JP2013255665A - Three-dimensional image display device and three-dimensional image display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately present perspective information between areas where difference in pixel values of original images is small while retaining the visibility of a long-distance area from a point of view.SOLUTION: A CPU 11 prepares a monochromatic three-dimensional image 32 and a depth image 33 (S1). Next, the CPU 11 specifies coordinates adr of each pixel in an image space (S2 and S5), a pixel value a of the monochromatic three-dimensional image 32 and a depth value Di in the coordinates adr are obtained (S3), and pixel values (R, G and B) of a polychromatic three-dimensional image 34 in the coordinates adr are determined (S4) according to a prescribed monotone function. Here, the CPU 11 monotonously increases or decreases variation of the density of a first color as the image is closer to the point of view, and monotonously decreases or increases variation of the density of a second color, different from the first color, in a converse manner from the variation of the density of the first color as the image is further away from the point of view. Then, the CPU 11 controls the polychromatic three-dimensional image 34 to be displayed in a display device 17 (S7).

Description

  The present invention relates to a three-dimensional image display device and a three-dimensional image display method, and more particularly to shading processing of a three-dimensional image display device and a three-dimensional image display method.

  3D images such as CT (Computed Tomography) images, MR (Magnetic Resonance) images, and ultrasound images can be identified by adding shading to the 2D images. Information). For example, in the example of a three-dimensional CT image (grayscale) by surface rendering, surface information of a tissue can be presented.

  However, in soft tissue where the difference in CT values is small, it is difficult to identify which is behind, that is, which is far from the viewpoint. Such a problem can be said not only between soft tissues but also between bone tissues.

  Conventionally, various methods for effectively presenting perspective information have been proposed for the above problems. These methods are roughly divided into two. The first method presents perspective information by distinguishing organs and tissues in advance and assigning different colors to the organs and tissues. The second method presents perspective information without distinguishing between organs and tissues. In the case of the second method, the depth is not evaluated for each organ or tissue, but the depth is evaluated for each pixel or region. Here, the “region” may be configured by a single pixel, or may be configured by connecting a plurality of adjacent pixels. A single region may or may not match the range of a single organ or tissue.

  For example, when the first technique is applied to a CT image, an organ or tissue having a small difference in CT value may not be accurately distinguished. If organs and tissues are not accurately distinguished, correct perspective information cannot be presented. Such a problem can be said not only for CT images but also for MR images, ultrasonic images, and the like.

  Therefore, it can be said that it is desirable to apply the second method to an organ or tissue having a small difference in CT value. Patent Documents 1 and 2 are disclosed as conventional techniques of the second method.

  Patent Document 1 discloses a virtual endoscope apparatus that generates and displays a virtual endoscopic image similar to an image viewed from an endoscope viewpoint by performing image processing on a three-dimensional image. . The virtual endoscopic device described in Patent Literature 1 solves the problem that “a sense of depth of an image is not sufficiently displayed as compared with a real endoscopic image, and in some cases, observation and diagnosis are difficult”. For this reason, it is described that “the brightness at the time of display of the pixels constituting the image is set so as to become darker as the distance increases” according to the distance from the viewpoint of the endoscope.

  Patent Document 2 discloses an image processing apparatus that converts a virtual object defined in a three-dimensional space into a two-dimensional image subjected to a fog (fog) effect. In Patent Document 2, as a description of the prior art, “In computer graphics, the distance from the viewpoint to the object is used to blend (blend) the brightness of the object and the brightness of the atmosphere, so that the farther away the object appears to be blurred. May be included. ”

JP 2000-148983 A Japanese Patent No. 3278501

  However, as in Patent Document 1, if the distance from the viewpoint is set to be darker as the distance from the viewpoint is larger, an area away from the viewpoint becomes darker, so that observation and diagnosis are difficult. In addition, as in Patent Document 2, when the distance from the viewpoint is made larger as the distance from the viewpoint becomes larger, an area that is far from the viewpoint is blurred, which makes observation and diagnosis difficult. In any case, in Patent Document 1 and Patent Document 2, in order to present perspective information, the visibility of an area that is far from the viewpoint is sacrificed.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to reduce the difference in pixel values of the original image while maintaining the visibility of an area far from the viewpoint. To provide a three-dimensional image display apparatus and a three-dimensional image display method capable of accurately presenting perspective information between regions.

