FR2807187A1 - Method of counting a stack of flat items placed on edge, tilts stack to formed stepped edge profile for stack and uses optical scanning and step recognition to make count - Google Patents

Abstract

The counting method displaces each item (1) in the stack (2) slightly relative to its neighbor, forming a stepped edge profile (5,6) for the stack. The steps are then counted. The stack has the items standing on their edge, and is tilted to one side to allow optical counting from the stepped profile. The profile is first captured then the steps detected.

Description

The present invention relates to a method of counting flat elements arranged in a stack. The flat elements are for example cards or plates of various materials such as plastic, metal, cardboard ...

In the field of data cards, and in particular smart cards, methods have been developed for counting cards when they are arranged in a stack, in particular to be placed in a package.

A first method consists in moving an optical cell along the stack of cards. This counting process generates a lot of errors so that its reliability is insufficient.

A second method is based on the observation that when the cards are light in color the area of separation between two adjoining cards appears darker. This method is implemented by illuminating the stack with a neon and by moving a linear camera along the stack to bring out by contrast the zone of separation between the cards and obtain a representation of the stacking in the form of an alternation of light and dark lines enabling the cards to be distinguished and counted. This process allows reliable counting on white cards but is not very effective when the cards are darker or transparent in color.

An object of the invention is to propose a means of counting flat elements whatever the color or the degree of transparency of the material constituting them.

In order to achieve this goal, there is provided, according to the invention, a method of counting flat elements arranged in a stack, comprising the steps of - shifting the flat elements with respect to each other so that the stacking has a profile comprising a succession of edges, - count the edges thus obtained. Each edge therefore corresponds to a card so that the cards can be easily counted by simply counting the edges. The degree of transparency and the color have little or no effect on the process and the risk of error is thus limited.

Advantageously, the offset is produced by tilting the flat elements relative to a longitudinal direction of the stack.

The shifting operation is then particularly simple and can be carried out by means of device having uncomplicated structure.

Preferably, the counting is carried out optically and includes phases for viewing the profile and recognizing the edges.

Counting is thus carried out without contact and is relatively fast.

Other characteristics and advantages of the invention will emerge on reading the following description of a particular non-limiting embodiment of the invention.

I1 will be referred to the accompanying drawings, among which - Figure 1 is a top view of a stack of cards before the implementation of the counting process, - Figure 2 is a view similar to that of Figure 1 d 'a stack of cards during the counting thereof, - Figure 3 is a schematic front view illustrating the implementation of the counting process.

With reference to FIG. 1, the method according to the invention makes it possible to count cards 1, for example cards conforming to ISO 7010 and 7816 standards whose dimensions are of the order of 85 mm in length, 54 mm in width. and 0.8 mm thick, arranged in a stack generally designated at 2. The cards 1 of the stack 2 are here supported by a conveying surface 3 making it possible, for example, to bring the cards 1 stacked to a post of packaging.

Referring to Figure 2, the counting process begins with the step of tilting the cards 1 relative to a longitudinal direction 4 of the stack.

The cards 1 are thus offset with respect to each other so that the stack 2 has a profile 5 comprising a succession of edges 6. Each edge corresponds to an edge of a card 1 is offset with respect to an edge d 'an adjacent card 1. The offset can be obtained for example by means of two strips which are each fixed to one side of the stack and slide 'one relative to the other parallel to the longitudinal direction 4. It is also possible to bring' stack against a rail extending in a direction forming an angle with the conveying direction. In the case of a stack extending in a vertical direction, the offset can be formed by applying against a side of the stack a plate forming an angle relative to the vertical.

With reference also to FIG. 3, the next step consists in lighting the stack 2 by means of a neon 7 extending parallel to the longitudinal direction 4 near the conveying surface 3. A camera 8 is fixed to the above the conveying surface 3 so that part of the stack 2 adjacent to the edge forming the edges 6 extend between the neon and the camera. The neon 7 may be partially covered with a cover 10 to delimit the beam of light.

It is thus possible to obtain a precise and contrasted visualization of the profile 5 of the stack 2 for example on a screen 9 connected to the camera 8. The visualization of the profile 5 is obtained whatever the nature of the material of which the cards and more particularly whatever its color or degree of transparency. In the case of a transparent card, the only difference in refractive index is sufficient to allow the sawtooth profile of the stack of cards to be properly viewed.

The next step is to count the edges of the profile. This counting can be carried out automatically using optical recognition software.

Of course, the invention is not limited to the embodiment described and it is possible to make variant embodiments without departing from the scope of the invention as defined by the claims.

In particular, although having been described in application to the counting of data cards such as integrated circuit cards, the method according to the invention usable for counting all types of flat elements such as metal plates, made of plastic material , cardboard ... and whatever. the shape thereof, for example circular or polygonal.

In addition, the counting process can be implemented by probing the profile instead of optical recognition. I1 can also be set up by illumination on one side of the stack and detection of reflected light on the same side of the stack as in traditional counting methods but by observing the profile and not the different shades of lines.

Although neon has been described as a light source and has been associated with a camera, it is possible to provide a light source in a non-visible range and use a corresponding profile detector.

Furthermore, the counting method can be used to form batches of a given number of cards by dividing a stack as the stack is scrolled in front of the camera.

Claims (5)

1. Method for counting flat elements (1) arranged in a stack (2), characterized in that it comprises steps of - shifting the flat elements (1) relative to each other so that the stack (2 ) has a profile (5) comprising a succession of edges (), - count the edges (6) thus obtained. 2. Counting method according to claim 1, characterized in that the offset is made inclining flat elements (1) relative to a longitudinal direction (4) of the stack (2). 3. counting method according to claim 1 or claim 2, characterized in that the counting is carried out optically and comprises phases of viewing the profile (5) and recognition of the edges 4. Counting method according to claim 1, characterized in that it comprises the step of viewing the profile of the stack and counting the edges from the display obtained. 5. counting method according to claim 4, characterized in that the display of the profile is obtained by arranging a light source (7) and a profile detector (8) so that an edge of the stack extends between these.