored laser light sources. In one embodiment, the light source may be globally modulated (luminance modulation) and / or spatially dimmed (local dimming) based on a signal (not shown) from a controller (e.g., 116).

[0036] The intermediate signal to the second modulator can, for example, be based on an optical field simulation that includes the point spread function of the light reflected by the first modulator and an offset. For instance, the intermediate signal to the second modulator can be based on the point spread function of the light reflected by the first modulator in each channel and an offset in each channel. The offsets in the channels can be the same, or the offsets of at least two channels can be different, and the intermediate signal to the second modulator in each channel is based on at least one of the offset and the offset differences between the channels.

[0037] Although Figure 1 The embodiments described herein are presented in the context of dual-modulation, multi-modulation projection systems; however, it should be understood that the techniques and methods of this application will be applicable to other dual-modulation, multi-modulation display systems. For example, a dual-modulation display system including a backlight, a first modulator (e.g., an LCD, etc.) and a second modulator (e.g., an LCD, etc.) can employ suitable optical components and image processing methods and techniques to influence the performance and efficiency discussed herein in the context of projection systems.

[0038] The first modulator 106 and the second modulator 110 can be configured as a digital micromirror device (DMD) consisting of multiple mirrors for adjusting the angle of incidence of light. To illustrate the effect of the angle of incidence and the DMD mirrors, Figures 2A to 2B An exemplary DMD 200 according to various aspects of this disclosure is shown. In particular, Figure 2A The diagram illustrates a plan view of the DMD 200, and Figure 2B The diagram illustrates the following: along Figure 2AThe figure shows a partial cross-sectional view of the DMD 200 taken by line IB. The DMD 200 includes a plurality of square micromirrors 202 arranged in a two-dimensional rectangular array on a substrate 204. Each micromirror 202 may correspond to a pixel of the final projected image and may be configured to tilt about a rotation axis 208 (shown for a specific subset of the micromirrors 202) due to electrostatic or other types of actuation. Each micromirror 202 has a width 212 and is arranged with a gap of width 210 between the micromirrors. The micromirrors 202 may be coated with or formed of any highly reflective material such as aluminum or silver, thereby specularly reflecting light. The gaps between the micromirrors 202 may be absorptive, such that input light entering the gaps is absorbed by the substrate 204.

[0039] Although Figure 2A Only some representative micromirrors 202 are explicitly shown, but in reality, the DMD 200 may include a greater number of individual micromirrors equal to the resolution of the projection system 100. In some examples, the resolution may be 2K (2048 × 1080), 4K (4096 × 2160), 1080p (1920 × 1080), consumer-grade 4K (3840 × 2160), etc. Furthermore, in some examples, the micromirrors 202 may be rectangular and arranged in a rectangular array; they may be hexagonal and arranged in a hexagonal array, etc. Moreover, although... Figure 2A The figure shows a rotation axis 208 extending in an inclined direction, but in some embodiments, the rotation axis 208 may extend vertically or horizontally.

[0040] like Figure 2B As can be seen, each micromirror 202 is rotatably connected to the substrate 204 via a yoke 214. The substrate 204 includes a plurality of electrodes 216. Although in Figure 2B In the cross-sectional view, only two electrodes 216 are visible for each micromirror 202, but each micromirror 202 can actually include additional electrodes. Although not shown in... Figure 2B The diagram is shown in detail, but the DMD 200 may further include spacer layers, support layers, hinge components for controlling the height or orientation of the micromirror 202, etc. The substrate 204 may include electronic circuitry associated with the DMD 200, such as complementary metal-oxide-semiconductor (CMOS) transistors, memory elements, etc.

[0041] Depending on the specific operation and control of electrode 216, each micromirror 202 can switch between an "on" position, an "off" position, and an unactuated or neutral position. If micromirror 202 is in the on position, it is actuated by an angle of, for example, -12° (i.e., 12° counterclockwise relative to the neutral position) to mirror-reflect input light 206 into on-state light 218. If micromirror 202 is in the off position, it is actuated by an angle of, for example, +12° (i.e., 12° clockwise relative to the neutral position) to mirror-reflect input light 406 into off-state light 220. The off-state light 220 can be directed toward a light collector that absorbs the off-state light 220. In some instances, micromirror 202 may be unactuated and parallel to substrate 204. Figures 2A to 2B The specific angles illustrated and described herein are exemplary and not limiting. In some embodiments, the open and closed position angles may be between ±11 degrees and ±13 degrees (inclusive). In other embodiments, the open and closed position angles may be between ±10 degrees and ±18 degrees (inclusive).

[0042] While the examples described herein primarily relate to DMDs, the first modulator 106 and / or the second modulator 110 can be different suitable modulation devices, such as MEMS arrays or other devices that include multiple analog or digital mirrors.

[0043] Bit sorting Typically, a typical DMD uses a single sequence per frame to obtain specific bit-per-pixel (e.g., 16 bits / pixel) modulation. As used herein, a “bit sequence” refers to how the micromirror 202 is turned on and off. A frame period is divided into multiple bit times or bit planes, allowing pixels to be turned on or off within each bit time. In many embodiments, the bit sequence can be modified such that higher-order bits are spread across the frame period, allowing them to be repeated multiple times. For example, in one embodiment, the most significant bit (e.g., the highest 12 bits out of 16) can be repeated within each subframe. This would allow a pattern with the highest 12 bits to be repeated, for example, 16 times (in a 1 / 16 subframe subdivision embodiment). Lower-significant bits would remain unaffected (e.g., spread across the entire frame period).

