Visual inspection method and visual inspection apparatus
View Patent ↗In a visual inspection method and apparatus, a picture processing unit converts an original picture, obtained by taking a photograph of a BGA illuminated by a ring illuminator from above, using a camera, and labels a binary picture obtained by this binary conversion. Then, it forms a rectangle circumscribing an outer circumference of a labeling picture obtained by the labeling, and inverts a labeling picture within the formed circumscribing rectangle, and removes a portion of a region formed by the outer circumference and the circumscribing rectangle in a picture obtained by the inversion, and then generates an inspection picture by adding a picture obtained by the removal to the labeling picture, and accordingly judges a pass or rejection of the inspection target sample based on the generated inspection picture. Thus, the inspection can be carried out at high accuracy irrespectively of a low cost.
1. A visual inspection method comprising:
taking a photograph of an illuminated inspection target sample from above to generate an original picture;
using a processor to perform steps comprising:
converting said original picture obtained by said taking into a binary picture;
labeling said binary picture obtained by said converting to generate a labeling picture;
calculating a summation of shade values of said original picture corresponding to said labeling picture generated by said labeling;
judging a pass or rejection of said inspection target sample based on said summation of the shade values obtained by said calculating;
calculating an area of said labeling picture;
calculating an average shade value of said original picture corresponding to said labeling picture by dividing said summation or said shade values of said original picture by said calculated area; and
calculating a total average shade value by averaging all or said calculated average shade values,
wherein said judging is performed by judging said pass or rejection of said inspection target sample based on said calculated total average shade value.
2. The visual inspection method according to claim 1 , further comprising:
generating a new labeling picture by converting pixels around a plurality of pixels forming an outer circumference of said labeling picture generated by said labeling into sub-pixels,
wherein said calculating is performed by calculating a summation of shade values of said original picture corresponding to said new labeling picture obtained by said generating.
3. The visual inspection method according to claim 1 , wherein said judging of said pass or rejection of said inspection target sample is performed based on a difference between said calculated average shade value and said calculated total average shade value, or a rate of said calculated average shade value to said calculated total average shade value.
4. A visual inspection apparatus comprising:
a camera which takes a photograph of an inspection target sample illuminated with an illuminator from above to output an original picture;
a binary conversion unit which converts said original picture outputted from said camera into a binary picture;
a labeling unit which labels said binary picture outputted from said binary conversion unit to generate a labeling picture;
a shade value summation calculation unit which calculates a summation of shade values of said original picture corresponding to said labeling picture generated by said labeling unit;
a judging unit which judges a pass or rejection of said inspection target sample based on said summation of the shade values calculated by said shade value summation calculation unit,
an area calculation unit which calculates an area of said labeling picture;
an average shade value calculation unit which calculates an average shade value of said original picture corresponding to said labeling picture by dividing said summation of the shade values of said original picture calculated by said shade value summation calculation unit by said area calculated by said area calculation unit; and
a total average shade value calculation unit which calculates a total average shade value by averaging all of said average shade values calculated by said average shade value calculation unit,
wherein said judging unit judges said pass or rejection of said inspection target sample based on said average shade value calculated by said average shade value calculation unit, and
said judging unit judges said pass or rejection of said inspection target sample based on said total average shade value calculated by said total average shade value calculation unit.
5. The visual inspection apparatus according to claim 4 , further comprising:
a sub-pixel generating unit which converts pixels around a plurality of pixels forming an outer circumference of said labeling picture generated by said labeling unit into sub-pixels to generate a new labeling picture,
wherein said shade value summation calculation unit calculates a summation of shade values of said original picture corresponding to said new labeling picture generated by said sub-pixel generating unit.
6. The visual inspection apparatus according to claim 4 , wherein said judging unit judges said pass or rejection of said inspection target sample, based on a difference between said average shade value calculated by said average shade value calculation unit and said total average shade value calculated by said total average shade value calculation unit, or a rate of said average shade value calculated by said average shade value calculation unit to said total average shade value calculated by said total average shade value calculation unit.