TWI508558B - Black level adjustment device and black level adjustment method - Google Patents
Black level adjustment device and black level adjustment method Download PDFInfo
- Publication number
- TWI508558B TWI508558B TW102126051A TW102126051A TWI508558B TW I508558 B TWI508558 B TW I508558B TW 102126051 A TW102126051 A TW 102126051A TW 102126051 A TW102126051 A TW 102126051A TW I508558 B TWI508558 B TW I508558B
- Authority
- TW
- Taiwan
- Prior art keywords
- black level
- pixels
- mask
- value
- color mixing
- Prior art date
Links
Landscapes
- Transforming Light Signals Into Electric Signals (AREA)
- Color Television Image Signal Generators (AREA)
Description
本發明係有關於黑階控制(black level control)，特別是有關於在一CMOS影像感測器中的一種黑階控制裝置及方法，其可藉由混色(dithering)來進行黑階控制處理。The present invention relates to black level control, and more particularly to a black level control apparatus and method in a CMOS image sensor that can perform black level control processing by dithering.
第1圖係顯示一傳統的CMOS影像感測器像素陣列(CMOS image sensor pixel array)。CMOS影像感測器像素陣列100可包括暗列(dark row)110及活動列(active row)120，如第1圖所示。在CMOS影像感測器像素陣列100中的像素(例如：R/B/Gr/Gb)會以貝爾圖樣(Bayer Pattern)的方式進行排列。暗列110會被完全遮蔽而不會接收到任何光線，而活動列120會用以接收光線或其入射影像。暗列110係主要在該CMOS影像感測器中的一類比前端中用以調整像素值以輸出適合的黑階。所謂的黑階控制/取消(BLC)處理可利用暗列的輸出像素值以降低由該CMOS影像感測器及不完美的類比電路設計之雜訊所導致的偏差及偏移。Figure 1 shows a conventional CMOS image sensor pixel array. The CMOS image sensor pixel array 100 can include a dark row 110 and an active row 120, as shown in FIG. The pixels (eg, R/B/Gr/Gb) in the CMOS image sensor pixel array 100 are arranged in a Bayer pattern. The dark column 110 will be completely obscured without receiving any light, and the active column 120 will be used to receive light or its incident image. The dark column 110 is mainly used in an analog front end of the CMOS image sensor to adjust pixel values to output a suitable black level. The so-called black level control/cancellation (BLC) process can utilize the output pixel values of the dark columns to reduce the bias and offset caused by the noise of the CMOS image sensor and the imperfect analog circuit design.
一般而言，在CMOS影像感測器中照下一張影像可包括下列步驟：重設並讀取(曝光處理)暗列中的像素；輸出暗列的 像素以進行黑階控制處理；校正類比電路並調整偏移值至合適的輸出黑階值以進行黑階控制處理；在暗列的末端固定黑階控制處理之設定；重設並讀取活動列之像素；依據所固定在暗列中之設定以對活動列之像素值進行黑階控制處理。In general, taking an image in a CMOS image sensor may include the steps of resetting and reading (exposure processing) pixels in a dark column; outputting a dark column The pixel is subjected to black level control processing; the analog circuit is corrected and the offset value is adjusted to an appropriate output black level value for black level control processing; the black level control processing setting is fixed at the end of the dark column; the active column is reset and read The pixel is subjected to black level control processing on the pixel value of the active column according to the setting fixed in the dark column.
除此之外，一般用於補償偏差值之方法是先計算暗 列的平均像素值，並接著將活動列的平均像素值減去暗列的平均像素值。在黑階控制處理中在數位電路中的平均像素值之計算，因為有限精確度的緣故，無法避免會有數值錯誤。在彩色感測器中，在顏色通道中所無法避免的數值錯誤會導致顯著的色彩顏色偏移，特別是當影像信號處理器採用高通道增益在不同的色彩通道的像素上。先前技術會使用一低成本的除法器以計算暗列的平均值。然而，無法避免的數值錯誤是無法被忽視的，且會導致色彩/亮度的閃動，特別是當後端的影像信號處理器使用大通道增益以進行影像處理。In addition, the method generally used to compensate for the deviation value is to calculate the dark first. The average pixel value of the column, and then the average pixel value of the active column is subtracted from the average pixel value of the dark column. The calculation of the average pixel value in the digital circuit in the black-order control process cannot avoid numerical errors due to limited accuracy. In color sensors, numerical errors that are unavoidable in the color channel can result in significant color shifts, especially when the image signal processor uses high channel gain on pixels of different color channels. The prior art uses a low cost divider to calculate the average of the dark columns. However, unavoidable numerical errors cannot be ignored and can cause color/brightness to flicker, especially when the back-end image signal processor uses large channel gain for image processing.
