Circuit arrangement, control device and laser projector

Abstract

Circuit device, control device, and laser projector. The circuit device is used for a laser projector that projects an image to a projection surface using a plurality of colors of laser light that differ in wavelength. The circuit device includes a distortion correction circuit and an output circuit. The distortion correction circuit performs distortion correction for each color of display image data for each color of the plurality of colors. The output circuit outputs the display image data after the distortion correction. The distortion correction circuit performs the distortion correction for each color using a distortion parameter that differs for each color.

Description

Technical Field

[0001] This invention relates to circuit devices, control devices, and laser projectors, etc. Background Technology

[0002] Laser projectors are known to display images by projecting laser light onto a projection surface. Patent Document 1 discloses a laser projector with a laser data buffer. The laser data buffer includes: a frame buffer that stores image data for each color; a write area set according to each laser color for writing one horizontal line of image data; and a readout area that stores the written horizontal line of image data. The laser projector, based on position offset information stored in a position offset information table, transfers one horizontal line of image data corresponding to a vertical position offset from the frame buffer to the laser data buffer, and adjusts the timing to drive the laser at a time corresponding to the horizontal position offset. Thus, the laser projector corrects for the vertical and horizontal position offsets of the laser on the projection surface.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2011-39326

[0004] In laser projectors, the display position of the image shifts according to the color of the laser, resulting in color shift in the displayed image. In the aforementioned Patent Document 1, to solve this color shift problem, in addition to the image processing circuit, an adjustment unit for adjusting the laser drive timing is also required, thus complicating the control circuit. Summary of the Invention

[0005] One aspect of this disclosure relates to a circuit device used in a laser projector that projects an image onto a projection surface using lasers of multiple colors with different wavelengths. The circuit device includes: a distortion correction circuit that performs distortion correction on display image data for each of the multiple colors; and an output circuit that outputs the distortion-corrected display image data, the distortion correction circuit performing the distortion correction on each color using a distortion parameter that varies according to each color.

[0006] Furthermore, another aspect of this disclosure relates to a control device for controlling a laser projector that projects an image onto a projection surface using lasers of multiple colors with different wavelengths. The control device includes: a distortion correction circuit that performs distortion correction for each of the multiple colors of the display image data; and an output circuit that outputs the distortion-corrected display image data. The distortion correction circuit performs the distortion correction for each of the colors using distortion parameters that differ for each color.

[0007] Furthermore, another aspect of this disclosure relates to a laser projector comprising: the circuitry described above; a plurality of laser light sources emitting lasers of the plurality of colors; a laser light source control circuit that controls the plurality of laser light sources based on the distortion-corrected display image data from the output circuit; and an optical system that projects the lasers of the plurality of colors onto the projection surface.

[0008] Furthermore, another aspect of this disclosure relates to a laser projector comprising: the control device described above; a plurality of laser light sources emitting lasers of the plurality of colors; and an optical system that projects the lasers of the plurality of colors onto the projection surface, wherein the control device includes a laser light source control circuit that controls the plurality of laser light sources based on the distortion-corrected display image data from the output circuit. Attached Figure Description

[0009] Figure 1 This is an example of the structure of a laser projector.

[0010] Figure 2 This diagram illustrates the color shift problem in traditional laser projectors.

[0011] Figure 3 This is an example of color shift in the displayed image of a laser projector.

[0012] Figure 4 This is the first structural example of the control device in this embodiment.

[0013] Figure 5 This is a diagram illustrating the distortion correction and color shift correction in this embodiment.

[0014] Figure 6 This is the first detailed structural example of a circuit device.

[0015] Figure 7 This is the second detailed structural example of a circuit device.

[0016] Figure 8 This is the second structural example of the control device in this embodiment.

[0017] Figure 9 This is the third structural example of the control device in this embodiment.

[0018] Figure 10 This is the first detailed structural example of the circuit device and the storage circuit in the third structural example of the control device.

[0019] Figure 11 This is the second detailed structural example of the circuit device and the storage circuit in the third structural example of the control device.

[0020] Label Explanation

[0021] 10: Projection surface; 20: Eye; 30: Virtual image; 50: Light source device; 51: Red laser light source; 52: Green laser light source; 53: Blue laser light source; 61, 62: Dichroic mirror; 71: Lens; 72: Reflector; 73: Actuator; 100: Circuit device; 110: Input circuit; 120: Storage circuit; 121: First storage circuit; 122: Second storage circuit; 123: Third storage circuit; 125: Memory controller; 127: Memory; 130: Distortion correction circuit; 131: First distortion correction circuit; 132: Second distortion correction circuit Circuit; 133: 3rd distortion correction circuit; 140: Output circuit; 150: Laser source control circuit; 160: Parameter storage circuit; 170: Access circuit; 171: 1st buffer circuit; 172: 2nd buffer circuit; 173: 3rd buffer circuit; 200: Processing device; 210: Image data output circuit; 220: Color space conversion circuit; 300: Control device; 400: Laser projector; IA, IBb, IBg, IBr, ICb, ICg, ICr: Display image data; WPb, WPg, WPr: Warp parameter. Detailed Implementation

[0022] The preferred embodiments of this disclosure are described in detail below. Furthermore, the embodiments described below do not unduly limit the scope of the claims, and the structures described in these embodiments are not necessarily all essential components.

[0023] 1. Example of the structure of a laser projector

[0024] Figure 1 This is a structural example of a laser projector 400. The laser projector 400 includes a light source device 50 that generates laser light and a control device 300 that controls the light source device 50. Here, an example of a laser projector 400 as a head-up display will be described.

[0025] The light source device 50 includes a red laser light source 51, a green laser light source 52, a blue laser light source 53, dichroic mirrors 61 and 62, a lens 71, a reflector 72, and an actuator 73.

