PORTLAND, Ore., July 29 -- FLIR Systems Inc. has reported revenue of $42.2 million for the second quarter ended June 30, 1999. This compares with last quarter's revenue of $34.4 million, and with the $49.4 million reported in the second quarter of 1998. Net earnings were $2.8 million, or 20 cents per diluted share, as compared with net earnings for the same period of 1998 of $3.4 million, or 27 cents per diluted share. The company had reported a net loss before acquisition-related charges of $2.6 million, or 18 cents per diluted share, during the first quarter of 1999.The results include the operations of Inframetrics Inc., which merged with FLIR Systems in March of 1999. The transaction was accounted for as a pooling of interests; prior periods have been restated accordingly.Sales to commercial customers totaled $28.7 million, or 68 percent of revenue, for the second quarter, reflecting strong sales of FLIR's ThermaCam 570. Commercial sales during the first quarter of 1999 were $27.6 million, while sales to commercial customers for the second quarter of 1998 totaled $33.6 million. The company reported $13.6 million, or 32 percent of revenue, in sales to government customers during the quarter, attributing the results to increased sales of FLIR's Star SAFIRE system. Government sales totaled $15.8 million during the same period in 1998, and $6.8 million during the first quarter of 1999.