  A first invention for achieving the above-mentioned object is a three-dimensional image display device for displaying a multi-color three-dimensional image in which perspective information of each region can be identified, and a single-color three-dimensional image is obtained from original image data. First creating means for creating, obtaining means for obtaining a pixel value of the depth image corresponding to the original image data, and determining a distance from the viewpoint in each region based on the pixel value of the depth image, and close to the viewpoint As a result, the density change of the first color is monotonously increased or decreased, and the density of the second color different from the first color is set to be opposite to the density change of the first color as the distance from the viewpoint increases. A second creating means for creating a plurality of three-dimensional images by adding a plurality of colors to the single-color three-dimensional image by monotonously decreasing or increasing a second color density change; Display system that controls the display of images A three-dimensional image display apparatus characterized by comprising a means.

  A second invention is a three-dimensional image display device for displaying a multi-color three-dimensional image in which perspective information of each region can be identified, determining a distance from a viewpoint in each region, and determining a density change of the first color. The density change of the second color is monotonously increased or decreased according to the distance from the viewpoint so that the density of the second color different from the first color is opposite to the density change of the first color. The three-dimensional image display device is characterized in that the multi-color three-dimensional image is created by decreasing or increasing the three-dimensional image.

  A third invention is a three-dimensional image display method for displaying a multi-color three-dimensional image in which perspective information of each region can be identified, and a first creation step of creating a single-color three-dimensional image from original image data; An acquisition step of acquiring a pixel value of the depth image corresponding to the original image data, and determining a distance from the viewpoint in each region based on the pixel value of the depth image, and the density of the first color as it approaches the viewpoint The change in the second color is monotonously increased or decreased, and as the distance from the viewpoint increases, the density change of the second color is changed so that the density of the second color different from the first color is opposite to the density change of the first color. A second creation step of creating a plurality of color three-dimensional images by adding a plurality of colors to the single-color three-dimensional image, and display control for controlling display of the plurality of color three-dimensional images Step and A three-dimensional image display method comprising Mukoto.

  According to the present invention, a three-dimensional image display capable of accurately presenting perspective information between regions having a small difference in pixel values of the original image while maintaining the visibility of a region far from the viewpoint. An apparatus and a three-dimensional image display method can be provided.

Example of hardware configuration of 3D image display apparatus according to embodiment of the present invention Example of single color 3D image by surface rendering The figure which shows the outline | summary of the process performed with a three-dimensional image display apparatus. The figure which shows the relationship between the density change of a 1st color, and the density change of a 2nd color The flowchart which shows the procedure of the process performed with a three-dimensional image display apparatus. Diagram showing the relationship between tomogram, origin plane and depth value Example of multiple color 3D image for single color 3D image of FIG. Other examples of multi-color 3D images Example of single-color 3D image using opacity Example of multiple color 3D image for single color 3D image of FIG. Example of operation screen

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an example of the hardware configuration of the three-dimensional image display device 1 according to the embodiment of the present invention will be described with reference to FIG.

  A three-dimensional image display device 1 shown in the example of FIG. 1 is a device that performs display processing of a three-dimensional image. Note that the three-dimensional image display device 1 according to the present invention may be configured by, for example, a general personal computer.

  As shown in FIG. 1, the three-dimensional image display device 1 is connected to a display device 17 and input devices such as a mouse 18 and a keyboard 19. In addition, a medical image photographing device 21 and the like are connected to the three-dimensional image display device 1 via a network 20.

As shown in FIG. 1, the three-dimensional image display device 1 is a CPU (Central
Processing Unit) 11, main memory 12, storage device 13, communication interface (communication I / F) 14, display memory 15, interface 18 with external devices such as mouse 18 and keyboard 19, etc. They are connected via a bus 10.

  The CPU 11 calls and executes a program stored in the main memory 12 or the storage device 13 in the work memory area on the RAM of the main memory 12, and drives and controls each unit connected via the bus 10, thereby obtaining a three-dimensional image. Various processes performed by the display device 1 are realized.

  The main memory 12 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The ROM permanently holds a computer boot program, a program such as BIOS, data, and the like. The RAM temporarily stores programs, data, and the like loaded from the ROM, the storage device 13, and the like, and includes a work area that the CPU 11 uses to perform various processes.