[0026] Red laser source 51 emits a single wavelength of red laser light belonging to the red region when the visible light wavelength region is divided into red, green, and blue regions. Green laser source 52 emits a single wavelength of green laser light belonging to the green region. Blue laser source 53 emits a single wavelength of blue laser light belonging to the blue region. A semiconductor laser may be used as the laser source, for example.

[0027] Dichroic mirror 61 allows red laser light to pass through and reflects green laser light, thereby combining the red and green laser light into a single beam. Dichroic mirror 62 allows the light emitted from dichroic mirror 61 to pass through and reflects blue laser light, thereby combining the light emitted from dichroic mirror 61 and blue laser light into a single beam.

[0028] Lens 71 converges the light emitted from dichroic mirror 62, so that the laser light projected onto projection surface 10 by reflector 72 is focused onto projection surface 10.

[0029] Reflector 72 reflects the laser light from lens 71 toward projection surface 10, thereby projecting the laser light onto projection surface 10. Actuator 73 changes the tilt of reflector 72, thereby changing the reflection angle of reflector 72 and the projection position of the laser light in projection surface 10. Specifically, actuator 73 changes the tilt of reflector 72 so that horizontal scan lines are scanned sequentially, as in so-called raster scanning. Actuator 73 is a device that converts electrical signals into mechanical action, such as a piezoelectric actuator or a motor.

[0030] The dichroic mirrors 61 and 62, lens 71, reflector 72 and actuator 73 constitute an optical system that projects red laser, green laser and blue laser onto projection surface 10.

[0031] The control device 300 drives the red laser source 51, the green laser source 52, and the blue laser source 53, and controls the emission timing and emission amount of these laser sources based on the displayed image data and timing control signals. Additionally, the control device 300 drives the actuator 73 to scan the laser on the projection surface 10 based on the timing control signals. The timing control signals may be, for example, horizontal synchronization signals and vertical synchronization signals.

[0032] The projection surface 10 is either a front screen or a wind screen of the movable body housing the laser projector 400, which serves as a head-up display. Alternatively, the projection surface 10 may be a dedicated screen for the head-up display, separate from the front screen or similar components. The laser projected by the laser projector 400 onto the projection surface 10 is reflected by the projection surface 10, and the reflected laser light enters the user's eye 20. As a result, a displayed image is presented as a virtual image 30 in the user's eye 20.

[0033] Furthermore, a laser projector can be any device that displays an image by projecting a laser beam onto a projection surface, such as a head-mounted display. In this case, the projection surface could be, for example, the final reflective surface of the light guide that directs the laser beam to the eye, or the retina of the eye.

[0034] In addition, the above explanation uses a laser projector that uses three RGB lasers as an example, but a laser projector can use more than two lasers.

[0035] Furthermore, the structure of an optical system that projects multiple colors of laser light onto a projection surface is not limited to... Figure 1 For example, the method of combining multiple colors of laser light into a single beam is not limited to dichroic mirrors; optical fibers can also be used. Alternatively, while the above examples illustrate laser projectors using laser scanning as their projection method, the projection method of laser projectors is not limited to this; optical systems corresponding to this projection method can also be used. For example, laser light can be projected onto the projection surface using a digital micromirror device or an LCOS panel. LCOS is an abbreviation for Liquid Crystal On Silicon. In these cases, laser light is irradiated onto the reflective surface of a digital micromirror device, etc., using a surface-emitting laser, etc. Furthermore, a projection method using a light guide array can also be employed. In a light guide array, the exit ends of multiple light guides are arranged in an array on the exit surface. Laser light is incident on these multiple light guides from their incident ends, and the laser light emitted from their exit ends is projected onto the projection surface, thereby forming an image.

[0036] 2. Example of the first structure of the control device

[0037] Figure 2 This diagram illustrates the color shift problem in traditional laser projectors. Color shift here refers to the color shift that occurs in the displayed image because the image's display position is offset according to each color of the laser.

[0038] In head-up displays and the like, distortion correction processing is performed on the input image to correct image distortion caused by distortion of the projection surface 10 or by the optical system. Conventionally, the same distortion correction processing is applied to each of the RGB input images. If the coordinate transformation based on this distortion correction is represented as f... -1 Then the pixel position of the corrected image is f. -1 (Xs, Ys).

[0039] When the corrected image is projected onto projection surface 10 via an optical system, the projection position gradually changes according to each wavelength of the laser due to laser interference and other factors. The coordinate transformation of the projected red image based on the red laser is represented as fr, the coordinate transformation of the projected green image based on the green laser as fg, and the coordinate transformation of the projected blue image based on the blue laser as fb. At this time, the pixel position in the red image is fr·f. -1 (Xs, Ys), the pixel position in the green image is fg·f -1 (Xs, Ys), the pixel position in the blue image is fb·f -1 (Xs, Ys).

[0040] For example, if distortion correction is performed based on a green image, then f = fg, therefore fg·f -1 (Xs, Ys) = (Xs, Ys). However, since fr ≠ fg ≠ fb, therefore fr·f -1 (Xs, Ys) ≠ (Xs, Ys), fb·f -1 (Xs, Ys) ≠ (Xs, Ys). This means that the pixel at position (Xs, Ys) in the input image is projected onto a position fr·f that differs according to color. -1 (Xs, Ys) ≠ fg·f -1 (Xs, Ys) ≠ fb·f -1 (Xs, Ys).

[0041] In addition, the same symbols (Xs, Ys) are used here to record the pixel positions of the input image and the projected image. However, the pixel position (Xs, Ys) of the projected image actually refers to the position on the projection surface 10 corresponding to the pixel position (Xs, Ys) of the input image.

