Defect detection apparatus and method

1. A defect detection apparatus comprising:

a region setter which sets a region of interest in an image including a plurality of pixels; and

a defect detector which divides the region of interest into a plurality of segments and generates a trend line for each of the segments based on gray level values of the pixels,

wherein the defect detector detects a stain in the image by comparing the gray level values of the pixels with the trend line.

2. The apparatus of claim 1 , wherein the defect detector calculates the gray level values of the pixels disposed in each of the segments along at least one of a vertical line and a horizontal line.

3. The apparatus of claim 1 , wherein the defect detector generates the trend line by applying a least squares method to the gray level values of the pixels.

4. The apparatus of claim 1 , wherein the defect detector detects the stain in the image by comparing a distance value between a gray level value variation line formed by connecting the gray level values of the pixels and the trend line with a preset value.

5. The apparatus of claim 1 , wherein the region setter converts the image into a black-and-white image and provides the black-and-white image to the defect detector.

6. A defect detection apparatus comprising:

a target object;

a photographing unit which generates an image having a plurality of pixels by photographing the target object; and

a defect determination unit which receives the image and determines whether the target object is defective by detecting a stain in the image,

wherein the defect determination unit divides the image into a plurality of segments, generates a trend line for each of the segments based on gray level values of the pixels, and detects the stain in the image by comparing the gray level values of the pixels with the trend line.

7. The apparatus of claim 6 , wherein the target object includes a protective film.

8. The apparatus of claim 6 , wherein the defect determination unit calculates the gray level values of the pixels disposed in each of the segments along at least one of a vertical line and a horizontal line.

9. The apparatus of claim 6 , wherein the defect determination unit generates the trend line by applying a least squares method to the gray level values of the pixels.

10. A defect detection method comprising:

setting a region of interest in an image including a plurality of pixels;

dividing the region of interest into a plurality of segments;

calculating gray level values of the pixels in each of the segments;

generating a trend line based on the calculated gray level values; and

detecting a stain in the image by comparing the gray level values with the trend line.

11. The method of claim 10 , wherein the calculating of the gray level values calculates the gray level values of the pixels disposed in each of the segments along at least one of a vertical line and a horizontal line.

12. The method of claim 10 , wherein the generating of the trend line generates the trend line by applying a least squares method to the gray level values of the pixels.

13. The method of claim 10 , wherein the detecting of the stain in the image detects the stain in the image by comparing a distance value between a gray level value variation line formed by connecting the gray level values of the pixels and the trend line with a preset value.

14. The method of claim 10 , further comprising:

converting the image into a black-and-white image.

15. The method of claim 10 , further comprising:

generating the image by photographing a target object before the setting of the region of interest.

16. The method of claim 15 , wherein the target object including a protective film.