This paper presents a hardware design, arrangement and measurement for optical tomography where optical tomography uses light sources as the transmitter and photodiodes as the receiver. By using parallel projection for 44 laser transmitters and photodiode receivers at the cross-sectional boundary, the existence of bubbles inside a vertical column pipeline is determined. Octagon modelling with an eight-sided jig is used for projection and the measurement method for this research is shown. An offline technique is used to collect readings from each signal and the image is reconstructed from the data received.