[0044] In one embodiment, a beam steering device (e.g., a mirror or other element)—such as the first modulator 106—can be switched rapidly and / or at a desired rate (e.g., 10 microseconds to 100 microseconds). This may be desirable so that the first modulator 106 can switch during a “dark” time between sequence repetitions. During this dark time, the display system may not output any light to be rendered and / or projected. This can help avoid obvious and / or undesirable visual effects. The bit-time of pixel on-time partially determines the resulting rank. The bit time is short enough that the bit-time is not noticeably visible, and the rank seen is the average on-time within the frame period. The frame rate of bit-ordering can differ from the video frame rate. For example, the bit-ordered frame rate of a 24 fps video can be four times the video frame rate, i.e., 96 fps. Additionally, the number of ranks that can be generated by bit-ordering is limited by the division of the frame period into bit times. The shortest duration of bit time determines the accuracy of the rank.

[0045] Figure 3 A high-level switching scheme 300 matching the bit sequence repetition pattern is depicted. Pattern 302 depicts the time periods during which the bit sequence repeats (e.g., 302a and 302b). Between these time periods is the dark time period 303 between sequence repetitions. As can be seen in pattern 304, the first modulator is capable of switching multiple times throughout the entire period and dark time (e.g., 304a, 304b, ..., 304n).

[0046] Dual-modulated DMDs, such as the first modulator 106 and the second modulator 110, can use synchronized bit ordering to generate display levels. In some instances, the bit ordering uses the same bit sequence for both the first modulator 106 and the second modulator 110, such that they are both turned on or off simultaneously. In other instances, different bit sequences are used, such that at any given time both the first modulator 106 and the second modulator 110 are on, both the first modulator 106 and the second modulator 110 are off, or only one of the first modulator 106 and the second modulator 110 is on.

[0047] When the bit ordering uses the same bit sequence for both the first modulator 106 and the second modulator 110 so that they are both turned on or off simultaneously, the frame time portion during which both modulators 106 and 110 are on determines the created display level. When both modulators 106 and 110 are off, the contribution to the display level is not zero, but rather a very small display level, which may only be significant if both modulators 106 and 110 are off for the entire frame time. For example, suppose... Y To display the level, and set both_on_ timeThe frame time portion is enabled for both the first modulator 106 and the second modulator 110. Let... Y _ on This refers to the display level when both the first modulator 106 and the second modulator 110 are enabled. Let... Y_off The display level is set to the condition when a single modulator is off, such that in the case of dual modulation, both the first modulator 106 and the second modulator 110 are off and a display level is created. Y_off 2 Display level 。 It should be understood that, in order to simplify these examples, Y_off The selection is the same for both modulators, and if Y_off If the two modulators are different, then Equations 1 and 2 will be modified accordingly. Therefore, the display level created for a specific positioning sequence is provided by Equation 1: Y = both _ on _ time Y _ on + (1 - both _ on _ time ) Y _ off 2 [Equation 1] Second item (1-both_on_time) Y _ off 2 It may not be significant compared to the first term, unless a black level is established when the first term is zero.

[0048] Figures 4A to 4C The illustration shows an example bit sequence that divides a frame into ten equal-sized sub-spaces. In other embodiments, the bit sequence may have significantly more sub-spaces or sub-spaces of different sizes. Figure 4A The bit sequence of the first modulator 106 within this frame is provided. Figure 4B The bit sequence of the second modulator 110 within this frame is provided. Figure 4C A dual-modulation transmittance rating is provided within this frame. As described herein, the transmittance rating can be interpreted as a normalized display rating.

[0049] exist Figures 4A to 4C In the example, the same bit sequence is used for both the first modulator 106 and the second modulator 110. Y_on The value is 1 (total transmittance), and Y_offThe value is 1 / 3000 (minimum transmittance). These values ​​are just examples. In particular, Y_off The value can vary based on the modulator's contrast ratio (e.g., 1 / contrast ratio). For the example described herein, the first modulator 106 and the second modulator 110 have a contrast ratio of 3000:1. The bit sequence causes the first modulator 106 and the second modulator 110 to be turned on at sub-intervals 3 and 8. Accordingly, both_on_time The value is 2 / 10. Solving equation 1, we obtain the display level as:

[0050] Second item (1-both_on_time) Y_off 2 This is a value that is visually insignificant compared to the first item and can be ignored. The pseudo-localization sequence is divided into ten equal-sized sub-intervals, with the display levels increasing by one-tenth (0 / 10, 1 / 10, 2 / 10, ..., 10 / 10), and only one number of levels is provided as many as the number of sub-intervals plus one. These display levels can be referred to as "coarse levels".

[0051] Due to the limitations of switching the micromirror 202 on and off... both_on_time It can be a value from a finite set of discrete values, including zero and a minimum value. The precision of the minimum value and other small values ​​may not be sufficient to produce all the levels required by the display. Other complementary schemes, such as dithering, can be used to produce other desired values.

