A method and system for conducting online market research is provided. Computer-readable instructions to a computing device of a participant, the computing device having a display, a network interface coupled to a network, and a camera configured to capture image sequences of a user of the computing device. The computer-readable instructions cause the computing device to simultaneously display at least one of an image, video, and text via the display and capture an image sequence of the participant via the camera, and transmit the captured image sequence to a server via the network interface. The image sequence is processed using an image processing unit to determine a set of bitplanes of a plurality of images in the captured image sequence that represent the hemoglobin concentration (HC) changes of the participant to detect the person's invisible emotional states based on HC changes. The image processing unit is trained using a training set comprising a set of subjects for which emotional state is known.
