Process for inspecting the quality of an article in particular one made of glass

• US 20010004401A1
• Filed: 12/13/2000
• Published: 06/21/2001
• Est. Priority Date: 12/15/1999
• Status: Abandoned Application

• Current Assignee: S.G.C.C.
• Original Assignee: S.G.C.C.
• Inventors: Gibrat, Fabrice, Dubois, Philippe
• Application Number:
  US09/734,717
• Publication Number:
  US 20010004401A1
• Time in Patent Office: Days
• US Class Current: 382/142
• CPC Class Codes: G01N 21/90 in a container or its contents G01N21/91 takes precedence
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G07C 3/143 Finished product quality control

Abstract

The article, for example a glass bottle, may exhibit at least one feature, in particular a defect, visible from outside the article, from among features of different types T₁, . . . , Ti, . . . , T_n. In this process, acquisition of a digital image of the article is carried out, this image is processed so as to extract therefrom a region corresponding to this visible feature, the type of the visible feature is identified from among the various types T_l by calculating at least one discriminating parameter P₁, . . . , P_j, . . . P_n characterizing the region, and the type of the feature is used to decide whether the quality of the article is adequate or inadequate. As appropriate, a reference parameter PR characterizing the region is calculated, this reference parameter PR is compared with a threshold parameter dependent on the type of the visible feature, and the result of this comparison is used to decide whether the quality of the article is adequate or inadequate.

Claims

1. A process for inspecting the quality of an article which may exhibit at least one feature, in particular a defect, visible from outside the article, from among features of different types T₁, . . . , T_i, . . . , T_n, in which:

acquisition of a digital image of the article is carried out by means of a matrix camera, and

this image is processed by filtering and segmentation so as to extract therefrom a region (R1, R2) corresponding to the visible feature,

wherein;

the type of the visible feature is identified from among the various types T_i by calculating at least one discriminating parameter P₁, . . . , P_j, . . . , P_n characterizing the region,

the type of the feature is used to decide whether the quality of the article is adequate or inadequate.

2. The process as claimed in

claim 1

, wherein

a reference parameter PR characterizing the region (R1, R2) is calculated,

this reference parameter PR is compared with a threshold parameter dependent on the type of the visible feature, and

the result of this comparison is used to decide whether the quality of the article is adequate or inadequate.

3. The process as claimed in

claim 2

, wherein the reference parameter PR is the number of pixels of the region.

4. The process as claimed in

claim 2

, wherein first and second sets of types T_i of features are distinguished, they being such that any type T_l of feature of the first set corresponds to an invalidating defect and any type T_l of feature of the second set corresponds to a defect whose invalidating nature depends on the reference parameter PR.

5. The process as claimed in

claim 4

, wherein a third set of types T_i of features is distinguished, it being such that no type T_i of feature of the third set corresponds to a possibly invalidating defect.

6. The process as claimed in

claim 1

, wherein, to identify the type of the visible feature from among the types T_i of feature,

a) with each discriminating parameter P_j there is associated,

a fuzzy discriminating parameter P_jF, and

for each type T_i of feature, a possibility distribution D_ij over the set of possible values of the discriminating parameter P_j, this distribution expressing the degree with which it is possible for a type T_l of feature to be identified in view of the discriminating parameter P_j,

b) the compatibility of the fuzzy parameter P_jF with the possibility distribution D_ij is evaluated so as to deduce the possibility A_ij of having identified the type T_i of feature in view of the discriminating parameter P_j.

7. The process as claimed in

claim 6

, wherein,

at least two distinct discriminating parameters P_j, P_k are calculated and

for each type T_i of feature, the two corresponding possibilities A_ij, A_lk of having identified the type T_i of feature in view of the two discriminating parameters P_j, P_k are calculated and the minimum possibility min (A_lj, A_ik) of having identified the type T_i of feature is determined, and

the minimum possibilities min (A_ij, A_ik) of each type T_l of feature are intercompared so as to decide which of the types T_i of feature corresponds to the visible feature.

8. The process as claimed in

claim 7

, wherein the type of the visible feature is considered to be the type T_i of feature having the highest minimum possibility min (A_ij, A_ik).

9. The process as claimed in

claim 7

, wherein the type of the visible feature is considered to be the type T_i of feature having the highest minimum possibility min (A_ij, A_ik), on condition that this highest minimum possibility min(A_ij, A_ik) is greater than a predetermined threshold.

10. The process as claimed in

claim 7

, wherein the type of the visible feature is considered to be the type T_i of feature having the highest minimum possibility min (A_ij, A_ik), on condition that the difference between the highest minimum possibility min (A_ij, A_ik) and the lowest minimum possibility min (A_lj, A_lk) is greater than a predetermined threshold.

11. The process as claimed in

claim 1

, wherein, should it be decided that the quality of the article is inadequate, the latter is sent to a recycling or rejection chain which depends on the type T_l of feature identified.

12. The process as claimed in

claim 1

, wherein each discriminating parameter of a region (R1, R2) is chosen from among parameters characterizing the aspect ratio of the region (R1, R2), the orientation of this region with respect to a reference direction (V), the shape of the region (R1, R2) with respect to a reference shape, such as a rectangle encompassing this region (R1, R2) or the perforated look of the region (R1, R2).

13. The process as claimed in

claim 1

, wherein at least three distinct types T_i of features are defined.

14. The process as claimed in

claim 1

, wherein the article is made of glass and constitutes for example a container.

15. The process as claimed in

claim 1

, wherein it is implemented by a computer program.