Sequentially polarization illumination unit for irradiating (100) the object (120), the image processing apparatus according to an embodiment of the present invention, each of the linearly polarized light of three or more linearly polarized light of three or more angles of the polarization plane is different When the subject is illuminated by the polarization image capturing section that sequentially captures a subject A (140), the polarization transmission axis at each pixel between the object (100) is illuminated by each of the linearly polarized light and a polarization imaging unit for obtaining polarization images obtained by changing three or more sequential orientation and (140). Furthermore, on the basis of the pixel signals output polarization imaging unit (140), to determine the relationship between the brightness value of each pixel and the angle of the polarization plane, the image processing apparatus, polarization intensity value is the maximum for each pixel change the brightness to generate the intensity modulation depth image YD is defined by the ratio of the average luminance and the amplitude of the variation in the luminance value due to a change of the polarization plane of each pixel and the maximum brightness angles image YPH, is defined by the angle of the surface a processing unit 160, the distribution estimating unit on the basis of the intensity modulation depth image and YD intensity maximum angle image YPH, to estimate the azimuthal distribution of the V-shaped groove present on the surface of the subject in one pixel of the (100) and (170) provided.本発明の実施形態における画像処理装置は、偏光面の角度が異なる3種類以上の直線偏光を、順次、被写体(100)に照射する偏光照明部(120)と、3種類以上の直線偏光の各々によって前記被写体が照射されているときに、順次、被写体を撮像する偏光撮像部(140)であって、直線偏光の各々によって被写体(100)が照射されている間に各画素で偏光透過軸の方向を順次3つ以上変化させることにより得られた複数の偏光画像を取得する偏光撮像部(140)とを備えている。この画像処理装置は、更に、偏光撮像部(140)から出力される画素信号に基づいて、偏光面の角度と各画素の輝度値との関係を求め、各画素について輝度値が最大となる偏光面の角度によって定義される輝度最大角画像YPH、および各画素について偏光面の変化にともなう輝度値の変動の振幅と輝度平均値との比率によって定義される輝度変調度画像YDを生成する変動輝度処理