[0052] Additionally, the bit order can be modified to create additional levels. Instead of limiting a set of bit sequences to those that turn one modulator on while turning another off, this could include bit sequences that simultaneously turn both the first modulator 106 and the second modulator 110 on or off. For example, suppose... one_on_time This is a portion of the frame time when only one modulator is on. The display level of the specific positioning sequence is then provided by Equation 2. Y : Y = both_on_time Y_on + one_on_time Y_off + (1 - both_on_time - one_ on_time) Y_off 2 [Equation 2] When both start times are low, the second item one_on_time Y_off and both_on_time Y_onThe comparison is not insignificant and can be manipulated. one_on _ time This allows for the creation of more bit sequences, resulting in more display levels. both_on_time Y_on and one_on_time Y_off This relationship can be viewed as a coarse level with fine adjustments, where fine adjustments are used to produce a more precise display level than if only the coarse level were used. These fine adjustments can hereafter be referred to as the "fine level".

[0053] Figures 5A to 5C The illustration shows another example bit sequence that divides a frame into ten equal-sized sub-spaces. In other embodiments, the bit sequence may have significantly more sub-spaces or sub-spaces of different sizes. Figure 5A The bit sequence of the first modulator 106 within this frame is provided. Figure 5B The bit sequence of the second modulator 110 within this frame is provided. Figure 5C The transmittance level within this frame is provided.

[0054] exist Figures 5A to 5C In the example, a different bit sequence is used for the first modulator 106 than for the second modulator 110. Y_on The value is 1, and Y_off The value is 1 / 3000. The first bit sequence turns on the first modulator 106 from 2.5 to 3.5 and from 7.5 to 8.5 (or turns it on at sub-intervals 3 and 8). The second bit sequence turns on the second modulator 110 at sub-intervals 3, 5, 6, and 8. Therefore, both_on_time It is 2 / 10, and one_on_time The value is 2 / 10. Solving equation 2, we obtain the display level as:

[0055] In this example, the second item one_on_time Y_off and the third item (1-both_on_time-one_one_ time) Y_off 2 Both and the first item both_on_time Y_on It is not visually significant.

[0056] When the desired display level is less than both_on_time These fine-tuning adjustments offer additional benefits when setting the display level produced at its minimum non-zero discrete level. To utilize these fine-tuning adjustments to produce these minimum display levels, [the following is a separate, unrelated instruction:] both_on_timeSet to zero, and manipulate one_on_time To create a smaller display level. Fine-tuning can also produce other desired levels, such as in... both_on_time The levels are between the first and second non-zero levels, or between other larger but lower coarse levels. As the coarse levels increase, their precision approaches the precision required by the display, and the practicality of fine-tuning decreases.

[0057] Figures 6A to 6C The illustration shows another example bit sequence that divides a frame into ten equal-sized sub-spaces. In other embodiments, the bit sequence may have significantly more sub-spaces or sub-spaces of different sizes. Figure 6A The bit sequence of the first modulator 106 within this frame is provided. Figure 6B The bit sequence of the second modulator 110 within this frame is provided. Figure 6C The transmittance level within this frame is provided.

[0058] exist Figures 6A to 6C In the example, a different bit sequence is used for the first modulator 106 than for the second modulator 110. Y_on The value is 1, and Y_off The value is 1 / 3000. The first bit sequence keeps the first modulator 106 off, and therefore... both_on_time It is set to zero. The second bit sequence turns on the second modulator 110 at sub-intervals 5 and 6. Therefore, one_on_time The value is 2 / 10. Solving equation 2, we obtain the display level as:

[0059] In this example, because both on time Y on The value is zero, therefore the second term one on time Y off Visually significant, this creates a useful dark level. With the first modulator 106 off throughout the frame, the second modulator 110 can be manipulated to create eleven useful discrete dark display levels.

[0060] Eleven dark levels are created by manipulating the second modulator 110 while the first modulator 106 remains off. These fine adjustment levels are visually significant, but much smaller than the first non-zero coarse level when both the first modulator 106 and the second modulator 110 are on, even if these modulators are only on within a single sub-interval. These eleven fine adjustment levels alone cannot completely fill the gap between the zero coarse level and the first non-zero level. To make the fine adjustments fill the gap between the coarse levels, the coarse levels can be arranged more closely together.

[0061] As an example, consider a bit sequence for a display, which is one of many bit ordering methods. Make this bit sequence similar to the one previously shown in... Figures 4A to 4C , Figures 5A to 5C as well as Figures 6A to 6C The bit sequence shown is shown, but the time frame is divided into 2. 12 The number of sub-intervals is such that the resulting coarseness level corresponds to a 12-digit value. Therefore, the value of the smallest coarseness level is 1 / (2^3). 12 Another example is that the same 2 can be produced by using a coarse bit sorting method supplemented by other methods such as dithering. 12 Dithering provides a level of precision, either individually or in a similar manner. Dithering is intentionally introduced noise used to randomize quantization errors and can also be used to create more display levels. While the embodiments described herein primarily relate to the use of a DMD, the use of dithering is not limited to displays using a DMD, as dithering operates on frames generated by any display technology. Dithering utilizes discrete levels created through other means, such as bit ordering described above for DMDs. Dithering alternates these discrete levels such that their average over time is an intermediate level, thus providing additional precision to the discrete levels created by bit ordering.

