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EP-4738322-A1 - CIRCUIT DEVICE AND HEAD-UP DISPLAY

EP4738322A1EP 4738322 A1EP4738322 A1EP 4738322A1EP-4738322-A1

Abstract

A circuit device includes an image selection circuit that selects selected image data that is image data of a selected area smaller than an input image from input image data that is image data of the input image, a buffer memory that stores the selected image data, and a distortion correction circuit that performs distortion correction on the input image and outputs output image data that is image data of an output image. The selected area includes a plurality of areas or a polygonal area. When input-side coordinates of the input image corresponding to output-side coordinates of the output image belong to the selected area, the distortion correction circuit generates pixel data of the output image data at the output-side coordinates from the selected image data stored in the buffer memory.

Inventors

  • Akiba, Yasutoshi

Assignees

  • Seiko Epson Corporation

Dates

Publication Date
20260506
Application Date
20251028

Claims (9)

  1. A circuit device comprising: an image selection circuit that selects selected image data that is image data of a selected area smaller than an input image from input image data that is image data of the input image; a buffer memory that stores the selected image data; and a distortion correction circuit that performs distortion correction on the input image and outputs output image data that is image data of an output image, wherein the selected area includes a plurality of areas or a polygonal area, and when input-side coordinates of the input image corresponding to output-side coordinates of the output image belong to the selected area, the distortion correction circuit generates pixel data of the output image data at the output-side coordinates from the selected image data stored in the buffer memory.
  2. The circuit device according to claim 1, wherein the distortion correction circuit sets the pixel data at the output-side coordinates to predetermined color data when the input-side coordinates do not belong to the selected area.
  3. The circuit device according to claim 1, wherein the selected area includes a first area and a second area as the plurality of areas, the image selection circuit selects first image data of the first area and second image data of the second area as the selected image data and stores the first image data and the second image data in the buffer memory, and the distortion correction circuit generates the pixel data at the output-side coordinates from the first image data stored in the buffer memory when the input-side coordinates belong to the first area, and generates the pixel data at the output-side coordinates from the second image data stored in the buffer memory when the input-side coordinates belong to the second area.
  4. The circuit device according to claim 3, wherein the image selection circuit converts the input-side coordinates into selected coordinates in the selected area in which the first area and the second area are combined, and stores the selected image data in the buffer memory, and the distortion correction circuit converts the input-side coordinates into the selected coordinates in the first area when the input-side coordinates belongs to the first area and refers to the first image data stored in the buffer memory based on the selected coordinates, and converts the input-side coordinates into the selected coordinates in the second area when the input-side coordinates belongs to the second area and refers to the second image data stored in the buffer memory based on the selected coordinates.
  5. The circuit device according to claim 1, comprising a storage circuit that stores area setting information for setting the selected area, wherein the distortion correction circuit determines whether the input-side coordinates belong to the selected area based on the area setting information.
  6. The circuit device according to claim 1, wherein the input image includes a plurality of display objects, and the selected area includes the plurality of areas each including each of the plurality of display objects or the polygonal area including the plurality of display objects.
  7. The circuit device according to claim 1, wherein the distortion correction circuit reads pixel data of a plurality of pixels around the input-side coordinates from the buffer memory and obtains pixel data of the output image data corresponding to the output-side coordinates by performing interpolation processing on the pixel data of the plurality of pixels, and performs the interpolation processing using pixel data of a pixel belonging to the selected area among the plurality of pixels when the input-side coordinates belong to the selected area and part of the plurality of pixels do not belong to the selected area.
  8. The circuit device according to claim 1, wherein an output interface circuit outputs the output image data to a display device that projects the output image using a projection optical system, and the distortion correction circuit corrects image distortion caused by distortion of the projection optical system or distortion of a projection surface.
  9. A head-up display comprising: the circuit device according to claim 1; and a display device that projects the output image using a projection optical system.

Description

The present application is based on, and claims priority from JP Application Serial Number 2024-190598, filed October 30, 2024, the disclosure of which is hereby incorporated by reference herein in its entirety. BACKGROUND 1. Technical Field The present disclosure relates to a circuit device, a head-up display, and the like. 2. Related Art JP-A-2011-097474 discloses an image processing apparatus including an image dividing unit, an image editing buffer, and an image editing unit. When sequentially cutting out a plurality of divided images from an input image, the image dividing unit provides an overlap area for the divided images adjacent to each other, the image editing buffer sequentially stores the plurality of divided images, and the image editing unit sequentially performs image editing processing on the plurality of divided images. This reduces the capacity of the image editing buffer. JP-A-2011-097474 is an example of the related art. When there is an area where a display object is not displayed in the image, the area is also stored in the buffer, and there is a problem that the memory capacity of the buffer increases. For example, in a head-up display, a display object is displayed only in a part of a display area, and most of the display area is a transparent area (a black area as an image). By buffering such a transparent area, the memory capacity increases. In JP-A-2011-097474, a line buffer of a plurality of lines is used. An input image is divided as it is and stored in the line buffer, and thus an area not required to be stored is also buffered. SUMMARY An aspect of the present disclosure relates to a circuit device including an image selection circuit that selects selected image data that is image data of a selected area smaller than an input image from input image data that is image data of the input image, a buffer memory that stores the selected image data, and a distortion correction circuit that performs distortion correction on the input image and outputs output image data that is image data of an output image, wherein the selected area includes a plurality of areas or a polygonal area, and when input-side coordinates of the input image corresponding to output-side coordinates of the output image belong to the selected area, the distortion correction circuit generates pixel data of the output image data at the output-side coordinates from the selected image data stored in the buffer memory. Another aspect of the present disclosure relates to a head-up display including the circuit device described above and a display device that projects the output image using a projection optical system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an example of an input image before distortion correction and an output image after distortion correction.FIG. 2 shows an example of a method of surrounding a display object by one rectangle and storing only image data in the rectangle in a buffer memory.FIG. 3 shows a configuration example of a head-up display including a circuit device of an embodiment.FIG. 4 shows an example of a plurality of selected areas.FIG. 5 shows an example of a plurality of selected areas.FIG. 6 shows an example of a polygonal selected area.FIG. 7 shows a first detailed configuration example of a distortion correction circuit.FIG. 8 shows an example of selected areas and an example of selected images stored in the buffer memory.FIG. 9 shows an example of a processing flow of the distortion correction circuit.FIG. 10 shows pixel interpolation at a boundary of the selected area.FIG. 11 shows a second detailed configuration example of the distortion correction circuit. DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present disclosure will be described in detail. The following embodiments do not unduly limit the description in "What is Claimed is", and not all of the configurations described in the embodiments are necessarily essential component elements. For example, an example in which a memory saving method of the present disclosure is applied to a head-up display will be described below. However, the memory saving method of the present disclosure can be applied to any image processing involving distortion correction, and can be applied to, for example, a head-mounted display, a projector, or a curved display. Hereinafter, the head-up display may be abbreviated as HUD. FIG. 1 shows an example of an input image before distortion correction and an output image after distortion correction. The distortion correction is to apply inverse image distortion to image distortion when an image is projected on a screen of the HUD to the image. As a result, the distortion due to the distortion correction and the distortion due to the projection cancel each other, so that image display with no or reduced distortion is obtained. The image distortion due to projection is image distortion due to a curved surface of a projection surface such as a screen, image distortion due t