Image processing device, method for processing image, and program for processing image
An image processing device is comprising: an input unit which inputs image data of a chart; and a streak detection processing unit which specifies an inspection region in the inputted image data, calculates a line average which is an average of all pixels on a line, for each line in a sub-scanning direction in the inspection region, calculates a width average value which is an average of the line averages of the lines corresponding to a series of main scanning pixels, the number of which is a specified width and whose center is a target pixel, for each target pixel, calculates a difference between the width average value, and the average of the line averages of the target pixel and a predetermined number of main scanning pixels, and determines that the target pixel is included in a streak when the difference exceeds the threshold value set in advance.
1. An image processing device comprising:
an input unit which inputs image data of a chart for inspection; and
a streak detection processing unit which specifies an inspection region in the image data inputted by the input unit,
calculates a line average value which is an average value of all pixels on a line, which corresponds to a main scanning pixel, for each line in a sub-scanning direction in the inspection region,
calculates a width average value which is an average value of the line averages of the lines corresponding to a series of main scanning pixels, the number of which is a specified width and whose center is a target pixel, for each target pixel which is a main scanning pixel selected sequentially in a inspection direction from the first main scanning pixel to the last main scanning pixel,
calculates a difference between the width average value, and the average value of the line average values of the target pixel and a predetermined number of main scanning pixels which are the nearest to the target pixel located at a backward side of the target pixel with respect to the inspection direction, and
determines that the target pixel is included in a streak when the difference exceeds the threshold value set in advance.
2. The image processing device according to claim 1 , wherein the streak detection processing unit calculates as the width average value a weighted average value from the line average values corresponding to the series of main scanning pixels using a weighting coefficient for the target pixel and another weighting coefficient for the main scanning pixels other than the target pixel.
3. The image processing device according to claim 1 , wherein when calculating the difference between the width average value, and the average value of the line averages of the target pixel and the predetermined number of main scanning pixels, the streak detection processing unit uses the line averages of the predetermined number of main scanning pixels which are the nearest to the target pixel among main scanning pixels which are determined to be not included in a streak.
4. The image processing device according to claim 1 wherein
an output device that displays detection result information, which includes information of a streak which is detected, is connected to the image processing device,
the streak detection processing unit stores the detection result information and outputs the detection result information to the output device.
5. The image processing device according to claim 1 , wherein
the streak detection processing unit calculates the difference for ID each color of R, G and B and compares it with a threshold value set in advance for each color of R, G, and B, respectively.
6. An image processing method comprising:
inputting image data of a chart for inspection;
specifying an inspection region in the image data;
calculating a line average value which is an average value of all pixels on a line, which corresponds to a main scanning pixel, for each line in a sub-scanning direction in the inspection region;
calculating a width average value which is an average value of the line averages of the lines corresponding to a series of main scanning pixels, the number of which is a specified width and whose center is a target pixel, for each target pixel which is a main scanning pixel selected sequentially in a inspection direction from the first main scanning pixel to the last main scanning pixel;
calculating a difference between the width average value, and the average value of the line average values of the target pixel and a predetermined number of main scanning pixels which are the nearest to the target pixel located at a backward side of the target pixel with respect to the inspection direction; and
determining that the target pixel is included in a streak when the difference exceeds a threshold value set in advance.
7. A non-transitory computer readable medium embodying an image processing program which causes a computer to execute a process comprising:
inputting image data of a chart for inspection;
specifying an inspection region in the image data;
calculating a line average value which is an average value of all pixels on a line, which corresponds to a main scanning pixel, for each line in a sub-scanning direction in the inspection region;
calculating a width average value which is an average value of the line averages of the lines corresponding to a series of main scanning pixels, the number of which is a specified width and whose center is a target pixel, for each target pixel which is a main scanning pixel selected sequentially in a inspection direction from the first main scanning pixel to the last main scanning pixel,
calculating a difference between the width average value, and the average value of the line average values of the target pixel and a predetermined number of main scanning pixels which are the nearest to the target pixel located at a backward side of the target pixel with respect to the inspection direction; and
determining that the target pixel is included in a streak when the difference exceeds a threshold value set in advance.