[0042] Figure 3 This is an example of color shift in the displayed image of a laser projector 400. Figure 3 The image shows an example of a laser projector 400 displaying prescribed markings, with a portion of it enlarged.

[0043] like Figure 3 As shown, the display positions of the red image, green image, and blue image are slightly different from each other. Therefore, for example, the edges of the markers are displayed with a slight offset for each color, making the edges of the markers appear to have a color they wouldn't normally have. Figure 3 In some examples, there is a possibility that the edges of the markers may appear green or blue. Thus, the offset in the display position of each color becomes a color offset perceived by the user in the displayed image. However, the control device 300 in this embodiment performs color offset correction using image data processing with distortion correction. The color offset correction in this embodiment will be explained below.

[0044] Figure 4 This is a first structural example of the control device 300 in this embodiment. The control device 300 includes a processing device 200, a circuit device 100, and a laser light source control circuit 150. Furthermore, an example using an RGB laser will be described here, but the laser color is not limited to RGB, and the number of colors is not limited to three. Additionally, from now on, red, green, and blue can be referred to as the first color, the second color, and the third color.

[0045] The processing device 200 sends display image data to the circuit device 100. In the first structural example, the processing device 200 sends the color space converted display image data to the circuit device 100. The processing device 200 includes an image data output circuit 210 and a color space conversion circuit 220. The processing device 200 is, for example, a processor such as a CPU or a microcomputer. Alternatively, the processing device 200 may also be an FPGA or an ASIC. CPU is an abbreviation for Central Processing Unit. FPGA is an abbreviation for Field-Programmable Gate Array. ASIC is an abbreviation for Application-Specific Integrated Circuit.

[0046] Image data output circuit 210 outputs display image data IA to color space conversion circuit 220. For example, image data output circuit 210 depicts an image based on image data stored in a memory (not shown), signals input from sensors installed on a moving body, or data obtained from an external device via communication, and outputs the image data as display image data IA.

[0047] Color space conversion circuit 220 converts the color space of display image data IA and outputs the converted display image data IBr, IBg, and IBb. IBr is red image data, IBg is green image data, and IBb is blue image data. Specifically, display image data IA is an RGB color image, representing colors in a specified color space. Color space conversion circuit 220 converts the specified color space of display image data IA to a color space obtained through RGB laser light. For example, color space conversion circuit 220 calculates the pixel data (DBr, DBg, DBb) in the converted display image data by multiplying the pixel data (DAr, DAg, DAb) in display image data IA by a 3x3 conversion matrix representing the color space conversion.

[0048] The circuit device 100 performs distortion correction on the display image data IBr, IBg, and IBb after color space conversion for each color, thereby performing color shift correction together with the distortion correction, and outputs the corrected display image data ID to the laser light source control circuit 150. The circuit device 100 includes an input circuit 110, a storage circuit 120, a distortion correction circuit 130, an output circuit 140, and a parameter storage circuit 160. The circuit device 100 is also referred to as a display controller. Furthermore, in the case where the laser projector 400 is a head-up display, the circuit device 100 is also referred to as a HUD controller. The circuit device 100 is an integrated circuit device with multiple circuit elements integrated on a semiconductor substrate. Alternatively, the circuit device 100 may also be a processor such as a CPU or a microcomputer.

[0049] Input circuit 110 receives color space converted display image data IBr, IBg, and IBb from processing device 200. Input circuit 110 can be a receiving circuit for various communication interfaces, such as LVDS, DVI, display port, GMSL, or GVIF. LVDS is an abbreviation for Low Voltage Differential Signaling, DVI is an abbreviation for Digital Visual Interface, GMSL is an abbreviation for Gigabit Multimedia Serial Link, and GVIF is an abbreviation for Gigabit Video Interface.

[0050] The storage circuit 120 stores the color space converted display image data IBr, IBg, and IBb received by the input circuit 110. The storage circuit 120 is, for example, a row latch circuit, or a semiconductor memory such as SRAM or DRAM.

[0051] The parameter storage circuit 160 stores the distortion parameters WPr, WPg, and WPb corresponding to each color. WPr is the distortion parameter used for the red image, WPg is the distortion parameter used for the green image, and WPb is the distortion parameter used for the blue image. The parameter storage circuit 160 is, for example, a non-volatile memory such as EEPROM, and the distortion parameters WPr, WPg, and WPb are written to the non-volatile memory during the manufacturing of the laser projector 400. Alternatively, the parameter storage circuit 160 can also be a volatile memory such as SRAM or DRAM, and the distortion parameters WPr, WPg, and WPb can be written to the volatile memory by the processing device 200.

[0052] The distortion correction circuit 130 performs distortion correction on the display image data IBr, IBg, and IBb for each color, and outputs the corrected display image data ICr, ICg, and ICb. Specifically, the distortion correction circuit 130 uses the distortion parameter WPr for red images to distort the red image data IBr, the distortion parameter WPg for green images to distort the green image data IBg, and the distortion parameter WPb for blue images to distort the blue image data IBb. The distortion parameters WPr, WPg, and WPb are parameters that establish a correspondence between the pixel positions in the display image data IBr, IBg, and IBb and the pixel positions in the distorted display image data ICr, ICg, and ICb. These parameters can be a lookup table that establishes a correspondence between pixel positions, or they can be coefficients of a polynomial representing the correspondence between pixel positions.

