ABSTRAKSI: Saat ini, IT Telkom menggunakan sistem presensi secara manual yakni melalui lembar presensi yang dicetak oleh bagian rooster. Mahasiswa dan dosen menandatangani lebar tersebut dan kemudian petugas rooster akan merekapitulasi presensi secara manual. Beberapa kekurangan dari metode tersebut antara lain : paper-loss, less-effective. Untuk memberikan alternatif untuk mekanisme presensi manual di lingkungan kampus IT Telkom maka dirancanglah sistem presensi otomatis berbasis barcode ini. Barcode tipe Code 39 yang telah tercetak di KTM mahasiswa akan digunakan sebagai tanda pengenal. Sistem mengenali barcode melalui proses cropping, pixel acquisition, pixel segmentation, thickness counting dan recognition. Algoritma yang dirancang dapat memberikan akurasi 100% dan waktu komputasi kurang dari satu detik.Kata Kunci : Presensi, barcode, recognition, real-timeABSTRACT: Today, IT Telkom use manual presence system that is printed – presence list. Students and lecturer must sign in the list and then rooster officer will check the list manually. Some of the disadvantages of this system are: paper-loss, less-effective. In order to give a new alternative for IT Telkom’s manual presence system mechanism, the automatic presence system based on barcode is designed. Code 39 type of barcode that have been printed in student’s ID card is used for personal identification .The system recognizing the barcode through cropping, pixel acquisition, pixel segmentation, thickness counting and recognition process. The algorithm is particularly useful for real-time recognition with high accuracy and less processing time.Keyword: Presence, barcode, recognition, real-time