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Image Processing and Computer Vision for MEMS Testing
Published in Wolfgang Osten, Optical Inspection of Microsystems, 2019
The following variations exist for digital camera interfaces: Parallel transmission of image information orientated towards pixel data, which uses single-ended TTL signals or signals corresponding with the specifications laid down in RS-422 or EIA-644 (low voltage differential signal, or LDVS). However, these specifications determine only the electrical aspects of the interfaces and do not cover those of transmission protocols, timing, or pin assignment. RS-422 specifies differential data transmission with a signal level of 5 volts, while EIA-644 (LVDS) specifies differential data transmission with signal levels of 3.3 or 3.1 volts.Three different variations of parallel image information transmission via several serial channels defined by the Camera-Link™ specification [3], derived from Channel-Link technology developed by National Semiconductor. The variation known as “base” includes four serial differential LVDS data channels and one differential LVDS clock channel. The variation known as “medium” possesses twice as many and the variation “full” three times the number of data and clock channels. For all these variations, in order to control camera functions (trigger, shutter, mode of operation, etc), four additional differential LVDS camera control channels and a bidirectional RS-232 interface with differential LVDS interface are provided. In addition to specifying electrical aspects, the Camera-Link™ specification defines pin assignment, transmission protocols, data widths (8, 12, and 24 Bits), and the maximum possible transmission rates (base: 255 MBytes/sec, medium: 510 MBytes/sec, and full: 680 MBytes/sec).Serial image information transmission in accordance with the standard IEEE 1394, also known as Fire-Wire and serial transmission in accordance with the USB3 Vision [4] and the GigE Vision [5] specification. All these standards define bidirectional, digital, high-speed communication via a cable, which is also capable of supplying an electrical current to the connected device.Cascadable and multiple serial image information transmission for high-speed/high-volume image acquisition in accordance with the standards CoaXPress [6] and Camera-Link HS [7].
Comparison of optimisation strategies for the improvement of depth detection capability of Pulse-Compression Thermography
Published in Quantitative InfraRed Thermography Journal, 2020
H. Malekmohammadi, S. Laureti, P. Burrascano, M. Ricci
A National Instrument PCI-6711 Arbitrary Waveform Generator (AWG) board and a National Instrument 1433 Camera Link Frame Grabber were connected to a PC, and an ad hoc virtual instrument developed in LabVIEW managed the signal generation/acquisition. The AWG board provided both the wanted linear chirp excitation and a reference clock signal (CLK) for triggering the IR camera acquisition, which was a Xenics Onca-MWIR-InSb camera placed in reflection mode. A sketch of the experimental set-up used is depicted in Figure 3. The coded signal was input into a TDK Lambda GEN 750W power supply that fed eight LED chips in the visible spectrum placed at about 30 cm from the SUT. The LED chips are capable to provide a maximum overall power of 400 W. The thermograms were acquired at 40 FPS.