[0053] The distortion correction circuit 130 is composed of logic circuits, such as gate arrays with automatic configuration and routing or standard cell arrays with automatic routing. The distortion correction circuit 130 can be a forward warping engine or a backward warping engine. Forward warping is a warping process that moves each pixel of the input image to a corresponding destination coordinate. In this case, the warping parameter is either a parameter that establishes a correspondence between each pixel of the input image and its corresponding destination coordinate, or a parameter that establishes a correspondence between each pixel of the input image and its relative movement to its corresponding destination coordinate. Backward warping is a warping process that moves each pixel of the output image to a reference source coordinate corresponding to that pixel, and calculates the pixel data of the output image based on the pixel data of the input image in the reference source image. In this case, the warping parameter is either a parameter that establishes a correspondence between each pixel of the output image and its corresponding reference source coordinate, or a parameter that establishes a correspondence between each pixel of the output image and its relative movement from its corresponding reference source coordinate.

[0054] The output circuit 140 sends the distortion-corrected display image data IBr, IBg, and IBb as output image data ID to the laser source control circuit 150. The output circuit 140 can be a transmitting circuit for various communication interfaces, such as LVDS, DVI, display port, GMSL, or GVIF.

[0055] The laser source control circuit 150 controls the light source device 50 based on the output image data ID and the timing control signal. Figure 1In the example structure, the laser source control circuit 150 drives the red laser source 51, the green laser source 52, and the blue laser source 53, controlling the emission timing and emission amount of these laser sources based on the output image data ID and timing control signals. Additionally, the laser source control circuit 150 drives the actuator 73, causing the laser to scan on the projection surface 10 based on the timing control signals. The timing control signals are, for example, horizontal synchronization signals and vertical synchronization signals. The laser source control circuit 150 is, for example, composed of a laser source drive circuit that drives the laser sources, an actuator drive circuit that drives the actuator 73, and a control circuit that controls them.

[0056] Figure 5 This diagram illustrates the distortion correction and color shift correction in this embodiment. The pixel positions of the display image data IBr, IBg, and IBb, which are used as input images, are set to (Xs, Ys). The pixel positions for RGB are the same.

[0057] Use coordinate transformation fr -1 This represents distortion correction for the red image data IBr, using coordinate transformation fg. -1 This represents distortion correction for green image data IBg, using coordinate transformation fb. -1 This represents distortion correction for the blue image data IBb. At this point, the pixel position in the corrected red image is fr. -1 (Xs, Ys), the pixel position in the green corrected image is fg -1 (Xs, Ys), the pixel position in the blue corrected image is fb. -1 (Xs, Ys). Due to fr -1 ≠fg -1 ≠fb -1 Therefore, fr -1 (Xs, Ys) ≠ fg -1 (Xs, Ys) ≠ fb -1 (Xs, Ys).

[0058] The coordinate transformation of the red image projected based on the red laser is represented as fr, the coordinate transformation of the green image projected based on the green laser is represented as fg, and the coordinate transformation of the blue image projected based on the blue laser is represented as fb. At this point, the pixel position in the red image is fr·fr. -1 (Xs, Ys) = (Xs, Ys), the pixel position in the green image is fg·fg -1 (Xs, Ys) = (Xs, Ys), the pixel position in the blue image is fb·fb -1 (Xs, Ys) = (Xs, Ys). That is, since the pixel positions in the red image, the pixel positions in the green image, and the pixel positions in the blue image are not offset, the color shift is corrected.

[0059] In addition, the same symbols (Xs, Ys) are used here to record the pixel positions of the input image and the projected image. However, the pixel position (Xs, Ys) of the projected image actually refers to the position on the projection surface 10 corresponding to the pixel position (Xs, Ys) of the input image.

[0060] In the above embodiments, the circuit device 100 is used in a laser projector 400 that projects images onto a projection surface 10 using lasers of multiple colors with different wavelengths. The circuit device 100 includes a distortion correction circuit 130 and an output circuit 140. The distortion correction circuit 130 performs distortion correction on the display image data IBr, IBg, IBb for each of the multiple colors. The output circuit 140 outputs the distortion-corrected display image data ICr, ICg, ICb. The distortion correction circuit 130 uses distortion parameters WPr, WPg, WPb, which vary for each color, to perform distortion correction on each color.

[0061] According to this embodiment, the distortion correction circuit 130 performs distortion correction for each color by using distortion parameters WPr, WPg, and WPb that are different for each color, thereby correcting the display position shift caused by each color. That is, by performing distortion correction for each color using the distortion correction circuit 130, the correction amount for each color can be different, thus enabling the distortion correction to include the correction of the display position shift for each color. In other words, the distortion correction circuit 130 can correct image distortion caused by distortion of the screen, etc., and can also correct the display position shift for each color. In this way, color shift correction can be performed through image data processing, thus simplifying the circuit compared to the method of adjusting scan timing as described in Patent Document 1.

[0062] In addition, such as in Figure 6 As described later, the distortion correction circuit 130 performs distortion correction for each color in parallel. However, it is not limited to this; the distortion correction circuit 130 can also perform distortion correction for each color in a time-division multiplexing manner. For example, in the case of using an RGB laser, the distortion correction circuit 130 can also perform distortion correction for red image data, distortion correction for green image data, and distortion correction for blue image data in a time-division multiplexing manner. In this case, it is not necessary to perform distortion correction for each color in a time-division multiplexing manner. Figure 6 By dividing the storage circuits by color, all colors of the display image data can be stored in the same storage circuit.

[0063] In addition, in this embodiment, the distortion parameters WPr, WPg, and WPb for each color are based on the image distortion caused by the distortion of the projection surface 10, the image distortion caused by the optical system, and the distortion parameters of the display position offset generated by each color.

[0064] The distortion correction circuit 130 uses such distortion parameters to perform distortion correction for each color, thereby enabling distortion correction for image distortion caused by the distortion of the projection surface 10 and the image distortion caused by the optical system, and also enabling correction of the display position offset generated by each color.

[0065] Furthermore, image distortion caused by distortion of the projection surface 10 is due to the non-planarity of the projection surface 10, such as curvature of the projection surface 10. Image distortion caused by the optical system is, for example, image distortion caused by aberrations of the optical system, or trapezoidal distortion caused by tilting relative to the projection angle of the projection surface 10. The display position offset generated for each color is as described above.

