Image display apparatus and image display method

1. An image display apparatus, comprising:

an image-light projection device configured to display a display image; and

processing circuitry configured to

determine whether a chromaticity of the display image is within a predetermined two-dimensional chromaticity coordinate area of background light of the display image, the predetermined two-dimensional chromaticity coordinate area including a plurality of different coordinates within a defined closed boundary, and

when determining that the chromaticity of the display image is within the predetermined two-dimensional chromaticity coordinate area of the background light of the display image, convert the chromaticity of the display image into a chromaticity outside the predetermined two-dimensional chromaticity coordinate area of the background light having the defined closed boundary.

2. The image display apparatus according to claim 1 , further comprising

a first detector configured to detect a chromaticity of the background light to determine the chromaticity coordinate area of the background light.

3. The image display apparatus according to claim 2 , wherein the detector is further configured to obtain a two-dimensional distribution of the background light.

4. The image display apparatus according to claim 3 , wherein when the two-dimensional distribution of the background light is obtained, a chromaticity coordinate area of the background light that overlaps with the display image is obtained for conversion performed by the processing circuitry.

5. The image display apparatus according to claim 1 , wherein

the chromaticity coordinate area of the background light is obtained by detecting and collecting a chromaticity of the background light in advance.

6. The image display apparatus according to claim 1 , further comprising a second detector configured to detect environmental light around the display image.

7. The image display apparatus according to claim 6 , wherein the processing circuitry is further configured to correct a brightness of the display image according to lightness of the environmental light detected by the second detector.

8. The image display apparatus according to claim 6 ,

wherein the second detector detects a chromaticity of the environmental light, and

the processing circuitry is further configured to correct the chromaticity coordinate area of the background light to a corrected chromaticity coordinate area of the background light, using the detected chromaticity of the environmental light, to convert the chromaticity of the display image into the chromaticity outside the corrected chromaticity coordinate area of the background light.

9. The image display apparatus according to claim 6 ,

wherein the processing circuitry is further configured to convert the chromaticity coordinate area of the background light into a corrected chromaticity coordinate area of the background light in which the detected environmental light is taken into consideration, using a chromaticity of the detected environmental light,

the processing circuitry is further configured to determine whether the chromaticity of the display image is within the corrected chromaticity coordinate area of the background light where the environmental light is taken into consideration, and

when the chromaticity of the display image is within the corrected chromaticity coordinate area, the processing circuitry is further configured to convert the chromaticity of the display image into a chromaticity outside the corrected chromaticity coordinate area of the background light.

10. The image display apparatus according to claim 1 , wherein

the processing circuitry is further configured to convert the chromaticity of the display image and a chromaticity of the chromaticity coordinate area of the background light such that a color difference between the chromaticity of the display image and the chromaticity of the chromaticity coordinate area of the background light becomes equal to or greater than a prescribed threshold.

11. The image display apparatus according to claim 1 , wherein the processing circuitry is further configured to obtain a vector in which any fixed point on the chromaticity coordinate area is a starting point and a chromaticity dot of the display image is an ending point, and set a point on an extension of the obtained vector extended from the ending point as a new chromaticity dot of the display image.

12. The image display apparatus of claim 11 , wherein the starting point of the vector obtained by the processing circuitry represents white.

13. The image display apparatus according to claim 1 , wherein

the image display apparatus is a heads-up display that displays the display image on a front windshield or combiner of a vehicle.

14. The image display apparatus of claim 1 , wherein when determining that the chromaticity of the display image is not within the predetermined chromaticity coordinate area of the background light of the display image, the processing circuitry is further configured to not convert the chromaticity of the display image.

15. A method of displaying an image, the method comprising:

determining whether a chromaticity of the display image is within a predetermined two-dimensional chromaticity coordinate area of background light of the display image, the predetermined two-dimensional chromaticity coordinate area including a plurality of different coordinates within a defined closed boundary, and

when determining that the chromaticity of the display image is within the predetermined two-dimensional chromaticity coordinate area of the background light of the display image, converting the chromaticity of the display image into a chromaticity outside the predetermined two-dimensional chromaticity coordinate area of the background light having the defined closed boundary.

16. The method according to claim 15 , further comprising:

obtaining the chromaticity coordinate area of the background light by detecting and collecting a chromaticity of the background light in advance.

17. The method according to claim 15 , further comprising:

detecting a chromaticity of the background light; and

determining the chromaticity coordinate area of the background light.

18. The method according to claim 15 , further comprising

detecting lightness of environmental light around the display image,

wherein the converting includes correcting brightness of the display image according to the detected lightness of the environmental light.

19. The method according to claim 15 , further comprising detecting a chromaticity of environmental light around the display image,

wherein the converting includes converting the chromaticity coordinate area of the background light into a corrected chromaticity coordinate area of the background light in which the environmental light is taken into consideration,

the convening includes determining whether the chromaticity of the display image is within the corrected chromaticity coordinate area of background light, and

when the chromaticity of the display image is within the corrected chromaticity coordinate area, the converting includes converting the chromaticity of the display image into a chromaticity outside the corrected chromaticity coordinate area of the background light.

20. The method according to claim 15 , wherein

the converting includes converting the chromaticity of the display image and a chromaticity of the chromaticity coordinate area of the background light such that a color difference between the chromaticity of the display image and the chromaticity of the chromaticity coordinate area of the background light becomes equal to or greater than a prescribed threshold.