1. A block noise detector that receives an input video signal including pixel values and a horizontal synchronizing signal, and detects block boundaries due to block noise with an assumed block width, comprising:
a spatial difference comparator for calculating spatial differences by calculating differences between the pixel values of mutually adjacent pixels in the input video signal, detecting edges by comparing the calculated spatial differences, and outputting a decision signal indicating, for each calculated spatial difference, whether an edge is detected at a corresponding position;
a phased accumulator including a plurality of counters for cyclically receiving the decision signal, counting edges detected at different phases in the receiving cycle, and outputting count values at a timing synchronized with the horizontal synchronizing signal; and
a maximum sum and phase detector for outputting a maximum value signal having a maximum value among the count values output by the counters at said timing, and a maximum phase signal indicating a phase at which the maximum value occurs; wherein
the block noise detector outputs a detected block phase signal indicating a detected block phase at which block boundaries occur, based on the maximum phase signal.
2. The block noise detector of claim 1, wherein the spatial difference comparator compares each spatial difference separately with a predetermined number of left-neighboring spatial differences and with a predetermined number of right-neighboring spatial differences, and detects an edge if a predetermined condition is satisfied with respect to either the left-neighboring spatial differences or the right-neighboring spatial differences.
3. The block noise detector of claim 2, wherein the predetermined condition is that the spatial difference be greater than all of the left-neighboring spatial differences, or greater than all of the right-neighboring spatial differences.
4. The block noise detector of claim 1, wherein the maximum phase signal is output as the detected block phase signal.
5. The block noise detector of claim 1, wherein the assumed block width is N pixels and the phased accumulator includes N counters, N being a positive integer.
6. The block noise detector of claim 5, wherein N is eight.
7. The block noise detector of claim 1, further comprising a phase consistency tester including a phase signal condition tester for receiving and comparing the maximum phase signal output by the maximum sum and phase detector for a plurality of consecutive horizontal lines, and outputting the detected block phase signal only if the maximum phase signal has identical values for all of the consecutive horizontal lines.
8. The block noise detector of claim 1, further comprising a thresholder for comparing the maximum value signal with a threshold value and outputting the maximum phase signal as the detected block phase signal, but outputting the detected block phase signal only when the maximum value signal is greater than the threshold value.
9. A block noise reducer including the block noise detector of claim 1 and a horizontal smoother, the horizontal smoother comprising:
a smoothing processor for smoothing the input video signal to generate a smoothed signal; and
a selector for selecting the input video signal and the smoothed signal for output as an output video signal, the smoothed signal being selected in a predetermined continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase, the input video signal being selected for phases outside the predetermined continuous range.
10. A block noise reducer comprising the block noise detector of claim 1, a luminance horizontal smoother, a blue color difference horizontal smoother, and a red color difference horizontal smoother, wherein:
the input video signal includes an input luminance signal, an input blue color difference signal, and an input red color difference signal;
the block noise detector outputs the detected block phase signal according to the input luminance signal;
the luminance horizontal smoother includes a smoothing processor for smoothing the input luminance signal to generate a smoothed luminance signal, and a selector for outputting the smoothed luminance signal as an output luminance signal in a first continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase, and outputting the input luminance signal as the output luminance signal for phases outside the first continuous range;
the blue color difference horizontal smoother includes a smoothing processor for smoothing the input blue color difference signal to generate a smoothed blue color difference signal, and a selector for outputting the smoothed blue color difference signal as an output blue color difference signal in a second continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase, and outputting the input blue color difference signal as the output blue color difference signal for phases outside the second continuous range; and
the red color difference horizontal smoother includes a smoothing processor for smoothing the input red color difference signal to generate a smoothed red color difference signal, and a selector for outputting the smoothed red color difference signal as an output red color difference signal in the second continuous range of phases, and outputting the input red color difference signal as the output red color difference signal for phases outside the second continuous range.