本發明係提供一種黑階調整方法，用於具有一像素陣列之一互補金屬氧化物半導體(CMOS)影像感測器，該像素陣列包括複數個暗列及複數個活動列。該黑階調整方法包括下列步驟：計算來自該等暗列之複數個像素之一平均值，其中該平均值包括一整數部分及一小數部分；依據該整數部分計算一黑階控制偏移值；依據該小數部分產生一混色遮罩；將該混色遮罩應用至該等活動列之複數個像素；以及將所計算之該黑階控制偏移值加至來自該等活動列中已混色後之該等像素以產生複數個結果像 素。The present invention provides a black level adjustment method for a complementary metal oxide semiconductor (CMOS) image sensor having a pixel array including a plurality of dark columns and a plurality of active columns. The black level adjustment method includes the following steps: calculating an average value of one of a plurality of pixels from the dark columns, wherein the average value includes an integer portion and a fraction portion; and calculating a black level control offset value according to the integer portion; Generating a color mixing mask according to the fractional portion; applying the color mixing mask to the plurality of pixels of the activity column; and adding the calculated black level control offset value to the mixed color from the activity columns The pixels to generate a plurality of result images Prime.
本發明更提供一種黑階調整裝置，用於具有一像素 陣列之一互補金屬氧化物半導體(CMOS)影像感測器，該像素陣列包括複數個暗列及複數個活動列，該黑階調整裝置包括：一運算單元，耦接至該等暗列，用以計算來自該等暗列之複數個像素的一平均值，其中該平均值包括一整數部分及一小數部分，且該運算單元更依據該整數部分計算一黑階控制偏移值；一遮罩產生單元，耦接至該運算單元，用以依據該小數部分產生一混色遮罩；一混色處理單元，耦接至該遮罩產生單元及該等活動列，用以應用該混色遮罩至來自該等活動列之複數個像素；以及一偏移計算單元，用以將所計算之該黑階控制偏移值加至來自該等活動列中已混色後的該等像素以產生複數個結果像素。The invention further provides a black level adjusting device for having one pixel a complementary metal oxide semiconductor (CMOS) image sensor of the array, the pixel array comprising a plurality of hidden columns and a plurality of active columns, the black level adjusting device comprising: an arithmetic unit coupled to the dark columns, Calculating an average value of the plurality of pixels from the dark columns, wherein the average value includes an integer part and a fractional part, and the operation unit further calculates a black level control offset value according to the integer part; a mask a generating unit coupled to the computing unit for generating a color mixing mask according to the decimal portion; a color mixing processing unit coupled to the mask generating unit and the activity columns for applying the color mixing mask to a plurality of pixels of the activity; and an offset calculation unit for adding the calculated black level control offset value to the pixels after the color mixing from the active columns to generate a plurality of result pixels .
