1. A block noise detecting method comprising:
detecting a pixel boundary difference across a pixel boundary on the basis of a difference value between pixel values of adjacent pixels across the pixel boundary on a picture plane of an input image frame, and a predicted pixel value on the pixel boundary predicted from at least a plurality of pixels on one side of the pixel boundary; and
accumulating the pixel boundary differences for one image frame to detect a block noise,
wherein the difference value between pixel values of the adjacent pixels is compared with a difference value between the predicted pixel value on the pixel boundary predicted from the plural pixels on one side of the pixel boundary and the predicted pixel value on the pixel boundary predicted from a plurality of pixels on the other side of the pixel boundary, and a smaller difference value is detected as a pixel boundary difference across the pixel border.
2. The block noise detecting method according to claim 1, wherein the pixel boundary differences are accumulated in a cycle of a block noise size.
3. The block noise detecting method according to claim 1, wherein the predicted pixel value on the pixel boundary is calculated from at least two pixels on one side of the pixel border.
4. The block noise detecting method according to claim 1, wherein when the pixel boundary difference is larger than a predetermined threshold value, the pixel border difference is excluded from a group of pixel boundary differences to be accumulated.
5. The block noise detecting method according to claim 1, wherein ratios each of which is a ratio of an accumulated value obtained by accumulating pixel boundary differences across a pixel boundary for one image frame to an accumulated value obtained by accumulating pixel boundary differences across a pixel boundary separated by a half of a block noise size from the former pixel boundary are compared with one another to determine a block noise generation intensity.
6. The block noise detecting method according to claim 1, wherein a block noise generation intensity is determined on the basis of a ratio of the largest value of accumulated values each of which is obtained by accumulating pixel boundary differences across a pixel boundary for one image frame to the second largest value of the accumulated values.
7. The block noise detecting method according to claim 1, wherein a difference between at least two image frames including the input image frame is determined, and determination conditions of block noise detection is controlled such that the block noise is difficult to be detected when a value of the difference is smaller than a predetermined threshold value.
8. The block noise detecting method according to claim 1, wherein when the block noise is detected on an image enlarged by a scaling factor of an integer multiple after the image is decoded, pixel boundary differences are accumulated in a cycle corresponding to the integer multiple of a block noise size.
9. The block noise detecting method according to claim 1, wherein when the same value is obtained as a result of detection of the block noise from successive plural image frames, this result of the detection is outputted.
10. A block noise detecting apparatus comprising:
pixel boundary difference detecting means for detecting a pixel boundary difference across a pixel boundary on the basis of a difference value between pixel values of adjacent pixels across the pixel boundary on a picture plane of an input image frame, and a predicted pixel value on the pixel boundary predicted from at least a plurality of pixels on one side of the pixel boundary;
accumulating means for accumulating the pixel boundary differences for one image frame; and
block noise detecting means for detecting a block noise on the basis of a result of accumulation by said accumulating means,
wherein the difference value between pixel values of the adjacent pixels is compared with a difference value between the predicted pixel value on the pixel boundary predicted from the plural pixels on one side of the pixel boundary and the predicted pixel value on the pixel boundary predicted from a plurality of pixels on the other side of the pixel boundary, and a smaller difference value is detected as a pixel boundary difference across the pixel border.
11. The block noise detecting apparatus according to claim 10, wherein said pixel boundary difference detecting means comprises:
an adjacent pixel difference value calculating unit for determining the difference value between pixel values of the adjacent pixels;
a predicted pixel difference value calculating unit for determining a difference value between the predicted pixel value on the pixel boundary predicted from a plurality of pixels on one side of the pixel boundary and the predicted value on the pixel boundary predicted from a plurality of pixels on the other side of the pixel boundary; and
a comparing unit for comparing results of calculation by the calculating units, and detecting a smaller difference value as a pixel boundary difference across the pixel boundary.
12. The block noise detecting apparatus according to claim 10, wherein said accumulating means accumulates the pixel boundary differences in a cycle of a block noise size.
13. The block noise detecting apparatus according to claim 10, wherein said predicted pixel difference value calculating unit calculates the predicted pixel value on the pixel boundary from at least two pixels on one side of the pixel boundary.
14. The block noise detecting apparatus according to claim 10, wherein when the pixel boundary difference is larger than a predetermined threshold value, said pixel boundary difference detecting means or said accumulating means excludes the pixel boundary difference from a group of pixel boundary differences to be accumulated.