11. A block noise reducer comprising the block noise detector of claim 1, a luminance horizontal smoother, and a color difference horizontal smoother, wherein:
the input video signal includes an input luminance signal and an input color difference signal;
the block noise detector detects block noise according to the input luminance signal and outputs the detected block phase signal;
the luminance horizontal smoother includes a smoothing processor for smoothing the input luminance signal to generate a smoothed luminance signal, and a selector for outputting the smoothed luminance signal as an output luminance signal in a first continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase, and outputting the input luminance signal as the output luminance signal for phases outside the first continuous range; and
the color difference horizontal smoother includes a smoothing processor for smoothing the input color difference signal to generate a smoothed color difference signal, and a selector for outputting the smoothed color difference signal as an output color difference signal in a second continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase, and outputting the input color difference signal as the output color difference signal for phases outside the second continuous range.
12. A block noise reducer comprising a luminance block noise reducer, a blue color difference block noise reducer, and a red color difference block noise reducer, the luminance block noise reducer, the blue color difference block noise reducer, and the red color difference block noise reducer each including the block noise detector of claim 1 and a horizontal smoother, wherein:
the input video signal includes an input luminance signal, an input blue color difference signal, and an input red color difference signal;
the block noise detector in the luminance block noise reducer receives the input luminance signal and outputs a first detected block phase signal indicating a detected luminance block phase;
the horizontal smoother in the luminance block noise reducer includes a smoothing processor for smoothing the input luminance signal and outputting the smoothed luminance signal, and a selector for outputting the smoothed luminance output signal as an output luminance signal in a first continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase, and outputting the input luminance signal as the output luminance signal at phases outside the first continuous range;
the block noise detector in the blue color difference block noise reducer receives the input blue color difference signal and outputs a second detected block phase signal indicating a detected blue color difference block phase;
the horizontal smoother in the blue color difference block noise reducer includes a smoothing processor for smoothing the input blue color difference signal to generate a smoothed blue color difference signal, and a selector for outputting the smoothed blue color difference signal as a blue color difference output signal in a second continuous range of phases including the detected blue color difference block phase, at least one phase preceding the detected blue color difference block phase, and at least one phase following the detected blue color difference block phase, and outputting the input blue color difference signal as the output blue color difference signal for phases outside the second continuous range;
the block noise detector in the red color difference block noise reducer receives the input red color difference signal and outputs a third detected block phase signal indicating a detected red color difference block phase; and
the horizontal smoother in the red color difference block noise reducer includes a smoothing processor for smoothing the input red color difference signal to generate a smoothed red color difference signal, and a selector for outputting the smoothed red color difference signal as a red color difference output signal in a third continuous range of phases including the detected red color difference block phase, at least one phase preceding the detected red color difference block phase, and at least one phase following the detected red color difference block phase, and outputting the input red color difference signal as the output red color difference signal for phases outside than the third continuous range.
13. A method of detecting block noise in an input video signal including pixel values and a horizontal synchronizing signal by detecting block boundaries, the method comprising:
calculating differences between the values of adjacent pixels in the input video signal and outputting the calculated differences as spatial differences;
detecting edges by comparing the calculated spatial differences and outputting a decision signal indicating, for each calculated spatial difference, whether an edge is detected at a corresponding position;
receiving the decision signal cyclically, counting edges detected at different phases in the receiving cycle, and outputting resulting count values at a timing synchronized with the horizontal synchronizing signal;
outputting a maximum value signal having a maximum value among the count values output at said timing, and a maximum phase signal indicating a phase at which the maximum value occurs; and
outputting a detected block phase signal indicating a phase at which the block boundaries occur, based on the maximum phase signal.
14. The method of claim 13, wherein detecting edges further comprises:
comparing each spatial difference separately with a predetermined number of left-neighboring spatial differences and with a predetermined number of right-neighboring spatial differences; and
detecting an edge if a predetermined condition is satisfied with respect to either the left-neighboring spatial differences or the right-neighboring spatial differences.
15. The method of claim 14, wherein the predetermined condition is that the spatial difference be greater than all of the left-neighboring spatial differences, or greater than all of the right-neighboring spatial differences.
16. The method of claim 13, further comprising receiving and comparing the maximum phase signal output for a plurality of consecutive horizontal lines, wherein the detected block phase signal is output only if the maximum phase signal has identical values for all of the consecutive horizontal lines.