100‧‧‧CMOS影像感測器像素陣列100‧‧‧ CMOS image sensor pixel array
110‧‧‧暗列110‧‧‧dark
120‧‧‧活動列120‧‧‧Events
10‧‧‧CMOS影像感測器10‧‧‧ CMOS image sensor
20‧‧‧像素陣列20‧‧‧pixel array
200‧‧‧黑階調整裝置200‧‧‧Black level adjustment device
210‧‧‧運算單元210‧‧‧ arithmetic unit
211‧‧‧累加器211‧‧‧ accumulator
212‧‧‧除法器212‧‧‧ divider
213‧‧‧減法單元213‧‧‧Subtraction unit
220‧‧‧遮罩產生單元220‧‧‧mask generation unit
230‧‧‧混色處理單元230‧‧‧Color mixing unit
240‧‧‧偏移計算單元240‧‧‧Offset calculation unit
250‧‧‧暗列250‧‧‧dark
260‧‧‧活動列260‧‧‧ activity column
BLC_target‧‧‧預定黑階值BLC_target‧‧‧ predetermined black level value
BLC_offset‧‧‧黑階控制偏移值BLC_offset‧‧‧Black level control offset value
Pd、Pa‧‧‧像素Pd, Pa‧‧ pixels
Pa_blc‧‧‧結果像素Pa_blc‧‧‧Result pixels
M‧‧‧閥值圖M‧‧‧ threshold map
Mdtr‧‧‧中間混色遮罩Mdtr‧‧‧Intermediate color mixing mask
D‧‧‧混色遮罩D‧‧‧Color mixing mask
i、j‧‧‧座標i, j‧‧‧ coordinates
DN‧‧‧數位數值DN‧‧‧ digits
Blk00 、Blk01 、Blk10 、Blk11 ‧‧‧方塊Blk 00 , Blk 01 , Blk 10 , Blk 11 ‧‧‧
第1圖係顯示一傳統的CMOS影像感測器像素陣列。Figure 1 shows a conventional CMOS image sensor pixel array.
第2圖係顯示依據本發明一實施例中在一CMOS感測器中的黑階調整裝置的方塊圖。2 is a block diagram showing a black level adjustment device in a CMOS sensor in accordance with an embodiment of the present invention.
第3圖係顯示依據本發明一實施例之運算單元210的方塊圖。Figure 3 is a block diagram showing an arithmetic unit 210 in accordance with an embodiment of the present invention.
第4A~4E圖係顯示依據本發明一實施例中用於遮罩產生單元220的閥值圖及混色遮罩的示意圖。4A-4E are schematic diagrams showing a threshold map and a color mixing mask for the mask generating unit 220 in accordance with an embodiment of the present invention.
第5圖係顯示依據本發明一實施例中應用混色遮罩至來自活動列之像素的示意圖。Figure 5 is a diagram showing the application of a color mixing mask to pixels from an active column in accordance with one embodiment of the present invention.
第6A-6C圖係顯示用於傳統黑階控制處理的四捨五入法(rounding)的模擬圖。Figures 6A-6C show a simulation of rounding for conventional black-order control processing.
第7A-7C圖係顯示依據本發明一實施例中用於黑階調整裝置中的混色處理之模擬圖。7A-7C are diagrams showing a simulation of color mixing processing for use in a black level adjustment apparatus in accordance with an embodiment of the present invention.
第8圖係顯示依據本發明一實施例中用於具有一像素陣列之一CMOS感測器中的黑階調整方法的流程圖。Figure 8 is a flow chart showing a black level adjustment method for use in a CMOS sensor having a pixel array in accordance with an embodiment of the present invention.
為使本發明之上述目的、特徵和優點能更明顯易懂，下文特舉一較佳實施例，並配合所附圖式，作詳細說明如下。The above described objects, features and advantages of the present invention will become more apparent from the description of the appended claims.
