Analyzing method and device for automatically sorting products such as fruit

An analysing device or the automatic sorting of products, the device comprising:

• a conveyer line for transporting the products along a longitudinal axis (x), the line having a plurality of rollers (3, 4) which are mounted so as to each rotate freely about a transverse axis of rotation orthogonal to the axis (x) and are spaced apart in such a way that two adjoining rollers (3, 4) define, between them, a seating for a product,
• means for analysing the surface of the products, which means are arranged above the conveyer line and have a number of successive stations (5-7) arranged at a distance from one another along the axis (x),
• means (20) for driving the rollers (3, 4) in rotation about their axes of rotation, which means are suitable for bringing about rotation of the rollers between the analysing stations (5-7) in such a way that different faces of the products are analysed at each station,
• and a processing unit adapted to receive information emanating from the analysing means, and to calculate workable sorting data from predefined, programmed criteria,
• wherein:
• the analysing means comprise three analysing stations, each of the analysing stations (5-7) having at least one camera (8, 9, 12, 14) which is orientated and adapted to make, with an adjustable frequency, photographs of the products transported by the conveyer line,
• one of the stations (5) having two cameras (8, 9) which are arranged on either side of the conveyer line in the same vertical plane orthogonal to the axis (x), and are orientated in such a way that their respective optical axes form a V which is centred on the axis (x) and has a vertex angle substantially in the range between 90° and 130°,
• the other two stations (6, 7) each comprising a camera (12, 14) which is arranged plumb with the conveyer line and is orientated in such a way that its optical axis is vertical and secant with the axis (x),
• the means (20) for driving the rollers (3, 4) in rotation are arranged in such a way as to bring about continuous rotation of the rollers along the analysing means, at a speed of rotation which is adapted so that a product of predetermined average diameter which is located in the plane of a camera (8, 9) at the first station (5) and is caused to revolve on itself along the whole of the analysing means under the effect of the rotation of the rollers, undergoes a rotation such that four complementary zones of its surface are viewed by the respective cameras (8, 9, 12, 14) of the first, second and third stations (5-7),
• the processing unit is adapted to:
• process, for each product, mi photographs of the products taken at the first station (5), where i≧3, nj photographs taken at the second station (6), where j≧1, and pk photographs taken at the third station (7), where k≧3,
• and to determine, by a comparison of the theoretical diameter of this product with the predetermined average diameter, from the photographs made at the three stations, the individual photographs from the three stations to be taken into account with a view to analysing the product, in such a way as to obtain a complete analysis, without overlapping or with a given overlap, of the total surface of the product.

An analysing method for sorting products which are transported along an axis (x) on a conveyer line having a plurality of rollers (3, 4) which are mounted so as to each rotate freely about a transverse axis of rotation orthogonal to the axis (x), and which are spaced apart in such a way that two adjoining rollers (3, 4) define, between them, a seating for a product, the analysing method consisting in using analysing means which are split up into a number of successive stations (5, 6, 7) arranged at a distance from one another along the axis (x), and in causing the rollers (3, 4) to revolve about their axes of rotation between the stations (5, 6, 7) in such a way as to display, at each of the stations, different faces of each product, wherein

• three analysing stations (5-7) are arranged along the conveyer line, and each of the analysing stations is equipped with at least one camera (8, 9, 12, 14) which is orientated and adapted to make, with an adjustable frequency, photographs of the products transported by the conveyer line,
• one of the stations (5) having two cameras (8, 9) which are arranged on either side of the conveyer line in the same vertical plane orthogonal to the axis (x), and are orientated in such a way that their respective optical axes form a V which is centred on the axis (x) and has a vertex angle substantially in the range between 90° and 130°,
• the other two stations (6, 7) each comprising a camera (12, 14) which is arranged plumb with the conveyer line and is orientated in such a way that its optical axis is vertical and secant with the axis (x),
• in a preliminary phase, there are determined the average diameter of the products to be analysed and, as a function of the average diameter, a speed of rotation of the rollers (3, 4) which is adapted so that a product of average diameter which is located in the plane of a camera (8, 9) at the first station (S) and is caused to revolve on itself along the whole of the analysing means under the effect of the rotation of the rollers, undergoes a rotation such that four complementary zones on its surface are viewed by the respective cameras (8, 9, 12, 14) of the first, second and third stations (5-7),
• and during the conveying of the products, the rollers (3, 4) are caused to revolve continuously at the predetermined speed of rotation, and for each product,
• at least three photographs of this product are made by each camera at the first station (5), at least one photograph of this product is made by each camera at the second station (6), and at least three photographs of this product are made by each camera at the third station (7),
• the theoretical diameter of this product is calculated from the photographs made, and
• comparing the theoretical diameter of this product with the predetermined average diameter to determine a selection of one of the photographs made at each of the cameras of the three stations to have a set of selected photographs allowing analysis of this product's complete surface with only a given overlap of surface between any two of the selected photographs.