  The storage device 13 is a device that reads and writes data from and to an HDD (hard disk drive) and other recording media, and stores a program executed by the CPU 11, data necessary for program execution, an OS (operating system), and the like. As for the program, a control program corresponding to the OS and an application program are stored. Each of these program codes is read by the CPU 11 as necessary, transferred to the RAM of the main memory 12, and executed as various means. Note that medical image data such as CT images may be stored in the storage device 13 and displayed on the display device 17.

  The communication I / F 14 includes a communication control device, a communication port, and the like, and mediates communication between the 3D image display device 1 and the network 20. In addition, the communication I / F 14 performs communication control with other computers, medical image capturing apparatuses 21 such as an X-ray CT apparatus and an MRI apparatus via the network 20. The I / F 16 is a port for connecting a peripheral device, and transmits / receives data to / from the peripheral device.

  The display memory 15 is a buffer that temporarily accumulates display data input from the CPU 11. The accumulated display data is output to the display device 17 at a predetermined timing.

  The display device 17 includes a display device such as a liquid crystal panel and a logic circuit for executing display processing in cooperation with the display device, and is connected to the CPU 11 via the display memory 15. The display device 17 displays the display data stored in the display memory 15 under the control of the CPU 11.

  The mouse 18 and the keyboard 19 output various instructions and information input by the user to the CPU 11. The user interactively operates the 3D image display apparatus 1 using external devices such as the mouse 18 and the keyboard 19.

  The network 20 includes various communication networks such as a LAN (Local Area Network), a WAN (Wide Area Network), an intranet, and the Internet, and communication between the medical image photographing apparatus 21 and other information devices and the 3D image display apparatus 1. Mediate the connection.

  Next, with reference to FIGS. 2 to 4, an outline of processing performed in the 3D image display apparatus 1 according to the embodiment of the present invention will be described. In the following, data obtained by an X-ray CT apparatus will be described as an example of original image data of a three-dimensional image. However, the present invention is not limited to this example, and data obtained by an MR apparatus, an ultrasonic imaging apparatus, or the like may be applied as original image data of a three-dimensional image.

  FIG. 2 is an example of a three-dimensional CT image (grayscale) by surface rendering. Since FIG. 2 is expressed by a density change of only “black”, it can be said to be a “single-color three-dimensional image”. Hereinafter, a three-dimensional image represented by a single color density change including a gray scale image is referred to as a “single-color three-dimensional image”. In contrast, a three-dimensional image expressed by density changes of a plurality of colors is referred to as a “multi-color three-dimensional image”.

  In the following, when “single-color three-dimensional image” is generically referred to, a reference numeral 32 is given and expressed as “single-color three-dimensional image 32”. When distinguishing individual images, a lower case alphabet is appended after the reference numeral 32. For example, the image in FIG. 2 is a single-color three-dimensional image 32a. Similarly, when “multiple-color three-dimensional image” is generically referred to, a reference numeral 34 is given and expressed as “multiple-color three-dimensional image 34”. When distinguishing individual images, a lower case alphabet is added after the reference numeral 34.

  As will be described later, in the three-dimensional image display apparatus 1 according to the embodiment of the present invention, between tissues A1 and A2 shown in FIG. 2 and tissues B1 and B2 having a small difference in CT values. On the other hand, perspective information can be accurately presented while maintaining the visibility of a region that is far from the viewpoint.

  As shown in FIG. 3, the three-dimensional image display device 1 creates a single-color three-dimensional image 32 from the original image data 31. In addition, the 3D image display apparatus 1 acquires the pixel value of the depth image 33 corresponding to the original image data. Here, the three-dimensional image display device 1 may create the depth image 33 in order to acquire the pixel value of the depth image.

  A depth image is an image formed by the depth method. The depth method is a method of applying a shadow according to the distance from each pixel on the CT image to the location where the pixel is projected.

  Then, the three-dimensional image display device 1 determines the pixel value of the multi-color three-dimensional image 34 for the same pixel based on the pixel value of the single-color three-dimensional image 32 and the pixel value of the depth image 33, and the multi-color three-dimensional image An image 34 is created. Hereinafter, the pixel value of the single-color three-dimensional image 32 may be abbreviated as “single-color shading value”. In addition, the pixel value of the depth image 33 may be abbreviated as “depth value”. In addition, the pixel values of the multi-color three-dimensional image 34 may be abbreviated as “color values”.