第2圖係顯示依據本發明一實施例中在一CMOS感測器中的黑階調整裝置的方塊圖。CMOS感測器10係包括一黑階調整裝置200及一像素陣列20，該像素陣列20包括暗列250及活動列260。在一實施例中，黑階調整裝置200可包括一運算單元210、一遮罩產生單元220、一混色處理單元(dithering process unit)230、以及一偏移計算單元240。如第2圖所示，Pa及Pa係分別表示來自暗列250及活動列260中所取得的像素，而BLC_target係表示在該黑階控制處理中的一預定黑階值。運算單元210係耦接至像素陣列20的暗列250以計算暗列250之像素的平均值，其中該平均值係以整數及小數的形態表示。在實用上，不想要有超出特定範圍(例如10~250)的輸出黑階值，因此會設定一使用者定義黑階值(註：BLC_target)。運算單元210更可將該預定黑階值BLC_target(註：使用者定義的黑階值)減去該整數值以計算一黑階控制偏移值 BLC_offset。除此之外，使用者定義之輸出黑階值是選擇性的，且可藉由將BLC_target之數值設定為0以將其忽略。遮罩產生單元220係耦接至運算單元210，其用以依據該小數值以產生一混色遮罩(dithering mask)。混色處理單元230係耦接至遮罩產生單元220及像素陣列20之活動列260，其用以接收來自遮罩產生單元220之混色遮罩，並將該混色遮罩用於來自活動列260之像素。偏移計算單元240係用以將所計的黑階控制偏移值加至混色後的像素以產生結果像素Pa_blc(註：調整過後的活動列之像素以用於後續處理)。2 is a block diagram showing a black level adjustment device in a CMOS sensor in accordance with an embodiment of the present invention. The CMOS sensor 10 includes a black level adjustment device 200 and a pixel array 20 including a dark column 250 and an active column 260. In an embodiment, the black level adjustment device 200 can include an operation unit 210, a mask generation unit 220, a dithering process unit 230, and an offset calculation unit 240. As shown in Fig. 2, Pa and Pa respectively indicate pixels obtained from the dark column 250 and the active column 260, and BLC_target indicates a predetermined black level value in the black level control process. The operation unit 210 is coupled to the dark column 250 of the pixel array 20 to calculate an average value of the pixels of the dark column 250, wherein the average value is expressed in the form of an integer and a decimal. Practically, it is not desirable to have an output black level value that exceeds a certain range (for example, 10 to 250), so a user-defined black level value (Note: BLC_target) is set. The operation unit 210 may further subtract the predetermined black level value BLC_target (the user-defined black level value) to calculate a black level control offset value. BLC_offset. In addition to this, the user-defined output black level value is optional and can be ignored by setting the value of BLC_target to zero. The mask generating unit 220 is coupled to the computing unit 210 for generating a dithering mask according to the decimal value. The color mixing processing unit 230 is coupled to the mask generating unit 220 and the activity column 260 of the pixel array 20 for receiving the color mixing mask from the mask generating unit 220 and using the color mixing mask from the active column 260. Pixel. The offset calculation unit 240 is configured to add the calculated black level control offset value to the mixed color pixels to generate the resulting pixel Pa_blc (note: the pixels of the adjusted active column for subsequent processing).
第3圖係顯示依據本發明一實施例之運算單元210的 方塊圖。請同時參考第2圖及第3圖，在一實施例中，運算單元210係包括一累加器211、一除法器212及一減法單元213。如第3圖所示，累加器211係用以接收來自暗列的像素Pd並計算所有像素Pd的加總值(註：累加值)。除法器212係將該加總值除以所接收的像素Pd之總數量以計算一平均值，其中該平均值係包括一整數部分及一小數部分。除法器212係輸出該小數部分至該遮罩產生單元220以產生該混色遮罩。減法單元213係用以將該預定黑階值減去該整數部分以計算黑階控制偏移值BLC_offset(註：可為正數或負數)。需注意的是所計算的該BLC偏移值係作為一參考黑階，且可利用該參考黑階以調整來自活動列的像素值，可在當使用通道增益至不同的色彩通道(註：在貝爾圖樣中的B,Gb,R及Gr等等)時，藉以維持顏色的一致性。Figure 3 is a diagram showing the operation unit 210 according to an embodiment of the present invention. Block diagram. Referring to FIG. 2 and FIG. 3 simultaneously, in an embodiment, the operation unit 210 includes an accumulator 211, a divider 212, and a subtraction unit 213. As shown in FIG. 3, the accumulator 211 is for receiving the pixels Pd from the dark columns and calculating the summed value of all the pixels Pd (note: accumulated value). The divider 212 divides the summed value by the total number of received pixels Pd to calculate an average value, wherein the average value includes an integer portion and a fractional portion. The divider 212 outputs the fractional portion to the mask generating unit 220 to generate the color mixing mask. The subtraction unit 213 is configured to subtract the predetermined black fraction value from the integer portion to calculate a black-order control offset value BLC_offset (note: may be positive or negative). It should be noted that the calculated BLC offset value is used as a reference black level, and the reference black level can be utilized to adjust the pixel value from the active column, which can be used when using channel gain to different color channels (Note: In the Bell pattern, B, Gb, R and Gr, etc., to maintain color consistency.
