Method and device for counting objects

A method for counting objects, comprising:

• illuminating a photosensitive assembly comprising at least one photoconducting element, by a source of uniform illumination;
• determining a reference current that is supplied by an illuminated region of the photosensitive assembly, wherein said illuminated region has an elementary surface area which is a given fraction of a surface area of the photosensitive assembly;
• placing objects to be counted against the photosensitive assembly, and illuminating the photosensitive assembly with said source, the objects masking a part of the surface of the photosensitive assembly;
• measuring a current supplied by the illuminated surface of the photosensitive assembly masked by the objects to be counted;
• and
• determining a count of objects based on the measured current and on the reference current,
• wherein the photosensitive assembly comprises a passive matrix of N rows and P columns of photoconducting elements, N and P being integers each greater than or equal to 1, each situated at an intersection between a row conductor and a column conductor of the passive matrix,
• wherein the passive matrix comprises at least one reference column having a known number k of non-illuminated elementary surfaces, k being an integer or zero, said reference column being used to determine the reference current corresponding to an illumination of a single elementary surface area, and
• wherein the passive matrix comprises at least one other reference column comprising k′ non-illuminated elementary surfaces, k′ being different from k, and the difference in the currents of the two reference columns is measured so as to deduce from this the current generated by the illumination of a single elementary surface area.