Artificial Perceptual Sensors - Artificial Human Sensors: Science and Applications - page 145

Figure 6.10. The automated crumb testing system (a), compared to the human perceptual
method (b). Figure (b) shows a person knocking on the bread with finger-tips. Photo cour-
tesy and copyright Peter Wide c 2010.
The human simply puts the fruit in a close proximity to the ear and when knock-
ing with the finger-tips at the rind, experiences the characteristic response of the
sound. This frequency related human-based sensing method identifies a sound
spectra that is corresponding to ripeness of the fruit. In both cases, the person is
able to make a measurement based on the individual's own perception abilities.
However, the “finger-tip” test is to verify that the baked bread is properly baked
or the ripeness of fruits.
A corresponding artificial sensor technique has been demonstrated in Fig. 6.10
to indicate the possibility of making a similar performance to the operator's per-
ceptual ability to recognise the status of proper crumb in the commercially baked
bread process. A unit pulse is automatically introduced on the base surface of the
baked bread when entering the cooling section after the oven unit. The response
sound when is artificially detected and further analysed.
The artificial sensor system presented in Fig. 6.10 uses the same principles
when applying a knocking on the bread surface. In Fig. 6.10(a), a detector prin-
ciple using a laser distance sensor and in Fig. 6.10(b), the human ear is used to
detect the response sound.
A very short duration impulse is applied to the base surface of the newly baked
bread. The applied pulse will simulate a theoretical unit pulse and the response
of the system is formed by the inside of the loaf bread, i.e., the crumb bounded
by the volume of the crusted surface. Two alternative measurement methods have
been tested to evaluate the response of an oscillating transient response function,
a microphone and a laser distance method. The procedure is similar to that of an
experienced operator's measurement by the sensing organs by applying a pulse
and detecting the following response sound.
The industrial food production process in general, and especially in the