第4A~4E圖係顯示依據本發明一實施例中用於遮罩 產生單元220的閥值圖及混色遮罩的示意圖。在一實施例中，遮罩 產生單元220可接收由運算單元210所產生的小數部分，並依據該小數部分及閥值圖M以產生一中間混色遮罩(intermediate dithering mask)，其中閥值圖M係如第4A圖所示。舉例來說，給定該小數部分A為7(註：二進位的0111)，當在閥值圖M中的元素小於該小數部分，則遮罩產生單元220會設定在中間混色遮罩Mdtr中的相關元素為16。否則，遮罩產生單元220會設定在中間混色遮罩Mdtr中的相關元素為0。在閥值圖M中小於該小數部分的元素會被標示，如第4B圖所示，且相關的中間混色遮罩Mdtr係如第4C圖所示。遮罩產生單元220更可將該中間混色遮罩Mdtr除以16以產生混色遮罩D。換言之，遮罩產生單元220會正規化(normalize)該中間混色遮罩以產生該混色遮罩D，如第4D圖所示。另一方面來說，該中間混色遮罩是可以忽略的。換言之，遮罩產生單元220可比較來自暗列250的像素與在閥值圖M中的各個相關像素。若該像素小於該相關元素，遮罩產生單元220會直接設定在該混色遮罩D中的該相關元素為1。否則，遮罩產生單元220會直接設定在該混色遮罩D中的該相關元素為0。需注意的是在該閥值圖M中的元素之順序並不限定於本發明之形式。舉例來說，每4個連續數字(例如0-3、4-7、8-11及12-15)可對稱地排列在閥值圖中之不同的矩陣，如第4E圖所示。4A-4E are diagrams for masking in accordance with an embodiment of the present invention A threshold map of the generating unit 220 and a schematic diagram of the color mixing mask. In an embodiment, the mask The generating unit 220 can receive the fractional portion generated by the computing unit 210, and generate an intermediate dithering mask according to the fractional portion and the threshold map M, wherein the threshold map M is as shown in FIG. 4A. . For example, given that the fractional part A is 7 (note: binary input 0111), when the element in the threshold map M is smaller than the fractional part, the mask generating unit 220 is set in the intermediate color mixing mask Mdtr. The relevant element is 16. Otherwise, the mask generating unit 220 sets the relevant element in the intermediate color mixing mask Mdtr to be zero. Elements smaller than the fractional part in the threshold map M are indicated, as shown in Fig. 4B, and the associated intermediate color mixing mask Mdtr is as shown in Fig. 4C. The mask generating unit 220 may further divide the intermediate color mixing mask Mdtr by 16 to generate a color mixing mask D. In other words, the mask generating unit 220 normalizes the intermediate color mixing mask to produce the color mixing mask D as shown in FIG. 4D. On the other hand, the intermediate color mixing mask is negligible. In other words, the mask generating unit 220 can compare the pixels from the dark column 250 with the respective related pixels in the threshold map M. If the pixel is smaller than the related element, the mask generating unit 220 directly sets the related element in the mixed color mask D to 1. Otherwise, the mask generating unit 220 directly sets the related element in the color mixing mask D to zero. It should be noted that the order of the elements in the threshold map M is not limited to the form of the present invention. For example, every 4 consecutive numbers (eg, 0-3, 4-7, 8-11, and 12-15) can be symmetrically arranged in different matrices in the threshold map, as shown in FIG. 4E.