[0062] Figure 7 The display level that should be displayed is shown. Y The perceptual quantizer (PQ) signal input (in nits), and the coarse discrete level displayed using a 12-bit bit sorting method with a Y value of 108 nits corresponding to a maximum 12-bit number. Figure 7 The example shows the lowest 200 PQ values. The number of discrete PQ levels is much larger than that of a coarse 12-bit linear level (in...). Figure 7 The quantity (represented by "X" in the text). Assume the same as the previous example. Y off The number of levels is sufficient to produce the maximum fine adjustment to fill the gaps between all coarse levels, and the number of fine levels is sufficient to produce all PQ levels. By controlling only one modulator during the off-time of one modulator, nearly 2 levels are added to each coarse level. 12 A fineness level is achieved if the second modulator 110 (e.g., the master modulator) is turned on for the entire duration that the first modulator 106 (e.g., the premodulator) remains off, thus achieving the maximum fineness level (by...). Figure 7 (The "O" indicates this). If the largest fine grade added to a coarse grade is greater than the next larger coarse grade, the gaps between coarse grades can be filled to produce all PQ grades.

[0063] For a dual-modulation DMD display, such as the dual-modulation DMD display provided by projection system 100, light from the first modulator 106 is projected onto the second modulator 110, but not with pixel-to-pixel precision. Instead, light from the pixels of the first modulator 106 (e.g., premodulator pixels) is projected onto a neighboring set of pixels (e.g., master pixels) of the second modulator 110. Existing methods can reduce errors under these conditions when pixel grading is generated with both the first modulator 106 and the second modulator 110 simultaneously on or off. However, when pixel grading is generated with the first modulator 106 off and the second modulator 110 on, neighboring pixels with the first modulator 106 on may project light onto master pixels that depend on the first modulator 106 being off, thus ruining the desired grading. This occurs whenever pixel grading is generated with the first modulator 106 off, especially when creating dark levels that must be generated only when the first modulator 106 is off.

[0064] To avoid this disruption, the frame time can be divided into two intervals: one interval for a coarse level created when both the first modulator 106 and the second modulator 110 are simultaneously on or off, and another interval for a fine level generated only when either the first modulator 106 or the second modulator 110 is on. These two intervals can be further divided into sub-intervals for two bit sequences, one for the coarse level and the other for the fine level. During the fine level frame interval, all premodulator pixels are off, thus preventing any premodulator pixel from projecting light onto the master pixel, which depends on the premodulator pixel being off. This fine level frame interval is hereby referred to as the premodulator off time.

[0065] Dedicating a portion of the frame interval to the premodulator-off time can produce fine gradation while preventing certain spatial artifacts. However, during the premodulator-off time, the display's peak brightness decreases by a fraction of the frame time that is devoted to the premodulator-off time. Therefore, the duration of the premodulator-off time can be limited to achieve the necessary gradation accuracy while maintaining sufficient peak brightness gradation.

[0066] Image artifacts and calibration As described, the first modulator 106 and the second modulator 110 include components (e.g., micromirrors 202) manipulated by a controller 116 to transmit signal code values ​​to create correct image levels. However, inaccurate display levels can produce visible image artifacts. For example, consider a gradient image displayed by a projection system 100. A gradient image contains levels that gradually increase from one end of the displayed image to the other. Figure 8The illustration shows an example range of display levels in a gradient image for a given PQ code value. When the display levels are accurately represented, the gradient image presents a smooth change in brightness, as shown by the function with solid circles. However, discontinuities may exist within the projection system 100, resulting in artifacts and discontinuities within the gradient image, where the change in display levels is no longer smooth, as shown by the function with hollow circles. In particular, the lower portion of the range may be incorrectly generated, resulting in discontinuities at the junction of the lower range (created when the first modulator 106 is always off) and the higher range (created when the first modulator 106 can be turned on within a specific subframe interval).

[0067] For example, a first set of display levels can be generated by modulating light while keeping the first modulator 106 off and operating only the second modulator 110. A second set of display levels can then be generated by modulating light by operating both the first modulator 106 and the second modulator 110. When the first modulator 106 is off to generate the first set of display levels, these levels are far more difficult to predict than when the first modulator 106 is on and modulating light. The first modulator-off levels (hereinafter referred to as premodulator-low level levels or premodulator-low image) may vary with image frames and different displays. Therefore, the display levels at the junction of the low range (e.g., first modulator 106 off) and the high range (e.g., first modulator 106 on) of display levels (hereinafter referred to as matching display levels) may be inconsistent and difficult to match, such as... Figure 8 The transition 802 is shown in the diagram. To account for these variations, the first modulator 106 and the second modulator 110 can be calibrated so that the lower and higher level ranges can connect at the matching display level without discontinuity. Calibration can identify a parameter that alters the operation of the second modulator 110 to ensure that the matching level is the same when the first modulator 106 is off and when the first modulator 106 is on.

