Effects of Spatial Frequency Content on Classification of Face Gender and Expression

Abstract

525The role of different spatial frequency bands on face gender and expression categorization was studied in three experiments. Accuracy and reaction time were measured for unfiltered, low-pass (cut-off frequency of 1 cycle/deg) and high-pass (cutoff frequency of 3 cycles/deg) filtered faces. Filtered and unfiltered faces were equated in root-mean-squared contrast. For low-pass filtered faces reaction times were higher than unfiltered and high-pass filtered faces in both categorization tasks. In the expression task, these results were obtained with expressive faces presented in isolation (Experiment 1) and also with neutral-expressive dynamic sequences where each expressive face was preceded by a briefly presented neutral version of the same face (Experiment 2). For high-pass filtered faces different effects were observed on gender and expression categorization. While both speed and accuracy of gender categorization were reduced comparing to unfiltered faces, the efficiency of expression classification remained similar. Finally, we found no differences between expressive and non expressive faces in the effects of spatial frequency filtering on gender categorization (Experiment 3). These results show a common role of information from the high spatial frequency band in the categorization of face gender and expression. Keywords: facial expression, emotional expression, spatial frequency, face gender.En tres experimentos se estudió el papel de diferentes bandas de frecuencias espaciales sobre la categorización del género y la expresión de las caras. Se tomaron medidas de precisión y tiempo de reacción a caras no filtradas y a caras filtradas a paso bajo (frecuencia de corte de 1 ciclo/grado) y a paso alto (frecuencia de corte de 3 ciclos/grado). Todas las caras fueron igualadas en energía de contraste. En ambas tareas, los tiempos de reacción a las caras filtradas a paso bajo fueron superiores a los de las caras filtradas a paso alto y no filtradas. En la tarea de expresión, se obtuvo este resultado tanto con caras expresivas presentadas por separado (Experimento 1) como con secuencias dinámicas en las que cada cara expresiva era precedida de una versión neutra de la misma cara presentada brevemente (Experimento 2). En el caso de las caras filtradas a paso alto se observaron efectos diferentes sobre la categorización de género y de expresión. Aunque tanto la rapidez como la precisión de la categorización de género se redujeron en esta condición, la eficiencia de la clasificación de la expresión quedó inalterada. Por último, no se encontraron diferencias entre caras expresivas y no expresivas en cuanto a los efectos de las distintas frecuencias espaciales sobre la categorización del género. Estos resultados muestran que la banda de altas frecuencias espaciales desempeña un papel importante en la categorización del género y la expresión de las caras.Palabras clave: expresion facial, expresion emocional, frecuencia espacial, genero de las caras.

Processing of Fear and Anger Facial Expressions: The Role of Spatial Frequency

“…They concluded that low SF bandwidths (<8 cycles/face) were diagnostic for classification of happy expressions, while high SF bandwidths (>32 cycles/face) were critical for processing of sad expressions. However their dependent measures, used also in other studies (Deruelle and Fagot, 2004; Aguado et al, 2010), give no indication as to the level of SF processing. The limitations of calculating a “critical bandwidth” for processing individual facial expressions are becoming increasingly clear, as can be seen from the findings that SF information is flexibly used depending on the task type (Schyns and Oliva, 1999) and/or viewing distance (Smith and Schyns, 2009).…”

“…While the integration of facial identity through SF information has been well documented (Costen et al, 1996; Näsänen, 1999; Goffaux et al, 2003; Rotshtein et al, 2007; Gao and Bentin, 2011), there is less information about how our neural representation of a facial emotion is related to specific SF ranges. Studies which have focused on this issue (Vuilleumier et al, 2003; Deruelle and Fagot, 2004; Aguado et al, 2010; Kumar and Srinivasan, 2011) have examined the effect of high and low SF on the perception of emotional expressions using removal of specific SF components from the target stimuli. For example, Kumar and Srinivasan (2011) showed that low (<8 cycles/face) and high-frequencies (>32 cycles/face) are more critical for the representation of happy and sad expressions, respectively.…”

“…For example, Kumar and Srinivasan (2011) showed that low (<8 cycles/face) and high-frequencies (>32 cycles/face) are more critical for the representation of happy and sad expressions, respectively. Aguado et al (2010) compared reaction time to classification of happy and anger faces and found an advantage of LSF (<12 cycles/degree) over HSF (>3 cycle/degree). Vuilleumier et al (2003), on the other hand, found no differences between reaction time and accuracy for discrimination of fear over neutral expression for low (2–8 cycles/face) and middle (8–16 cycles/face) SF band-pass filtered images.…”

Patch-based probabilistic image quality assessment for face selection and improved video-based face recognition

“…The proposed method is also unlikely to detect minor expression variations, as only low frequency information is used. According to [3,34], expression changes mainly lie in high frequency bands. However, many of the recent face recognition algorithms are capable of handling relatively minor variations in both illumination and expression [15,17,24,28], thus these characteristics of the quality assessment method might be more of a feature than a limitation.…”

Reduced visual discrimination in cochlear implant users

“…Spatial frequency discrimination is known to represent a fundamental building block of visual perception and it is essential for the analysis of fine details in a visual scene [16]. Therefore, we compared spatial frequency discrimination in normal hearing participants and in individuals with a cochlear implant.…”