15. The block noise detecting apparatus according to claim 10, wherein said block noise detecting means comprises:
means for comparing, with one another, ratios each of which is a ratio of an accumulated value obtained by accumulating pixel border differences across a pixel border for one image frame by said accumulating means to an accumulated value obtained by accumulating pixel border differences across a pixel border separated by a half of a block noise size from the former pixel boundary to determine a block noise generation intensity.
16. The block noise detecting apparatus according to claim 10, wherein said block noise detecting means comprises:
means for determining a block noise generation intensity on the basis of a ratio of the largest value of accumulated values each of which is obtained by accumulating pixel border differences across a pixel boundary for one image frame by said accumulating means with the second largest value of the accumulated values.
17. The block noise detecting apparatus according to claim 10, further comprising:
frame difference detecting means for determining a difference between at least two image frames including the input image frame; and
controlling means for, when a value of the difference detected by said frame difference detecting means is smaller than a predetermined threshold value, controlling determination conditions of block noise detection by said block noise detecting means such that the block noise is difficult to be detected.
18. The block noise detecting apparatus according to claim 10, wherein when the block noise is detected on an image enlarged by a scaling factor of an integer multiple after the image is decoded, said accumulating means accumulates the pixel border differences in a cycle corresponding to the integer multiple of a block noise size.
19. The block noise detecting apparatus according to claim 10, further comprising:
block noise detection result inspecting means for, when the same value is obtained as a result of detection by said block noise detecting means from successive plural image frames, outputting this result of the detection.
20. A block noise reducing method comprising:
detecting a pixel boundary difference across a pixel boundary on the basis of a difference value between pixel values of adjacent pixels across the pixel boundary on a picture plane of an input image frame, and a predicted pixel value on the pixel boundary predicted from at least a plurality of pixels on one side of the pixel boundary;
accumulating the pixel boundary differences for one image frame to detect a block noise; and
performing a block noise reducing process on the input image frame on the basis of the detected block noise,
wherein the difference value between pixel values of the adjacent pixels is compared with a difference value between the predicted pixel value on the pixel boundary predicted from the plural pixels on one side of the pixel boundary and the predicted pixel value on the pixel boundary predicted from a plurality of pixels on the other side of the pixel boundary, and a smaller difference value is detected as a pixel boundary difference across the pixel border.
21. The block noise reducing method according to claim 20, wherein a filtering intensity of a filtering process as being the block noise reducing process is controlled on the basis of ratios each of which is a ratio of an accumulated value obtained by accumulating pixel border differences across a pixel boundary for one image frame to an accumulated value obtained by accumulating pixel border differences across a pixel boundary separated by a half of a block noise size from the former pixel boundary.
22. The block noise reducing method according to claim 20, wherein a filtering intensity of a filtering process as being the block noise reducing process is controlled on the basis of a ratio of the largest value of accumulated values each of which is obtained by accumulating pixel boundary differences across a pixel boundary for one image frame to the second largest value of the accumulated values.
23. The block noise reducing method according to claim 20, wherein a region on the picture plane to which the block noise reducing process is applied is limited to a pixel boundary and vicinity thereof where a block noise is generated on the basis of the result of block noise detection.
24. The block noise reducing method according to claim 20, wherein when the pixel boundary difference is equal to or larger than a threshold value, the block noise reducing process is not performed.
25. A block noise reducing apparatus comprising:
pixel boundary difference detecting means for detecting a pixel boundary difference across a pixel boundary on the basis of a difference value between pixel values of adjacent pixels across the pixel boundary on a picture plane of an input image frame, and a predicted pixel value on the pixel boundary predicted from at least a plurality of pixels on one side of the pixel boundary;
accumulating means far accumulating the pixel boundary differences for one image frame;
block noise detecting means for detecting a block noise on the basis of a result of accumulation by said accumulating means; and
block noise reducing means for performing a block noise reducing process on the input picture frame on the basis of the block noise detected by said block noise detecting means,
wherein the difference value between pixel values of the adjacent pixels is compared with a difference value between the predicted pixel value on the pixel boundary predicted from the plural pixels on one side of the pixel boundary and the predicted pixel value on the pixel boundary predicted from a plurality of pixels on the other side of the pixel boundary, and a smaller difference value is detected as a pixel boundary difference across the pixel border.
