Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Photoacoustic measurement in an imaging system is a unique method as it uses optical disturbance but observes its effect acoustically. Acoustical observation increases the quality of a measurement by reducing the scattering effect that often occurs in optical research. However, a few problems, such as cost and complexity, hinder development of a photoacoustic system. This report presents a design of a photoacoustic system using a laser diode and a commercial microphone as the acoustic emission source and sensor, respectively. Analysis of the photoacoustic signal received by the microphone was performed with software-based Fourier transformation, which makes the photoacoustic system simpler and lower in cost. By measuring the amplitude of the signal, the system accurately detects surface micrometer cracks. The report shows that the system is capable of producing a photoacoustic image of an object with micro-cracks on its surface. The results indicate that the photoacoustic imaging system developed in the experiment is a more promising way to generate images of cracks than optical imaging

Abstrak :
ABSTRAK
Belimbing manis merupakan buah yang memiliki kualitas rasa dan tekstur yang optimal jika berada pada tingkat kematangan yang tepat. Pada penelitian ini, sebuah pencitraan hiperspektral telah dirancang untuk memprediksi nilai soluble solids content (SSC) dan firmness serta memprediksi tingkat kematangan buah belimbing yang diklasifikasikan dalam tiga kelas yaitu mentah, matang dan terlalu matang. Pengklasifikasian ini akan dilakukan berdasarkan informasi spasial, informasi spektral dan kombinasi informasi spektral dan spasial dari citra hiperspektral dengan wilayah panjang gelombang 400-1000 nm. Tahapan-tahapan pengolahan citra yang dilakukan adalah akuisisi citra, koreksi citra, segmentasi, ekstraksi dan seleksi fitur, pemodelan kuantitatif menggunakan algoritma principal component regression (PCR) dan partial least square regression (PLSR) serta pemodelan kualitatif menggunakan algoritma support vector machines (SVM). Pengujian kinerja model kualitatif untuk memprediksi tingkat kematangan dapat dilihat berdasarkan nilai error klasifikasi dan pengujian kinerja model kuantitatif untuk memprediksi nilai SSC dan firmness dapat dilihat dari nilai koefisien korelasi dan root mean square error. Model kualitatif terbaik diperoleh dengan error klasifikasi 6,5%. Model kuantitatif untuk memprediksi SSC diperoleh dengan mengimplementasikan PLSR dengan nilai koefisien korelasi dan RMSE sebesar 0,98 dan 0,42. Model kuantitatif untuk memprediksi firmness diperoleh dengan mengimplementasikan PLSR dengan nilai koefisien korelasi dan RMSE sebesar serta 0,94 dan 4,72.

---

ABSTRACT
Starfruit is a fruit that has a quality of taste and texture optimal if it is at the right level of ripeness. In this study, a hyperspectral imaging has been designed to predict the soluble solids content (SSC) and firmness values and to predict the starfruit ripenesslevels classified in three classe unripe, ripe and overripe. This classification will be based on spatial information, spectral information and a combination of spectral and spatial information from hyperspectral image with the region of the waveleght 400-1000 nm. Steps of image processing are image acquisition, image correction, segmentation, feature extraction and selection, quantitative modeling using principal component regression (PCR) and partial least square regression (PLSR) algorithms and qualitative modeling using support vector machines (SVM) algorithm . Qualitative model performance test to predict ripeness level can be seen based on classification error value and quantitative model performance test to predict the value of SSC and firmness can be seen from the correlation coefficient and root mean square error. The best qualitative model is obtained with a classification error of 6.5%. The quantitative model for predicting SSC was obtained by implementing PLSR with correlation coefficient and RMSE of 0.98 and 0.42. Quantitative models for predicting firmness are obtained by implementing PLSR with correlation coefficient and RMSE of 0.94 and 4.72.

Abstrak :
Uji kontrol kualitas pada sistem pencitraan sinar-X diperlukan untuk mengetahui kualitas sistem pencitraan sinar-X. Kualitas sistem pencitraan sinar-X yang baik akan menghasilkan kualitas citra yang baik dengan mengikuti prinsip ALARA (as low as reasonably achievable). Penelitian ini dilakukan untuk mendapatkan analisa dalam melakukan uji kontrol kualitas dengan menggunakan fantom in-house. Parameter Modulation Transfer Function (MTF) dan Signal Difference to Noise Ratio (SDNR) digunakan sebagai parameter yang merepresentasikan kualitas sistem pencitraan sinar-X dan kualitas citra yang dihasilkan. MTF merupakan parameter performa sistem pencitraan sinar-X. Penelitian menunjukkan bahwa MTF tidak memiliki korelasi dengan faktor eksposi dan kualitas berkas sinar-X. Resolusi spasial tertinggi yang didapatkan pada penelitian ini adalah 2.57 lp/mm. Sementara itu, SDNR merupakan parameter kuantitatif dari kualitas citra yang dihasilkan. Pengukuran SDNR menunjukkan bahwa kualitas citra memiliki korelasi linear dengan kualitas berkas sinar-X. Semakin tinggi kualitas berkas sinar-X maka kualitas citra yang dihasilkan juga akan semakin tinggi. Studi ini menunjukkan perlunya penelitian lebih lanjut mengenai analisa kualitas sistem pencitraan sinar-X dengan fantom in-house untuk memudahkan uji kontrol kualitas. ......A quality control is needed to determine the quality of the X-ray imaging system. A good quality in X-ray imaging system will produce a good image quality according to the principle of ALARA (as low as reasonably achievable). This study was conducted to analyze quality control tests using in-house phantom. Modulation Transfer Function (MTF) dan Signal Difference to Noise Ratio (SDNR) are used as representative parameters of quality of the X-ray imaging system and image quality. MTF is a performance parameter of an X-ray imaging system. Research shows that MTF has no correlation with the exposure factors and beam quality. The highest spatial resolution obtained in this study was 2.5740 cycles/mm. Meanwhile, SDNR is a quantitative parameter of the image quality produced. SDNR measurements show that image quality has a linear correlation with the beam quality. If the X-ray beam quality increased, the image quality will also be higher. This study shows the need for further research on the quality analysis of X-ray imaging systems with in-house phantom to facilitate quality control testing.