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US 7,443,543 B2Granted
Image processing apparatus and image processing method
AssigneeCanon Kabushiki Kaisha
InventorHiroshi Kaburagi
Life of this patent
Estimating the term…
Abstract
A smoothing process is performed on image data to obtain improved image quality. Output image data is switched among image data subjected to smoothing, image data subjected to second bit conversion, and image data subjected to pseudo halftone representation process. In this manner, jaggies at edges can be smoothed even in multilevel image data subjected to image forming process such as screen processing. Smoothing for image data with degraded image quality due to, for example, lossy compression such as JPEG compression can also be achieved. Furthermore, degradation in image quality that occurs when a conventional smoothing process is applied to image data subjected to particular image processing can be avoided.
Claims24
An image processing system comprising:
- an input unit for inputting N-bit image data;
- a pseudo halftone representation unit for converting the N-bit image data into M-bit image data;
- a first bit conversion unit for converting the N-bit image data into L-bit image data;
- a control signal generation unit for generating a control signal from the L-bit image data;
- a first edge detection unit for detecting a first edge from the control signal generated by the control signal generation unit;
- a second edge detection unit for detecting a second edge from the control signal generated by the control signal generation unit;
- a second bit conversion unit for converting the L-bit image data into M-bit image data;
- a smoothing unit for smoothing the L-bit image data and generating M-bit image data;
- and
- an output image data switching unit for switching output image data between the image data output by the smoothing unit, the image data output by the second bit conversion unit, and the image data output by the pseudo halftone representation unit, wherein the output image data depends on the first and second edges detected by the first and second edge detection units.
7 more elements
An image processing system comprising:
- an input unit for inputting N-bit image data;
- a pseudo halftone representation unit for converting the N-bit image data into M-bit image data;
- a first bit conversion unit for converting the N-bit image data into L-bit image data;
- a control signal generation unit for generating a control signal from the M-bit image data;
- a first edge detection unit for detecting a first edge from the control signal generated by the control signal generation unit;
- a second edge detection unit for detecting a second edge from the control signal generated by the control signal generation unit;
- a second bit conversion unit for converting the L-bit image data into M-bit image data;
- a smoothing unit for smoothing the L-bit image data and generating M-bit image data;
- and
- an output image data switching unit for switching output image data among the image data output by the smoothing unit, the image data output by the second bit conversion unit, and the image data output by the pseudo halftone representation unit, depending on the first and second edges detected by the first and second edge detection units.
7 more elements
An image processing method comprising:
- an input step of inputting N-bit multilevel image data;
- a pseudo halftone representation step of converting the N-bit image data into M-bit image data;
- a first bit conversion step of for converting the N-bit image data into L-bit image data;
- a control signal generation step of generating a control signal from the L-bit image data;
- a first edge detection step of detecting a first edge from the control signal generated in the control signal generation step;
- a second edge detection step of detecting a second edge different from the first edge from the control signal generated in the control signal generation step;
- a second bit conversion step of converting the L-bit image data into M-bit image data;
- a smoothing step of smoothing the L-bit image data and generating M-bit image data as a result of the smoothing;
- and
- an output image data switching step of switching output image data among the image data output in the smoothing step, the image data output in the second bit conversion step, and the image data output in the pseudo halftone representation step, depending on the first and second edges detected in the first and second edge detection steps.
7 more elements
An image processing method comprising:
- an input step of inputting N-bit multilevel image data;
- a pseudo halftone representation step of converting the N-bit image data into M-bit image data;
- a first bit conversion step of for converting the N-bit image data into L-bit image data;
- a control signal generation step of generating a control signal from the M-bit image data;
- a first edge detection step of detecting a first edge from the control signal generated in the control signal generation step;
- a second edge detection step of detecting a second edge from the control signal generated in the control signal generation step;
- a second bit conversion step of converting the L-bit image data into M-bit image data;
- a smoothing step of smoothing the L-bit image data and generating M-bit image data as a result of the smoothing;
- and
- an output image data switching step of switching output image data among the image data output in the smoothing step, the image data output in the second bit conversion step, and the image data output in the pseudo halftone representation step, depending on the first and second edges detected in the first and second edge detection steps.
7 more elements
Dependencies are inferred from the claim text.