[0068] To calibrate the projection system 100, the controller 116 creates nearly identical images using unadjusted parameters in two scenarios: (i) when the first modulator 106 is off and (ii) when the first modulator 106 is on. The images can be, for example, uniform grayscale images at matching levels. A camera is used to capture both images, and the images are compared to correlate them and adjust the parameters. The first image has a level at the top of the lower level range created when the first modulator 106 is off. As an example, this can be achieved by turning off the first modulator 106 for the entire frame or for the entire duration of capturing the first image. The second image has the same display level at the bottom of the higher level range created when the first modulator 106 is on. In some embodiments, the first image can be captured while the projection system 100 displays the first calibration image (e.g., an image with a level near the top of the lower level range created when the first modulator 106 is off), and the second image can be captured while the projection system 100 displays the second calibration image (e.g., an image with a level near the bottom of the higher level range created when the first modulator 106 is on). As an example, a first calibration image can be displayed by controlling the first modulator 106 with a bit sequence in which the first modulator 106 is turned off in each sub-interval of the first series of frames, and by controlling the second modulator 110 with a bit sequence in which the second modulator 110 is turned on in a first portion of the sub-intervals of the first series of frames. In some examples, the first portion can be determined such that the display level of the first calibration image is at or just above the bottom of the higher level range created when the first modulator 106 is turned on (because the levels when the first modulator 106 is turned on and off should preferably match or overlap, rather than have gaps). As a non-limiting example, the first portion in which the second modulator 110 is turned on can be 100% of the sub-intervals of the first series of frames. Further, a second calibration image can be displayed by controlling the first modulator 106 with a bit sequence in which the first modulator 106 is turned on in a second portion of the sub-intervals of the second series of frames, and by controlling the second modulator 110 with a bit sequence in which the second modulator 110 is turned on in a third portion of the sub-intervals of the second series of frames. As a non-limiting example, the second portion of the first modulator 106 being activated could be 1% of the sub-intervals on a second series of frames. In this case, the second modulator 110 could be modulated with an image based on estimates from the pre-modulator underlying layer, thereby attempting to create a second calibration image that is nearly identical to the first calibration image.In some examples, the degree of overlap and non-overlap between the second and third portions can be determined such that the display level of the second calibrated image is at or just below the top of the lower level range created when the first modulator 106 is off (because the levels when the first modulator 106 is on and off should preferably match or overlap, rather than have gaps). In this example, overlap refers to sub-intervals where both modulators are on (e.g., ...). Figures 5A to 5C Sub-spacing 3), and non-overlapping refers to sub-spacing where only one modulator is on (e.g., sub-spacing 3). Figures 5A to 5C In the sub-intervals 5 and 6 and in Figures 6A to 6C (In sub-intervals 5 and 6). It should be noted that for this calibration image, the partial grades produced when only one modulator is on are not visually significant compared to those produced when both modulators are on. Additionally, it should be noted that the degree of overlap and non-overlap between the first portion of the first calibration image, and the second and third portions of the second calibration image, and between the second and third portions, can be spatially varied across the first and second modulators to reduce or eliminate spatial variations in matching between the first and second calibration images (see, for example...). Figures 9A to 9B The two images are compared to create parameters for altering the operation of the second modulator 110 and / or the first modulator 106 (or, if parameters have already been created, to improve them). In some examples, the first portion of the first calibration image, and / or the second and third portions of the second calibration image, as well as the degree of overlap and non-overlap between the second and third portions, can be iteratively adjusted until the first and second calibration images achieve the desired degree of matching. It should be understood that the two images shown may not be the example images described, and if so, their values ​​will be taken into account when creating or improving the parameters.

[0069] In some instances, the two images are converted into linear luminance (Y) values, and the initial estimate of the premodulator's underlying image is scaled using the ratio of these two images, resulting in a new estimate of the premodulator's underlying image. This estimation of the parameters can be used to connect lower-level ranges with higher-level ranges without discontinuities. Since the same camera and display are used for both images, any distortion caused by the camera itself or by the display, except for inaccurate estimations of the parameters, is ignored.

[0070] As an example, Figure 9A The diagram illustrates the red light field. Figure 9B The diagram illustrates the green light field, and Figure 9C The illustration shows the blue light fields that form an estimate of the underlying image of the premodulator. Figures 9A to 9CThe light field representation can be created by keeping the first modulator 106 off and controlling only the second modulator 110, resulting in the brightest display level. Figures 9A to 9C In the example, estimation is used to control the second modulator to display a value of 1 × 10 across the entire image frame. -4 A uniform grayscale image. The first image is the image to be displayed. When a second image is captured while the first modulator 106 is controlled to be on for at least one subframe interval to attempt to create the same display image, the image may be different. An input parameter is created or improved by determining the difference between the image in the first image and the image in the second image. In some instances, this difference is the ratio of the first image to the second image. In the example above, the parameter is equal to Figures 9A to 9C The light field is improved by scaling according to the image ratio.

[0071] This parameter is used to adjust the control signal sent to the second modulator 110 when the display creates any level within the lower level range generated when the first modulator 106 is off. This parameter can also be used when the pre-modulator underlying image is visually significant relative to the level generated by the first modulator when the first modulator 106 is slightly on, as the first modulator 106 is nearly off.

[0072] In some instances, calibration is performed multiple times (e.g., iteratively) to adjust parameters. For example, calibration is performed again after parameters are applied to the control signal of the second modulator 110. Any further differences between the two images are identified and used to update the parameters. This process is repeated until there are no differences between the two images.

