A housing of inkjet head has a projection that is formed with a plurality of opening grooves defined between adjacent two of projecting parts, and tip ends of the projecting parts are fixed to a diaphragm plate. Workpieces are portioned both to shape and weight, such as to a weight-specific uniform shape, by adjusting a desired template shape until the desired weight is achieved depending on the varying thickness of each workpiece. The spectra of emitted infrared wavelengths in each zone can have the same or different profile. The initial offer is a combination and preferably an addition of each of the displayed values. Correlated double sampling can be used to obtain the pixel output value, which is also free from common-mode noise, from the differential reset and pixel signals.