第5圖係顯示依據本發明一實施例中應用混色遮罩 至來自活動列之像素的示意圖，其中i及j係分別表示B像素的水平及垂直座標。因此，混色處理單元230可接收來自遮罩產生單元220之混色遮罩，並應用(apply)混色遮罩至活動列260之像素。更進一步而言，使用該混色遮罩係表示該混色處理單元230係將活動列 260之像素減去在混色遮罩中的相關數值(元素)。如第5圖所示，混色處理單元230可將在方塊Blk00 、Blk01 、Blk10 及Blk11 中的B像素減去在混色遮罩中的相關數值。接著，在處理一圖像中的所有方塊後可得到一調整後的圖像。需注意的是混色處理單元230可進行一類似的混色處理(註：使用該混色遮罩)至來自其他色彩通道(例如：R/Gb/Gr)的像素。Figure 5 is a diagram showing the application of a color mixing mask to pixels from an active column in accordance with an embodiment of the present invention, wherein i and j represent the horizontal and vertical coordinates of the B pixel, respectively. Accordingly, the color mixing processing unit 230 can receive the color mixing mask from the mask generating unit 220 and apply the color mixing mask to the pixels of the active column 260. Still further, the use of the color mixing mask indicates that the color mixing processing unit 230 subtracts the associated value (element) in the color mixing mask from the pixels of the active column 260. As shown in FIG. 5, the color mixing processing unit 230 can subtract the correlation values in the color mixture mask for the B pixels in the blocks Blk 00 , Blk 01 , Blk 10, and Blk 11 . Then, an adjusted image is obtained after processing all the squares in an image. It should be noted that the color mixing processing unit 230 can perform a similar color mixing process (note: use the color mixing mask) to pixels from other color channels (eg, R/Gb/Gr).
第6A-6C圖係顯示用於傳統黑階控制處理的四捨五 入法(rounding)的模擬圖。第7A-7C圖係顯示依據本發明一實施例中用於黑階調整裝置中的混色處理之模擬圖。擷取在各色彩通道中的暗列的像素。第6A及7A圖係顯示在各色彩通道在30張影像中的的黑階值。第6B及7B圖係顯示在各色彩通道在30張影像中的黑階值之變異數(variance)。第6C及7C圖係顯示在B及R色彩通道之差值及其變異數。在先前技術中，在運算單元210中用於黑階控制處理的除法器213係設計為定點運算(fixed-point operation)，並可在除法器所得到之平均值中的小數部分使用四捨五入法(或捨去法)。因此，在黑階控制處理(註：取消該偏移值)後的數值錯誤可達到1DN，如第6B圖所示，其中DN係表示一「數位數值」(註：一基礎單位)。Figure 6A-6C shows the four-five-five for traditional black-order control processing A simulation of the rounding. 7A-7C are diagrams showing a simulation of color mixing processing for use in a black level adjustment apparatus in accordance with an embodiment of the present invention. Draws the pixels of the dark columns in each color channel. Figures 6A and 7A show the black level values in 30 images for each color channel. Figures 6B and 7B show the variance of the black level values in the 30 images of each color channel. Figures 6C and 7C show the difference between the B and R color channels and their variance. In the prior art, the divider 213 for the black-order control processing in the arithmetic unit 210 is designed as a fixed-point operation, and can be rounded off in the fractional part of the average value obtained by the divider ( Or give up the law). Therefore, the numerical error after the black-order control processing (note: canceling the offset value) can reach 1DN, as shown in Fig. 6B, where DN represents a "digit value" (note: a basic unit).
舉例來說，當各像素之精度為8位元時，該數位數值 (註：DN)可為256。因為各色彩通道(例如：R/B/Gr/Gb)之黑階控制處理是獨立進行的，各個色彩通道均會有數值錯誤。因此，在兩個色彩通道(例如：R及B通道)之間的差值可達到2DN(±1DN)，如第6C圖所示，這些差值會導致明顯的色彩顏色偏移，或是色彩/亮度閃動。在本發明中，可使用所揭示之混色處理，將各色彩通 道中的數值錯誤(註：其變異數)降低至大約0.4DN，如第7C圖所示，且因此在各兩個色彩通道之間的差值可降低至0.8DN。For example, when the precision of each pixel is 8 bits, the digit value (Note: DN) can be 256. Since the black level control processing of each color channel (for example, R/B/Gr/Gb) is performed independently, each color channel has a numerical error. Therefore, the difference between two color channels (for example, R and B channels) can reach 2DN (±1DN). As shown in Figure 6C, these differences can cause significant color shifts, or colors. / Brightness flashes. In the present invention, the disclosed color mixing process can be used to The numerical error in the track (note: its variation) is reduced to approximately 0.4 DN, as shown in Figure 7C, and thus the difference between each of the two color channels can be reduced to 0.8 DN.