[0073] The calibration process can be repeated with the roles of the first modulator 106 and the second modulator 110 interchanged. The result can be different parameters, i.e., the underlying image of the second modulator, and this result can be obtained by, for example... Figures 9A to 9C The value in [the table] represents the value. The underlying image of the second modulator is useful when the second modulator 110 is off or nearly off. As an example, suppose the underlying image of the second modulator is as follows: Figures 9A to 9C The premodulator bottom layer image shown is the same, and we consider the original black image produced when both modulators 106 and 110 are off. The original black image will be the product of the premodulator bottom layer image and the second modulator bottom layer image. Since the premodulator bottom layer image and the second modulator bottom layer image are the same in this example, the value of the original black image will be... Figures 9A to 9C The value shown is the square of the value. If the original black image is used to display black, its brightness will be undesirably uneven and its chromaticity will also be inconsistent. For this example, the display black level can be defined as (3x10). -4 ) 2This value will be greater than the original black image at any point on the image frame, and is the lowest level that the display can allow under controlled conditions. Using the first and second parameters, and with the first modulator 106 off, the second modulator 110 can be slightly turned on to produce a black image.

[0074] The calibration process can also be used to improve parameters that are not part of the modulator's underlying image. An image can be generated using an estimate of this parameter, and another reference image can be generated without using that parameter. These two images can be identical or have some known differences. These two images can be captured and compared to improve the parameters. The parameter can be isolated as the cause of the differences between the two images. For example, this parameter could be the PSF model used to generate light field estimates. The first image will use the PSF model, while the second image will not. The image differences will be due to errors in the PSF estimates.

[0075] Figure 10 The diagram illustrates the process of... Figure 1 A block diagram of an example method 1000 executed by the projection system 100. Method 1000 may be executed, for example, by a controller 116. Figure 10 The steps provided are merely examples and can be performed in different orders or simultaneously.

[0076] At step 1002, the controller 116 sends (e.g., transmits) a first control signal to the first modulator 106 during a first time period. The first control signal can control the first modulator 106 such that the plurality of micromirrors 202 of the first modulator 106 are controlled to be in the off position during the first time period.

[0077] At step 1004, the controller 116 sends a second control signal to the second modulator 110 during the first time period. The second control signal can control the second modulator 110 such that the plurality of micromirrors 202 of the second modulator 110 are controlled to modulate light (e.g., controlled to be in an on position) during the first time period.

[0078] At step 1006, controller 116 captures a first image of the light modulated by second modulator 110 during a first time period. For example, controller 116 controls a camera to capture an image projected onto screen 114 by projection lens 112 during the first time period. In some embodiments, controller 116 receives an image of the light modulated by second modulator 110 as input from a separate external device communicatively connected to controller 116.

[0079] At step 1008, the controller 116 sends a third control signal to the first modulator 106 during the second time period. The third control signal can control the first modulator 106 such that the plurality of micromirrors 202 of the first modulator 106 are controlled to modulate light during the second time period.

[0080] At step 1010, the controller 116 sends a fourth control signal to the second modulator 110 during the second time period. The fourth control signal can control the second modulator 110 such that the plurality of micromirrors 202 of the second modulator 110 are controlled to modulate light during the second time period.

[0081] At step 1012, controller 116 captures a second image of the light modulated by both the first modulator 106 and the second modulator 110 during a second time period. For example, controller 116 controls a camera to capture an image projected onto screen 114 by projection lens 112 during the second time period. In some embodiments, controller 116 receives an image of the light modulated by the second modulator 110 as input from a separate external device communicatively connected to controller 116.

[0082] At step 1014, controller 116 determines the difference between the first image and the second image. For example, the first and second images are compared to generate parameters for changing the operation of the second modulator 110, as previously described. In some instances, the difference between the first and second images is then used to adjust the operation of the projection system 100, such as adjusting the second and / or fourth control signals used to control the second modulator 110, applying corrections to the PSF model (e.g., regarding...). Figures 9A to 9C (As described), adjusting the stored parameter values ​​used by the projection system 100, etc.

[0083] The systems, methods, and apparatus according to this disclosure may employ any one or more of the following configurations.

[0084] (1) A method for calibrating a multimodulation display system, the multimodulation display system comprising: a light source; a first modulator irradiated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator irradiated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator, wherein the method comprises: sending a first control signal to the first modulator such that the first plurality of mirrors are controlled to be in an off position during the first time period; sending a second control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during the first time period; capturing a first image of light modulated by the second modulator during the first time period; sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to modulate light during the second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to modulate light during the second time period; capturing a second image of light modulated by the first modulator and the second modulator during the second time period; and determining a difference between the first image and the second image.

[0085] (2) The method according to (1), wherein the first time period includes a first plurality of sub-intervals forming a first series of frames, wherein during the first time period, the first plurality of mirrors are controlled to be in the closed position in each sub-interval of the first series of frames, and wherein during the first time period, the second plurality of mirrors are controlled to modulate light in a first portion of the sub-intervals of the first series of frames.

[0086] (3) The method according to (2), wherein the second time period includes a second plurality of sub-intervals forming a second series of frames, wherein during the second time period, the first plurality of mirrors are controlled to modulate light in a second portion of the sub-intervals of the second series of frames, and wherein during the second time period, the second plurality of mirrors are controlled to modulate light in a third portion of the sub-intervals of the second series of frames.