[0066] In addition, in this embodiment, the displayed image data IBr, IBg, and IBb are image data that have been converted to a color space corresponding to the wavelength of the laser.

[0067] The color space of the display image data before color space conversion is usually different from the color space obtained by laser. Therefore, if the display image data is displayed directly, it will be displayed as a color different from the intended color. According to this embodiment, the display image data after color space conversion to a color space corresponding to the wavelength of the laser is displayed, thus displaying the display image with appropriate colors.

[0068] Furthermore, in this embodiment, the multiple colors include red, green, and blue.

[0069] Therefore, laser projectors use at least the three primary colors of RGB lasers to display images, thus enabling them to display RGB color images.

[0070] Figure 1 The hardware structure of the control device 300 described herein is one example. That is, the hardware structure of the control device 300 is not limited to any particular configuration, as long as it is configured in the following manner. Figure 1The control device 300 controls the laser projector 400, which uses lasers of multiple colors with different wavelengths to project images onto the projection surface 10. The control device 300 includes a distortion correction circuit 130 and an output circuit 140. The distortion correction circuit 130 performs distortion correction on the display image data IBr, IBg, IBb for each of the multiple colors. The output circuit 140 outputs the distortion-corrected display image data ICr, ICg, ICr. The distortion correction circuit 130 uses distortion parameters WPr, WPg, WPb, which vary for each color, to perform distortion correction on each color, thereby correcting the display position offset caused by each color.

[0071] 3. Detailed structural examples of the first and second circuit devices

[0072] Figure 6 This is the first detailed structural example of the circuit device 100. Furthermore, structural elements identical to those already described are labeled with the same reference numerals, and descriptions of those structural elements are appropriately omitted.

[0073] The storage circuit 120 includes a first storage circuit 121 for storing red image data IBr, a second storage circuit 122 for storing green image data IBg, and a third storage circuit 123 for storing blue image data IBb. The first storage circuit 121, the second storage circuit 122, and the third storage circuit 123 are storage circuits capable of reading data simultaneously in parallel. That is, each storage circuit has a separate row latch circuit or memory corresponding to it, allowing for independent assignment of a read address to each storage circuit.

[0074] The distortion correction circuit 130 includes a first distortion correction circuit 131, a second distortion correction circuit 132, and a third distortion correction circuit 133. The first distortion correction circuit 131 uses a distortion parameter Wpr for red images to distort the red image data IBr stored in the first storage circuit 121, and outputs distortion-corrected red image data ICr. The second distortion correction circuit 132 uses a distortion parameter WPg for green images to distort the green image data IBg stored in the second storage circuit 122, and outputs distortion-corrected green image data ICg. The third distortion correction circuit 133 uses a distortion parameter WPb for blue images to distort the blue image data IBb stored in the third storage circuit 123, and outputs distortion-corrected blue image data ICb.

[0075] Taking reverse distortion as an example, when the first distortion correction circuit 131 calculates the pixel data of a certain pixel position in the red image data ICr, which is the output image, it calculates the pixel position of the reference source red image data IBr corresponding to that pixel position through distortion processing. The first distortion correction circuit 131 specifies the readout address corresponding to that pixel position, reads the pixel data of the red image data IBr from the first storage circuit 121, and uses the readout pixel data to calculate the pixel data in the red image data ICr. The second distortion correction circuit 132 and the second storage circuit 122 perform the same processing on the green image data IBg, and the third distortion correction circuit 133 and the third storage circuit 123 perform the same processing on the blue image data IBb.

[0076] In the above embodiment, there is a storage circuit for each color that stores the display image data IBr, IBg, IBb for each color.

[0077] According to this embodiment, data can be read out by independently specifying a read address for each of the storage circuits for each color. Therefore, distortion correction and color shift correction for each color can be achieved without increasing the operating clock frequency; that is, at the same operating clock frequency as in the case where the same distortion correction is performed for all colors.

[0078] More specifically, the circuit device 100 includes: a first storage circuit 121 storing first display image data of a first color among a plurality of colors including a first color, a second color, and a third color; a second storage circuit 122 storing second display image data of a second color; and a third storage circuit 123 storing third display image data of a third color. The distortion correction circuit 130 includes a first distortion correction circuit 131, a second distortion correction circuit 132, and a third distortion correction circuit 133. The first distortion correction circuit 131 performs distortion correction on the first display image data from the first storage circuit 121 using a first distortion parameter corresponding to the first color. The second distortion correction circuit 132 performs distortion correction on the second display image data from the second storage circuit 122 using a second distortion parameter corresponding to the second color. The third distortion correction circuit 133 performs distortion correction on the third display image data from the third storage circuit 123 using a third distortion parameter corresponding to the third color.

[0079] exist Figure 6In the example, the first, second, and third colors are red, green, and blue, respectively. The first displayed image data is red image data IBr, the second displayed image data is green image data IBg, and the third displayed image data is blue image data IBb. The first distortion parameter is the distortion parameter WPr used for the red image, the second distortion parameter is the distortion parameter WPg used for the green image, and the third distortion parameter is the distortion parameter WPb used for the blue image.

[0080] According to this embodiment, the first distortion correction circuit can independently assign read addresses to the first storage circuit, the second distortion correction circuit can independently read data from the second storage circuit, and the third distortion correction circuit can independently read data from the third storage circuit. Therefore, distortion correction and color shift correction for each color can be achieved without increasing the operating clock frequency; that is, at the same operating clock frequency as in the case where the same distortion correction is performed on all colors.

