Cuk Imawan

Automatic tilting correction system for inhibition zones dimension measurement using low-cost camera

Currently, manual tools such as rulers or calipers have been used to measure the diameter of the inhibition zone of an antimicrobial. The inhibition zone is the main indicator of an antimicrobial effectiveness. The current camera technology supports for a virtual instrumentation application in measuring the dimension of an object. The presence of another supporting device such as light sources, causing the camera is not an upright position to the measured object. In this study, an automatic tilting correction system is introduced using the low-cost camera to measure the dimension of the inhibition zones in the flexible tilting angle. The hardware of the system consists of a set of the tilt measuring instruments, a source light and a camera that connected to PC. The software consists of image processing techniques performing camera calibration, spatial calibration, geometrical transformations and transforming pixel value to a meter value. The experiments have been conducted using standard checkerboard calibrator objects and inhibition zone objects at various orientations and the angle of rotation of the object. Tilt correction system improves the measurement system performance with a reduction in estimated errors up to 39,6%. The maximum angle with a tolerance level that is acceptable is 40°. The system has been successfully implemented and could be used as an instrument for antimicrobial effectiveness evaluation in flexible tilting position.

Antimicrobial effectiveness measurement using non-metric camera

Currently, an antimicrobial effectiveness that indicated by the diameter of the inhibition zones of antimicrobial was measured using manual tools such as rulers or calipers. In this paper, a camera-based system for virtual measurement of the diameter of the inhibition zones is introduced using a non-metric camera. The hardware consists of a set of measuring instruments, light source, and a camera that connected to PC directly. The software consists of image processing techniques performing camera calibration, spatial calibration, virtual ruler interface and transforming pixel value to a meter value. A standard checkerboard with certain dimension and shape was used as calibrator object to generate camera and spatial calibration parameter. The measurement system was evaluated using a set of standard checkerboard object at various camera object distances, camera angles and object orientation. The average measurement error between actual and computed inhibition diameter obtained from the antimicrobial object are 0.932%, 0.847% and 1.136% at camera-object distance 15 cm, 20 cm and 25 cm, respectively. Finally, the proposed measurement system is very promising and could be used as an instrument for antimicrobial effectiveness evaluation.

Colorimetrie method by using natural dye for monitoring fish spoilage

It is important for a consumer to know whether a fish is fresh or not. One of the simplest and the easiest methods for monitoring fish spoilage can be done through colorimetric method. In this research, a colorimetric label for monitoring fish spoilage by using natural color extract which contains anthocyanin has been developed. The colorimetric label which has been developed is created from cellulose paper coated with the extract through dip coating method. Using the label, fish spoilage measurement is then experimented by monitoring fish chunks placed inside a bottle together with a colorimetric label. Subsequently, monitoring is then performed in a 13 °C, 25 °C and 40 °C temperature condition. Digital photography is used for observing the color change, and the change is further analyzed with ImageJ color analyzer for 0, 2, 17 and 24 hours. From the study, it can be inferred that the colorimetric label used for detecting fish spoilage is marked by the labels color change from purplish pink, when the fish condition is fresh, to purplish blue, when the fish becomes spoiled. In general, there is an indication that the measurements temperature may influence the time for the indicator labels color change. Rising temperature then triggers the color change of the indicator label to become faster. Overall, it is proven by the research that monitoring fish spoilage can be simply and practically done by using the developed colorimetric label.

A green label for acetic acid detection based on chitosan and purple sweet potatoes extract

Acetic acid is commonly found in food ingredients, and it can be used as an antiseptic. Measuring concentration of acetic acid could be done by simply using colored label. As acetic acid detection in food ingredients proliferates, developing toxic-free labels is now a necessity. This research reported the result of an experiment on developing green labels for detecting acetic acid. The green label is made from the extract of chitosan and purple sweet potatoes as smart materials. The extraction color of the purple sweet potatoes changes from red to purple for pH buffer condition from 2 to 7. Chitosan solution and the extract then undergo a casting process in order to make a label, resulting in a transparent thin bright yellow plastic label. The concentration of the detected acetic acid solutions in the experiment was varied from 0% to 15%. The evidences from the experiment showed that the label changed its color from bright yellow to dark yellow in accordance to the changed of acetic acid concentration, which was increasing gradually. By using UV-Vis spectrometer, characterization for the label color change before and after detecting acetic acid was done. By the result, the green label made from extract of chitosan and purple sweet potatoes can be used effectively for detecting acetic acid as simply and quickly.

Local and global human activity detection for room energy saving model

Energy saving is an effort to decrease and minimize unnecessary energy consumption. The energy saving and energy efficiency is one of the famous issues in the last decade since the energy resource is rapidly depleted. Reducing unnecessary energy consumption could be performed by architectural design or automatic system approach. This paper proposes an idea to develop a model of energy usage in a room by detecting and counting the number of peoples and detecting their activities. In order to achieve the energy consumption model, the method consists of two modules: the human detection and the activity quantization of each detected object. The human is detected using multiple registered image channels that computed in linear and non-linear transformations of the input image. The activity of each detected object is approached by computing the movement of an object in a certain time. Moreover, the human activities were represented based on local and global motion of all detected object. Videos were recorded in a classroom to evaluate the performance of the method. In evaluation, the cooling load weight model of student walking and pointing hand activities were computed in certain schema. The results show that the method can predict human activity effectively. The proposed technique is suitable for a small cost of the room energy controller and achieves the goal of energy saving.

Pesticide colorimetric sensor based on silver nanoparticles modified by L-cysteine

This work investigated a new colorimetric sensor for pesticide based on L-cysteine-modified silver nanoparticles (L-cys-AgNPs). The colorimetric sensor was prepared by reducing silver nitrate solutions in the existence of Diospyros blancoi leaf infusion which were then mixed by L-cysteine solution. The L-cys-AgNPs were characterized by UV-Visible Spectrophotometer measuring optical absorbance. Pesticides, namely monosultap and cypermethrin, were detected by mixing them with silver nanoparticles. The fresh L-cys-AgNPs had brownish yellow color inasmuch as surface plasmon resonance absorbance centered at 422 nm. NaCl stimulated color change from brownish yellow to clear which was relied on pesticide concentration of 20, 50 and 100 ppm. In the presence of cypermethrin, L-cys-AgNPs color turned clear and the peak absorbance dropped to 0.17 from 1.15. However, the effect of monosultap toward L-cys-AgNPs was negligible. This sensor allows a direct quantitative check for the detection of cypermethrin.