17. The method of claim 13, further comprising comparing the maximum value signal with a threshold value, wherein the maximum phase signal is output as the detected block phase signal but the detected block phase signal is output only when the maximum value signal is greater than the threshold value.
18. A method of reducing block noise, comprising:
detecting block noise by the method of claim 13;
smoothing the input video signal to generate a smoothed signal;
outputting the smoothed signal as an output video signal in a predetermined continuous range of phases including the detected block phase, at least one phase preceding the detected block phase, and at least one phase following the detected block phase; and
outputting the input video signal as the output video signal for phases outside the predetermined continuous range.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A bicycle gear changing apparatus comprising:
an upshifting input;
a downshifting input; and
a controller operatively coupled to the upshifting input and the downshifting input to receive upshift signals and downshift signals,
the controller outputting control signals to control a first gear changing device and a second gear changing device in accordance with a synchro-downshift route and a synchro-upshift route that is different from the synchro-downshift route in response to receiving the upshift signals and the downshift signals, the synchro-downshift route having a synchro-downshift point and the synchro-upshift route having synchro-upshift point that is different from the synchro-downshift point, and at least one of the synchro-upshift point and synchro-downshift point being adjustable.
2. (canceled)
3. (canceled)
4. The bicycle gear changing apparatus according to claim 1, wherein
the controller is configured to receive a synchro-downshift point signal to adjust the synchro-downshift point to be an adjusted synchro-downshift point and a synchro-upshift point signal to adjust the synchro-upshift point to be an adjusted synchro-upshift point.
5. The bicycle gear changing apparatus according to claim 4, wherein
the controller stores the adjusted synchro-downshift point and the adjusted synchro-upshift point.
6. A bicycle gear changing apparatus comprising:
an upshifting input;
a downshifting input; and
a controller operatively coupled to the upshifting input and the downshifting input to receive upshift signals and downshift signals,
the controller outputting control signals to control a first gear changing device and a second gear changing device in accordance with a synchro-downshift route and a synchro-shift route that is different from the synchro-downshift route in response to receiving the upshift signals and the downshift signals, the synchro-downshift route having a synchro-downshift point and the synchro-upshift route having a synchro-upshift point that is different from the synchro-downshift point,
the controller operating a rear gear changing device, corresponding to one of the first and second gear changing devices, before operating a front gear changing device, corresponding to the other of the first and second gear changing devices, to accomplish a synchro-upshifting operation.
7. A bicycle gear changing apparatus comprising:
an upshifting input;
a downshifting input; and
a controller operatively coupled to the upshifting input and the downshifting input to receive upshift signals and downshift signals,
the controller outputting control signals to control a first gear changing device and a second gear changing device in accordance with a synchro-downshift route and a synchro-upshift route that is different from the synchro-downshift route in response to receiving the upshift signals and the downshift signals, the synchro-downshift route having a synchro-downshift point and the synchro-upshift route having synchro-upshift point that is different from the synchro-downshift point,
the controller operating a front gear changing device, corresponding to one of the first and second gear changing devices, before operating a rear gear changing device, corresponding to the other of the first and second gear changing devices, to accomplish a synchro-upshifting operation.
8. The bicycle gear changing apparatus according to claim 1, further comprising
a first derailleur that corresponds to the rear gear changing device; and
a second derailleur that corresponds to the front gear changing device.
9. The bicycle gear changing apparatus according to claim 1, wherein
the controller outputs the control signals to control a gear ratio established by the first gear changing device and the second gear changing device such that the gear ratio changes in an ascending order during an upshift operation and in a descending order during a downshift operation.
10. The bicycle gear changing apparatus according to claim 1, wherein
the controller outputs the control signals to control a gear ratio established by the first gear changing device and the second gear changing device such that the gear ratio changes in an ascending order during an upshift operation.
11. The bicycle gear changing apparatus according to claim 1, wherein
the controller outputs the control signals to control a gear ratio established by the first gear changing device and the second gear changing device such that the gear ratio changes in a descending order during a downshift operation.