[0081] Taking reverse distortion as an example, when the distortion correction circuit 130 calculates the pixel data for a certain pixel position in the output image ID, the pixel position of the reference source corresponding to that pixel position is different according to color. That is, the address of the pixel data read by the first distortion correction circuit 131 from the first storage circuit 121, the address of the pixel data read by the second distortion correction circuit 132 from the second storage circuit 122, and the address of the pixel data read by the third distortion correction circuit 133 from the third storage circuit 123 are different. According to this embodiment, the distortion correction circuit 130 can independently read data from the first storage circuit 121, the second storage circuit 122, and the third storage circuit 123, so the first distortion correction circuit 131, the second distortion correction circuit 132, and the third distortion correction circuit 133 can perform distortion correction processing in parallel.

[0082] In addition, Figure 6 The example given is a laser with three colors, but two or more colors are acceptable. As an example, the following explains the case of using a four-color laser. Figure 7 This is the second detailed structural example of the circuit device 100. Furthermore, structural elements identical to those already described are labeled with the same reference numerals, and descriptions of those structural elements are appropriately omitted.

[0083] The second detailed structural example is a case where a laser projector 400 uses four-color lasers to display images. The four-color lasers are, for example, obtained by adding lasers of arbitrary wavelengths other than red, green, and blue lasers.

[0084] The color space conversion circuit 220 of the processing device 200 converts the RGB display image data IA into color space to generate display image data of four colors: IBr, IBg, IBb, and IBw. IBw is referred to as the fourth color image data.

[0085] Storage circuit 120 includes a first storage circuit 121, a second storage circuit 122, a third storage circuit 123, and a fourth storage circuit 124. Each storage circuit can independently read data. The fourth storage circuit 124 stores the fourth color image data received by the input circuit 110.

[0086] The parameter storage circuit 160 stores the distortion parameters WPr, WPg, WPb, and WPw corresponding to each color. WPw is the distortion parameter used for the fourth color image.

[0087] The distortion correction circuit 130 includes a first distortion correction circuit 131, a second distortion correction circuit 132, a third distortion correction circuit 133, and a fourth distortion correction circuit 134. The fourth distortion correction circuit 134 uses the distortion parameter WPw for the fourth color image to distort the fourth color image data IBw stored in the fourth storage circuit 124, and outputs the distortion-corrected fourth color image data ICw.

[0088] The output circuit 140 sends the distortion-corrected display image data IBr, IBg, IBb, and IBw as output image data ID to the laser source control circuit 150.

[0089] 4. Examples of the second and third structures of the control device

[0090] Figure 8 This is a second structural example of the control device 300 in this embodiment. In this second structural example, the color space conversion circuit 220 is not included in the processing device 200, but is included in the circuit device 100. Furthermore, structural elements that are the same as those already described are marked with the same reference numerals, and descriptions of these structural elements are appropriately omitted.

[0091] The processing device 200 includes an image data output circuit 210. The processing device 200 sends the display image data IA output by the image data output circuit 210 to the circuit device 100.

[0092] The circuit device 100 includes an input circuit 110, a color space conversion circuit 220, a storage circuit 120, a distortion correction circuit 130, an output circuit 140, and a parameter storage circuit 160. The input circuit 110 receives display image data IA from the processing device 200. The color space conversion circuit 220 converts the color space of the display image data IA and outputs the color space-converted display image data IBr, IBg, and IBb. The storage circuit 120 stores the color space-converted display image data IBr, IBg, and IBb output by the color space conversion circuit 220. The rest of the structure is the same as in the first example.

[0093] In this embodiment described above, the circuit device 100 includes a color space conversion circuit 220. The color space conversion circuit 220 converts the input image data into a color space and outputs color space-converted display image data IBr, IBg, and IBb.

[0094] According to this embodiment, the circuit device 100, which serves as a display controller or HUD controller, is capable of color space conversion. By performing color space conversion, display image data that has been converted to a color space corresponding to the wavelength of the laser is displayed, thus displaying the display image with appropriate colors.

[0095] Figure 9 This is a third structural example of the control device 300 in this embodiment. In this third structural example, the storage circuit 120 is provided externally to the circuit device 100. For example, imagine that the circuit device 100 is a processor such as a microcomputer, and a memory IC is provided externally as the storage circuit 120. Furthermore, structural elements that are the same as those already described are marked with the same reference numerals, and descriptions of these structural elements are omitted as appropriate.

[0096] The circuit device 100 includes an input circuit 110, an access circuit 170, a distortion correction circuit 130, an output circuit 140, and a parameter storage circuit 160.

[0097] Access circuit 170 controls write and read access to storage circuit 120. Access circuit 170 writes the color space converted display image data IBr, IBg, and IBb received from input circuit 110 to storage circuit 120. Additionally, access circuit 170 reads the display image data IBr, IBg, and IBb stored in storage circuit 120. Furthermore, storage circuit 120 is a semiconductor memory, such as a volatile memory like DRAM.

[0098] The distortion correction circuit 130 performs distortion correction on each color of the display image data IBr, IBg, and IBb read from the access circuit 170, and outputs the corrected display image data ICr, ICg, and ICb. The rest is the same as in the first structural example.

[0099] Figure 10 This is a first detailed structural example of the circuit device 100 and the storage circuit 120 in the third structural example of the control device 300. Additionally, in Figure 10 The diagram of parameter storage circuit 160 is omitted.

[0100] Access circuit 170 includes a first buffer circuit 171 for buffering red image data IBr, a second buffer circuit 172 for buffering green image data IBg, and a third buffer circuit 173 for buffering blue image data IBb. Storage circuit 120 includes a memory controller 125, a first memory MM1 for storing red image data IBr, a second memory MM2 for storing green image data IBg, and a third memory MM3 for storing blue image data IBb.

