Apparatus for and method of recording image based on detected recording duty ratio
View Patent ↗The intensity of a light beam is controlled accurately depending on an image to be recorded on a photosensitive medium. An apparatus for recording an image by scanning a photosensitive medium with a light beam generated based on an image signal has a recording duty ratio detector for detecting a recording duty ratio of an image to be recorded on the photosensitive medium based on the image signal, and a light beam intensity correcting memory for modulating the intensity of the light beam based on the detected recording duty ratio. Since the intensity of the light beam is modulated based on the recording duty ratio of the image recorded on the photosensitive medium, the amount of light of the light beam can be adjusted depending on the image actually recorded on the photosensitive medium.
1. An apparatus for recording an image by scanning a photosensitive medium with a light beam generated based on an image signal, comprising:
recording duty ratio detecting means for detecting a recording duty ratio of an image to be recorded on the photosensitive medium based on the image signal; and
light beam intensity modulating means for modulating the intensity of the light beam based on the detected recording duty ratio,
wherein said photosensitive medium is of such a nature that an area irradiated with light remains as an image, and
wherein said light beam intensity modulating means comprises means for modulating the intensity of the light beam to a higher level when recording pixels are in a highlight area of the image when compared to recording pixels in other areas of the image that have higher gradation values.
2. An apparatus according to claim 1 , wherein said highlight area is defined by a given area on said photosensitive medium with a gradation value that is less than 25% of all gradations of said image recorded on said photosensitive medium.
3. An apparatus according to claim 1 , wherein said recording duty ratio detecting means comprises a low-pass filter.
4. An apparatus according to claim 1 , wherein said recording duty ratio detecting means comprises means for detecting a recording duty ratio corresponding to a given area in the image recorded on said photosensitive medium.
5. The apparatus according to claim 1 , wherein the intensity of the light beam is set to a first intensity value for a highlight area that has a gradation value less than or equal to 6% of a maximum permissible gradation value for a given area on said photosensitive medium, and
wherein the intensity of the light beam is set to a second intensity value, which is lower than the first intensity value, for an area of the image that has a gradation value greater than or equal to 25% of all gradations of said image recorded on said photosensitive medium.
6. The apparatus according to claim 5 , wherein the intensity of the light beam transitions linearly from the first intensity value to the second intensity value for areas of the image that have gradation values between 6% and 25% of all gradations of said image recorded on said photosensitive medium.
7. A method of recording an image by scanning a photosensitive medium with a light beam generated based on an image signal, comprising the steps of:
detecting a recording duty ratio of an image to be recorded on the photosensitive medium based on the image signal; and
modulating the intensity of the light beam based on the detected recording duty ratio,
wherein said photosensitive medium is of such a nature that an area irradiated with light remains as an image, and said step of modulating the intensity of the light beam comprises the step of modulating the intensity of the light beam to a higher level when recording pixels are in a highlight area of the image when compared to recording pixels in other areas of the image that have higher gradation values.
8. A method according to claim 7 , wherein said highlight area is defined by a given area on said photosensitive medium with a gradation value that is less than 25% of all gradations of said image recorded on said photosensitive medium.
9. The method according to claim 7 , wherein the intensity of the light beam is set to a first intensity value for a highlight area that has a gradation value less than or equal to 6% of a maximum permissible gradation value for a given area on said photosensitive medium, and
wherein the intensity of the light beam is set to a second intensity value, which is lower than the first intensity value, for an area of the image that has a gradation value greater than or equal to 25% of all gradations of said image recorded on said photosensitive medium.
10. The method according to claim 9 , wherein the intensity of the light beam transitions linearly from the first intensity value to the second intensity value for areas of the image that have gradation values between 6% and 25% of all gradations of said image recorded on said photosensitive medium.
11. An apparatus for recording an image by scanning a photosensitive medium with a light beam generated based on an image signal, comprising:
a recording duty ratio detecting circuit that detects a recording duty ratio of an image to be recorded on the photosensitive medium based on the image signal; and
a light beam intensity modulating circuit that modulates the intensity of the light beam based on the detected recording duty ratio,
wherein said photosensitive medium is of such a nature that an area irradiated with light remains as an image, and
wherein said light beam intensity modulating circuit modulates the intensity of the light beam to a higher level when recording pixels are in a highlight area of the image when compared to recording pixels in other areas of the image that have higher recording duty ratios.
12. The apparatus according to claim 11 , wherein said highlight area is defined by a given area on said photosensitive medium with a gradation value that is less than 25% of all gradations of said image recorded on said photosensitive medium.
13. The apparatus according to claim 11 , wherein the intensity of the light beam is set to a first intensity value for a highlight area that has a gradation value less than or equal to 6% of a maximum permissible gradation value for a given area on said photosensitive medium, and
wherein the intensity of the light beam is set to a second intensity value, which is lower than the first intensity value, for an area of the image that has a gradation value greater than or equal to 25% of all gradations of said image recorded on said photosensitive medium.
14. The apparatus according to claim 13 , wherein the intensity of the light beam transitions linearly from the first intensity value to the second intensity value for areas of the image that have gradation values between 6% and 25% of all gradations of said image recorded on said photosensitive medium.