Inspection of eggs in the presence of blood

A method for inspecting eggs for the presence of blood, in which:

• light is transmitted through an egg to be inspected by means of an LED, which light comprises a first wavelength which is not selectively absorbed by blood and comprises a second wavelength which is selectively absorbed by blood,
• the light transmission through the egg to be inspected at the two wavelengths is converted into corresponding signals, said signals each being representative of the light transmission at the wavelength concerned,
• based on the signals, the ratio is determined between the light transmission associated with the first wavelength and the light transmission associated with the second wavelength and it is decided on the basis of this ratio whether or not an egg contains blood, and
• wherein a variation in the ratio between the light transmission associated with the first wavelength and the light transmission associated with the second wavelength is detected during an inspection of a plurality of eggs in succession and an effect of the variation in the ratio on the decision whether or not an egg contains blood is corrected.

A method for inspecting eggs, using a device for inspecting eggs for the presence of blood, wherein

• light within a certain narrow spectrum is produced by a one or more identical LED's (Light Emitting Diode) and is passed through an egg to be inspected, which narrow spectrum comprises both a first and a second wavelength, wherein the light of the first wavelength is not selectively absorbed by blood and the light of said second wavelength is selectively absorbed by blood,
• light transmission through the egg to be inspected for each of the two wavelengths is converted by detection means into corresponding signals, each of the said signals being representative of the light transmission at the relevant wavelength,
• a ratio between the light transmission associated with the first wavelength and the light transmission associated with the second wavelength is determined by signal processing means based on the signals emanating from the detection means and a decision signal which is representative of the decision whether or not an egg contains blood on the basis of this ratio is emitted by the signal processing means,
• wherein the signal-processing means is designed to detect a variation in the ratio between the light transmission associated with the first wavelength and the light transmission associated with the second wavelength during an inspection of a plurality of eggs in succession and to correct an effect of the variation in the ratio on the decision whether or not an egg contains blood.