[0101] The first memory MM1, the second memory MM2, and the third memory MM3 are physically independent memories, each consisting of one or more memory ICs. The memory controller 125 controls the writing and reading of data to the first memory MM1, the second memory MM2, and the third memory MM3 based on write access and read access from the access circuit 170.

[0102] Access circuit 170 writes the red image data IBr received by input circuit 110 into the first memory MM1. First distortion correction circuit 131 specifies the read address of the first memory MM1 corresponding to the pixel data read during distortion correction. Access circuit 170 reads the pixel data of red image data IBr from this read address and outputs the pixel data to the first distortion correction circuit 131. First buffer circuit 171 temporarily buffers the red image data IBr when access circuit 170 writes or reads it into the first memory MM1. Second distortion correction circuit 132, second memory MM2, and second buffer circuit 172 perform the same processing on green image data IBg. Third distortion correction circuit 133, third memory MM3, and third buffer circuit 173 perform the same processing on blue image data IBb.

[0103] Figure 11 This is a second detailed structural example of the circuit device 100 and the storage circuit 120 in the third structural example of the control device 300. Additionally, in Figure 11 The diagram of parameter storage circuit 160 is omitted.

[0104] The storage circuit 120 includes a memory controller 125 and a memory 127.

[0105] The memory 127 is composed of one or more memory ICs. Within the memory 127, there are three logical units: a first memory bank BK1, a second memory bank BK2, and a third memory bank BK3. The first memory bank BK1 stores red image data IBr, the second memory bank BK2 stores green image data IBg, and the third memory bank BK3 stores blue image data IBb. The memory controller 125 controls write and read access to the first memory bank BK1, the second memory bank BK2, and the third memory bank BK3.

[0106] Access circuit 170 writes the red image data IBr received by input circuit 110 into the first memory bank BK1. First distortion correction circuit 131 specifies the read address of the first memory bank BK1 corresponding to the pixel data read during distortion correction. Access circuit 170 reads the pixel data of red image data IBr from this read address and outputs the pixel data to the first distortion correction circuit 131. First buffer circuit 171 temporarily buffers the red image data IBr when access circuit 170 writes or reads it into the first memory bank BK1. Second distortion correction circuit 132, second memory bank BK2, and second buffer circuit 172 perform the same processing on green image data IBg. Third distortion correction circuit 133, third memory bank BK3, and third buffer circuit 173 perform the same processing on blue image data IBb.

[0107] The circuit arrangement described above, according to this embodiment, is used in a laser projector that projects images onto a projection surface using lasers of multiple colors with different wavelengths. The circuit arrangement includes: a distortion correction circuit that performs distortion correction for each color of the display image data; and an output circuit that outputs the distortion-corrected display image data. The distortion correction circuit performs distortion correction for each color using distortion parameters that vary for each color.

[0108] According to this embodiment, the distortion correction circuit uses a distortion parameter that varies for each color to perform distortion correction for each color, thereby correcting the display position shift caused by each color. That is, the distortion correction circuit performs distortion correction for each color, thus allowing the correction amount for each color to be different, and therefore enabling the distortion correction to include the correction of the display position shift for each color. In other words, the distortion correction circuit can correct image distortion caused by distortion of the screen, etc., and can also correct the display position shift for each color. In this way, color shift correction can be performed through image data processing, thus simplifying the circuit compared to methods that adjust the scanning timing.

[0109] Alternatively, in this embodiment, the circuit device may also include a storage circuit for each color that stores display image data for each color.

[0110] According to this embodiment, data can be read out by independently specifying a read address for each of the storage circuits for each color. Therefore, distortion correction and color shift correction for each color can be achieved without increasing the operating clock frequency; that is, at the same operating clock frequency as in the case where the same distortion correction is performed for all colors.

[0111] In addition, in this embodiment, the distortion parameter for each color can also be based on image distortion caused by the distortion of the projection surface, image distortion caused by the optical system, and distortion parameters based on the display position offset generated for each color.

[0112] The distortion correction circuit uses such distortion parameters to correct the distortion of each color, thereby correcting the image distortion caused by the distortion of the projection surface and the image distortion caused by the optical system, and correcting the display position offset caused by each color.

[0113] Alternatively, in this embodiment, the displayed image data may also be image data that has been converted to a color space corresponding to the wavelength of the laser.

[0114] The color space of the display image data before color space conversion is usually different from the color space obtained by laser. Therefore, if the display image data is displayed directly, it will be displayed as a color different from the intended color. According to this embodiment, the display image data after color space conversion to a color space corresponding to the wavelength of the laser is displayed, thus displaying the display image with appropriate colors.

[0115] In addition, in this embodiment, the circuit device may also include a color space conversion circuit, which performs color space conversion on the input image data and outputs color space converted display image data.

[0116] According to this embodiment, the circuit device is capable of color space conversion. By performing color space conversion, the display image data after color space conversion to a color space corresponding to the wavelength of the laser is displayed, thus displaying the display image with appropriate colors.

[0117] In addition, in this embodiment, the multiple colors may include red, green and blue.

[0118] Therefore, laser projectors use at least the three primary colors of RGB lasers to display images, thus enabling them to display RGB color images.

[0119] Additionally, in this embodiment, the circuit device may also include: a first storage circuit storing first display image data of the first color from a plurality of colors including a first color, a second color, and a third color; a second storage circuit storing second display image data of the second color; and a third storage circuit storing third display image data of the third color. The distortion correction circuit may include a first distortion correction circuit, a second distortion correction circuit, and a third distortion correction circuit. The first distortion correction circuit can use a first distortion parameter corresponding to the first color to perform distortion correction on the first display image data from the first storage circuit. The second distortion correction circuit can use a second distortion parameter corresponding to the second color to perform distortion correction on the second display image data from the second storage circuit. The third distortion correction circuit can use a third distortion parameter corresponding to the third color to perform distortion correction on the third display image data from the third storage circuit.