第8圖係顯示依據本發明一實施例中用於具有一像 素陣列之一CMOS感測器中的黑階調整方法的流程圖。請同時參考第2圖及第8圖，像素陣列20係包括暗列250及活動列260。在步驟S810，運算單元210可計算來自暗列250之複數個像素的一平均值，其中該平均值係包括一整數部分及一小數部分。在步驟S820，運算單元210更可依據該整數部分以計算一黑階控制偏移值(註：BLC_offset)。更進一步而言，運算單元210可將一預定黑階值BLC_target減去該整數部分以產生該黑階控制偏移值。在步驟S830，遮罩產生單元220係依據該小數部分產生一混色遮罩。 在步驟S840，混色處理單元230可使用該混色遮罩(註：執行混色處理)至來自活動列260之複數個像素。在步驟S850，偏移計算單元240係將所計算的黑階控制偏移值加至混色後之像素以產生複數個結果像素Pa_blc(註：調整後之活動列的像素)。Figure 8 is a diagram showing an image for use in accordance with an embodiment of the present invention. A flow chart of a black level adjustment method in a CMOS sensor. Referring to FIGS. 2 and 8 simultaneously, the pixel array 20 includes a dark column 250 and an active column 260. In step S810, the operation unit 210 may calculate an average value of a plurality of pixels from the dark column 250, wherein the average value includes an integer portion and a fractional portion. In step S820, the operation unit 210 may further calculate a black level control offset value according to the integer part (Note: BLC_offset). Further, the operation unit 210 may subtract the predetermined black code value BLC_target from the integer portion to generate the black level control offset value. In step S830, the mask generating unit 220 generates a color mixing mask according to the decimal portion. In step S840, the color mixing processing unit 230 may use the color mixing mask (note: performing a color mixing process) to a plurality of pixels from the active column 260. In step S850, the offset calculation unit 240 adds the calculated black level control offset value to the mixed color pixels to generate a plurality of result pixels Pa_blc (note: pixels of the adjusted active column).
本發明雖以較佳實施例揭露如上，然其並非用以限定本發明的範圍，任何所屬技術領域中具有通常知識者，在不脫離本發明之精神和範圍內，當可做些許的更動與潤飾，因此本發明之保護範圍當視後附之申請專利範圍所界定者為準。The present invention has been disclosed in the above preferred embodiments, and is not intended to limit the scope of the present invention. Any one of ordinary skill in the art can make a few changes without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.
10‧‧‧CMOS影像感測器10‧‧‧ CMOS image sensor
20‧‧‧像素陣列20‧‧‧pixel array
200‧‧‧黑階調整裝置200‧‧‧Black level adjustment device
210‧‧‧運算單元210‧‧‧ arithmetic unit
220‧‧‧遮罩產生單元220‧‧‧mask generation unit
230‧‧‧混色處理單元230‧‧‧Color mixing unit
240‧‧‧偏移計算單元240‧‧‧Offset calculation unit
250‧‧‧暗列250‧‧‧dark
260‧‧‧活動列260‧‧‧ activity column
BLC_target‧‧‧預定黑階值BLC_target‧‧‧ predetermined black level value
BLC_offset‧‧‧黑階控制偏移值BLC_offset‧‧‧Black level control offset value
Pd、Pa‧‧‧像素Pd, Pa‧‧ pixels
Pa_blc‧‧‧結果像素Pa_blc‧‧‧Result pixels
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW102126051A TWI508558B (en) | 2013-07-22 | 2013-07-22 | Black level adjustment device and black level adjustment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW102126051A TWI508558B (en) | 2013-07-22 | 2013-07-22 | Black level adjustment device and black level adjustment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| TW201505444A TW201505444A (en) | 2015-02-01 |
| TWI508558B true TWI508558B (en) | 2015-11-11 |
Family
ID=53019070
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| TW102126051A TWI508558B (en) | 2013-07-22 | 2013-07-22 | Black level adjustment device and black level adjustment method |
Country Status (1)
| Country | Link |
|---|---|
| TW (1) | TWI508558B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101843089A (en) * | 2007-10-31 | 2010-09-22 | 美商豪威科技股份有限公司 | One-step black level calibration for image sensors |
| US20110090238A1 (en) * | 2009-10-21 | 2011-04-21 | Himax Imaging, Inc. | Black level calibration method and system |
| TW201121306A (en) * | 2009-12-11 | 2011-06-16 | Himax Imaging Inc | Multi-phase black level calibration method and system |
| US20110199518A1 (en) * | 2010-02-18 | 2011-08-18 | Omnivision Technologies, Inc. | Image sensor with improved black level calibration |
