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"ABSTRAKTelah dilakukan percobaan penerapan tapis pada cuplikan citra skala keabuan 8 bit [0-255] yang terkubur dalam bising elektronik akibat dari perekaman pada illumiasi rendah dengan metoda logaritmik, metoda homomorfik dan difinisi sendiri metoda konvolusi dikrit dengan beberapa penopeng [masking]. Disamping itu dilakukan juga pada cuplikan citra yang terkubur dalam bising periodik dan bising acak dengan tapis metoda pemotongan puncak spektral bising, serta tapis median.Dari percobaan tersebut telah diperoleh beberpa metoda yang tepat dan dapat direkomendasikan untuk meningkatkan kualitas ketajaman kontras obyek citra, meminimalkan bising sehingga obyek citra tersebut dapat diidentifikasi. Untuk kasus citra hilal yang tampak blur diterapkan tapis metoda konvolusi diskirit difinisi sendiri, dan tapis metoda homomorfik, sedangkan untuk kasus cuplikan citra hilal dan kendaraan dalam kegelapan, selain dengan tapis seperti metoda tersebut, juga diterapkan metoda pemekaran kontras secara logaritmik.Pada percobaan ini kualitas citra secara visual [tampak mata] yang baik dinilai dari lebar spektrum intensitas skala keabuan pada analisa histogramnya, kontras simultan skala keabuan [Efek Mach Band] dan perubahan frekuensi intensitas tepi [edge] obyek citra terhadap piksel sekitarnya."

"A nonconductor optical technique, having lateral resolution of about 5 μm and vertical resolution of about 0.09 μm, for surface profile (roughness) measurement was studied. It based on a heterodyne interferometer in which two orthogonal polarized beams of slightly different frequencies were used in a modified interference microscope. The beams scanned the surface of a work piece, and the reflected beams were allowed to interfere with one another. The phase of the beat frequency of the interfering return beams is directly proportional to the surface height. The result of a surface measurement include graphical displays of surface profile, roughness (Ra), root mean square (rms) and peak to valley (P-V) value."

"An unpolarized light beam will change to a linear polarized beam by using a polarizing filter. In turn the linear polarized beam can be rotated in an active medium such as glass if a magnetic field exists. This phenomenon, which is known as Faraday effect, is there for can used as a current sensor. In this experiment, the current to be measured was flowed in Helmohltz coils where a homogeneous magnetic field was generated. Bismuth and Flumbo alloys were used as glass medium. An analyzer detected the linear polarized beam came from the glass. The analyzer was adjustable and has a capability to detect a light signal up to 1 mill radian per degree. The values of the rotation of the polarized light beams in the active medium were determined by Verdet's constant. The characteristics of the glasses were represented by plotted curves of rotation angle versus the wavelengths of the light beam, which shows parabolic form. The sensing current by Faraday effect shows a linear feature of rotation angle with respects to the current value, as predicted by the theory. The result also shows that the glass of Bismuth alloy is more sensitive than the Plumbo alloy."

"An experiment demonstrating the principle of mode recognition has been performed. In the experiment, a He-Ne laser with phase synchronized TEMo1 mode is used. This laser has two stable (bistable) states corresponding to be emission of a right- and left- hand helical waves. Injection of light of one state can switch the laser emission to this state. A hologram is used to convert an image to the state of the laser and in turn irradiation of the image into the hologram produces radiation corresponding to the state. Injection of this radiation into a second laser causes the laser switch to the respective state and remain in that state. A second hologram convert the laser states into two images and using the second hologram, the two images can be recognized, distinguished and stored."

"ABSTRACTFor the purpose of optically cooling, trapping, detecting and accelerating Cesium atoms in a "fountain clock", semiconductor lasers with external resonator have been designed, built and tested in their spectral characteristic and their long-term frequency drift. Multiple Quantum Well lasers with AR coating on one end face and a high reflection coating on the other end face have been used which produce 50 mW at 852 nm ( single end output ). With an external grating resonator the line width was reduced to 150 KHz. Doppler emitted and saturated absorption spectra of the two Cs fine structure transitions were recorded. The saturated absorption lines (Lamb dips) were utilized as optical discriminators in order to stabilize the laser frequencies off line center as is required for optical cooling. Beat frequency measurements between two external resonator laser diodes permitted to measure the 150 KHz line width, and to observe the quality of the long-term frequency stabilization. "