[0120] According to this embodiment, the first distortion correction circuit can independently assign read addresses to the first storage circuit, the second distortion correction circuit can independently read data from the second storage circuit, and the third distortion correction circuit can independently read data from the third storage circuit. Therefore, distortion correction and color shift correction for each color can be achieved without increasing the operating clock frequency; that is, at the same operating clock frequency as in the case where the same distortion correction is performed on all colors.

[0121] Furthermore, the control device of this embodiment controls a laser projector that projects images onto a projection surface using lasers of multiple colors with different wavelengths. The control device includes: a distortion correction circuit that performs distortion correction for each color of the display image data; and an output circuit that outputs the distortion-corrected display image data. The distortion correction circuit performs distortion correction for each color using distortion parameters that vary for each color.

[0122] In addition, in this embodiment, the control device may also include a color space conversion circuit, which converts the input image data to a color space corresponding to the wavelength of the laser, thereby outputting display image data.

[0123] Alternatively, in this embodiment, the control device may also include a storage circuit for each color that stores display image data for each color.

[0124] Furthermore, in the control device of this embodiment, the distortion parameter for each color can also be based on image distortion caused by the distortion of the displayed image, image distortion caused by the distortion of the optical system, and distortion parameters based on the display position offset generated for each color.

[0125] Furthermore, in the control device of this embodiment, multiple colors may include red, green, and blue.

[0126] In this embodiment, the control device may also include: a first storage circuit storing first display image data of the first color from a plurality of colors including a first color, a second color, and a third color; a second storage circuit storing second display image data of the second color; and a third storage circuit storing third display image data of the third color. The distortion correction circuit may include a first distortion correction circuit, a second distortion correction circuit, and a third distortion correction circuit. The first distortion correction circuit can use a first distortion parameter corresponding to the first color to perform distortion correction on the first display image data from the first storage circuit. The second distortion correction circuit can use a second distortion parameter corresponding to the second color to perform distortion correction on the second display image data from the second storage circuit. The third distortion correction circuit can use a third distortion parameter corresponding to the third color to perform distortion correction on the third display image data from the third storage circuit.

[0127] Furthermore, the laser projector of this embodiment includes: the circuit device described in any one of the above; a plurality of laser light sources that emit lasers of multiple colors; a laser light source control circuit that controls the plurality of laser light sources based on distortion-corrected display image data from the output circuit; and an optical system that projects lasers of multiple colors onto a projection surface.

[0128] Furthermore, the laser projector of this embodiment includes: a control device as described in any of the above claims; a plurality of laser light sources that emit lasers of multiple colors; and an optical system that projects the lasers of multiple colors onto a projection surface. The control device includes a laser light source control circuit that controls the plurality of laser light sources based on distortion-corrected display image data from an output circuit.

[0129] Furthermore, although this embodiment has been described in detail above, those skilled in the art will readily understand that various modifications can be made without substantially departing from the novel aspects and effects of this disclosure. Therefore, all such modifications are included within the scope of this disclosure. For example, in the specification or drawings, any term that is described at least once with a different term that is more general or synonymous can be replaced with that different term anywhere in the specification or drawings. Furthermore, all combinations of this embodiment and its modifications are also included within the scope of this disclosure. Additionally, the structure and operation of circuit devices, laser light source control circuits, control devices, light source devices, and laser projectors are not limited to those described in this embodiment, and various modifications can be implemented.

Claims

1. A circuit device used in a laser projector that projects images onto a projection surface using lasers of multiple colors with different wavelengths, characterized in that it comprises: A distortion correction circuit that performs distortion correction for each of the multiple colors in the display image data for each color; and The output circuit outputs the distortion-corrected display image data. The distortion correction circuit uses a distortion parameter that varies for each color to perform distortion correction for each color, thereby enabling the correction of display position offset caused by each color to be included in the distortion correction. The distortion parameter is a parameter that establishes a correspondence between the pixel positions in the displayed image data and the pixel positions in the distortion-corrected displayed image data. The displayed image data is image data that has been converted to a color space corresponding to the wavelength of the laser. The circuit device includes a color space conversion circuit, which performs color space conversion on the input image data, thereby outputting the color space-converted display image data.

2. The circuit device according to claim 1, characterized in that, The circuit device includes a storage circuit for each of the colors, storing the display image data for each color.

3. The circuit device according to claim 1 or 2, characterized in that, The distortion parameter for each color is based on image distortion caused by the distortion of the projection surface, image distortion caused by the optical system, and distortion parameters resulting from the display position offset for each color.

4. The circuit device according to claim 1 or 2, characterized in that, The colors include red, green, and blue.

5. The circuit device according to claim 1, characterized in that, The circuit device includes: A first storage circuit stores first display image data of the first color among the plurality of colors including a first color, a second color, and a third color; A second storage circuit stores the second display image data of the second color; and The third storage circuit stores the third display image data of the third color. The distortion correction circuit includes: A first distortion correction circuit uses a first distortion parameter corresponding to the first color to perform distortion correction on the first display image data from the first storage circuit; A second distortion correction circuit performs distortion correction on the second display image data from the second storage circuit using a second distortion parameter corresponding to the second color; and The third distortion correction circuit uses a third distortion parameter corresponding to the third color to perform the distortion correction on the third display image data from the third storage circuit.

6. A laser projector, characterized in that, This laser projector includes: The circuit device according to any one of claims 1 to 5; Multiple laser light sources that emit lasers of the multiple colors; A laser source control circuit that controls the plurality of laser sources based on the distortion-corrected display image data from the output circuit; and An optical system that projects the laser beams of the plurality of colors onto the projection surface.

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