  Specifically, the three-dimensional image display device 1 determines the distance from the viewpoint in each region based on the depth value 36, and monotonously increases or decreases the density change of the first color as it approaches the viewpoint. As the distance from the viewpoint increases, the density of the second color, which is different from the density of the first color, is monotonically reduced or increased by changing the density change of the second color so as to be opposite to the density change of the first color. A plurality of colors are attached to the image 32 to create a multi-color three-dimensional image 34.

  For example, one of the first color and the second color is gray. In this case, the 3D image display apparatus 1 determines the distance from the viewpoint in each region based on the depth value 36, and is expressed in gray shades in the region close to the viewpoint, and a color different from gray as the distance from the viewpoint increases. A multi-color three-dimensional image 34 that is expressed so as to increase the density ratio is generated. On the other hand, the 3D image display apparatus 1 determines the distance from the viewpoint in each region based on the depth value 36, and the region close to the viewpoint is expressed by light and shade of a color different from gray and is far from the viewpoint. Accordingly, a multi-color three-dimensional image 34 that is expressed so that the ratio of gray shades increases may be created.

  For example, when the single-color three-dimensional image 32 is a grayscale image, the multi-color three-dimensional image 34 is added to the single-color three-dimensional image 32 by changing one of the first color and the second color to gray. The color of the minute is added. Thereby, the user can easily compare the single-color three-dimensional image 32 and the multi-color three-dimensional image 34.

  In the graph shown in FIG. 4, the horizontal axis represents the distance from the viewpoint, and the vertical axis represents the density. As shown in FIG. 4, when the density change of the first color is monotonously decreased, the density change of the second color is monotonously increased. Conversely, when the density change of the first color is monotonously increased, the density change of the second color is monotonously decreased. The three-dimensional image display device 1 adds a plurality of colors having such density changes to the single-color three-dimensional image 32 to create a multi-color three-dimensional image 34.

  Next, with reference to FIGS. 5-11, the detail of the process performed with the three-dimensional image display apparatus 1 which concerns on embodiment of this invention is demonstrated.

  As shown in FIG. 5, the CPU 11 creates a single-color three-dimensional image 32 and a depth image 33 from the original image data 31 (S1). Note that the CPU 11 may directly acquire the depth value Di in S3 without creating the depth image 33 here.

  Next, the CPU 11 designates the coordinate adr of the first pixel in the image space (S2). The image space is a two-dimensional plane having the horizontal direction as the X axis and the vertical direction as the Y axis. The size of the image space (X, Y) and the sampling interval are arbitrary, but the single-color three-dimensional image 32, the depth image 33, and the multi-color three-dimensional image 34 are all set to the same size and sampling interval. In S2 and S5 described later, the CPU 11 designates the coordinates adr from the image space (X, Y) one by one like (X0, Y0), (X1, Y1),.

Here, the depth value Di will be described with reference to FIG. FIG. 6 shows the relationship between the tomographic image 41, the origin plane 42, and the depth value Di. The cross section of the tomographic image 41 is a plane perpendicular to the body axis direction of the subject. The present invention is not limited to the tomographic image 41, but is also an MPR (Multi Planar Reconstruction) image or CPR (Curved).
(Planar Reconstruction) It may be applied to images.

  The example shown in FIG. 6 is based on the parallel projection method in which the viewpoint is regarded as a plane and projected by parallel projection lines from this plane to the projection plane. The origin plane 42 means a plane that is the origin of the projection line.

  In the example shown in FIG. 6, the starting surface 42 is not a flat surface but a curved surface having irregularities. This solves the problem that the observation target organ cannot be observed when another organ that blocks the observation target organ exists, that is, when another organ exists between the viewpoint and the observation target organ. It is. A line of intersection between the tomographic image 41 and the starting point plane 42 is a starting point curve 43. In the example of FIG. 6, the organ to be observed is the kidney. As shown in FIG. 6, in order to make the kidney observable, the starting curve 43 is a line graph. In the case of the starting point curve 43 shown in FIG. 6, there is no other organ between the viewpoint and the kidney.

  The depth value Di is a value based on the distance from the starting point curve 43 (starting point surface 42) to the pixel whose pixel value satisfies the threshold condition. By using such a depth value Di, the three-dimensional image display device 1 can create a multi-color three-dimensional image 34 in which an organ to be observed can be observed. In the example shown in FIG. 6, as the simplest example, the direction of the projection line (→) is the vertical direction (the Y-axis direction of the image space). However, the direction is not limited to this, and any direction can be used. good.