[0087] (4) The method according to (3), wherein the second portion of the sub-space and the third portion of the sub-space overlap, such that both the first plurality of mirrors and the second plurality of mirrors are controlled to modulate light within at least one sub-space of the second series of frames.

[0088] (5) The method according to any one of (1) to (4) further includes converting the first image and the second image into linear brightness values.

[0089] (6) The method according to any one of (1) to (5), wherein the first image and the second image are captured using the same camera.

[0090] (7) The method according to any one of (1) to (6), wherein the first image and the second image are correlated by known differences.

[0091] (8) The method according to any one of (1) to (7), wherein the second control signal causes the second modulator to perform a jitter operation.

[0092] (9) The method according to any one of (1) to (8), wherein the first modulator is selected from the group consisting of DMD, SLM and PLM.

[0093] (10) The method according to any one of (1) to (9) further includes adjusting the second control signal based on the difference.

[0094] (11) The method according to (10), wherein adjusting the second control signal includes applying a correction to the PSF model.

[0095] (12) The method according to any one of (1) to (11) further includes adjusting at least one stored parameter value used by the multimodulation display system during image projection based on the determined difference between the first image and the second image.

[0096] (13) A method for calibrating a multimodulation display system, the multimodulation display system comprising: a light source; a first modulator irradiated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator irradiated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator, wherein the method comprises: sending a first control signal to the first modulator such that the first plurality of mirrors are controlled to be in a closed position during all sub-intervals of a first time period; sending a second control signal to the second modulator such that the second plurality of mirrors are controlled to be in an open position during a first portion of the sub-intervals of the first time period; capturing a first image of light modulated by the second modulator during the first time period; sending a third control signal to the first modulator such that the first plurality of mirrors are controlled to be in an open position during a second portion of all sub-intervals of a second time period; sending a fourth control signal to the second modulator such that the second plurality of mirrors are controlled to be in an open position during a third portion of all the sub-intervals of the second time period; capturing a second image of light modulated by the first modulator and the second modulator during the second time period; and determining a difference between the first image and the second image.

[0097] (14) The method according to (13), wherein the second portion of the sub-interval and the third portion of the sub-interval overlap, such that both the first plurality of mirrors and the second plurality of mirrors are controlled to modulate light within at least one sub-interval in the second time period.

[0098] (15) The method according to any one of (13) to (14) further includes converting the first image and the second image into linear brightness values.

[0099] (16) The method according to any one of (13) to (15), wherein the first image and the second image are captured using the same camera.

[0100] (17) The method according to any one of (13) to (16), wherein the first image and the second image are correlated by known differences.

[0101] (18) The method according to any one of (13) to (17), wherein the second control signal causes the second modulator to perform a jitter operation.

[0102] (19) The method according to any one of (13) to (18), wherein the first modulator is selected from the group consisting of DMD, SLM and PLM.

[0103] (20) The method according to any one of (13) to (19) further includes adjusting the second control signal based on the difference.

[0104] (21) The method according to any one of (13) to (20), wherein adjusting the second control signal includes applying a correction to the PSF model.

[0105] (22) The method according to any one of (13) to (21) further includes adjusting at least one stored parameter value used by the multimodulation display system during image projection based on the determined difference between the first image and the second image.

[0106] (23) An apparatus for calibrating a multimodulation display system, the multimodulation display system comprising: a light source; a first modulator irradiated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator irradiated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator, the apparatus comprising: an electronic processor configured to perform operations including the method according to any one of (1) to (22).

[0107] (24) A non-transitory computer-readable storage medium having an instruction program recorded thereon, the instruction program being executable by a device to perform the method according to any one of (1) to (22).

[0108] (25) A computer-readable medium comprising an instruction program that can be executed by a device to perform the method according to any one of (1) to (22).

[0109] (26) A computer program product comprising instructions that can be executed by a device to perform the method according to any one of (1) to (22).

[0110] 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 specific ordered sequence, these processes can be practiced using the described steps performed in a different order than that described herein. Furthermore, it should be understood that some steps may be performed simultaneously, other steps may be added, or certain steps described herein may 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.

[0111] Accordingly, it should be understood that the above description is intended to be illustrative rather than restrictive. Many embodiments and applications beyond the examples provided will become apparent upon reading the above description. The scope should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. It is anticipated and desired that the techniques discussed herein will evolve in the future, and the disclosed systems and methods will be incorporated into such future embodiments. In conclusion, it should be understood that modifications and changes are possible with this application.

[0112] All terms used in the claims are intended to be given the broadest reasonable interpretation and common meaning as understood by one skilled in the art described herein, unless expressly indicated otherwise herein. In particular, the use of singular articles such as “a,” “the,” and “the” should be understood to refer to one or more of the indicated elements, unless the claims expressly limit this to the contrary.

[0113] An abstract of this disclosure is provided to allow the reader to quickly determine the nature of this technical disclosure. This abstract is submitted on the premise that it will not be used to interpret or limit the scope or meaning of the claims. Furthermore, as can be seen in the foregoing detailed description, various features are combined together in various embodiments for the purpose of making this disclosure a coherent whole. The method of this disclosure should not be construed as reflecting an intention to incorporate more features than expressly recited in each claim in the claimed embodiments. Rather, as reflected in the appended claims, the inventive subject matter lies in fewer than all the features of a single disclosed embodiment. Therefore, the appended claims are thus incorporated into the detailed description, each claim being an independent subject matter claimed.