| CN102647566A (en) * | 2011-02-17 | 2012-08-22 | 全视科技有限公司 | Analog row black level calibration for cmos image sensor |
| TW201304531A (en) * | 2011-07-11 | 2013-01-16 | Novatek Microelectronics Corp | Image sensor and black level calibration method thereof |
-
2013
- 2013-07-22 TW TW102126051A patent/TWI508558B/en active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101843089A (en) * | 2007-10-31 | 2010-09-22 | 美商豪威科技股份有限公司 | One-step black level calibration for image sensors |
| US20110090238A1 (en) * | 2009-10-21 | 2011-04-21 | Himax Imaging, Inc. | Black level calibration method and system |
| TW201121306A (en) * | 2009-12-11 | 2011-06-16 | Himax Imaging Inc | Multi-phase black level calibration method and system |
| US20110199518A1 (en) * | 2010-02-18 | 2011-08-18 | Omnivision Technologies, Inc. | Image sensor with improved black level calibration |
| CN102647566A (en) * | 2011-02-17 | 2012-08-22 | 全视科技有限公司 | Analog row black level calibration for cmos image sensor |
| TW201304531A (en) * | 2011-07-11 | 2013-01-16 | Novatek Microelectronics Corp | Image sensor and black level calibration method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| TW201505444A (en) | 2015-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4351658B2 (en) | Memory capacity reduction method, memory capacity reduction noise reduction circuit, and memory capacity reduction device | |
| TWI668998B (en) | High dynamic range image sensor | |
| US8175378B2 (en) | Method and system for noise management for spatial processing in digital image/video capture systems | |
| US6924841B2 (en) | System and method for capturing color images that extends the dynamic range of an image sensor using first and second groups of pixels | |
| US7907195B2 (en) | Techniques for modifying image field data as a function of radius across the image field | |
| US9516290B2 (en) | White balance method in multi-exposure imaging system | |
| US8233737B2 (en) | Noise correction circuit, imaging apparatus, and noise correction method adding random number after noise removal | |
| US8089533B2 (en) | Fixed pattern noise removal circuit, fixed pattern noise removal method, program, and image pickup apparatus | |
| WO2008130832A1 (en) | Methods, systems and apparatuses for high-quality green imbalance compensation in images | |
| TWI479454B (en) | Method and apparatus for correcting for vignetting in an imaging system | |
| WO2007133898A1 (en) | Compensating for non-uniform illumination of object fields captured by a camera | |
| US10659738B2 (en) | Image processing apparatus, image processing method, and image processing program product | |
| KR20130012935A (en) | Imaging array having photodiodes with different light sensitivities and associated image restoration methods | |
| US10750108B2 (en) | Image sensor with correction of non-uniform dark current | |
| JP2011520386A (en) | Column gain correction method and column gain correction apparatus | |
| JP2015011127A5 (en) | ||
| US8717208B2 (en) | Image processing | |
| US8620102B2 (en) | Methods, apparatuses and systems for piecewise generation of pixel correction values for image processing | |
| JP2017158062A5 (en) | ||
| TWI508558B (en) | Black level adjustment device and black level adjustment method | |
| Kumar | Sensor non uniformity correction algorithms and its real time implementation for infrared focal plane array-based thermal imaging system | |
| US8878965B1 (en) | Black level adjustment device and method for CMOS image sensor | |
| CN104349085B (en) | Black contrast engagement positions and black contrast adjusting method | |
| Song et al. | A study on digital color reproduction for recording color appearance of cultural heritage | |
| TWI393428B (en) | Image calibration method and image processing system utilizing the method |