  In addition, the CPU 11 sets another reference plane parallel to the starting surface 42 separately from the starting surface 42 defined as the set of the starting point curves 43, and the distance from the reference surface to the specific pixel that satisfies the threshold value is set to the depth. The value Di may be used. Hereinafter, the “starting surface” includes this reference surface.

  Next, the CPU 11 acquires a pixel value (single color shading value) a and a depth value Di of the single-color three-dimensional image 32 at the coordinates adr (S3). When the depth image 33 is not created in S1, the CPU 11 may calculate the depth value Di in S3.

  Next, the CPU 11 determines (R, G, B) which are pixel values (color values) of the multi-color three-dimensional image 34 at the coordinates adr according to a predetermined monotone function (S4). The color value is generally calculated by the following formula.

(R, G, B) = (f1 (a, Di), f2 (a, Di), f3 (a, Di)) (1)

  Here, a is a single color shading value, Di is a depth value, and f1, f2, and f3 are arbitrary monotone functions.

  Expression (1) means that the color value is obtained according to a monotone function having the depth value Di of the same pixel and the single color gray value a of the same pixel as variables. The three-dimensional image display device 1 obtains a color value according to such a monotone function, thereby monotonously increasing or decreasing the density change of the first color as it approaches the viewpoint, and the first color as it becomes far from the viewpoint. Applying a plurality of colors to the single-color three-dimensional image 32 by monotonously decreasing or increasing the density change of the second color so that the density of the second color different from that of the first color is opposite to the density change of the first color. Can do.

  Further, a third color, a fourth color, and the like different from the first color and the second color may be defined. In this case, for the third color, the fourth color, etc., for example, the distance to the viewpoint monotonously increases or decreases near the middle, and “0” (no color is added at a position close to or far from the viewpoint. It may mean.)

  Next, the CPU 11 designates the coordinates adr of the next pixel in the image space (S5), and confirms whether all the coordinates in the image space have been designated (S6). If there is a coordinate that has not been specified (No in S6), the CPU 11 repeats the process from S3. If all the coordinates have been specified (Yes in S6), the CPU 11 controls the display device 17 to display the multi-color three-dimensional image 34 and stores the data of the multi-color three-dimensional image 34 in the storage device 13. Store (S7).

  As a simple example of the multi-color three-dimensional image 34, FIG. 7 shows a multi-color three-dimensional image 34a created in accordance with the following equation with respect to the single-color three-dimensional image 32a shown in FIG.

(R, G, B) = (C1 × a + C2 × Di, a, C1 × a + C2 × Di) (2)

  Here, C1 and C2 are positive constants. In the example of FIG. 7, the first color is “gray” and the second color is “purple”. In addition, since a color image cannot be used in the patent drawing, FIG. 7 is grayscale converted by a general-purpose image processing software from what was originally a color image.

  In FIG. 8, as another example, multi-color three-dimensional images 34b and 34c are shown. In FIG. 8, the closer to the viewpoint, the higher the density of “purple” of the second color, and the farther from the viewpoint, the higher the density of “gray” of the first color.

  FIG. 9 shows a single-color three-dimensional image 32b using opacity as another example of the single-color three-dimensional image 32. In the single-color three-dimensional image 32b, the depth value Di is a distance from the origin plane 42 until the virtual ray is reduced to a predetermined percentage (including 0%).

  FIG. 10 shows a multi-color three-dimensional image 34d created according to the following equation with respect to the single-color three-dimensional image 32b shown in FIG.

(R, G, B) = (a, C1 × a + C2 × Di, a) (3)

  Here, C1 and C2 are positive constants. In the example of FIG. 10, the first color is “gray” and the second color is “green”. In addition, since a color image cannot be used in the patent drawing, in FIG. 10, the original color image is grayscale converted by general-purpose image processing software.

  As shown in FIGS. 7 and 10, by adding a positive value (C2 × Di) to the single color shading value a as shown in the equations (2) and (3), as shown in FIGS. Color brightness does not decrease. That is, since a positive value (C2 × Di) is added to all the pixels, the luminance increases in all the pixels (however, when C2 × Di = 0, the increase in luminance is 0). Therefore, it can be said that visibility is maintained even in a region that is far from the viewpoint because it is neither darkened nor blurred as compared with the single-color three-dimensional image 32.