Claims

1. A method for calibrating a multi-modulation display system, the multi-modulation display system comprising: light source; A first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; And a second modulator irradiated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator, wherein the method includes: Send a first control signal to the first modulator so that the first plurality of reflectors are controlled to be in the off position during the first time period; Send a second control signal to the second modulator so that the second plurality of mirrors are controlled to modulate light during the first time period; Capture a first image of the light modulated by the second modulator during the first time period; A third control signal is sent to the first modulator, causing the first plurality of mirrors to be controlled to modulate light during the second time period; A fourth control signal is sent to the second modulator, causing the second plurality of mirrors to be controlled to modulate light during the second time period; A second image of light modulated by the first modulator and the second modulator during the second time period is captured; and Determine the differences between the first image and the second image.

2. The method as described in claim 1, wherein, The first time period includes a first plurality of sub-intervals forming a first series of frames, wherein, during the first time period, the first plurality of mirrors are controlled to be in the closed position within each sub-interval of the first series of frames, and wherein, during the first time period, the second plurality of mirrors are controlled to modulate light within a first portion of the sub-intervals of the first series of frames.

3. The method as described in claim 2, wherein, The second time period includes a second plurality of sub-intervals forming a second series of frames, wherein, during the second time period, the first plurality of mirrors are controlled to modulate light within a second portion of the sub-intervals of the second series of frames, and wherein, during the second time period, the second plurality of mirrors are controlled to modulate light within a third portion of the sub-intervals of the second series of frames.

4. The method of claim 3, wherein, The second portion of the sub-space and the third portion of the sub-space overlap, such that both the first plurality of reflectors and the second plurality of reflectors are controlled to modulate light within at least one sub-space of the second series of frames.

5. The method of any one of claims 1 to 4, further comprising converting the first image and the second image into linear brightness values.

6. The method according to any one of claims 1 to 5, wherein, The first image and the second image were captured using the same camera.

7. The method according to any one of claims 1 to 6, wherein, The first image and the second image are correlated by known differences.

8. The method according to any one of claims 1 to 7, wherein, The second control signal causes the second modulator to perform a jitter operation.

9. The method according to any one of claims 1 to 8, wherein, The first modulator is selected from one of the group consisting of DMD, SLM and PLM.

10. The method of any one of claims 1 to 9, further comprising adjusting the second control signal based on the difference.

11. The method of claim 10, wherein, Adjusting the second control signal includes applying corrections to the PSF model.

12. The method of any one of claims 1 to 11, further comprising adjusting at least one stored parameter value used by the multimodulation display system during image projection based on the determined difference between the first image and the second image.

13. A method for calibrating a multi-modulation display system, the multi-modulation display system comprising: light source; A first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; And a second modulator irradiated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator, wherein the method includes: Send a first control signal to the first modulator so that the first plurality of mirrors are controlled to be in the off position during all sub-intervals of the first time period; Send a second control signal to the second modulator so that the second plurality of mirrors are controlled to be in the open position during a first portion of the sub-interval in the first time period; Capture a first image of the light modulated by the second modulator during the first time period; A third control signal is sent to the first modulator, such that the first plurality of reflectors are controlled to be in the open position during the second portion of all sub-intervals in the second time period; A fourth control signal is sent to the second modulator, such that the second plurality of mirrors are controlled to be in the open position during the third portion of all the sub-intervals in the second time period; A second image of light modulated by the first modulator and the second modulator during the second time period is captured; and Determine the differences between the first image and the second image.

14. The method of claim 13, wherein, The second portion and the third portion of the sub-interval overlap, such that both the first plurality of reflectors and the second plurality of reflectors are controlled to modulate light within at least one sub-interval in the second time period.

15. The method of claim 13 or claim 14, further comprising converting the first image and the second image into linear brightness values.

16. The method according to any one of claims 13 to 15, wherein, The first image and the second image were captured using the same camera.

17. The method according to any one of claims 13 to 16, wherein, The first image and the second image are correlated by known differences.

18. The method according to any one of claims 13 to 17, wherein, The second control signal causes the second modulator to perform a jitter operation.

19. The method according to any one of claims 13 to 18, wherein, The first modulator is selected from one of the group consisting of DMD, SLM and PLM.

20. The method of any one of claims 13 to 19, further comprising adjusting the second control signal based on the difference.

21. The method of claim 20, wherein, Adjusting the second control signal includes applying corrections to the PSF model.

22. The method of any one of claims 13 to 21, further comprising adjusting at least one stored parameter value used by the multimodulation display system during image projection based on the determined difference between the first image and the second image.

23. An apparatus for calibrating a multi-modulation display system, the multi-modulation display system comprising: light source; A first modulator illuminated by the light source, the first modulator including a first plurality of mirrors for modulating light from the light source; and a second modulator irradiated by light from the first modulator, the second modulator including a second plurality of mirrors for modulating light from the first modulator, the device comprising: An electronic processor configured to perform operations including the method as described in any one of claims 1 to 22.

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