26. The block noise reducing apparatus according to claim 25, further comprising:
filter controlling means for controlling a filtering intensity of a filtering process as being the block noise reducing process by said block noise reducing means on the basis of ratios each of which is a ratio of an accumulated value obtained by accumulating pixel boundary differences across a pixel boundary for one image frame by said accumulating means to an accumulated value obtained by accumulating pixel boundary differences across a pixel boundary separated a half of a block noise size from the former pixel boundary.
27. The block noise reducing apparatus according to claim 25, further comprising:
filter controlling means for controlling a filtering intensity of a filtering process as being the block noise reducing process by said block noise reducing means on the basis of a ratio of the largest value of accumulated values each of which is obtained by accumulating pixel boundary differences across a pixel boundary for one image frame by said accumulating means to the second largest value of the accumulated values.
28. The block noise reducing apparatus according to claim 25, further comprising:
filtering region controlling means for limiting a region on the picture plane to which the filtering process is applied by said block noise reducing means to a pixel boundary and vicinity thereof where a block noise is generated on the basis of a result of detection by said block noise detecting means.
29. The block noise reducing apparatus according to claim 25, further comprising:
filter interruption controlling means for controlling to interrupt the filtering process by said block noise reducing means when the pixel boundary difference is equal to or larger than a threshold value.
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 method for error diagnosis of an ambient-pressure sensor and an intake-manifold pressure sensor of an internal combustion engine, comprising:
measuring a signal of the ambient-pressure sensor and a signal of the intake-manifold pressure sensor while the internal combustion engine is stopped;
comparing an ambient pressure represented by the signal of the ambient-pressure sensor to a first intake-manifold pressure represented by the signal of the intake-manifold pressure sensor to determine a pressure difference; and
if the pressure difference is greater than a predetermined maximum value, measuring at least one additional sensor signal while the internal combustion engine is running, wherein the at least one additional sensor signal is used for identifying a defective sensor.
2. The method as recited in claim 1, wherein the at least one additional sensor signal is delivered by an air volume flow meter.
3. The method as recited in claim 2, wherein a second intake-manifold pressure is determined from the at least one additional sensor signal delivered by the air volume flow meter, using a computing model.
4. The method as recited in claim 3, wherein the second intake-manifold pressure is compared to the first intake-manifold pressure, and wherein the intake-manifold pressure sensor is classified as defective if a pressure difference between the second intake-manifold pressure and the first intake-manifold pressure is greater than a predetermined maximum value.
5. The method as recited in claim 3, wherein the second intake-manifold pressure is compared to the first intake-manifold pressure, and wherein the ambient-pressure sensor is classified as defective if a pressure difference between the second intake-manifold pressure and the first intake-manifold pressure is one of: a) less than a predetermined maximum value; and b) equal to the predetermined maximum value.
6. A method for error diagnosis of an ambient-pressure sensor and an intake-manifold pressure sensor of an internal combustion engine, comprising:
determining an ambient pressure, while the internal combustion engine is stopped, from a signal of the ambient-pressure sensor;
determining a first intake-manifold pressure value, while the internal combustion engine is stopped, from a signal of the intake-manifold pressure sensor;
setting an error entry if a pressure difference between the ambient pressure and the intake-manifold pressure is greater than a first predetermined maximum pressure difference;
determining a second, modeled intake-manifold pressure value from a measured air volume, during operation of the internal combustion engine;
determining a third intake-manifold pressure value, while the internal combustion engine is running, from the signal of the intake-manifold pressure sensor;
setting an error entry for the intake-manifold pressure sensor if a pressure difference between the second, modeled intake-manifold pressure value and the third intake-manifold pressure value is greater than a second predetermined maximum pressure difference; and
setting an error entry for the ambient-pressure sensor if the pressure difference between the second, modeled intake-manifold pressure value and the third intake-manifold pressure value is one of: a) less than the second predetermined maximum pressure difference; and b) equal to the second predetermined maximum pressure difference.
7. A control unit for error diagnosis of an ambient-pressure sensor and an intake-manifold pressure sensor of an internal combustion engine, comprising:
a means for comparing a signal of the ambient-pressure sensor and a signal of the intake-manifold pressure sensor measured while the internal combustion engine is stopped, to determine a first difference quantity; and
a means for determining a modeled intake-manifold pressure value during operation of the internal combustion engine, if the first difference quantity is greater than a first predetermined maximum value;
a means for determining a second difference quantity between the modeled intake-manifold pressure value and an intake-manifold pressure value measured during operation the internal combustion engine; and
a means for identifying a defective sensor, based on a comparison of the second difference quantity and a second predetermined maximum value.