  FIG. 11 shows an example of the operation screen 51. The operation screen 51 includes a monochrome / color selection radio button 52 and a color selection radio button 53. On the operation screen 51, the first color is fixed to “gray” and the second color is selected by the user. In FIG. 11, “color” is selected for the monochrome / color selection radio button 52, and “other” is selected for the color selection radio button 53. When the color selection radio button 53 is “other”, the CPU 11 displays a color palette screen on the display device 17 as a pop-up screen, and allows the user to select a desired color. In the example shown in FIG. 11, “purple” is selected as the second color. In addition, since a color image cannot be used in the patent drawing, in FIG. 11, the original color image is grayscale converted by general-purpose image processing software.

  As described above, according to the three-dimensional image display device 1 according to the embodiment of the present invention, perspective information between regions where the difference in the pixel value of the original image is small while maintaining the visibility of the region that is far from the viewpoint. Can be accurately presented.

  The preferred embodiments of the three-dimensional image display device and the like according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

1 ... 3D image display device 11 ... CPU
12 ......... Main memory 13 ......... Storage device 14 ......... Communication I / F
15: Display memory 16: I / F
17 ... …… Display device 18 ... …… Mouse 19 ... …… Keyboard 20 ... …… Network 21 ... …… Medical image capture device 31 ... …… Original image data 32 ……… Single color 3D image 33 ……… Depth Image 34... Multiple color 3D image 35... Single color gray value (pixel value of single color 3D image)
36 ... Depth value (pixel value of depth image)
37 ......... Color value (pixel value of multi-color 3D image)
41 ... …… Tomographic image 42 ... …… Starting point 43 ……… Starting point curve 51 ……… Operation screen 52 ……… Black / white / color selection radio button 53 ……… Color selection radio button

Claims (6)

A three-dimensional image display device that displays a multi-color three-dimensional image in which perspective information of each region can be identified,
First creation means for creating a single-color three-dimensional image from original image data;
Obtaining means for obtaining a pixel value of a depth image corresponding to the original image data;
The distance from the viewpoint in each region is determined based on the pixel value of the depth image, and the density change of the first color is monotonously increased or decreased as the distance from the viewpoint increases, and the first color increases as the distance from the viewpoint increases. A plurality of colors in the single color three-dimensional image by monotonically decreasing or increasing the density change of the second color so that the density of the second color different from the density change of the first color is opposite to the density change of the first color. A second creating means for creating the multi-color three-dimensional image;
Display control means for controlling display of the multi-color three-dimensional image;
A three-dimensional image display device comprising: The second creating means colors the single-color three-dimensional image according to a monotonic function having the pixel value of the depth image of the same pixel and the pixel value of the single-color three-dimensional image of the same pixel as variables. The three-dimensional image display apparatus according to claim 1. 3. The three-dimensional image display device according to claim 1, wherein the pixel value of the depth image is a value based on a distance from a starting surface to a pixel in which the pixel value satisfies a threshold condition. 4. The three-dimensional image display device according to claim 1, wherein the second creating unit sets one of the first color and the second color to gray. 5. A three-dimensional image display device that displays a multi-color three-dimensional image in which perspective information of each region can be identified,
The distance from the viewpoint in each region is determined, the density change of the first color is monotonously increased or decreased according to the distance from the viewpoint, and the density of the second color different from the first color is set to the first color. A three-dimensional image display device that creates the multi-color three-dimensional image by monotonously decreasing or increasing the density change of the second color so as to be opposite to the density change. A three-dimensional image display method for displaying a multi-color three-dimensional image in which perspective information of each region can be identified,
A first creation step of creating a single color three-dimensional image from the original image data;
An acquisition step of acquiring a pixel value of a depth image corresponding to the original image data;
The distance from the viewpoint in each region is determined based on the pixel value of the depth image, and the density change of the first color is monotonously increased or decreased as the distance from the viewpoint increases, and the first color increases as the distance from the viewpoint increases. A plurality of colors in the single color three-dimensional image by monotonically decreasing or increasing the density change of the second color so that the density of the second color different from the density change of the first color is opposite to the density change of the first color. A second creation step of creating the multi-color three-dimensional image;
A display control step for controlling display of the multi-color three-dimensional image;
A three-dimensional image display method comprising: